Saturday, June 2, 2012

Quiz #18 Answer: EKG - AV Block, Second Degree

2-day old baby (Tetralogy of Fallot) developed this rhythm during cardiac catheterization.
Question: What is this catheter-induced rhythm?

Answer: Second degree AV Block

Arrows indicate P waves. There is 2:1 conduction. The conducted P waves are conducted with a prolonged PR interval (HR 83 bpm; PR interval 180-190 ms).

(At the onset, this was 3rd degree AV Block. This occurred during catheter manipulations in RV, attempting to cross a severely stenotic pulmonary valve. Intermittently, the catheter cross the VSD and entered the aorta. Presumably, the His bundle was affected during one of these times. Rhythm recovered spontaneously  to 2nd degree over time. Because the baby was unstable with ventricular rate of 83 bpm, Isoproterenol infusion was started after recording this EKG. Sinus rhythm was restrored after ~ 8 -12 hrs)

(Click on the image to enlarge)

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