Common Medication Used To Treat Heart Attacks Might Kill Women, New Study Finds

A recent study found that beta blockers, medications that lower blood pressure and heart rate, might not be effective for a large part of the population. Beta blockers are used to treat conditions like hypertension, angina, arrhythmias, heart failure and migraines, and are often prescribed to patients who've had a heart attack to prevent future attacks. 

Shockingly, the study published in the European Heart Journal revealed that women who were treated with beta-blockers after a heart attack and had slight heart damage were prone to getting another heart attack. There was also a high risk of hospitalisation among women for heart failure. They are nearly three times more likely to die compared to women not given the drug.

But an Indian doctor told NDTV that this "is not a blanket statement" and it "should be taken like that". 

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The study was basically a sub-analysis of a large clinical trial called REBOOT (Treatment with Beta-Blockers after Myocardial Infarction without Reduced Ejection Fraction), which studied over 8,000 men and women treated for heart attacks at 109 hospitals in Spain and Italy for nearly four years. It was also published on Saturday in The New England Journal of Medicine and presented at the European Society of Cardiology Congress.

"These findings will reshape all international clinical guidelines on the use of beta-blockers in men and women and should spark a long-needed, sex-specific approach to treatment for cardiovascular disease," senior study author Dr Valentin Fuster, president of Mount Sinai Fuster Heart Hospital in New York City and general director of the National Center for Cardiovascular Investigation in Madrid, said as quoted in the report.

"This was especially true for women receiving high doses of beta-blockers," lead study author Dr Borja Ibanez, scientific director for Madrid's National Center for Cardiovascular Investigation claimed as quoted by CNN.

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"The total number of women in the clinical trial was the largest ever included in a study testing beta-blockers after myocardial infarction (heart attack), so this is a significant finding," said Ibanez, who is also a cardiologist at Madrid's Jimenez Diaz Foundation University Hospital.

Beta blockers help slow down the heart rate, reduce the force of heart contractions and lower blood pressure. This reduces the heart's workload and oxygen demand. They can help prevent subsequent heart attacks and improve cardiac function during recovery.

As per the report by CNN, the findings only applied to women with a left ventricular ejection fraction above 50 per cent, which is considered normal function.

Indian doctor reacts to the study

Dr Dhiman Kahali, Cardiologist, BM Birla Heart Hospital, told NDTV, "This is not a blanket statement which should be taken like that, especially not relevant much to our country."

He said in many countries, including European countries or Japan, China, and the US, heart attacks in about seventy per cent of the population are treated with angioplasty immediately, which salvages a lot of damaged heart muscle. And as a result, the ejection fraction of the heart becomes more than 50 per cent.

"And it is known to us for long that beta blockers are not good in this group of patients. So this is not a new message," he said.

"So these patients above the ejection fraction of 50%, they do not do well with beta blockers. They can develop bradycardia, hypertension, especially with a very high dose of beta blockers."

Explaining his point, Dr Kahali further said that it can't be taken as a "blanket statement" in our country, as in India, very few patients come within the first few hours of a heart attack. Patients often come very late. And as a result, they come with a damaged heart muscle.

"So we know that beta blockers, both in males and females, are very good with patients with heart failure and especially with a heart with reduced ejection fraction below 40 per cent."

"So there is no doubt about it. There is no controversy. There is no confusion regarding it."

"Beta blockers are the mainstay of treatment, and the foundation therapy number one drug in the foundation therapy in this group of patients."

Why do beta-blockers harm women more than men?

Dr Andrew Freeman, director of cardiovascular prevention and wellness at National Jewish Health in Denver, said that the drug can have unpleasant side effects. 

"The drugs can lead to low blood pressure, low heart rate, erectile dysfunction, fatigue and mood swings," said Freeman, who was not involved in the research. "Anytime we use these drugs, we always have to balance risk versus benefit."

"That's actually not surprising," Freeman said. "Gender has a lot to do with how people respond to medication. In many cases, women have smaller hearts. They're more sensitive to blood pressure medications. Some of that may have to do with size, and some may have to do with other factors we have yet to fully understand."

The report also mentioned that early research on the heart focused majorly on men. And how do heart diseases affect women wasn't studied well.