Long-term incidence of malignant ventricular arrhythmia and shock therapy in patients with primary defibrillator implantation does not differ from event rates in patients treated for survived cardiac arrest.
BACKGROUND
Recent trials have demonstrated benefit of prophylactic defibrillator (ICD) implantation compared to conventional treatment in high-risk patients. However, many patients have rare or no sustained arrhythmias following implantation. Our study addresses the question, whether patients with prophylactic defibrillator implantation have a lower risk for life-threatening ventricular tachycardia (VT) or ventricular fibrillation (VF) compared to sudden cardiac death (SCD) survivors.


RESULTS
Over 7 years we enrolled 245 patients. Occurrence of spontaneous sustained VT/VF resulting in adequate ICD treatment was the endpoint. Incidence, type, and treatment of sustained arrhythmia in 43 previously asymptomatic ICD recipients (group B) were compared to data of 202 survivors of imminent SCD (group A). All patients had severely impaired left ventricular ejection fraction (<45%). Group B patients had long runs (>6 cycles, <30 s) of VT during Holter monitoring and inducible sustained arrhythmia. Incidence of rapid VT and VF (cycle length <240 ms/heart rate >250 bpm) after 4 years (35% in both groups, P = ns) and adequate defibrillator therapies (57% vs 55%, P = ns) were similar in both groups after univariate and multivariate analysis. Cumulative mortality tended to be lower in group B compared to group A, but the difference was not statistically significant.


CONCLUSIONS
During long-term follow-up, incidence of sustained rapid ventricular arrhythmia in prophylactically treated patients is as high as that of SCD survivors. Benefit from defibrillator implantation for primary prevention (group B) appears to be comparable to that for survived cardiac arrest (group A).
Backenköhler
Ulrich
U
Division of Cardiology, Department of Internal Medicine, Justus-Liebig-University Hospital of Giessen, D-35392 Giessen, Germany. ulrich.bacnkenkoehler@innere.med.uni-giessen.de
Erdogan
Ali
A
Steen-Mueller
Mary-Kay
MK
Kuhlmann
Christoph
C
Most
Astrid
A
Schaefer
Christian
C
Stertmann
Wilhelm
W
Waas
Wolfgang
W
Tillmanns
Harald
H
Waldecker
Bernd
B
D000328:Adult; D016757:Death, Sudden, Cardiac / Q000517:prevention & control; D017147:Defibrillators, Implantable; D004554:Electric Countershock; D015716:Electrocardiography, Ambulatory; D005260:Female; D006323:Heart Arrest / Q000628:therapy*; D006801:Humans; D015994:Incidence; D008297:Male; D011322:Primary Prevention; D017180:Tachycardia, Ventricular / Q000453:epidemiology / Q000517:prevention & control*; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000453:epidemiology / Q000517:prevention & control*