CRT Beneficial in Mild Heart Failure
ORLANDO — Cardiac resynchronization therapy improves key clinical outcomes in patients with mild heart failure, a randomized trial has shown.
In the European cohort of the Resynchronization Reverses Remodeling in Systolic Left Ventricular Dysfunction (REVERSE) trial, patients with cardiac resynchronization therapy switched on had a 62% relative risk reduction in the combined end point of heart failure hospitalization or death, compared with those assigned to CRT-off, at 24 months' follow-up, Dr. Cecilia Linde said at the annual meeting of the American College of Cardiology.
Patients with the CRT device turned on also had significantly improved left ventricular function, as reflected in their ejection fraction and end-diastolic and end-systolic volumes. (See box.) All these outcomes combined suggest that reverse ventricular remodeling had occurred, added Dr. Linde, professor of cardiology at Karolinska Hospital, Stockholm.
The follow-up analysis involved 262 patients who underwent implantation of a biventricular pacemaker and were then randomized 2:1 to have CRT switched on or off.
All subjects had New York Heart Association class II or previously symptomatic class I heart failure, a left ventricular ejection fraction of 40% or less, and a wide QRS interval of at least 120 ms. All were on optimal guideline-recommended medical therapy.
The goal of REVERSE was to learn whether heart failure patients who improved with potent medications to the point of being asymptomatic or mildly symptomatic could maintain that status with CRT. The answer, Dr. Linde said, is clearly yes.
There was a 10% major complication rate related to the CRT devices in REVERSE. Lead dislocation, perforation of the coronary sinus, and other complications were concentrated in the left ventricular lead during the first year and the right lead in year 2.
The 12-month REVERSE results, presented last year, showed only a nonsignificant trend favoring better outcomes in the CRT-on group. Why the difference a year later? “It takes time to have an effect in patients with asymptomatic or mildly symptomatic heart failure, so of course when you follow patients for 24 months you're going to find more than if you follow them for 12 months,” she observed.
Today CRT is indicated in clinical practice for patients with class III or ambulatory class IV heart failure. Dr. Linde predicted that if the new REVERSE findings are confirmed in the much larger ongoing Automatic Defibrillator Implantation With Cardiac Resynchronization Therapy (MADIT-CRT) trial and Rythmol SR Atrial Fibrillation Trial (RAFT), as she expects, the indications for CRT will broaden to incorporate the large population of patients with class I and II heart failure.
Dr. Jean-Claude Daubert of the REVERSE steering committee noted that since most patients were asymptomatic or mildly symptomatic at entry, there was little room for functional or symptomatic improvement.
“We suspect that to show functional benefit we'll need a much longer follow-up,” said Dr. Daubert, professor of cardiology at Central University Hospital, Rennes, France.
REVERSE was sponsored by Medtronic Inc. Dr. Linde and Dr. Daubert serve as consultants to, and are on the speakers bureaus for, Medtronic and St. Jude Medical.
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