PVCs precede heart failure in older adults

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 - Heart Failure - Don't use until 3/1/12

Older adults who experienced frequent premature ventricular contractions (PVCs) had an increase in incident heart failure and mortality, according to an analysis of a community-based cohort study published online in the July 14 issue of  Journal of the American College of Cardiology.

The study included people who had a normal ejection fraction based on echocardiography and no history of heart failure at baseline. All patients underwent 24-hour Holter monitoring.

Previous research has shown people with heart failure with frequent PVCs who underwent ablation had improvements in their disease. Gregory M. Marcus, MD, a study author and electrophysiologist from the University of California, San Francisco, said it was common to see PVCs when patients undergoing Holter monitoring. However, people with more PVCs in this study appeared to be at higher risk of heart failure.

“PVCs clearly preceded the decline in ejection fraction and the heart failure,” Marcus told  Cardiovascular Business. “It doesn’t prove causality, but it proves those PVCs predict heart failure. Prediction doesn’t necessarily mean cause, but even if those PVCs didn’t cause heart failure, that’s still potentially valuable information because if you could identify the people ahead of time who were destined to develop heart failure, you might intervene with other therapies.”

If doctors find frequent PVCs on Holter monitoring in asymptomatic patients with a normal ejection fraction, Marcus said the best course of action remained unclear. Some electrophysiologists are now performing surveillance echocardiograms every year to monitor the patients.

In this analysis, the researchers examined 1,139 participants in the Cardiovascular Health Study, which included people who were at least 65 and were Medicare beneficiaries when they enrolled in 1989 or 1990.

At baseline, patients underwent a physical examination, laboratory testing, 12-lead electrocardiography and medical history. For the next 10 years, they had annual clinic visits and semi-annual telephone interviews. They then had telephone contact every 6 months.

This analysis included the participants who were randomly assigned to 24-hour Holter monitoring. They were excluded if they had normal left ventricular ejection fraction or had prevalent coronary heart failure. They had 2D echocardiography, 2D targeted M-mode and Doppler imaging at baseline.

After a median 22.2 hours of Holter monitoring, PVCs accounted for 0.011 percent of all heartbeats. Three participants had atrial fibrillation and 63 had ventricular tachycardia (VT), although VT was not sustained in any of the adults.

At a median follow up of 13.7 years, 27 percent of participants developed congestive heart failure. Adults in the upper quartile of PVC frequency had a three times greater risk of a decrease in LVEF, a 48 percent increased risk of congestive heart failure and a 31 percent increased risk of death compared with participants in the lowest quartile.

Marcus said the results suggested giving patients with a large number of PVCs beta-blockers or having them undergo ablation therapy to possibly help prevent heart failure. Currently, those therapies are reserved for symptomatic patients or patients who already have heart failure, so electrophysiologists are not typically prescribing medications or performing ablations for asymptomatic patients who have a normal ejection fraction.

“Our study by itself is not sufficient to change that practice,” Marcus said. “We need to identify who are the patients at highest risk. We don’t know whether this is causal or not. However, I do think this study in addition to work from others, justifies such research to answer those questions.”