ABSTRACT
Background:
The effect of
cardiac resynchronization therapy (CRT) on the
risk of ventricular arrhythmias is controversial. Several studies reported a decreased
risk, but some studies reported a potential proarrhythmic effect of epicardial left ventricular pacing resolved upon discontinuation of
biventricular pacing (BiVp). Case
Summary:
A 67-year-old
woman with a
history of
heart failure due to nonischemic
cardiomyopathy and
left bundle branch block was hospitalized for CRT
device implantation. Unpredictably, as soon as the leads have been connected to the generator, an electrical storm (ES) occurred with relapsing
self-resolving polymorphic
ventricular tachycardia (PVT) triggered by ventricular extra beats with short-long-short sequences. The ES was resolved without interrupting BiVp switching to unipolar left ventricular (LV) pacing. This allowed to keep CRT active with extreme clinical benefit for the
patient and to demonstrate that the cause of the PVT was the anodic capture of bipolar LV stimulation. Reverse
electrical remodeling was also demonstrated after 3 months of effective BiVp.
Discussion:
Proarrhythmic effect of CRT is a rare but significant complication of CRT, and it may compel to discontinuation of the BiVp. The reversal of the physiological transmural activation sequence of epicardial LV pacing and subsequent prolonging of corrected QT interval have been speculated as the most probable explanation, but our case highlights the possibility that the anodic capture may
play a relevant
role in PVT genesis.
