Duration of QRS Complex in Resting Electrocardiogram Is a Predictor of Sudden Cardiac Death in Men
Is QRS duration an independent predictor of sudden cardiac death (SCD)?
The subjects of this study were 2,049 randomly-chosen men in Finland between the ages of 42 and 60 years (mean age 53 years) who underwent clinical evaluation, including an electrocardiogram. The subjects were enrolled in 1984-1989 and SCDs were tabulated at the end of 2008.
There were 156 SCDs during a mean follow-up of 19.1 years. The independent predictors of SCD were QRS duration, smoking, exercise capacity, prior myocardial infarction, type 2 diabetes, systolic blood pressure, body mass index, and left ventricular fractional shortening by echocardiography. Both in the presence and absence of bundle branch block, each 10 ms increase in QRS duration was associated with a 27% higher risk of SCD. QRS duration was not a predictor of non-SCD.
The authors concluded that QRS duration is an independent predictor of SCD.
It is possible that widening of the QRS is related to fibrosis in the His-Purkinje system and that the fibrosis also affects the ventricular myocardium. Fibrosis can predispose to ventricular tachycardia/fibrillation, perhaps explaining why QRS widening was found to be a predictor of SCD.
Keywords: Myocardial Infarction, Body Mass Index, Finland, Diabetes Mellitus, Smoking, Echocardiography
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