Troponin T elevation after implanted defibrillator discharge predicts survival.
BACKGROUND
Cardiac troponin T (cTnT) elevations have been reported to occur after implantable cardioverter-defibrillator (ICD) discharges, but their prognostic significance is unknown.


OBJECTIVE
To evaluate whether cTnT elevations occurring after ICD discharges have an impact on survival.


METHODS
Prospective observational study.


METHODS
174 patients (mean (SD) age 68 (12) years, 32 women) who received spontaneous (n = 66) or induced (n = 108) ICD discharges were studied. The mean (SD) left ventricular ejection fraction was 29 (11)%.


METHODS
Troponin T was measured between 12 and 24 h after ICD discharge. Patients received between 1 and 19 discharges (mean (SD) 2.4 (2.4)), with total delivered energy ranging from 6 to 288 J (mean (SD) 41 (63) J). The relationship between cTnT levels and all-cause mortality was assessed in univariate and multivariate analyses.


RESULTS
During a median follow-up period of 41.8 months (range 3-123), 56 patients died. Patients with a post-discharge cTnT level of >/=0.05 ng/ml had worse survival than those with cTnT <0.05 ng/ml. The significant relationship between raised cTnT and survival was retained in Cox multivariate analysis adjusted for total ICD energy delivered during an arrhythmia episode, age, sex, presence of coronary artery disease, left ventricular ejection fraction and serum creatinine.


CONCLUSIONS
Elevation of troponin T after ICD discharge, even when it occurs after device testing, is a risk factor for mortality that is independent of other common clinical factors that predict survival in such patients.
Department of Medicine, Cardiac Electrophysiology Service, Bridgeport Hospital, Yale University School of Medicine, Bridgeport, CT 06610, USA. dblendea@me.com
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Banker
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McPherson
D000368:Aged; D001145:Arrhythmias, Cardiac / Q000097:blood / Q000401:mortality*; D003324:Coronary Artery Disease / Q000097:blood / Q000401:mortality; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000401:mortality; D005260:Female; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D011379:Prognosis; D011446:Prospective Studies; D020107:Troponin T / Q000378:metabolism*
D020107:Troponin T