Table 2.
Main studies evaluating the role of dynamic ventricular repolarization measures in predicting arrhythmic and non arrhythmic events
| Ref. | Clinical setting | Number of patients | Parameter evaluated | Cut-off suggested | End-points (mean follow-up) | Results |
| Chevalier et al[46], 2003 | Acute myocardial infarction | 265 | QT dynamicity and HRV (24-h Holter) LVEF Late potential | QTe slope: 0.18 | Sudden death and total mortality (follow-up 81 ± 27 mo) | Increased diurnal QTe dynamicity independently associated with sudden death |
| Haigney et al[47], 2004 | Postinfarction patients (low LVEF) | 871 | QT variability (QTVN) QTVI (QTVN adjusted for heart rate variance) | Arrhythmic events (VT or VF) (follow-up 2 yr) | Increased QT variability associated with an increased risk for VT/VF | |
| Jensen et al[48], 2005 | Postinfarction patients | 481 | QT/RR slope and intercept QT/RR VR LVEF VPB and VT | All-cause mortality (follow-up 3 yr) | VR, LVEF, VPB and age made up the optimal Cox model for risk stratification. VR was a promising risk factor for identifying sudden arrhythmic death | |
| Iacoviello et al[49], 2007 | NIDCM (no history of SVT/VF) | 179 | QTe slope (24 h Holter) LVEF NSVT QRS duration QTc and QTd at ECG | QTe-slope: 0.19 | Major arrhythmic events, (VT or VF or SCD) (follow-up 39 ± 22 mo) | Increased QTe slope is associated with occurrence of major arrhythmic events. The presence of NSVT and/or QTe slope > 0.19 showed 90% sensitivity and 60% specificity in identifying patients with arrhythmic events |
| Cygankiewicz et al[50], 2009 | CHF patients. IDCM/NIDCM LVEF ≥ 35% | 294 | QTe slope SDNN TS LVEF | QTe slope: 0.21 | Primary endpoint: total mortality Secondary endpoint: sudden death (follow-up 44-mo) | Combination of SDNN, TS, and QTe slope is a predictor of increased risk of mortality and sudden death |
BRS: Baroreflex sensitivity; CHF chronic heart failure; EPS Electrophysiological study; ICD Implantable cardioverter defibrillator; IDCM: Ischemic dilated cardiomyopathy; HR Heart rate; HRV: Heart rate variability; LVEF: Left ventricular ejection fraction; MCE: Major cardiac events; NIDCM: Non ischemic dilated cardiomyopathy; NSVT: Non sustained ventricular tachycardia; OHR: Onset heart rate; QTc: QT interval corrected for heart rate; QTe: QT interval calculated at the end of T-wave; SCD: Sudden cardiac death; SDNN: Standard deviation of RR intervals; SR: Sinus rhythm; TS: Turbulence slope; PVB: Premature ventricular beats; VT: Ventricular tachycardia; VR: Variability ratio.