Wednesday, May 30, 2007

Gone Fishin'

Seriously. I have a chance to do some fishing this week in Florida. Hope I catch one like this. Blogging is likely to suffer, but, boy, will I have tales to tell (and maybe a few pictures, too)!

See you again Monday.


Tuesday, May 29, 2007

Epidemiology of Atrial Fibrillation

A nice report from Scotland regarding the epidemiology of atrial fibrillation (AF) is presented in the most recent issue of the journal Heart. What is striking are the statistics regarding the prevelance of atrial fibrillation as people age:
The prevalence of AF was 8.7/1000 and was higher in men (9.4/1000) than in women (7.9/1000). Prevalence increased with age from 0.3/1000 in <45 years to 30.5/1000 in 65–74 years, and more than doubling to 70.7/1000 in >85 years.
And the poor use of warfarin (Coumadin®) in women and the elderly (those at higher risk of stroke):
Our observations confirm the finding of other recent studies from the UK that about 40% of patients receive warfarin, a considerably higher proportion than in earlier reports. Although we do not know what proportion of patients should have been treated with warfarin (because we did not know which of our patients had an indication or contraindication to warfarin), other investigators have estimated that between 40–60% of patients might benefit from anticoagulation. Paradoxically, however, warfarin was less likely to be prescribed in women and in older people, both of whom are at greater risk of stroke. This has been a repeated finding in both older and more recent studies, and suggests that there is still an educational deficit in these respects.
If you have atrial fibrillation, this study lets you know you're not alone.


Grand Rounds - Volume 3, Number 36

The week's compilation of medical blogging's finest can be found this week at MedSkool.


Monday, May 28, 2007

Food Labeling Innuendos

Your Doritos might reduce heart disease soon. At least that's what Frito-Lay wants you to think.

In January, 2007, Frito-Lay petitioned the FDA for permission to label its foods processed with reduced saturated fats that says their chips may reduce heart disease. While on the surface, one might think that sounds reasonable, the data to support this claim does not exist. Instead, the FDA said that such labeling claims can be inferred:
Under section 403(r)(3)(C) (21 U.S.C. § 343(r)(3)(C)) of the Federal Food, Drug, and Cosmetic Act (the FD&C Act), a manufacturer may submit to FDA a notification of a health claim based on an authoritative statement from an appropriate scientific body of the United States Government or the National Academy of Sciences (NAS) or any of its subdivisions.
It seems the basis for Frito Lay's request lies in data from 1989:
The following statements from the 1989 NAS report titled Diet and Health: Implications for Reducing Chronic Disease Risk listed in the January 24 notification are considered authoritative statements.

"Clinical and animal studies provide firm evidence that omega-6 polyunsaturated fatty acids when substituted for saturated fatty acids result in a lowering of serum total cholesterol and LDL cholesterol and usually also some lowering of HDL cholesterol levels."

"Clinical studies indicate that substitution of monounsaturated for saturated fatty acids results in a reduction of serum total cholesterol and LDL cholesterol without a reduction in HDL cholesterol."
Now, while I respect the fact that lowering LDL and raising HDL can reduce the risk of heart disease, can we extrapolate these findings from older lipid studies to a direct heart disease risk-reduction by the consumption of chips and products manufactured by low saturated fat oils? Or might carbohydrate bolus consumed by eating these "heart-healthy" chips add to the metabolic syndrome epidemic and near runaway incidence of childhood diabetes in America?

Or worse still, could these food labels be detrimental to our public's health, as questioned in New Zealand, by providing an excuse for people eating more of these products because they are labeled "heart healthy?" One only needs to look at New Zealand's "heart healthy" promotion for lamb and beef that carry a "National Heart Foundation" seal to see the potential conflicts of interest inherent in such food labeling.

I guess this is what we get when the guys asking for permission are paying the FDA's bills: industry-sponsored health claims that coerce and misinform.


Addendum 29 May 2007 08:30: More from Weighty Matters

Cicada Central

I took my dog for a walk this morning and heard a crunching under my feet. There, smashed to smithereens, were the shells from the cicadas on a nearby tree. The periodical cicadas were continuing to emerge en masse. I happened upon this tree and returned to grab my camera for a few up-close pictures of these fascinating insects at various stages of their life cycle. (In case you want a really good look at them, just click on any of the pictures for an up-close and personal look at these guys.)

Here they can be seen erupting from their exoskeletons that kept them safe for 17 years underground:

I noted the squirrels were snacking on these critters and my dog found them quite entertaining as their flapping wings brushed her nose. And when the insect departs, they leave behind their shell for some lucky child to find:

Once their wings have dried, they soon head off to a nearby tree from our Adirondack chair:

In a few days, the shrill of these devils will be deafening.


28 May 2007 2137: Addendum: Being a t-shirt guy, I couldn't resist...

Friday, May 25, 2007

They're Here!

Lots of fun had by all...

At least until they crawl near your eye!


Diagnosis Wenkebach

From the Class of 2010 at the University of Alberta, one of the better med student music videos, complete with some great moon-walk dancing:



Thursday, May 24, 2007

A Sticky Situation

I have a complaint. A small one, mind you. But a complaint, nonetheless.

You see it all starts when I see patients on inpatient ward rounds. Being a “good” doctor, I’ve been trained that we have to wash our hands before, and perhaps especially after, touching the patient. This makes good sense, I’m told. You don’t want to spread all those nasty germs between patients, after all.

I was on call this past weekend. For those of you unfamiliar with this responsibility, call is one of those necessary evils of medicine. Every doctor knows it. Lives and practices are shaped by this responsibility. It is the opportunity to be sure patients care continues over the weekend in an uninterrupted manner and acute issues that cannot wait until the following week are addressed immediately. After all, the practice of medicine does not care if someone becomes sick on the weekend, after 5 PM, or on holidays. Life happens. Illness happens. And so too, therefore, does call.

I have learned over many years that rounding very early in the morning is to your advantage. Patients are seen more efficiently because the nurses are busy documenting in their charts about events of the prior evening (can't stop and chat); the patient is most interested in getting a few more winks of sleep before the daily grind occurs in the hospital (questions are kept to a necessary minimum); and family members have not arrived yet to slow your work progress through the myriad of patients that need to be seen. It is not uncommon for a call physician to round on well over 20-30 patients while fielding new consults, performing some testing, and answering patient phone calls. Since housestaff and patients have yet awoken or arrived to see their patients, a brief uninterrupted work period ensues.

Recently, our hospital (and I’m sure many others) has adopted the use of alcohol hand gels (in lieu of hand-washing) when seeing patients. These gels are handy, since water is really not necessary to rinse the residue from your hands. The gel is good for most bacterial contageon in the hospitals, but some bugs still require the old hand-washing technique (like c. difficile, I'm told). And so the old soap must stay. But this is where I’ve found it gets, er, sticky.

The damn dispensers are always in a different place from room to room. You have to play hide-and-go-seek to find them, sometimes. But that’s not the real problem. Oh, no.

You see there’s another medical error that occurs because of mistaken identity - especially early in the morning when the lights are low in a patient's room. We all know how bad having the wrong patient can be, but what about the wrong soap?

