Slide 1: Ah, the age-old question: What’s the rhythm? [EKG] Some useful context: 80yo M, hx of prior CABG. Now with: progressive decrease in exercise tolerance.

Slide 2: Step 1: evaluate P-waves. [EKG with arrows over p waves/buried p waves] In summary…prolonged p-p interval: 5+ small boxes = sinus bradycardia. Buried p waves: SV tachy? escape rhythm? Ddx is wide!

Slide 3: Step 2: check the PR intervals! [EKG] In summary…progressively prolonged PR interval with a dropped QRS complex. That pattern sounds familiar. Ringing any bells?

Slide 4: Step 3: Describe the QRS! [EKG shows both narrow and wide QRS’s] In summary…Isolated, widened QRS complexes without p waves: escape rhythm – junctional vs ventricular. The “escape” complexes differ in morphology from the native! Points us toward ventricular escape rhythm!

Slide 5: Official interpretation: sinus bradycardia with AV block (2nd degree, type I) and ventricular escape beats. Swipe right for the tx!

Slide 6: What’s next? What do we fix? The advanced 2nd degree AV block. How? A pacemaker! Indications for the pacemaker? (Class I indications in acquired AV block, that is) Symptomatic bradycardia, ventricular arrhythmias due to AV block, asystole 3+ seconds, afib and pause 5+ seconds, escape rate <40 bpm, iatrogenic AV ablation/injury, exercise in the absence of MI, LV dysfunction or cardiomegaly (3rd degree only). Side note: these apply to 3rd degree AV block too!