Improved Stratification of Autonomic Regulation for risk prediction in post-infarction patients with preserved left ventricular function (ISAR-Risk)

Abstract

AimsTo investigate the combination of heart rate turbulence (HRT) and deceleration capacity (DC) as risk predictors in post-infarction patients with left ventricular ejection fraction (LVEF) > 30%.Methods and resultsWe enrolled 2343 consecutive survivors of acute myocardial infarction (MI) (<76 years) in sinus rhythm. HRT and DC were obtained from 24 h Holter recordings. Patients with both abnormal HRT (slope ≤ 2.5 ms/RR and onset ≥ 0%) and abnormal DC (≤4.5 ms) were considered suffering from severe autonomic failure (SAF) and prospectively classified as high risk. Primary and secondary endpoints were all-cause, cardiac, and sudden cardiac mortality within the first 5 years of follow-up. During follow-up, 181 patients died; 39 deaths occurred in 120 patients with LVEF ≤ 30%, and 142 in 2223 patients with LVEF>30% (cumulative 5-year mortality rates of 37.9% and 7.8%, respectively). Among patients with LVEF > 30%, SAF identified another high-risk group of 117 patients with 37 deaths (cumulative 5-year mortality rates of 38.6% and 6.1%, respectively). Merging both high-risk groups (i.e. LVEF ≤ 30% and/or SAF) doubled the sensitivity of mortality prediction compared with LVEF ≤ 30% alone (21.1% vs. 42.1%, P < 0.001) while preserving 5-year mortality rate (38.2%).ConclusionIn post-MI patients with LVEF>30%, SAF identifies a high-risk group equivalent in size and mortality risk to patients with LVEF ≤ 30%.

Nonlinear Measures of Heart Rate Variability and Mortality Risk in Hemodialysis Patients

“…DC calculated from short (four beats) overlapping segments is generally used. Currently, abnormal HRT and reduced DC are the most powerful predictors of post-MI mortality (9,10,12,13). Scaling exponents are calculated by detrended fluctuation analysis (11).…”

“…Clinically, three measures have gained recent interest: heart rate turbulence (HRT) quantifying heart rate responses to premature beats (9), deceleration capacity (DC) estimating ability to decelerate heart rate on specific time scales (10), and fractal scaling exponents assessing fractal organization of heart rate regulation based on chaos theory (11). Several studies have indicated that these nonlinear HRV measures have greater predictive power than conventional HRV measures for mortality after myocardial infarction (MI) (12)(13)(14). In hemodialysis patients, the nonlinear measures might have greater discrimination ability than conventional measures, because cardiac vagal dysfunction is almost commonly observed among these patients (15)(16)(17).…”

Electrocardiogram‐Based Predictors of Sudden Cardiac Death in Patients With Coronary Artery Disease

“…41 Another recent prospective study involving 2343 patients following myocardial infarction found that the combination of HRT and deceleration capacity could be used together to identify a high-risk group equivalent in size and mortality to patients with LVEF <30%. 42 In contrast, in a retrospective analysis of 884 patients enrolled in the Multicenter Autonomic Defibrillator Implantation Trial II study, HRT parameters were not found to be predictive of outcome, after adjustment for confounding covariates. 43 However, HRT parameters in this study were obtained from 10-minute ECG recordings, which may have limited the ability to derive accurate HRT data.…”

Noninvasive risk stratification after myocardial infarction: Rationale, current evidence and the need for definitive trials

“…Of the combinations assessed, abnormal TWA combined with impaired BRS or HRT best predicted outcome. The Improved Stratification of Autonomic Regulation for risk prediction (ISAR-Risk) study (72) assessed the utility of adding DC to HRT for risk prediction. They found that this combination identified a subgroup of patients with an LVEF greater than 0.30 at high risk of death, cardiac death and sudden death.…”