This is an egregious error, my friends.

Look at these two dispensers for soap below. One is for the hand gel (that evaporates quickly and requires no water to rinse from your hands), and the other for garden variety liquid soap. (Quickly, can you tell which one? No reading allowed.)

After squirting some of the liquid soap on my hands and walking half way to the next patient’s room, I discovered to my horror that the gunk in my hands had to be rinsed off rather than air-dried.

Damn, what a mess.

And did I feel like a fool…


Wednesday, May 23, 2007

Grand Rounds - Belatedly

Better a day late, than never: Medical Grand Rounds is up over at ImpactED Nurse.

I don't know, Grand Rounds flowed freely from my view...

Is There Something in the Water?

I don't know what it is, but it's been ridiculously busy around here. It's like someone put something in the water... Blogging, unfortunately, has suffered. I'll be back as time permits. I realize there's lots of controversy about the Avandia meta-analysis that showed up in the New England Journal of Medicine this week.

Unfortunately, I can offer litle to what's already been said. I only know that if I had submitted a meta-analysis to the New England Journal of Medicine regarding any other drug, it likely would have been summarily rejected due to methological flaws inherent to such studies. While the study certainly raises important questions, it still leaves open the possibility that there might be one or more confounding variables to explain the cardiovascular risks with this drug reported.

But it is also important to realize that people much wiser than me had an opportunity to critically review the study and, perhaps due to the inability of the investigators to acquire the raw ("patient-level") data, felt the implications of the findings were important enough to publish. There can be no denying that the Journal is taking a stand on how to manage patients with heart disease taking this drug. But I question whether these results really required an "Online First" designation (meaning the results were important to disseminate quickly). I could see this if there were a prospective randomized trial sufficiently powered to make a claim about changing treatments, but a meta-analysis as "Online First?" Have we lost our minds?


Addendum: 2158PM 23 Mar 07: Some saner minds prevail:
To avoid unnecessary panic among patients, a calmer and more considered approach to the safety of rosiglitazone is needed. Alarmist headlines and confident declarations help nobody.
22:23PM 23 Mar 07: Hmmm... it seems some folks are happy with the way this study was presented. And we wonder why the cost of healthcare is skyrocketing?

Monday, May 21, 2007

Cicadas: They're Coming!

We're starting to see the little mounds of dirt from their burrows appear on our front lawn....

The 17-year cicadas are coming!

Anyone know the nutritional value of these little devils? They might be tasty in chocolate...


Photo credit.

Addendum 21 May 2007 @ 1937: I already found one recipe...

21 May 2007 @ 1947: Even more recipes... but none with chocolate.... but quiche?

Sunday, May 20, 2007

Medical Bloggers: Held to a Privacy Double Standard?

I took a much-needed blog-break while on call this weekend, but have been reeling from the recent loss of some of the most creative and outspoken members of the medical blog-o-sphere. These were anonymous physician bloggers - folks who made an honest attempt to conceal people's identities by concealing their name as well. The cloak of anonymity permitted these doctors to add an unfettered and unique voice to the humdrum of daily medical, legal and corporate vernacular. At least so we thought.

But with the advances of information technology via the Internet comes the ability to track URL's and individual computers via IP addresses. Anonymity, it seems, runs only so deep. Advertisers know this. So do marketers and politicians. And yes, lawyers.

Two examples stand out: first, was Flea - by one poll the most popular medical blogger of 2006. Flea is a pediatrician who was sued and exposed his experiences preparing for his upcoming malpractice trial in great detail. At least until one lawyer exposed the legal entanglement of that approach: within a week his blog had disappeared from the internet.

The second was that of Fat Doctor, a sharp-tongued witty physician who shared her insights and experiences via her blog, but whose blog was revealed by a co-worker to her boss, and in the interest of preserving her job, she pulled her blog from the internet. What the issues were we are left to surmise, but the recent issue of the USA Today might offer some clues:
Such stories, of course, raise a question: Should we all worry that our doctors are blogging about us — and potentially violating our privacy?
While this concern is worthy of consideration, are we asking physician bloggers to uphold a double standard? While most physician bloggers I know are keenly aware of the perils of patient identity disclosure, it seems we must go to unprecedented lengths to conceal the identity of any case we discuss. This is in stark contrast to case reports discussed in prestigious medical journals like the New England Journal of Medicine (NEJM), which only requires that a release form be signed by an identifiable patient before publication. Does this fulfill enough of the requirements for informed consent for a patient? The Journal of the American Medical Association (JAMA), goes further and requires patients to sign a release, a consent to publish (in print and online), and must be shown the manuscript before its publication. But as others have argued, such disclosure, in some circumstances, could be deemed unethical:
Society cannot tolerate blindly trusting the wouldbe author to appropriately balance patients’ needs against professional opportunity. Physicians can be selfserving and amoral. Professional judgments may be poor when doctors are impaired by medical or psychiatric illness. Ethics committees and institutional review boards exist to protect the rights of patients and research subjects. Nazi doctors’ experiments, Tuskegee syphilis experiments, trading sex for medications, and other outrages remain in our collective professional minds.

The publication of a disguised case history without permission, however, is not comparable to these moral and ethical violations. Authors who do not believe that a particular patient’s permission should be sought are not necessarily unethical: they weigh their obligations differently. In other ethical controversies, it is well recognized that reasonable people reach opposite conclusions. On the one hand, many psychiatric patients are too fragile, ashamed, private, or well known for the therapist to write about them. On the other hand, physicians need to read about difficult patients with poor ego defenses, chronic instability, paranoid psychopathology, or chaotic sexual lives because we need the perspectives of others to guide our difficult work. We believe psychiatry should continue to have trust in the professional’s judgment and goodness rather than create a standard that will either backfire and hurt patients or severely limit professional opportunities to benefit from this pedagogical vehicle.
In the past and even now, physicians have understood the value of a good case report. A unique case that discloses a new physical finding, constellation of symptoms, or nuance of a well-established disease presentation can be an invaluable instructional tool. One need only turn to a recent New England Journal of Medicine (NEJM) to see such an example. In this particular case report, a 59 year-old man's facial picture is displayed. His features are clearly recognizable - particularly to the patient humself. Was the NEJM's release form enough to protect the patient from, say, potential discrimination by his workplace regarding the disease discussed? Or does the publishing of the picture better serve the interests of the NEJM who stands to profit from their subscriptions based on content provided, in part, by this patient's contribution? Ethical lines become blurred. So, is a blogger's attempt to conceal patients' identities by "cloaking" themselves in an anonymous pseudonym, changing patient gender, age, or case specifics ethically substandard compared to our journalistic counterparts?

To better define a blogger's reponsibilities to avoid such ethical conflicts, I like what Dr. Rob has started: a medical bloggers’ code of conduct. I encourage all to review it and comment as medical bloggers collectively try to wrestle with the ethical domain of the internet, especially as it relates to our patients’ privacy and wellbeing. While every case is unique, medical generalities gained from a case can also be beneficial to future patients. Better defining a physician blogger's responsibilities relative to their patients' circumstances will only strengthen the doctor-patient relationship.


