Cardiac amyloidosis (CA) is generally associated with a poor prognosis and significantly increased mortality. We sought to identify predictors of longer-term survival in patients with endomyocardial biopsy (EMB)-documented CA. Forty-five consecutive patients with EMB-documented CA were studied from January 1998 to December 2003. Age, gender, New York Heart Association class, medications, presence of light-chain amyloid, and electrocardiographic voltage were recorded. Baseline left ventricular (LV) ejection fraction, deceleration time, diastolic function, LV mass, ventricular septal thickness, and myocardial performance index ([isovolumic contraction time + isovolumic relaxation time]/ejection time) were recorded. Mean age was 66 +/- 10 years with 34 men (76%). New York Heart Association class >II was noted in 26 patients (58%) and low voltage on electrocardiogram (S wave [lead V(1)] + R wave [lead V(5)] < or =15) in 12 (27%). Mean LV ejection fraction, ventricular septal thickness, and LV mass were 46 +/- 13%, 1.7 +/- 0.42 cm, and 303 +/- 114 g, respectively. Deceleration time < or =150 ms was found in 19 (42%) and myocardial performance index >0.6 in 15 (33%). At a median follow-up of 1.7 years, there were 25 deaths (56%). On univariate Kaplan-Meier analysis, New York Heart Association class >II, deceleration time <150 ms, and beta-blocker use were associated with increased mortality (log-rank statistic p values <0.001, <0.05, and 0.01, respectively). On Cox proportional hazard survival analysis, only New York Heart Association class was significantly associated with increased mortality (hazard ratio 3.92, 1.92 to 7.95, p = 0.0002). In conclusion, in patients with EMB-documented CA, longer-term survival is more strongly associated with New York Heart Association functional class compared with electrocardiographic and echocardiographic variables.