Electrical Risk Score Beyond the LVEF to Predict SCD
Does an electrocardiogram (ECG) risk score improve the ability to identify individuals at high risk of sudden cardiac death (SCD)?
Multiple ECG parameters were measured from an archived 12-lead ECG recorded up to 2 years prior to cardiac arrest in 522 patients (mean age 65.3 years) with SCD and 736 controls enrolled in the Oregon Sudden Unexpected Death Study, most of whom had coronary artery disease (CAD). A risk score was derived from this analysis and externally validated in the Atherosclerosis Risk in Communities Study.
The ECG parameters that were independently associated with SCD and that were incorporated into the risk score were heart rate, left ventricular (LV) hypertrophy, QRS transition zone, QRS-T angle, QTc, and Tpeak-Tend interval. After adjustment for clinical parameters and LV ejection fraction (LVEF), the presence of ≥4 abnormal ECG parameters was independently associated with SCD (odds ratio [OR], 21.2). In the subgroup of patients with LVEF >35%, the OR was 26.1. In the validation cohort, >4 ECG abnormalities were independently associated with SCD (hazard ratio, 4.8).
An ECG risk score is independently associated with SCD and may be especially useful for risk stratification when the LVEF is >35%.
The results suggest that the ECG risk score described in this study may be clinically useful for identifying patients with CAD who should receive a prophylactic implantable cardioverter-defibrillator despite having an LVEF >35%. However, prospective validation is needed before incorporating the ECG risk score into clinical practice.
Keywords: Arrhythmias, Cardiac, Coronary Artery Disease, Death, Sudden, Cardiac, Defibrillators, Implantable, Electrocardiography, Heart Arrest, Hypertrophy, Left Ventricular, Primary Prevention, Risk, Stroke Volume
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