Addendum: 21 May 2007 @ 1230 PM CST - TBTAM adds her thoughts.
Addendum #2: 21 May 2007 @ 1433 CST - Dr J.'s Housecalls tribute to Flea and other reflections.

Addendum #3: 21 May 2007 @ 19:46 I just realized that commentary was somehow inhibited by Blogger. It is back on. I regret the error.

Friday, May 18, 2007

Abstracts Are As Good As Gold

In another display of the importance of new trial data moving the financial markets, the Wall Street Journal reports this morning on the power of preliminary scientific study abstracts sent to physician-members ahead of their annual meeting to move pharmaceutical markets.
Shares of ImClone Systems have tumbled more than 9% since Tuesday on heavy volume after embargoed data from an important cancer trial was released to 24,000 physicians expected to attend the conference of one of the largest oncology groups, the American Society of Clinical Oncology, or ASCO. Shares of Regeneron Pharmaceuticals have fallen almost 15% since and Genentech is down 3%, while Onyx Pharmaceuticals is up almost 10%, as investors pass around abstracts, or summaries, of data to be released as part of the ASCO meeting.
Although the abstracts are sent with a “warning” instructing the recipient not to “publish the information or provide it to others or use it for trading purposes,” according to Kristin Ludwig, senior director of communications and patient information at ASCO. Certainly, ASCO must be aware of this practice: why would they even mention the use for “trading purposes” in their instructions to their members?

But it seems doctors get to take the fall:
Doctors who trade on the information could be in violation of insider-trading laws, say securities experts. If they tell another investor about the data it gets murkier, but it could be problematic if the doctor knows that the recipient will trade on the information.
Hey, if you release the information to 24,000 members of a society – it seems that those abstracts are pretty public information to me.


Thursday, May 17, 2007

Great Poster

Click to Enlarge

My favorite poster at the Heart Rhythm Society Meeting in Denver, Colorado last week came from Dr. A. Kondur, MD et al, of the Wayne State University, Detroit Michigan and the University of Kansas Hospital, Kansas City, KS entitled "Implantable Cardiovertor Defibrillators Save Lives from Lightning Related Electrocution Too..."

They reported on a 75 year-old man who suffered a side flash injury from lightning while adjusting his radio antenna on a rainy night. A year prior he had received a biventricular implantable cardiac defibrillator for treatment of his congestive heart failure and a weakened heart muscle. It seems his scalp and right index finger were burned from the lighning strike and his heart went into ventricular fibrillation. Fortunately, defibrillators have voltage shunting circuitry (so people with such devices can have external defibrillation if necessary without fear of harming the device circuitry). Therefore, the device circuitry was not harmed by the high voltage lightning strike. The defibrillator successfully detected the abnormal heart rhythm (ventricular fibrillation) caused by the lightning and shocked his heart back to normal rhythm after the episode!

The best part of the poster, though, was the disclaimer:

"The authors do not advise implanting ICD prophylactically for lightning strikes."

You've got to love investigators with a sense of humor.


Boston Scientific In Talks to Settle Defibrillator Suits

Boston Scientific, still reeling from the burden of over well over 1000 product laibility suits over its acquired Guidant implantable defibrillator portfolio, has successfully leaked that they are in the process of settling 1,350 of the cases:
...people familiar with the matter said Boston Scientific, of Natick, Mass., is in talks to settle 1,350 product-liability lawsuits it inherited when it purchased Guidant Corp. last year. The suits allege that Guidant negligently sold several models of implantable defibrillators after learning of defects in the devices that caused them to fail.

In a recent filing with the Securities and Exchange Commission, Boston Scientific reported that it raised the sum it had set aside for potential damages in the case to $732 million, from $485 million at the end of 2006. A spokesman for Boston Scientific said the company was "committed to an aggressive defense."

Previous talks in September between the company and plaintiffs reached no resolution. This week's talks come on the eve of a hearing tomorrow in U.S. District Court in Minneapolis on patients' efforts to seek punitive damages from the company.
Could Medtronic be next?


Wednesday, May 16, 2007

Is Your Child Coughing?

... you might want to check the bus:
For weeks, Tony Anders' daughter complained to her dad about the cigarette smoke on her school bus. When the 4th grader started coughing up phlegm earlier this year, Anders decided to check out the bus for himself.

When the bus pulled up, Anders followed his daughter aboard -- and into a smoky haze. Incredulous, he asked the driver if he had been smoking. "He kind of waited a minute," Anders recalled. "We're sitting in a fog of smoke so he couldn't lie about it. He was just like, 'Yeah.'"
I won't spoil the story, but fortunately, it ends happily for all.


Exercise at Your Desk

Imagine being stuck behind a desk and losing weight. Impossible?

Well, not according to Dr. James Levine. It seems he's helped develop a desk that has a treadmill built in, and permits users to walk, instead of sit, while working. It is based on a "NEAT" principle: non-exercise activity thermogenesis. It appears that NEAT is far more important for calorie-burning than exercise in nearly everyone. From his paper in the British Medical Journal, the mean energy expenditure while being seated at work in an office chair was 72 + 10 kcal/hour whereas the energy expenditure while walking-and-working at a self-selected velocity of 1.1 + 0.4 mph, was 191 + 29 kcal/hour. The mean increase in energy expenditure for walking-and-working over sitting was 119 + 25 kcal/hour.

The desk is made by Steelcase and costs approximately $2000 US.

Only problem is: they can't make these desks fast enough!


hat tip: The Health Blog.

Tuesday, May 15, 2007

Jerry Falwell - Another Victim of Sudden Death

Today, Jerry Falwell was found unconcious in his office and could not be resuscitated, likely from cardiac causes:
The Rev. Jerry Falwell, who founded the Moral Majority and built the religious right into a political force, died Tuesday shortly after being found unconscious in his office at Liberty University, a school executive said. He was 73.

Ron Godwin, the university's executive vice president, said Falwell, 73, was found unresponsive around 10:45 a.m. and taken to Lynchburg General Hospital. "CPR efforts were unsuccessful," he said. Mr. Godwin said he was not sure what caused the collapse, but he said Mr. Falwell "has a history of heart challenges."

"I had breakfast with him, and he was fine at breakfast," Mr. Godwin said. "He went to his office, I went to mine, and they found him unresponsive."

Mr. Falwell had survived two serious health scares in early 2005. He was hospitalized for two weeks with what was described as a viral infection, then was hospitalized again a few weeks later after going into respiratory arrest. Later that year, doctors found a 70% blockage in an artery, which they opened with stents.
You wonder what his ejection fraction was and if an automatic defibrillator might have prevented this...


Monday, May 14, 2007


Ms. F. desired a return phone call from Dr. Wes:

Ms. F: “He starting having nightmares about a month ago.”

Wes: “Really? What are they about?”

Ms. F: “He can’t say, he just gets up and looks like he’s having a panic attack. It happens almost every night. He just looks so concerned. He hasn't slept well for weeks.”

Wes: “Can you get him on the phone?”

Ms. F: “Sure.”

