Common Pacing Modes

VVI

Ventricular pacing on demand w/ single lead in RV. Sensed ventricular beat inhibits V pacing. Used in chronic AF with symptomatic bradycardia.

DDD

A & V sensing/pacing (RA & RV leads). Native A beat inhib A pacing & triggers V pacing → tracking of intrinsic atrial activity. Maintains AV synchrony, ↓ AF.

Mode Switch

In atrial tachyarrhythmia (eg, AF), PPM ∆s from DDD to nontracking mode (eg, VVI). Prevents PPM from pacing at max V rate in response to rapid atrial rate.

Magnet over generator

PPM: fixed rate pacing (VOO/DOO). ICD: no shock, pacing preserved. Indic: ✓ capture; surgery; inapprop PPM inhib/ICD shock, PM-mediated tachy

Leadless intracardiac PPM for RV or AV synchronous pacing (JACC Clin EP 2020;6:94). His or L bundle pacing: more physiologic than RV pacing or even CRT (JACC 2018;72:927).