Factors easily measured on an electrocardiogram (ECG) predict outcomes among patients with atrial fibrillation, two studies showed.
Among participants in two atrial fibrillation trials, resting heart rate, QRS duration, PR interval, and correct QT interval were all associated with mortality or hospitalization outcomes for ECGs conducted in atrial fibrillation or sinus rhythm, Jason Andrade, MD, of the Montreal Heart Institute, reported at the Canadian Cardiovascular Congress in Toronto.
"Our studies offer a means to identify patients at increased risk of adverse 'hard' cardiovascular outcomes using a group of simple parameters easily recognized on a simple 12-lead surface ECG," Andrade said in an email to MedPage Today, noting that the strength of the results was surprising.
The identification of high-risk individuals using these parameters "has the potential to significantly alter the way these patients are cared for," he said. "Ideally, targeted interventions could be undertaken with a goal to alter their adverse clinical course."
Previous studies have suggested, although not definitively, that findings on a resting ECG are independently associated with poor outcomes in patients with and without a history of known cardiovascular disease, but the analyses have not focused specifically on patients with atrial fibrillation, for whom there is a lack of validated risk stratification tools.
To explore the issue, Andrade and his colleagues performed two post hoc analyses of combined data from the AFFIRM and AF-CHF trials, which included 5,436 patients with a history of non-permanent atrial fibrillation. One analysis looked at resting heart rate and the other looked at other ECG parameters.
A higher baseline heart rate in sinus rhythm — but not in atrial fibrillation — was associated with a greater risk of cardiovascular death and all-cause death.
Compared with patients with a baseline heart rate of less than 56 beats per minute (bpm), those with a heart rate of more than 73 bpm had about twice the risk of cardiovascular mortality and all-cause mortality during follow-up.
31/10/2012 : By Todd Neale / MedPage Today
Medically Reviewed by Robert Jasmer, MD.
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