Wes to Mr. F: “Are you having nightmares?”

Mr. F: “Yeah, it’s scary. I just feel so panicked.”

Wes: “What medications are you on? Have any of them changed?”

Mr. F: “My doctor gave me a sleeping pill, and that helps for a little while early in the evening, but otherwise, nothing’s changed – I’m still taking the same medications: I take 14 medications in the morning, 9 at noon, and 5 in the evening. It’s tough to remember, you know, I have to write them all down.”

Wes: “Can you read me the bottles?”

Mr. F: “Sure.” And he proceeds to read me the medications – a veritable encyclopedia of medications: allopurinol, colchicine, lasix, digoxin, zocor, phoslo, prednisone, mirtazipine, pantoprazole, coumadin, aspirin, etc., etc., etc.

Not knowing where to begin, I suggested he make an appointment. He thanked me and hung up.

. . .

I saw the patient one week later. He was feeling a bit better.

“What did your doctor say?”

“He wasn’t sure what it was but doubled my Lasix.”

I looked down and saw his swollen legs. And then it hit me. I am such an idiot. How could I have missed this?

It wasn’t nightmares he was having; it was paroxysmal noctural dyspnea (or “PND” as we call it): that suffocating feeling that occurs in people with congestive heart failure that prompts them to rise from bed and sit up in order to improve their shortness of breath. I shared with him my revelation.

“That’s exactly how I felt! Like I couldn’t catch my breath!”

But it was the words that followed that really gave me a nightmare:

“Thanks, son.”


Surgical FlashLites

Found this at the Heart Rhythm Society meeting, and finally had a chance to download a few pics from my camera. Check out this little flashlite that uses a small adhesive disk to attach to surgical gloves or an electrocautery pen:

It might just help bail someone out of a surgical "hole" when you can't find that bleeder in the back of a sugical pocket. The sterile mini-flashlite seels for $19 each and uses a small LED lite bulb. I suspect the glove or electrocautery pen should be dry before attaching, so you might have to change gloves before applying one of these. Here's a closer view:

The device, called SiteLight® is made by Pressure Products, Inc., which makes lots of little gizmos for the electrophysiology surgical suite. We also saw sterile laser pointers for teaching, too, although I could not find either of these devices yet on their website, yet. The shelf life of the packaging is about three years, we were told, due to sterility issues.

This might also be useful for folks in the ER. It's almost like this small company is becoming the Sharper Image or Brookstone of electrophysiology surgical products.


Sunday, May 13, 2007

Two Mothers

Two mothers: one asleep, one awake.

Each bore children.

Each has seen their children cry.

Each cooks well.

Both have attended their kids’ ball games.

Both like flowers and coffee.

Each has lain awake at night waiting for their kids to arrive home.

Both have fed me.

Both have kissed me.

Both have held me.

Both have believed in me.

Both have taught me.

Both have done my laundry.

Both have expanded by horizons.

Both have shown me the world.

Both love people, and parties, and life.

But now one sleeps lightly from exhaustion, and the other is exhausted yet awake.

One sleeps because husband is up with the kids, the other awake because her husband is up short of breath.

Both are strong.

Both are beautiful.

Both are miraculous, indeed.


Saturday, May 12, 2007

The Electrophysiologist's Theme Song

Heard this song coming back from Denver on XM radio and laughed out loud - I think this should be every electrophysiologist's theme song:


Heart Rhythm 2007: Recapitulating

Now that the Heart Rhythm Society meeting in Denver, CO is nearing its' close, it’s time to reflect on this year’s meeting.

As always, it’s nice to see old friends and colleagues, especially other folks I trained with many years ago. Denver, too, seemed to have been placed on its best weather behavior for the meeting – it was beautiful all week. The hotel and city life seemed acceptable to most of the folks I spoke with. There were some great posters and abstract presentations, and overall, I think the meeting was well-received.

Unlike prior years though, there seemed to be little “buzz” about implantable devices like pacemakers and defibrillators (except for perhaps the iPod story) – no doubt the Big Three wanted to keep their noses clean to let the recall dust settle a bit more. And there was little new “buzz” about catheter ablation of atrial fibrillation – it seemed to be more of the same – except for revealing new “guidelines” for a procedure whose method, safety, and efficacy are still a work in progress. If there was any area that generated any new "buzz," at all, most seemed to focus on the mapping systems and robotics. At least until potential customers heard about Hansen Medical’s robotic price tag of about $650,000 or an even heftier price tag for the Sterotaxis robotic system installation for over a million dollars. Enthusiasm waned a bit then.

But there was also something else different about this meeting. It was almost imperceptible. It was insidious. There was a tacit sensation throughout the meeting.

What was it?

People were so polite.

Everyone was on their best behavior throughout the meeting. Pleasantries were shared with polite smiles and handshakes. Invitees to the Afib Summit thanked the co-chairs profusely for allowing them to be invited to the meeting, then went about their way telling their story, their pitch. Some reviewed studies and presented data well, others presented experiences or techniques rather than data, but they all pitched. Whether it was the greatest way to perform ablation, or the next block-buster drug to look for, they told their story.

And no one said a word. They were too busy being polite. Oh sure, there were many, many topics covered, and even a few oral abstract presentations with brief periods of rebuttal in small rooms, but the biggest venues were reserved for platitudes and anecdotes. Only at the end of the Afib Summit, when the invitees were discussion the “state of the art” regarding atrial fibrillation ablation was there a hint of concern that perhaps we were at risk of overstating our success rates with atrial fibrillation ablation as a profession, and risking our credibility with our referring doctors and patients. Just when it started to get juicy, the Summit ended.

Maybe it was the fact that corporate people or analysts outnumbered doctors about three to one (I’m guessing, but that’s how it seemed). Many fewer doctors appeared at this meeting than I remembered in prior years, especially doctors from overseas (could the geography of Denver played a role? I don’t know.) Perhaps that’s why most people were polite – they were on their best corporate behavior.

I remember prior meetings when abstracts would be presented in huge auditoriums and tons of microphones would line the aisles of the large amphitheater and people would get up to rebut a study’s findings or review how they had done the same study 18 years ago, and skewer the poor sole on the podium. Politeness was out. Scientific rigor was in. People were not afraid to make their opinion known. Quality and limitations of studies quickly became apparent to all. Reputations were made by thoughtful intellectual commentary, rather than strictly the number of cases performed.

Instead, attendees this year were greeted to carefully staged sets for the speakers, with plenty of nice lighting and special effects, and no forum for lively discourse, all seemingly to calm the sole and remind folks to be polite.

After all, we wouldn’t want the corporate sponsors to get upset.


