Cardiovascular Diseases - Electrophysiology - Entrainment.pptx

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1. Entrainment Amit Gulati, PGY4 Fellow, Cardiovascular Diseases

2. Mechanistic definition of transient entrainment Transient entrainment of a tachycardia occurs during pacing at a rate faster than the tachycardia rate when each orthodromic wave front from the pacing impulse resets the tachycardia to the pacing rate, and each antidromic wave front from the pacing impulse either collides with the orthodromic wave front of the previous beat or is otherwise blocked.

3. Constant fusion During a tachycardia, when pacing at a constant rate that is faster than the rate of tachycardia and which fails to interrupt it, there is the demonstration of constant fusion beats in the ECG except for the last captured beat which is not fused.

4. Progressive fusion As the pacing rate increases the CL shortens and also the antidromic wavefront penetrates the circuit to a greater degree. The degree of fusion is different at each rate. The different degree of fusion in the ECG leads at each pacing rate, which entrains but fails to interrupt the tachycardia is called progressive fusion.

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