Tuesday, July 29, 2008

EKG Du Jour - #10

Ah, it's been a while since I've pulled an EKG from the EKG Hall of Fame series, so here's the tenth installment for your enjoyment:*

A 28 year old man presents to your office with an implantable cardiac defibrillator (ICD) in place. He shows you his EKG, shown here:

Click image to enlarge

You are asked for a second opinion to see if he really needs his ICD. He has no reports from the other hospital with him.

What is the differential diagnoses offered by this EKG, and of those, given his age and EKG findings, what might be the most likely diagnosis?


* Prior "EKGs Du Jour" can be reviewed by typing "Du Jour" in the search box on the right side bar of this blog.


The Happy Hospitalist said...

I'll take a stab at congenital QT prolongation.

Justin said...

I am noting an odd (can't put my finger on it ...) P wave in V1, V2, aVL consistent with right atrial block and also a possible pathologic q-wave in II, III, aVf consistent with inferior STEMI. It is possible that either of these could have resulted in a reentry loop. Maintenance of an ICD in either case could certainly be life-saving, but I don't know much about the data to say that it is truly necessary.

The patient is also bradycardic; if he is asymptomatic and his physical exam is consistent with physiological bradycardia (e.g. if he is a bodybuilder), then the ICD is not necessary for this reason alone and in fact would be increasing his mortality if he is being unnecessarily paced during the day should he become even more bradycardic.

Long QT is possible. So is intermittent AV block, but I do not see evidence of any bundle blocks or first-degree block.

Incidentally, it is also possible that he received the ICD in the first place because he has ARVD; although the only possible ECG sign I see towards that is precordial progression noted between V2 and V3, ARVD is still a clinical diagnosis.

In short, I would probably have to know more about this patient before recommending removal. However, I would be hard-pressed to maintain this ICD considering its effect on LV functional impairment.

shadowfax said...

I'm too tired to do the calculation, but I think the QT does not look long, especially with the relative bradycardia. The ST changes make me think of Brugada's, but they're not really classic. The changes with Brugada's, however, can be variable, even in the same patient, so I dunno.

I don't see anything exciting about the P wave or AV nodal conduction, so if there is an abnormality it's probably ventricular (which would make sense if someone thought it was worthwhile putting in an ICD). CAD/MI are of course unlikely at this age, but cardiomyopathy is certainly possible, and that also can give you the ST changes. QRS is nice and tight, so I dount WPW or an accessory pathway (again, which wouldn't generally buy you a box).

Well, as an ER doc I have a statutory limitation on my differential of two items, so I'll go with Brugada's vs cardiomyopahty.

Anonymous said...

IHSS, Cheney's Disease. Yes, you need the ICD, hell, I'd like one myself.

Robert W Donnell said...

Right ventricular cardiomyopathy would be my guess. (T wave abnormality V 1-4, and are those epsilon waves in I and II?).

LQTS is possible---T wave definition is poor, and TU fusion may be present.

DrWes said...

I appreciate all that have ventured a guess on this most recent EKG. The history of this case was left intentionally vague, in hopes that people commenting here would cover the gamut of possibilities for the marked T wave inversions seen on this EKG in the precordial leads V1 through V4.

The underlying rhythm here was sinus bradycardia with a slight sinus arrhythmia. The QT interval is a bit long (about 480 msec), but the obsessive compulsives out there will note that the rate, being a bit slower than 60 beats per minute (in this case 52 b/min (or an RR interval of 1.12 sec) was used), “corrects” this QT interval to 0.480 sec / (1.12 sec^0.5) = 0.453 sec or 453 msec: a normal QT interval. This is not to say that this reading alone would exclude the possibility of Long QT syndrome in this man, but it moves the diagnosis down the differential.

T wave inversions, particularly in the anterior precordial leads (V1 though V4) can be caused by many things and have a braod differential diagnosis. Heart muscle disorders (called cardiomyopathies) are one such cause but are often accompanied by findings of ventricular hypertrophy due to the enlargement or thickening of the heart in this disorder. We do not see increased voltage amplitude to support this diagnosis on this EKG, so this diagnosis also moves down the differential list.

Metabolic disturbances or drug influences could also lead to deep T wave inversions, but are usually more diffusely noted across all of the EKG. Unfortunately, these T wave abnormalities are just not classic for Brugada’s syndrome, with its J point elevation.

Other rare diseases, like Takayasu’s arteritis, anomalous coronary, or hyperlipidemia causing coronary artery disease could result in such a finding, but are unusual in a patient this age. Other even less likely things like sarcoidosis or amylodosis can cause non-specific T wave abnormalities as well, but characteristically are not limited to anterior precordial T wave abnormalities.

One commonly forgotten aspect of the anterior precordial leads, is that they are greatly influenced by anterior cardiac structures, specifically, the right ventricle. Enlargement or pathologic features of the right ventricle often manifest in these leads V1->V3 or V4. An herein lies this man’s diagnosis.

This was a young competitive cyclist who tried to race cars up the Grand Corniche in Monaco. One day, he developed a rapid heart rhythm that “stopped me in my tracks” and was later found to be in a wide complex tachycardia of a left bundle branch morphology (suggesting the arrhythmia was arising from the right ventricle). He was administered adenosine because his doctors thought it was more likely SVT with aberrancy, he became hypotensive, and was cardioverted. His echo was completely normal. On EP study, he had six different left bundle branch morphology ventricular tachycardias induced, and MRI disclosed fatty infiltration of the right ventricle muscular architecture, diagnostic of arrhythmogenic right ventricular dysplasia (ARVD) with an RV ejection fraction of 30 percent and a left ventricular ejection fraction of 58 percent.

(Nice job, Justin & RW!)