Effect of cardiac resynchronization therapy on the incidence of electrical storm.
BACKGROUND
Hemodynamic improvement from biventricular pacing is well documented; however, its electrophysiologic effects have not been systematically studied. In this study, incidence and risk factors for electrical storm (ES) were investigated in 729 ICD and biventricular defibrillator (CRT-D) heart failure patients.


METHODS
168 consecutive CRT-D and 561 ICD patients were retrospectively analyzed for the occurrence of VT/VF and predisposing factors. Electrical storm was defined as ventricular tachycardia or fibrillation ≥3 times during 24 h. Mean follow-up was 41 months.


RESULTS
In 168 CRT-D patients only one patient experienced electrical storm compared to 39 patients out of 561 ICD patients (0.6% vs. 7%, p<0.01). 33% of the patients with electrical storm died within one year. In the CRT-D group 81 patients (48%) developed VT or VF and received at least one appropriate therapy, compared to 281 patients (50%) in the ICD group. Mean ejection fraction was 21.7% in the CRT-D group and 34.7% (p<0.01) in the ICD group. Stratifying the patients according to primary or secondary prevention and ejection fraction demonstrated that VT/VF clusters were significantly associated with ICD indication for secondary prevention, previous myocardial infarction and LVEF<30%.


CONCLUSIONS
The development of electrical storm is accompanied with a highly increased mortality risk even if an ICD/CRT-D is implanted. In CRT-D patients electrical storm is much less common than in ICD patients. Secondary prevention and ejection fraction<30% are predictors of electrical storm. Beside hemodynamic improvements cardiac resynchronization therapy may reduce the arrhythmia burden in heart failure patients.
Department of Internal Medicine I, University Hospital Würzburg, Germany.
Peter
P
Nordbeck
Bernhard
B
Seidl
Beatrix
B
Fey
Wolfgang R
WR
Bauer
Oliver
O
Ritter
D000368:Aged; D058406:Cardiac Resynchronization Therapy / Q000401:mortality* / Q000706:statistics & numerical data; D005260:Female; D005500:Follow-Up Studies; D006333:Heart Failure / Q000401:mortality* / Q000628:therapy*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D016019:Survival Analysis; D017180:Tachycardia, Ventricular / Q000401:mortality* / Q000517:prevention & control; D014693:Ventricular Fibrillation / Q000401:mortality* / Q000517:prevention & control