QRS duration—one of several measures of heart function recorded during electrocardiograms—can be a significant predictor of sudden cardiac death, according to a study in the Aug. 17 online edition of European Heart Journal.
Peter Okin, MD, professor of medicine at Weill Cornell Medical College and a cardiologist at the Ronald O. Perelman Heart Institute at NewYork-Presbyterian Hospital/Weill Cornell Medical Center in New York City, and colleagues analyzed data drawn from the LIFE study—an analysis of 9,193 patients with hypertension conducted from 1995 to 2001.
The researchers sought to determine whether QRS duration predicts sudden cardiac death in patients with left ventricular hypertrophy and treated hypertension.
The investigators reported that over 4.8 years of follow-up, 1.9 percent of the patients with electrocardiographic evidence of left ventricle hypertrophy (LVH) who were treated with atenolol- or losartan-based regimens suffered sudden cardiac death.
In multivariable analysis including randomized treatment, changing blood pressure over time and baseline differences between patients with and without sudden cardiac death, Okin and colleagues said that QRS duration was independently predictive of sudden cardiac death (HR per 10 ms increase = 1.22). Baseline QRS duration remained a significant predictor of sudden cardiac death even after controlling for the presence or absence of left bundle branch block (HR = 1.17) and for changes in electrocardiographic LVH severity over the course of the study (HR = 1.16).
"No one has ever really looked at this," said Okin. "Because of the wealth of data collected during the LIFE study, we were able to fine-tune our efforts and control for potential confounders, such as left bundle branch block…. We also controlled for abnormal enlargement of the left ventricle, known as LVH…. Once these variables were controlled for in our analyses, a clear link between abnormal QRS duration and the risk of sudden death emerged."
Okin said that since an increase in QRS duration during an electrocardiogram indicates an increased risk of sudden cardiac death, “we hope that physicians will start paying more attention to QRS duration as a warning signal. If they do, lives could be saved."