Beta blockers, a group of medicines generally prescribed to heart attack patients, may not increase the chances of survival in patients who have not suffered subsequent heart failure, suggests British research studying 179,810 patients.
Researchers at the UK's University of Leeds investigated whether beta blockers -- drugs which regulate heart activity -- were beneficial to heart attack patients who did not suffer from heart failure, a heart attack complication whereby the heart muscle is damaged and no longer functions properly.
Currently, beta blockers are systematically prescribed after a heart attack on the recommendation of current medical guidelines -- irrespective of whether patients have heart failure -- to lower the risk of further heart attack and abnormal ventricular heart rhythms, helping to prevent a certain number of sudden deaths.
For heart attack patients with heart failure, beta blockers decrease the activity of the heart and lower blood pressure to help the damaged heart work more effectively.
In addition, aspirin (to prevent the formation of new clots), statins (to reduce cholesterol levels) and ACE (angiotensin-converting enzyme) inhibitors (to combat high blood pressure) are also generally prescribed.
The scientists studied data from the UK's national heart attack register for 179,810 patients who suffered a heart attack between 2007 and 2013 but who did not suffer from heart failure. They found that taking beta blockers did not increase the chances of survival one year after the heart attack in patients who had not suffered heart damage (compared to the 9,335 patients who were not prescribed the treatment).
The study also observed that patients who weren't prescribed beta blockers were more frequently comorbid and of higher ischemic risk, such as diabetes (15.4% vs. 11.6%), chronic renal failure (3.2% vs. 1.6%), asthma or chronic obstructive pulmonary disease (20.6% vs. 7.8%), cerebrovascular disease (7.0% vs. 3.8%), and with an intermediate or high Global Registry of Acute Coronary Events risk score (76.5% vs. 69.8%).
One year after hospitalization, 9,373 deaths (5.2% of participants) were recorded, according to the study.
The findings challenge established medical practices and suggest that beta blockers may be being over prescribed.
The study is published in the Journal of the American College of Cardiology.