Here's a recent pacemaker interrogation showing a simultaneous surface EKG (top tracing), right atrial marker channel (center tracing) and right atrial electrogram (bottom tracing) from a patient who underwent aortic valve replacement over 30 years ago and later mitral valve replacement about 6 years ago. He has had multiple bouts of symptomatic atrial flutter that have responded to electrical cardioversion. His echocardiogram has demonstrated a nearly 7-centimeter left atrium, among other things. He was now fairly asymptomatic at the time of this recording:
Click image to enlarge
How does one explain what's seen?
hat tip: Alan D. Kogan, MD for supplying the tracing.