Long-term clinical course of patients after termination of ventricular tachyarrhythmia by an implanted defibrillator.
BACKGROUND
The implanted cardioverter defibrillator (ICD) improves survival in high-risk cardiac patients. This analysis from the MADIT-II trial database examines the long-term clinical course and subsequent mortality risk of patients after termination of life-threatening ventricular tachyarrhythmias by an ICD.


RESULTS
Life-table survival analysis was performed, and proportional hazards regression analysis was used to evaluate the contribution of baseline clinical factors and time-dependent defibrillator therapy to mortality during long-term follow-up. Of 720 patients with an ICD (average follow-up 21 months), 169 patients received 701 antiarrhythmic device therapies for ventricular tachyarrhythmias. Few baseline characteristics distinguished patients who received appropriate ICD therapy for their first ventricular tachyarrhythmic episode. The probability of survival for at least 1 year after first therapy for ventricular tachycardia (VT) or ventricular fibrillation (VF) was 80%. The hazard ratios for the risk of death due to any cause in those who survived appropriate therapy for termination of VT and VF were 3.4 (P<0.001) and 3.3 (P=0.01), respectively, compared with those who survived without receiving ICD therapy, with a high frequency of heart failure and late nonsudden cardiac death after first successful ICD therapy for VF.


CONCLUSIONS
Successful appropriate therapy by an ICD for VT or VF is associated with 80% survival at 1 year after arrhythmia termination. These patients are at increased risk for heart failure and nonsudden cardiac death after device termination of VT or VF and should receive special attention for the prevention and management of progressive left ventricular dysfunction during long-term follow-up.
Moss
Arthur J
AJ
Cardiology Unit of the Department of Medicine, University of Rochester Medical Center, Rochester, NY 14642, USA. heartajm@heart.rochester.edu
Greenberg
Henry
H
Case
Robert B
RB
Zareba
Wojciech
W
Hall
W Jackson
WJ
Brown
Mary W
MW
Daubert
James P
JP
McNitt
Scott
S
Andrews
Mark L
ML
Elkin
Adam D
AD
D002318:Cardiovascular Diseases / Q000401:mortality; D015331:Cohort Studies; D017147:Defibrillators, Implantable; D018450:Disease Progression; D004554:Electric Countershock; D005500:Follow-Up Studies; D006333:Heart Failure / Q000453:epidemiology; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D015993:Life Tables; D011379:Prognosis; D016016:Proportional Hazards Models; D016032:Randomized Controlled Trials as Topic; D012306:Risk; D016019:Survival Analysis; D017180:Tachycardia, Ventricular / Q000628:therapy*; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000453:epidemiology