Clinical course and long-term follow-up of patients receiving implantable cardioverter-defibrillators.
BACKGROUND
Implantable cardioverter-defibrillators (ICDs) are increasingly used for primary and secondary prevention of sudden cardiac death. Defibrillators were introduced into clinical practice in 1980. Since that time, factors affecting long-term survival and the natural history of defibrillator patients have not been described.


OBJECTIVE
The purpose of this study was to identify clinical predictors of long-term survival in patients receiving ICDs.


METHODS
The prognostic value of several clinical variables on the likelihood of survival or appropriate ICD therapy in 1,382 consecutive patients receiving ICDs from 1980 to 2003 were evaluated. Data were collected at the time of device implantation, and follow-up was completed through March 2005.


RESULTS
In 70 +/- 51 months of follow-up (range 0-282 months), 792 patients died and 421 patients received appropriate ICD therapy at least once. Age, left ventricular ejection fraction, New York Heart Association (NYHA) functional class, Charlson comorbidity index, and antiarrhythmic drug use correlated with mortality. beta-Blocker and angiotensin-converting enzyme inhibitor use was associated with improved survival. Only NYHA functional class correlated with ICD therapy. Patients free of shocks for the first 5 years after ICD implantation had continued risk of arrhythmia recurrence.


CONCLUSIONS
The heart failure characteristics of patients predicted ICD shock probability and survival better than the arrhythmia characteristics or the underlying heart disease. Antiarrhythmic drug use was associated with increased mortality. Beta-blocker and angiotensin-converting enzyme inhibitor use was associated with improved survival. A measurable arrhythmic risk even after prolonged shock-free intervals indicates the need for continued ICD therapy in all patients with appropriate ICD indications.
Tandri
Harikrishna
H
Division of Cardiology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.
Griffith
Lawrence S
LS
Tang
Tania
T
Nasir
Khurram
K
Zardkoohi
Omeed
O
Reddy
Chandrasekhar Vasam
CV
Capps
Melissa
M
Calkins
Hugh
H
Donahue
J Kevin
JK
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016757:Death, Sudden, Cardiac / Q000209:etiology / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D015996:Survival Rate; D017180:Tachycardia, Ventricular / Q000150:complications / Q000401:mortality / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome