Treatment with metoprolol may benefit patients with obstructive hypertrophic cardiomyopathy (HCM), according to a new study published in the Journal of the American College of Cardiology.
According to the authors, their study was the first randomized, double-blind, placebo-controlled trial to evaluate the clinical impact of beta-blockers (BBs) in symptomatic patients with obstructive HCM. The group aimed to examine the impact of metoprolol on left ventricular outflow tract (LVOT) gradient reduction, symptoms, and exercise capacity in obstructive HCM patients.
The analysis included data from 29 patients who were randomly chosen to receive either metoprolol or a placebo at a single facility in Denmark.
Sixty-two percent of patients were male, and the mean patient age was 60 years old.
The authors found that the LVOT gradients were considerably lower at rest, at peak exercise, and five minutes post-exercise during metoprolol treatment compared with treatment with a placebo.
Another key finding was that the proportion of patients in New York Heart Association (NYHA) functional class III or higher was 38% during placebo treatment compared with 14% during metoprolol treatment.
In addition, the proportion of patients in Canadian Cardiovascular Society (CCS) class III or higher was 10% during placebo treatment vs 0% during metoprolol treatment.
Improvements were also seen in patient Kansas City Cardiomyopathy Questionnaire Overall Summary Score Overall Summary Score after metoprolol treatment.
The authors noted, however, that measures of exercise capacity, peak oxygen consumption, and N-terminal pro–B-type natriuretic peptide did not differ between the study groups. Also, certain side effects (fatigue, cold sensation of the hands and feet, diarrhea and tingling of hands or feet) were reported that clinicians should know about.
“The present study provides important clinical information on what to expect when initiating blocking agents (BB) treatment in symptomatic patients with obstructive HCM,” wrote lead author Anne M. Dybro, MD, a cardiologist at Aarhus University Hospital in Denmark, and colleagues. “One intriguing question is whether the beneficial effect of metoprolol outweighs the potential side effects that some patients experience. Our experience from this study suggests that a reasonably high dosage of metoprolol is generally well tolerated, but it is not preferable for all patients.”
Dybro et al. concluded that data from the study support the guideline recommendations that BBs should be the drugs of choice for patients with obstructive HCM who develop symptoms of heart failure.
Read the full study here.
In a related study from August 2021, researchers found that metoprolol may be a safe and effective treatment option for COVID-19 patients diagnosed with acute respiratory distress syndrome. Read more about that analysis here.
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