Measurement is inexpensive, simple to perform, yields instant result, study says
TUESDAY, June 10 (HealthDay News) -- Hospitalized heart failure patients who have a longer than normal QRS duration (a measurement of the electrical conducting time of the heart on an electrocardiogram) appear to have a high risk of death or rehospitalization, U.S. researchers report.
They analyzed data from 2,962 patients hospitalized for heart failure who had a left ventricular ejection fraction (LVEF -- a measure of how well the left ventricle of the heart pumps with each contraction) of 40 percent or less. Of those patients, 1,641 had a normal QRS duration (less than 120 ms) and 1,321 had a prolonged QRS duration (120 ms or greater).
During follow-up of 9.9 months, 678 of the patients died, including 1,641 patients (18.7 percent) with normal QRS duration and 371 patients (28.1 percent) with prolonged QRS duration. Rates of cardiovascular death or rehospitalization for heart failure were 32.4 percent for patients with normal QRS and 41.6 percent for those with prolonged QRS duration.
After they adjusted for a number of variables, the researchers concluded that patients with prolonged QRS duration were 24 percent more likely to die and 28 percent more likely to suffer cardiovascular-related death or rehospitalization for heart failure than those with normal QRS duration.
The study appears in the June 11 issue of the Journal of the American Medical Association.
"In this analysis, a prolonged QRS duration was present in 45 percent of patients admitted with heart failure, and reduced LVEF, did not appear to significantly change during hospitalization, and was independently associated with high post-discharge mortality and readmission rate. This high morbidity and mortality was observed even though patients were well-treated with standard medical therapy that included beta-blockers and angiotensin-converting enzyme [ACE] inhibitors or angiotensin II receptor blockers [ARBs]," wrote the researchers from the Northwestern University Feinberg School of Medicine in Chicago.
"Measurement of the QRS duration on an ECG has significant advantages as a tool in the clinical setting. It is relatively inexpensive, simple to perform, and yields an instant result. The measurement is objective and does not require specialized training to interpret. In addition, the QRS duration is stable in the majority of patients during the course of their hospitalization. Perhaps most important, a prolonged QRS duration becomes a potential target for intervention [with existing therapy], which may improve post-discharge mortality and morbidity," the researchers wrote.
The American Heart Association has more about heart failure.
-- Robert Preidt
SOURCE: Journal of the American Medical Association, news release, June 10, 2008
All rights reserved