Friday, May 11, 2007

Former FDA Commissioners Admit Drug Company Influences

Dr. Anthony Robbins from the Department of Family and Public Health at Tufts University, joined the chorus about concerns over the FDA's new funding bill to reauthorize drug and device user fees and ensure the safety of medical products:
On Feb 21, 2007, 40 experts, and four times as many reporters and students, assembled at the George Washington University School of Public Health for a meeting organised by Scientific Knowledge and Public Policy (SKAPP). The attendees listened to four former commissioners from the US Food and Drug Administration (FDA) dissect their experiences—Donald Kennedy, Frank Young, David Kessler, and Jane Henney. What is wrong with the FDA, and how can it be fixed? Kessler confessed that this meeting was the first time he had talked publicly about his stint at the FDA. Among the stories, the consensus was that FDA drug regulation had come to reflect the needs and demands of the drug industry.
Other concerns were expressed by the commissioners as well:
The former commissioners worried about the Prescription Drug User-Fee Act (PDUFA). The worries became more real when one of the scholars described the detrimental consequences of speedier drug approvals and the increased likelihood that such approvals would be flawed. To comply with the user-fee law, the FDA has shifted appropriated funds into the drug-approval process, diminishing all resources available for other mandated functions across the whole agency. Surely shortchanged in this process is the epidemiology of adverse reactions in already approved drugs.

The strongest consensus emerged about the need for a very sizeable increase in resources. Despite money from drug makers, allocated in secret negotiations with the FDA—“a corporatist model”—far larger appropriation is needed, not only for the activities mandated by law but also to increase the science capacity and communicate the public-health mission more effectively. Participants were envious about how the NIH's constituency of researchers and patients' advocates had delivered on a plan to double the Institutes' budget. Could the new FDA Alliance do the same?
I guess these drug industry influences should not come as a surprise. Given the 93-1 vote of approval that the Senate has already garnered from both sides of the aisle, and the fact that the pharmaceutical manufacturers have had one of the largest political action committee contributions to our members of Congress, it seems unlikely that anything is going to stop this train.


References:'s Webcast of the Conference

Thursday, May 10, 2007

Atrial Fibrillation Ablation: What's Missing?

"Did you attend the AFib Sumnmit?"

"Yeah," I said.

"So what's the answer?"

I paused. What was this person from industry trying to ask me? I pondered his question a bit not sure where he was going. So I gave him my honest answer:

"I dunno," I said, in my most professional tone.

"I don't either," he said. "I mean, we've been hearing about the same thing for the past two years now. All these approaches to afib ablation, lots of these guys getting up there telling us how we should do this: pulmonary vein altral isolation, ganglionic plexus targetting, ablating every little small, fractionated potential everywhere in the left atrium... I mean, what are we doing?"

"I dunno," I said again. "But it does work sometimes..."

"Yeah, but no one has the answer to how to make this procedure easy, reliable, and safe, do they?"

"Well, we're getting better at it - I still have trouble knowing an endpoint to ablation though."

"Exactly. I mean, even the consensus statement for ablation of afib states that terminating afib does not mean you were not effective at ablation saying 'in patients with longstanding persistent atrial fibrillation ... an endpoint of noninducibility of AF does not appear to be feasible or even necessary.' I mean, when do you quit? When all of the atrium is destroyed?"

That got me thinking. I knew that not all of the atrium had to be 'destroyed' to achieve success, but is a carpet-bombing approach or precise creation of an ablation line what is needed? Do we need both approaches, or will one suffice?

These questions are important, in part because industry thinks we need fancy new robots and things to drive catheters around inside the heart. They want us to spend considerable financial, spacial, and temporal commitments to buy theit gizmos to help us drive around in the atrium, yet we still don't know where to go, or what lesion sets we need to achieve the best outcomes. All the "Gee-Wizardly" gizmos in the world will never substitute for careful observation and prospective randomized multi-center trials.

Dr. Eric Prystowsky, in his introductory remarks at the beginning of the AF Summit yesteday, estimated that there will have been 8,473,000 catheter ablation procedures for atrial fibrillation performed in the world between 2000 and 2007. Yet as of now, guidelines have already been published jointly by the Heart Rhythm Society, European Heart Rhythm Asociation, and the European Cardiac Arrhythmia Society that admit that only five randomized clinical trials with different endpoints and comparisons have been performed on a TOTAL of 605 patients. Furthermore, there are wide variations in the reported efficacy and complication rates, and the duration of follow-up has been less than 12 months in all of the studies performed so far.

Fortunately, at least one large, multi-center NIH-sponsored trial, the Catheter Ablation vs Antiarrhythmic Drug Therapy for Atrial Fibrillation (CABANA) Trial, is underway to determine the mortality benefit of catheter ablation compared to drug therapy in a population similar to the AFFIRM population in over 4000 patients. Unfortunately that study is estimated to take five years to complete. But at least it's a step in the right direction.

I just hate saying "I dunno" all the time.


Addendum (5:30 PM MST): I met briefly with Dan Starks from St. Jude Medical briefly today and asked him what he thought about Dr. Prystowky's estimate regarding the number of atrial fibrillation ablation procedures being performed. He stated that last year, St. Jude estimated that about 55,000 atrial fibrillation procedures were performed in the United States. If one assumes approximately 100,000 procedures were perfomed in the world, then the MOST procedures performed from 2000-2007 would likely be closer to 500,000-600,000. Still the point remains, we need more prospective randomized clinical trials, especially trials evaluating the safety, efficacy, and mortality benefit of afib ablation.

Wednesday, May 09, 2007

Heart Rhythm Society: Afib Summit - Day 1

The Atrial Fibrillation Summit held as part of the Heart Rhythm Society’s annual meeting in Denver, Colorado has just concluded. Why a "summit" would be held in the basement of the Colorado Convention Center seems a bit odd, but perhaps it was to be sure the fancy colored lights behind the speaker’s podium radiated a professional glow.

The event was a virtual “Who’s Who” of catheter ablation, assembled by the two program coordinators, Douglas Packer, MD of the Mayo Clinic, and Hugh Calkins, MD of Johns Hopkins Medical Center.

Eric Prystowsky, MD kicked off the sessions with a great review of the history of atrial fibrillation: its mechanisms and early historical observations by scientists of an earlier era, and put us in our place after demonstrating that most things we know seem to have already been observed by prior electrophysiologic minds from the 1940’s. He also hinted at a work published in Nature 2001 Vol 409 regarding a tarantula peptide that can reduce atrial stretch, and might be a pharmacologic target for reducing atrial fibrillation. Hmmm. But his most important message to those performing atrial fibrillation ablation procedures at the close of his talk was: “PRESERVE THE BRAIN.” Wise man.

Jose Jalife, MD (SUNY, NY) then followed with some elegant videos of his work on tissue cultured atrial cells interspersed with varying amounts of fibroblasts (that make fibrous tissue) and showed how fibrosis within the atrial architecture can contribute to the development of the erratic activations of the atrium, and that fibrosis increases in the settings of hypertension and heart failure.

Peng-Sheng Chen, MD (Krannert Institute, Indianapolis) was supposed to talk on Neural Networks in the generation and treatment of atrial fibrillation, but the message must have gotten out about his thick accent, so we never heard from him. Shin-Ann Chen, MD (Taipei) took over instead and reviewed nice basic scientific work on the contribution of atrial stretch causing atrial after-depolarizations, and might account why the initiation of atrial fibrillation always occurs after a pause and then a sinus beat, then atrial fibrillation.

