Open AccessECG Morphological Variability in Beat Space for Risk Stratification After Acute Coronary Syndrome
Author(s) -
Liu Yun,
Syed Zeeshan,
Scirica Benjamin M.,
Morrow David A.,
Guttag John V.,
Stultz Collin M.
Publication year - 2014
Publication title -
journal of the american heart association
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.494
H-Index - 85
ISSN - 2047-9980
DOI - 10.1161/jaha.114.000981
Subject(s) - medicine , cardiology , ejection fraction , timi , myocardial infarction , heart failure , heart rate variability , acute coronary syndrome , hazard ratio , coronary artery disease , heart rate turbulence , electrocardiography , thrombolysis , heart rate , blood pressure , confidence interval
Background Identification of patients who are at high risk of adverse cardiovascular events after an acute coronary syndrome ( ACS ) remains a major challenge in clinical cardiology. We hypothesized that quantifying variability in electrocardiogram ( ECG) morphology may improve risk stratification post‐ ACS . Methods and Results We developed a new metric to quantify beat‐to‐beat morphologic changes in the ECG : morphologic variability in beat space ( MVB ), and compared our metric to published ECG metrics (heart rate variability [ HRV ], deceleration capacity [ DC ], T‐wave alternans, heart rate turbulence, and severe autonomic failure). We tested the ability of these metrics to identify patients at high risk of cardiovascular death ( CVD ) using 1082 patients (1‐year CVD rate, 4.5%) from the MERLIN ‐ TIMI 36 (Metabolic Efficiency with Ranolazine for Less Ischemia in Non‐ ST ‐Elevation Acute Coronary Syndrome—Thrombolysis in Myocardial Infarction 36) clinical trial. DC , HRV/low frequency–high frequency, and MVB were all associated with CVD (hazard ratios [HRs] from 2.1 to 2.3 [ P <0.05 for all] after adjusting for the TIMI risk score [ TRS ], left ventricular ejection fraction [ LVEF ], and B‐type natriuretic peptide [ BNP ]). In a cohort with low‐to‐moderate TRS (N=864; 1‐year CVD rate, 2.7%), only MVB was significantly associated with CVD (HR, 3.0; P =0.01, after adjusting for LVEF and BNP ). Conclusions ECG morphological variability in beat space contains prognostic information complementary to the clinical variables, LVEF and BNP, in patients with low‐to‐moderate TRS . ECG metrics could help to risk stratify patients who might not otherwise be considered at high risk of CVD post‐ ACS .