abstract

presented

at the 1997 AHA

Orlando, Florida

November 9 - 12, 1997

The prevention of sudden death in patients (pts) with dilated cardiomyopathy (DCM) remains to be therapeutic target. Microvolt-level T wave alternans (TWA) has been proposed as a powerful tool for identification of pts at high risk for ventricular arrhythmia and sudden death in coronary artery disease. However, the clinical significance of TWA in pts with DCM is unknown. In 26 DCM pts, TWA was measured at rest and during controlled bicycle exercise testing using the CH 2000 system (Cambridge Heart, Inc.). Positive TWA was defined as an alternans voltage > 1 &micro; V at rest or > 1.9 &micro; V during exercise at a heart rate of 105-120 bpm, with an alternans ratio > 3. NYHA, late potentials, QTc dispersion (QTcd), Dd and % FS detected by echocardiogram, and the grade of ventricular arrhythmia were obtained in all pts. Results: TWA was positive in 11 pts (TWA+) and negative in 15 pts (TWA-). There was no significant difference in NYHA, late potentials, Dd, or % FS between the two groups (TWA+ and TWA-). QTcd in TWA+ was significantly greater than that in TWA- (p<0.005). The percentage of ventricular tachycardia (VT) in TWA+ was significantly higher than that in TWA- (p<0.01). The sensitivity (Se), specificity (Sp), and predictive accuracy (PA) of TWA for VT were 88% , 78% , and 81% , respectively. Those predictive values of QTcd for VT were 63% for Se, 56% for Sp, and 58% or PA. The predictive values of TWA for VT were superior to those of QTcd.

Conclusion: TWA is a useful noninvasive predictor for VT in pts with DCM.

*p<0.005, **p<0.01 vs TWA-

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