3-10-99
Metoprolol CR/XL Randomized Intervention Trial in 
Heart Failure (MERIT-HF)

	The model of CHF treatment has shifted in 
the past decade to a neurohormonal theory, supporting 
ACE inhibitors, Aldactone, and beta-blockers. Two 
large beta-blocker trials using carvedilol and 
busoprolol showed a significant 30-40% mortality 
reduction with these drugs.
	Another beta-blocker study using metoprolol 
CHF patients has recently been completed by Dr. Ake
Hjalmarson from Sahlgrenska University Hospital in 
Sweden. This study was a randomized, double-blind 
trial of 3991 patients in Europe and the USA, 
comparing metoprolol with placebo. The primary 
endpoint was death at 1 year.
	1990 patients were in the metoprolol group and
2001 in the the placebo group. The average age was 64 
years. 77% were men. Average EF was 28%. 65% had CAD, 
48% had a previous heart attack, 44% had high blood 
pressure and 25% had diabetes mellitus.
	The starting dose of metoprolol was 12.5-20mg.
The low starting doses went up every week, when 
tolerated, to final dose of 100-200mg per day, with 
an average dose of 159mg per day. When cause of death 
was analyzed, patients were more likely to die of CHF 
than sudden death in Class 4 patients (56% vs 33%). 
Class 2 patients were more likely to die of sudden 
death than CHF (12% vs 64%).
	RESULTS: There was significantly less 
mortality in the metoprolol group (7%) than the placebo
group (11%) at one year. This is a 34% relative risk
reduction. There was also a 38% relative risk reduction
in cardiovascular death, a 41% relative risk reduction in
sudden death, and a 49% relative risk reduction in CHF.
The benefits of metoprolol were found in all patients, 
regardless of heart class, EF, sex or ischemic heart 
disease.
	CONCLUSION: Metoprolol provided a 34% relative
reduction in mortality to CHFers, which is similar to 
earlier Coreg and busoprolol trials. Metoprolol had a 
good safety profile. However, one important limit of the 
trial is that few Class 4 patients were studied. It is 
also unclear which beta-blocker is best, since there 
have been no comparative trials. One advantage of 
metoprolol is that it is less expensive than Coreg.