[Microvolt T wave alternans as a predictor for sudden cardiac death].

The microvolt T wave alternans(MTWA) is a new promising method for identifying patients with lethal ventricular tachyarrhythmias. MTWA is dependent on heart rate, so that MTWA can be measured during exercise, pharmacological stress, or cardiac pacing to increase heart rate. For predicting sudden cardiac death after myocardial infarction, sensitivity of MTWA by exercise was 92%, specificity 61%, positive predictive value 7%, negative predictive value 99%. High sensitivity and negative predictive value are suggested that MTWA could be a screening test for sudden cardiac death after myocardial infarction. In addition, it is reported that MTWA is useful for predicting sudden cardiac death in patients with DCM or impaired cardiac function. Although the development of ICD has provided the effectiveness of prevention of sudden cardiac death, it is difficult to identify the patients with malignant ventricular tachyarrhythmias for primary prevention. MTWA can increase referrals of appropriate patients for further electrophysiologic evaluation and therapy.