Methods: The study population consisted of 66 severe heart failure pts with CRTD, (9 ? and 57?), mean age 61±14 years, with underlying disease ischemic cardiomyopathy in 34 and dilated cardiomyopathy in 32. Forty six pts received CRTD as primary prevention (group A) and 20 pts as secondary prevention (group B). Eight pts had permanent atrial fibrillation (AF) and 13 pts sustained at least one episode of PAF before device implantation. We analyzed the occurrence of ventricular tachycardia including appropriate VT therapies and atrial fibrillation as well.
Results: Forty eight pts were clinical responders, 8 super responders and 10 pts poor responders. After 10 years follow-up including at least one device replacement, we found almost similar incidence of sustained ventricular tachycardia (VT) (15%) and AF (25%) in both groups, irrelevant to clinical improvement and underlying substrate. Seven patients died of pump failure. Pts who received CRTD as secondary prevention, although good responders, continued to experience VT and appropriate therapies. In all groups development of electrical storm and resistant fast AF was a harbinger of heart failure deterioration.
Conclusion: Due to electrical and mechanical heterogeneity among severe heart failure pts the antiarrhythmic effect of CRTD is unpredictable. The arrhythmia risk in CRT pts is independent to CRT-induced improvement of the failing heart and irrelevant to heart failure origin.