Comparison of T-Wave Alternans and QT interval Dispersion to Predict Ventricular Tachyarrhythmia in Patients with Dilated Cardiomyopathy and without Antiarrhythmic Drugs.

Abstract

SUMMARYMicrovolt T-wave alternans (TWA) and QT interval dispersion (QTD), which reflect temporal and spatial repolarization abnormalities, respectively, have been proposed as useful indices to identify patients at risk for ventricular tachyarrhythmias (VTs). The purpose of this study was to clarify which repolarization abnormality marker is more useful in predicting arrhythmic events in patients with dilated cardiomyopathy (DCM).Forty-two consecutive nonischemic DCM patients underwent the assessment of TWA and QTD. Patients undergoing antiarrhythmic pharmacotherapy, except β-blockers and those with irregular basic rhythms, were excluded from entry. Eight patients were also excluded because of indeterminate test results. Therefore, 34 DCM patients were prospectively assessed. The end point of the study was the documentation of VT defined as ≥ 5 consecutive ectopic beats during the follow-up period.TWA and QTD (≥65 msec) were positive in 24 (80%) and 11 (37%) of 30 patients with available follow-up data, respectively. There was no relationship between TWA and QTD. During a follow-up of 13±11 months, VTs occurred in 13 patients (43%). In Cox regression analysis, TWA was a significant risk stratifier (p=0.02), whereas QTD was not. The sensitivity, specificity, and positive and negative predictive values of TWA in predicting VTs were 100%, 35%, 54%, and 100%, respectively.TWA could be a useful noninvasive index to identify patients at risk for VTs in the setting of DCM. This study may suggest that temporal repolarization abnormality is associated more with arrhythmogenesis than with spatial repolarization abnormality in DCM patients. (Jpn Heart J 2001; 42: 451-457)

American Heart Association/American College of Cardiology Foundation/Heart Rhythm Society Scientific Statement on Noninvasive Risk Stratification Techniques for Identifying Patients at Risk for Sudden Cardiac Death

“…45,51,52 Several recent studies have found no relation between QT dispersion and outcome. 24,46,[53][54][55] Lack of a clear physiological correlate further clouds the utility of this parameter.…”

Predictive significance for sudden death of microvolt-level T wave alternans in New York Heart Association class II congestive heart failure patients

“…Therefore, MTWA has been proposed as a new noninvasive tool for stratification of patients at high risk of SCD and ventricular arrhythmias in CHF patients with ischemic or nonischemic cardiomyopathy [9][10][11][12][13][14].…”

Combined prognostic value of peak O2 uptake and microvolt level T-wave alternans in patients with idiopathic dilated cardiomyopathy

“…The results of several studies [15][16][17][18][19][20][21][22]30,31] demonstrated that MTWA is a promising predictor of SCD or major arrhythmic events in patients with DCM.…”

“…Several clinical and experimental studies [12][13][14] have shown that MTWA is strictly correlated with presence of inducible and spontaneous ventricular tachycardia/fibrillation (VT/VF). Therefore, MTWA has been proposed as a new non-invasive tool for stratification of patients with DCM at high risk of SCD and malignant arrhythmias [15][16][17][18][19][20][21][22].…”