Virend Somers, MD (Mayo Clinic) did a great job reviewing the mechanisms of why obstructive sleep apnea might exacerbate atrial fibrillation (or might even be a cause it) but cautioned his theories were only based on observational studies and not based on prospective studies. However, the mechanisms postulated were: low oxygen periods (hypoxemia), sympathetic activation, extreme blood pressure surges, transmural pressure gradients (see my prior post) as much as -40 to -80 mmHg during attempts to breath against a closed airway, and systemic inflammation with elevated C-reactive protein levels. Treated sleep apnea (with CPAP) had a 50% reduction in recurrent afib after cardioversion compared to folks who refused or could not tolerate the CPAP machine.

Patrick Ellinor, MD, PhD from Mass General reviewed the genetics of atrial fibrillation. He said something about the long arm of chromosome 10, but then I fell asleep briefly. I’m told he did a good job reviewing this.

After resuscitation with a coffe break, the late morning session kicked off with Michel Haissaguerre, MD (Bordeaux, France) reviewing his step-wise approach to atrial fibrillation.

Carlo Pappone, MD followed with his “Milan (Italy) Approach” to atrial fibrillation – which basically seemed to be that he ablates a lot more than he used to, because, truth be told, he’s had some recurrences. (Who knew!). He ended his discussion remarking that one patient that had chronic atrial fibrillation took him three procedures and a total procedure of 20 hours to render him afib-free, suggesting we still need better tools to approach this population. It was the first time I heard him speak to reality, and it was appreciated.

Warren (Sonny) Jackman, MD (Oklahoma City, OK) then spoke eloquently on the topic of the importance of the vagal ganglionic plexi (nerve inputs) at supporting afib, and demonstrated that stimulating one ganglionic plexus on one side of the heart could cause a pulmonary vein on the opposite side of the heart to increase its firing frequency, suggesting that afferent and efferent limbs of the vagus nerve are at play in maintaining atrial fibrillation. Brilliant work and magnificent observation. I’m just glad I’m not his fellow, because I can’t imaging how long his procedures must last when collecting this information!

Koonlawee Nadamanee, MD (Inglewood, CA) then demonstrated his results with catheter ablation targeting just the small (0.05-0.12mV) electrograms that last between 50 and 120 msec WITHOUT isolating the pulmonary veins. His data suggested about the same outcomes as others, but also showed that sometimes waiting as long as 6 -12 months might be needed to rid a patient of atrial fibrillation after his procedure in some patients. I didn’t see too many other people using solely this approach, but more seem to be incorporating some of his lesion sets.

The afternoon session was mainly made up of reviews of left atrial anatomy, by Siew Yen Ho, PhD (London, UK), followed by the new imaging and robotic techniques used for catheter ablation.

Douglas Packer, MD (Mayo Clinic) listed his pros and cons of the Stereotaxis and Hansen Robotic systems. It seems all of the current robotics suffer from an inability to reliably register anatomic locations from one imaging modality to another imaging or robotic modality. Much work needs to be done here. Bottom line: Stereotaxis had better image integration with 3D electroanatomical mapping systems, but Hansen was less expensive, portable, and could use any catheter, but limited by a slightly higher perforation risk. Some interesting data there: it seems 10-20 grams of force on the ablation catheter gave the best lesions in dogs while limiting performations.

Henry Halperin, MD (Johns Hopkins, MD) spoke to the use of real-time MR for ablating tissue and its benefits for reducing ionizing radiation and spoke to its utility at being able to see lesions in the myocardium. David Haines, MD asked at the end of the session about the resolution of 1.5Telsa MRI scanners, to which is was admitted that the 3-5mm resolution might not be enough to see left atrial walls that are only 2 mm thick in places. Henry seems to think that 3 Telsa MR scanners might improve on this. But the cost???

Vivek Reddy, MD showed some interesting work on rotational CT imaging performed during an AF ablation procedure and uses one fifth the amount for fluoroscopy to image the left atrium compared to spiral CT’s obtained pre-procedure. He also showed how these 3D volumes could then be projected onto fluoroscopic images to better localize the ablation catheter intra-operatively. Kind of cool.

The remainder of the afternoon was spent talling about the possible complications of atrial fibrillation procedures. Tamponande, gastroparesis and pyloric spasm, lasso entrapment, and minimizing embolic events with anticoagulation were all covered by Dr. Dipen Shah, MD. Esophageal perforations, heralded by chest pain, dysphagia (difficulty swallowing) and fever, were nicely reviewed by Dr. John Day, MD (Salt Lake City, UT). It seems they had two back in 2004 after ablating the posterior left atrium with an 8mm tipped catheter at 70W output for 20 seconds with each burn. Each patient presented 2-3 weeks after the (initially) uncomplicated procedure. The first died (we were left to assume) because the diagnosis was not recognized early. The other was treated aggressively with esophageal stenting, broad spectrum antibiotics (including antifungals) and nasogastric tube feedings, and survived, and has been followed 3 years and is still doing well.

Frank Marchlinski, MD (Philadelphia, PA) reviewed management of pulmonary vein stenosis, pericardial tamponde, and the phrenic nerves, and Samuel Asirvatham, MD (Mayo Clinic, Rochester, MN) help cap the anatomical relationships that can lead to these complications.

Whew! Lots covered on Day 1. Now off to poster sessions…


Sleep Apnea and Atrial Fibrillation

Interesting information from Dr. Virend Somers at Mayo Clinic today at the AFib Summit portion of the Heart Rhythm Society meeting. He proposed a mechanism that might explain why the left atrium is enlarged in patients with obstructive sleep apnea: the negative intrathoracic pressure generated during periods of apnea repetitively during the evening may cause a dilation and stretch of the left atrium due to a trans-atrial wall pressure gradient.

Sometimes simple explanations may be some of the best....

Perhaps Medtronic could resurrect their Chronicle hemodynamic monitor to look at this, eh?


Monday, May 07, 2007

Travel Blogging

I'll be traveling out to Denver, CO for the annual Heart Rhythm Society Meeting tomorrow. I'll see if I can find anything new (and perhaps different) out there relating to heart rhythm therapies.

Stay tuned...


Medtronic Can Ignore Atrial Fibrillation No Longer

With the decline in defibrillator implantations, and lack-luster performance of their expensive direct-to-consumer campaign to ignite their defibrillator implantations, it seems Medtronic has finally moved to shore up a glaring hole in its cardiac electrophysiology product line: catheter ablation - especially catheter ablation of atrial fibrillation. From the press release regarding their alliance with Biosense Webster:
Biosense Webster, Inc. (a Johnson and Johnson Company) the world leader in cardiac mapping and ablation, and Medtronic, Inc. (NYSE:MDT), the world leader in implanted cardiac rhythm devices, today announced plans to collaborate on a clinical trial, educational initiatives and a product development program, all of which are aimed at advancing the care of patients with cardiac arrhythmias, also known as irregular heartbeats.

