Detectable troponin levels predict poor prognosis in patients with left ventricular dysfunction undergoing internal defibrillator implantation.
BACKGROUND
Troponin levels have been demonstrated to predict mortality in patients with cardiomyopathy. Implantable cardiac defibrillator (ICD) devices have been demonstrated to improve survival. It is not clear if ICDs would mitigate the negative outcome predicted by elevated troponin levels.


METHODS
We collected baseline blood samples for troponin T (TnT) and creatinine kinase-MB fraction in consecutive patients immediately before successful pectoral transvenous ICD implant. Patients were followed for total mortality. For analysis, patients were grouped by TnT detectability (>or=0.01 ng/mL).


RESULTS
Fifty-two men, aged 68 +/- 10 years, were studied. Mean ejection fraction was 29 +/- 12% and 65% had ischemic cardiomyopathy. Follow-up duration was 17 +/- 8 months. None of the patients had abnormal creatinine kinase-MB fraction levels (1.7 +/- 1.1 ng/mL). There were 37 patients with no detectable TnT (Group I) and 15 with detectable TnT (Group II). There was no difference between the two groups in terms of age (68 vs 69, P = NS), ejection fraction (30 vs 29%, P = NS), or proportion of patients with ischemic cardiomyopathy (68 vs 60%, P = NS). During follow-up 16 (31%) patients died. Patients in group I had mortality of 16% (6/37) compared to 67% mortality (10/15, P < 0.001) in group II. On multivariate analysis, detectable TnT remained an independent predictor of mortality (HR 4.5, CI 1.4-14.25, P = 0.01).


CONCLUSIONS
In a cohort of patients with cardiomyopathy undergoing ICD implantation for standard clinical indications, presence of detectable TnT was associated with high mortality despite ICD implantation. TnT obtained before ICD implantation may be useful for risk stratification.
Sonel
Ali F
AF
Department of Cardiology, VA Pittsburgh Healthcare System and the University of Pittsburgh, Pittsburgh, Pennsylvania 15240, USA.
Shalaby
Alaa
A
McConnell
Joseph P
JP
Czarnecki
Tammy
T
Hogen
Scott
S
Zahid
Maliha
M
Amidi
Morteza
M
D000368:Aged; D016009:Chi-Square Distribution; D052279:Creatine Kinase, MB Form / Q000097:blood; D017147:Defibrillators, Implantable; D006801:Humans; D008297:Male; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D012044:Regression Analysis; D018570:Risk Assessment; D020107:Troponin T / Q000097:blood*; D018487:Ventricular Dysfunction, Left / Q000097:blood / Q000401:mortality / Q000628:therapy*
D020107:Troponin T; D052279:Creatine Kinase, MB Form