Ambulatory ECG-Based T-Wave Alternans and Heart Rate Turbulence Predict High Risk of Arrhythmic Events in Patients With Old Myocardial Infarction

Abstract

Background: Few studies have explored risk stratification of arrhythmic events in patients with ischemic heart diseases according to T-wave alternans (TWA) using modified moving average (MMA) method and heart rate turbulence (HRT). Methods and Results: A retrospective analysis of 63 patients who underwent MMA-based TWA and HRT divided the patients into 3 groups: group-C of 21 controls, group-O of 21 patients with old myocardial infarction (OMI) showing no episodes of sustained ventricular tachyarrhythmia (SVT), and group-V of 21 OMI patients with episodes of SVT who received an implantable cardioverter-defibrillator. Among the 3 groups, positive TWA (≥65 μV) and impaired HRT were observed most frequently in group-V (P<0.05). Using a logistic regression model, TWA yielded an odds ratio of 4.9 (95% confidence interval: 1.2-19.6, P<0.05), which was the only significant covariate for the incidence of life-threatening ventricular arrhythmias during a mean follow-up of 72 months. Conclusions: Patients with OMI showing episodes of SVT have a high risk for cardiac death because of abnormal repolarization and autonomic regulation. The analysis of MMA-based TWA and HRT can be a useful tool for predicting OMI patients at high risk of arrhythmic events. (Circ J 2009; 73: 2223 -2228

Noninvasive Predictors of Malignant Arrhythmias

“…Also, in agreement with the index report, some strong evidence has suggested that T-wave alterations (based on the modified moving average method, MMA-TWA) and HRT were both independent predictors of cardiac mortality and fatal arrhythmic events in post-MI patients [21,22]. Thus, the adverse effects of derangements in autonomic heart rhythm regulation in post-MI patients represent a real threat [23].…”

T-Wave Alternans and Left Ventricular Wall Thickness in Predicting Arrhythmic Risk in Patients With Hypertrophic Cardiomyopathy

“…Several lines of evidence support the use of TWA as a reliable predictor of VTAs and arrhythmia event-free survival in at-risk populations, including ischemic, non-ischemic dilated cardiomyopathy. [16][17][18][19] Although a few previous studies investigated the contribution of hypertrophic myocardial phenotype and regional structural variation to the genesis of arrhythmia vulnerability, 20,21 these relation-PUNTMANN VO et al…”

Characterization of Repolarization Alternans in the Coronary Artery Disease

“…Repolarization alternans (RA), an electrophysiologic phenomenon consisting on everyother-beat changes of the repolarization morphology (amplitude, shape, and, sometimes, polarity) unaccompanied by gross changes in the heart-cycle length, is generally recognized as a promising electrocardiographic (ECG) predictor of sudden cardiac arrest (SCA; Bloomfield et al, 2006, Chow et al 2006, Ikeda et al, 2006, Klingenheben et al, 2000, Leino et al, 2009, Maeda et al, 2009, Narayan, 2006, Rosenbaum et al, 1994, Sakaki et al, 2009, Salerno-Uriarte et al, 2007, Stein et al, 2008, that is one of the leading causes of death in developed countries (over 300,000 lives per year in the U.S.; Montagnana at al., 2008, Zheng et al, 2001). On the ECG tracing, RA consists of an alternation of either the ST-segment (Nearing et al, 1991, Rosenbaum et al, 1994, or the T-wave, or even the U-wave (Habbab & el-Sherif, 1992).…”

“…Recent investigations on RA rely on automatic detection of microvolt RA from the digital ECG signal by means of specifically designed techniques, among which the spectral method (implemented in the commercial ECG machine CH2000 and Heartwave, Cambridge Heart Inc., Bedford, MA; Smith et al, 1988, Rosenbaum et al, 1994, Rosenbaum et al, 1996, the complex demodulation method (Nearing et al, 1991, Nearing & Verrier, 1993, the modified moving average method (implemented in the commercial ECG machine CASE-8000, GE Medical Systems, Milwaukee, WI; Nearing & Verrier, 2002), the Laplacian likelihood ratio method (Martínez & Olmos, 2005, Martínez et al, 2006, our adaptive match filter method (Burattini et al, 2008, Burattini et al, 2009b and others (Burattini et al, 1999, Martínez & Olmos, 2005. Microvolt RA has been found to be much more common than visible RA (Adachi et al, 1999, Chow et al, 2007, Ikeda et al, 2006, Klingenheben et al, 2000, Narayan et al, 2007, Reddy et al, 1984 and linked to inducible (Narayan and Smith, 2000, Rosenbaum et al, 1994, Smith et al, 1988 as well as spontaneous (Bloomfield et al, 2006, Klingenheben et al, 2000, Maeda et al, 2009, Narayan, 2006, Verrier et al, 2003 ventricular arrhythmias.…”