The initiative was announced today to coincide with the start of Heart Rhythm 2007, the Heart Rhythm Society’s 28th Annual Scientific Sessions, taking place in Denver May 9-12. Heart Rhythm 2007 is the premier medical and scientific conference for electrophysiologists.
Biosense Webster is best known for their three-dimensional electrophysiology mapping system, CARTO XP, which uses magnetic fields to determine ablation catheter locations within the heart during catheter ablation procedures. Their THERMOCOOL abaltion catheter and LASSO mapping catheters also facilitate atrial fibrillation ablation procedures.

With this partnership, Biosense Webster will benefit by increasing their distribution lines and Medtronic gains a much needed foothold in the growing atrial fibrillation ablation business.


Be Careful Screening Job Applicants

Especially when you want to employ an alcoholic as a beer tester: he might sue:
A Brazilian court has ordered local brewer Ambev to pay 100,000 reals (US$49,400; euro36,400) to an alcoholic beer taster who drank about a liter and a half (3.2 pints) of beer each day.

The unidentified employee alleged that the company did not provide the health measures needed to keep him from developing alcoholism, a labor court in the Rio Grande do Sul state said in a statement Friday.

The employee said in his lawsuit that for more than a decade, he drank between 16 and 25 small glasses of beer during his eight-hour shifts at the company

The employee said he also received a bottle of beer after each shift.

An initial ruling had favored Ambev, or Companhia de Bebidas das Americas, which can still appeal the decision. The company alleged the employee already was an alcoholic before becoming a beer taster.

Judge Jose Felipe Ledur said the company still was negligent because an alcoholic should never have been made a beer taster.
I wonder if the hospital had enough Valium to get the guy through D.T.'s.


Saturday, May 05, 2007

From Salad Mixers to Blood Products

The Food and Drug Administration (FDA) launched their direct-to-consumer website today, so I thought I'd check out the Heart Health link on their page. I found the side-bar on the right handy since it disclosed most of the major recalls and approvals granted by the agency recently. But I was struck by the reports found under the Recalls and Safety Info button. Under this button is all of the FDA's Enforcement Reports for a particular year. Some of these reports contain everything from recalls of salad mixers and cantaloupes to blood products potentially contaminated with malaria.

Now admittedly this is great information, but can the public really use this in its present form?

And tell me, what does a salad mixer have to do with the heart?


St. Jude's New Line of Zephr Pacemakers

MedGadget does a nice review. Personally, I like all of the new features except the AF suppression algorithm - I've had to turn that off too many times because patients with frequent PAC's often track near their upper rate limit.


On Lizards: Legal and Far From Laudible

Illinois is proposing to tax businesses making over $2 million a year (who will pass this expense on to consumers) to support a sweeping health care and education funding plan. The 0.08-1.95% tax (called the Gross Receipts Tax or GRT) is in addition to our already high 8% sales tax. Businesses, understandably, are outraged. That is, everyone except businesses in the food industry and medical industries, which are exempt.

I wonder if the health insurance and pharmaeutical industries consider themselves "medical" industries?

But his question is a mute one, I suppose, because most of the Lizards in these industries are based outside our state anyway. UnitedHealth, the largest health care insurer in America for instance, is based in Minneapolis, MN and has been noted to practice many slithering techniques. Blue Cross and Blue Shield, Aetna and Cigna have been similarly implicated in slimy behaviours.

Remarkably, it seems likely that the health insurance industry and pharmaceutical industries will have to contribute nothing to the control of health care costs in our state while enjoying few restrictions to raising costs.

Why is this a problem? Because not only does small business have to get taxed more based on the Illinois plan, they also have to endure the threat of retribution of insurers like what UnitedHealth did to one small business in Ohio:
Despite the 40 percent ceiling (on annual health care premium rate increases) in Ohio, for instance, United Healthcare early this year levied an increase of more than 100 percent on the premiums of CBG Biotech, a 26-employee hospital supplies maker in Macedonia, near Akron. The insurer argued that the high increase was justified because CBG had violated its contract.

Ohio permits insurers to solicit advance medical information from employees. One CBG worker had failed to disclose his wife’s multiple illnesses — including cirrhosis, gout and an ulcer — when he signed up for coverage, according to a letter from United that became part of a court record.

When United learned of the omission after the woman was admitted to a hospital, where she died, “they decided to punish the entire company,” said CBG’s chairman, Gerald W. Camiener.

United raised CBG’s total premium for the duration of the contract to $18,000 a month, from $8,800, he said, and demanded $118,000 in back payments.

CBG sought a federal injunction against the increase. In February, Judge Ann Aldrich of the United States District Court in Cleveland denied the CBG request, saying that United Healthcare’s actions were permissible under its contract and “very likely legal, but also very far from laudable.”

Mr. Camiener, in an e-mail message, lamented that ruling. “In the past, the policy of health insurers was to disqualify the employee when wrong information was furnished to them,” he wrote.

“Now,” he continued, “the insurers will be coming to the employer and demanding exorbitant sums of money with the threat that the entire group will be cut off forthwith, even in the middle of a policy year.” Mr. Camiener changed his company’s health coverage to Aetna, paying about $15,400 a month in premiums, and he complained to senior executives at United.
If we think for even one moment that these practices couldn't happen here in Illinois, we're deluding ourselves. And it will be legal, but far from laudible indeed that the insurance industry won't have to contribute a dime to the health care costs in our state. Meanwhile, we've had to suck up another tax to feed those greedy lizards that prey on small business.


Photo credit.

Thursday, May 03, 2007

Victims of Our Own Success

This week’s JAMA has confirmed the large drop in death by coronary heart disease in the setting of the acute heart attack. Trumpets have sounded, bands have blared, and patients have benefited. The study of over 44,000 patients proposed that the reasons for these improved outcomes were several:
  • Improved adoption of coronary interventions (angioplasty and stenting) as the preferred method of treating an acute heart attack.
  • The broad adoption of statin drugs to treat hyperlipidemia (high cholesterol).
  • And the broader use of antiplatelet agents (like clopidogrel) in addition to aspirin (aspirin use stayed constant over the study period).
While there is no question that patients are doing better, nationally cardiologists are presently feeling about a 4-6% drop in coronary intervention rates. As such, interventional cardiologists are getting nervous. People are scrambling to explain the drop, since it affects every cardiology group across the country. Is it the statins? Is it the use of CT scans for earlier diagnosis?

Certainly the guidelines on the management of the acute heart attack have helped improve patient outcomes, but perhaps the reason the overall rate of coronary interventions have fallen and fewer patients are dying as a result of their heart attack is something much simpler.


The Radiation Risk of CT Scanning

There is lots of buzz in the cardiology and business community about CT scanning as a means to detect coronary disease non-invasively.
Many patients with chest pain are put through a series of tests, including electrocardiograms and stress tests that are time consuming and expensive: In the U.S. alone, such testing costs $10 billion to $12 billion a year. Other patients go on to have an invasive angiography, or a cardiac catherization to look at the arteries, even though as many as 20% to 40% of these cases reveal no clinically significant narrowing of the arteries.

