Noninvasive Risk Stratification Using Microvolt-Level T-Wave Alternans, Non-Sustained Ventricular Tachycardias and Autonomic Tone in MADIT-II-Type Patients

Thomas Klingenheben MD, Gerian Groenefeld, Pawel Ptaszynski, Stefan H. Hohnloser, J.W. Goethe University Frankfurt, Frankfurt, Germany.

Background: Primary prevention of sudden cardiac death (SCD) by prophylactic ICD implantation has been shown to be effective in CAD patients with LVEF£30%. However, only one fifth of the respective patients will use the ICD during follow-up. Refinement of risk stratification of MADIT-II-like patients is therefore mandatory. Methods: Patients after myocardial infarction and a LVEF£30% underwent assessment of microvolt T-wave alternans (TWA; spectral method), non-sustained ventricular tachycardia (nsVT), and heart rate variability (HRV, both derived from Holter recordings). The composite primary endpoint was SCD, sustained ventricular tachycardia, and resuscitated ventricular fibrillation. Results: One-hundred and sixteen patients (58±11 years; 81% males; LVEF 26±4%) were followed over 27±17 months during which time period 12 primary endpoint events (10%) occured. A positive TWA was found in 44 pts (38%), TWA was negative in 31 and indeterminate in 41 pts. Twenty-one pts (18%) had nsVT during Holter monitoring, HRV was impaired in 53 pts (46%). Only a positive TWA (RR 3.27; 95%CI:1.1-9.6; p=0.03) and the combination of TWA and nsVT (RR 5.66; 95%CI:2.1-14.9;p<0.001) were significant predictors of the composite endpoint. The graph depicts Kaplan-Meier-Analysis of event-free survival. Conclusion: TWA alone and in combination with nsVT identifies a subgroup of MADIT-II like pts at particularly high risk for ventricular tachyarrhythmic events. A prospective study of primary prevention of arrhythmic death in such patients stratified by means of TWA is warranted.