Abstract 2851: Repolarization Time Variety Measured From Body Surface Mapping as a Predictor of Cardiac Death in Patients With Previous Myocardial Infarction Without Heart Failure
Background: The identification of patients at risk of cardiac death in patients with a previous history of myocardial infarction (MI) without heart failure (HF) still remains an important goal. Repolarization time variety (RTV) measured from body surface mapping (BSM) and signal-averaged electrocardiogram (SAECG) provides useful prognostic information in MI patients. We investigated whether RTV and SAECG could predict cardiac death in MI patients without HF.
Methods: A total of 87 leads using BSM, SAECG and left ventriculography were performed in 84 patients (72 men, mean age 63±9 years) with a history of MI without HF. We measured repolarization time (the interval between QRS onset and the time of maximum dV/dt in the ST-T segment) in 87 leads using BSM. RTV was defined as the coefficient variation of the repolarization time and repolarization time dispersion (RTD) was defined as the difference between maximum and minimum repolarization time. The filtered QRS duration (f-QRS) and root mean square voltage of the terminal 40ms of the QRS complex (RMS40) were obtained by SAECG.
Results: During the follow-up period (mean 106±38 months), cardiac death occurred in 9 of 84 patients. Cardiac death was significantly associated with ventricular ejection fraction (LVEF) (p=0.0047), left ventricular end-diastolic volume (p=0.0019), RTV (p=0.0014) and RTD (p=0.0142), while SAECG was not significantly associated. RTV (p=0.0349, hazard ratio 2.625 for each 0.1 increase in RTV, 95%CI 1.070 to 6.436) was independently associated with cardiac death. Patients with RTV greater than 1.1 had a higher risk of cardiac death (log rank p=0.007).
Conclusion: Repolarization time variety may be used as a long-term predictor of cardiac death in patients with a previous history of myocardial infarction without heart failure.