Abstract 15908: Association of Heart Rate Turbulence, Deceleration Capacity and Morphologic Variability with Sudden Cardiac Death Following Non-ST-Elevation Acute Coronary Syndrome: Results from the MERLIN-TIMI 36 Trial
Background: Electrocardiographic (ECG) parameters such as heart rate turbulence (HRT), deceleration capacity (DC) and morphologic variability (MV) have previously been shown to identify patients at high risk of adverse outcomes following acute coronary syndrome (ACS). We assessed the relationships among HRT, DC and MV and sudden cardiac death (SCD) in a large post-NSTEACS patient population.
Methods: HRT, DC and MV were calculated in 4557 patients from the MERLIN-TIMI 36 trial using the first 24 hours of continuous ECG after randomization. For each measure, patients were partitioned into risk groups using cutpoints chosen from the literature (HRT categories 0 [n=2266], 1 [n=1206] and 2[n=401]; DC categories 0 [n=3024], 1 [n=1126] and 2 [n=407]; low MV [n=3675] and high MV [n=882]).
Results: There were 81 cases of SCD during a median follow-up of one year. Each ECG variable, except HRT category 1, was associated with SCD in univariate and multivariate analyses (Table). The model constructed using the TIMI risk score (AUC=0.65) showed improved discrimination and reclassification of risk for SCD when both DC (AUC=0.67) and MV (AUC=0.69) were added (p<0.03 for NRI and IDI).
Conclusions: ECG parameters may provide supplemental value in risk stratification for SCD in patients post-NSTEACS. These metrics may therefore be clinically useful in identifying patients requiring more intense monitoring or therapy.
- © 2010 by American Heart Association, Inc.