A pill prescribed for decades after heart attacks continues to help many patients despite modern treatments that prevent lasting muscle damage, two new studies suggest.
The issue still unsettled is whether all patients benefit equally from beta-blocker drugs, or only some. These medicines are commonly given to nearly every patient following a heart attack.
Conflicting Findings In Madrid
Two large trials delivered sharply different results at a major cardiology congress in Madrid and in the New England Journal of Medicine.
“It is not unusual for studies to disagree,” said Dr Borja Ibanez of the Centro Nacional de Investigaciones Cardiovasculares Carlos III in Madrid, who led one of the trials. “What is unusual is to see two trials with opposing outcomes revealed on the same day.”
Both groups agreed, however, that beta-blockers cut the combined risk of another attack, heart failure, or death in patients without heart failure but with mildly weakened heart function.
The Uncertain Majority
The key question is whether these drugs help people with hearts pumping normally. This group represents around 80% of patients after their first heart attack.
Pharmaceutical makers of beta-blockers include Pfizer, Novartis, Abbott, Teva, Sun Pharma, Lupin, Mylan, Amneal, ANI Pharmaceuticals and Eagle Pharmaceuticals.
These drugs lower heart rate and blood pressure by blocking hormones such as epinephrine and norepinephrine. The result is less stress on the heart and reduced oxygen demand.
Scandinavian Trial Shows Benefit
The BETAMI–DANBLOCK study in Norway and Denmark tracked 5,574 survivors. Patients given beta-blockers were 15% less likely to die or suffer a major cardiovascular event, particularly a repeat attack, compared with those not on the medication.
Southern Europe Trial Finds No Effect
The REBOOT trial in Italy and Spain followed 8,438 patients. It reported no difference in deaths, repeat attacks, or hospital admissions for heart failure between patients who took beta-blockers and those who did not.
Differences may relate to the types of beta-blockers used, or the fact that Scandinavian participants were slightly older and more likely to have mild heart impairment, said Dr Dan Atar of the University of Oslo, who co-led the research.
Adverse Effects In Women
Among women in REBOOT, higher doses of beta-blockers in patients with strong heart function were linked to worse outcomes. Findings were published in the European Heart Journal.
Subgroup Shows Clear Advantage
In both REBOOT and BETAMI–DANBLOCK, patients with a left ventricular ejection fraction between 40% and 49% — indicating mildly reduced function — showed fewer attacks, cases of heart failure, and deaths when given beta-blockers.
This effect was supported when data from both studies were pooled with results from a Japanese trial, published in The Lancet.
What Doctors Should Know
Dr Ibanez concluded: “We can now say with certainty that beta-blockers help patients with mild heart impairment. But there is still doubt about their value for those with fully normal heart function.”
Dr Atar added that further analysis on patients with normal function will be shared at a US cardiology meeting in November.