"Because stress tests are not perfect, there are many patients who go to cath lab who don't need it," said Harvey Hecht, chief of cardiovascular computer tomography at Lenox Hill Hospital in Manhattan. "All of those will be eliminated by doing cardiac CT."
Well, maybe not, Dr. Hecht. A relatively recent article on CT scanning from Circulation demonstrated that such high resolution scanners still could only make a diagnosis 75% of the time at best, since coronary calcium and even a single irregular heart beat could distort an acquired image. But companies want to market to the worried well, offering piece of mind that a heart scan will reassure them they are not at risk of heart disease, and turn a profit.

But what these companies also fail to mention is the radiation exposure these scans supply to the average man and woman. (Yes, ladies, women get much more radiation than men with these scans).

So, in the interest of public disclosure, I thought I'd assemble here some interesting data that I culled from various sources regarding radiation exposures and cancer risks with common diagnostic cardiovascular tests. Hopefully this will serve as a wake-up call to patients considering these tests. It should be mandatory that radiation dose be disclosed with these tests, especially as the number of x-ray elements grows from 64-slice to 128-slice scans. From the FDA's website:
The effective doses from diagnostic CT procedures are typically estimated to be in the range of 1 to 10 mSv. This range is not much less than the lowest doses of 5 to 20 mSv received by some of the Japanese survivors of the atomic bombs. These survivors, who are estimated to have experienced doses only slightly larger than those encountered in CT, have demonstrated a small but increased radiation-related excess relative risk for cancer mortality.

Radiation dose from CT procedures varies from patient to patient. A particular radiation dose will depend on the size of the body part examined, the type of procedure, and the type of CT equipment and its operation. Typical values cited for radiation dose should be considered as estimates that cannot be precisely associated with any individual patient, examination, or type of CT system. The actual dose from a procedure could be two or three times larger or smaller than the estimates. Facilities performing "screening" procedures may adjust the radiation dose used to levels less (by factors such as 1/2 to 1/5 for so called "low dose CT scans") than those typically used for diagnostic CT procedures. However, no comprehensive data is available to permit estimation of the extent of this practice and reducing the dose can have an adverse impact on the image quality produced. Such reduced image quality may be acceptable in certain imaging applications.

The quantity most relevant for assessing the risk of cancer detriment from a CT procedure is the "effective dose" . Effective dose is evaluated in units of millisieverts (abbreviated mSv; 1 mSv = 1 mGy in the case of x rays.) Using the concept of effective dose allows comparison of the risk estimates associated with partial or whole-body radiation exposures. This quantity also incorporates the different radiation sensitivities of the various organs in the body.
So to update the FDA's table, I added a few lines regarding average radiation doses of current cardiovascular tests for comparison:

Radiation Dose Comparison

Diagnostic ProcedureTypical Effective Dose (mSv)Number of Chest
X rays (PA film) for Equivalent Effective Dose
Time Period for Equivalent Effective Dose from Natural Background Radiation
Chest x ray (PA film)0.0212.4 days
Mammogram0.136.515.8 days
CT head2.0100243 days
CT abdomen10.05003.3 years
Coronary Angiogram3.41701.1 years
64-slice CT (male)15.27605.1 years
64-slice CT (females)21.410707.1 years
Dual-isotope (3.0mCi Tl-201+30mCi Tc-99) Thallium scan27.313659.1 years
128-slice CT?????????

So think about this when you get your next CT scan "just to find out" your coronary disease risk: is it worth the radiation exposure?


12:21 PM CST: Data for mammogram and dual-isotope Thallium test added. Reference: Thompson RC and Cullom SJ. J Nucl Cardiol 2006; 13: 19-23.

Wednesday, May 02, 2007

Defibrillator Complacency

It's been quite busy lately, making blog maintenance a bit tough. But I came across a good review article from the Journal of the American Medical Association (JAMA) that highlights the decision-making process that practitioners must negotiate when considering a defibrillator implantation on their patient with a reduced ejection fraction and well-compensated ischemic cardiomyopathy.

It's a very common scenario: an older gentleman, Mr. M, is 7 years out from his large anterior wall myocardial infarction (heart attack) who has been doing fairly well as a car salesman, but notes exertional fatigue. He wonders why he might need an ICD, even this late after his heart attack:
I’ve been talked to about putting a device in my chest that is supposed to regulate the heart. I’ve talked to a few different doctors on it, and I thought I had a grasp on the situation. But my understanding of it is that at the present time it's not a necessary thing. I’m 6 years removed from having my original procedure; I want to know why it's important to do it now. Right now, for me, right at this particular moment, there's no reason for me to do it. That's why I’m having such a hard problem as far as making a decision on it.
But the discussant does a good job explaining the rationale for recommending a defibrillator, even this late after a heart attack:
Mr M is beyond the early post-MI phase, but is well-represented by 2 of the previously cited trials. The control groups of the MUSTT and MADIT 2 trials enrolled patients an average of 3 and 7 years following MI, respectively. These trials included patients with a high incidence of CHF and a modest rate of -blocker and ACEI use and found that during a mean follow-up of 3 years, mortality rates were more than twice those documented in VALIANT. A substudy from MADIT 2 evaluated the influence of time post-MI on benefit derived from ICD implantation. In this analysis the reduction in mortality associated with ICD implantation persisted even in patients enrolled longer than 10 years following an MI. Therefore, current practice is to wait at least 6 weeks post-MI but not to limit how long after MI an ICD will be considered. In summary, Mr M can assume he continues to be at elevated risk for arrhythmia despite the 7 years that have passed since his MI, and that an ICD could reduce that risk.
I hear this resistance to implanting patients with ICD's late after myocardial infarction often. But our reluctance to advise patients about these devices might just cost someone their life.

This article does a great job reviewing the pro's and con's of defibrillator implantation and their benefits late after a prior heart attack. Unfortunately, it requires a prescription to view the entire text of the article, but I encourage doctors to review this piece if they care for patients that might be eligible candidates for this technology.


Tuesday, May 01, 2007

Book Club for Doctors

Book clubs for health care professionals build empathy and combat workplace burnout:
The program, created by the Maine Humanities Council and now operating in 17 states, is simple. Groups of people who work at a health care site, usually a hospital, read books related to health care and discuss them under the guidance of a facilitator.

But the impact is complex. An evaluation of the program in 2006 found that 88 percent of participants said they had had more empathy toward patients. The program also increased communication among hospital staffers; gave participants a better understanding of cultural differences; and countered burnout by giving people a renewed sense of purpose, the evaluation found.
But who's got the time?


Should Movie Smoking Be Banned?

What do we get when the Harvard School of Public Health says depictions of smoking should be banned from movies, a healthier populace or artistic censorship? Joel Stein sounds off:
Even amid the teenage consumption of coverage of Paris and Lindsay and Britney's partying, getting rid of smoking in movies might have some effect in signaling that smoking is socially unacceptable. But even if Leonardo DiCaprio's chain smoking in "Blood Diamond" causes kids to try cigarettes, that's the price of liberty. Art is empty propaganda if it just shows the world as we want it to be. The Harvard report states that "most smoking in movies is both unnecessary and cliched." But most everything in movies is unnecessary and cliched.
An ad by the group Smoke Free Movies suggests that "each month that passes without a studio consensus of the R-rating costs 5,000 tobacco deaths, in the US alone."

To this I have one word to say: baloney.