Virginia Commonwealth University researchers have revealed that erectile dysfunction drugs may be more effective than nitroglycerin in protecting the heart from damage before and after a severe heart attack.

During a heart attack, the heart is deprived of oxygen, which can result in significant damage to heart muscle and tissue. After the attack, most patients require treatment to reduce and repair the damage and improve their chances of survival. With the exception of early reperfusion, there are no available therapies that are truly effective in protecting or repairing such damage clinically.

Rakesh C Kukreja, Ph.D., professor of medicine and Eric Lipman Chair of Cardiology at VCU, and colleagues compared nitroglycerine with two erectile dysfunction drugs -- Viagra, generically known as sildenafil, and Levitra, generically known as vardenafil -- to determine the effectiveness of each for heart protection following a heart attack.

Nitroglycerin is a drug used to treat angina, or chest pain. It is a vasodilator and opens blood vessels in order to improve the flow of blood to a patient's heart.

The research team reported that in an animal model, sildenafil and vardenafil reduce damage in the heart muscle when given after a severe heart attack. In contrast, nitroglycerin failed to reduce the damage in the heart when administered under similar conditions.

"Erectile dysfunction drugs can prevent damage in the heart not only when given before a heart attack, as we discovered previously, but also lessen the injury after the heart attack," said Kukreja, who is the lead author of the study.

According to Kukreja, the protective effects on the heart produced by these erectile dysfunction drugs may be potentially useful as adjunct therapy in patients undergoing elective procedures, including coronaryartery bypass graft, coronary angioplasty or heart transplantation. In addition, he said another potential application could be to prevent the multiple organ damage that occurs following cardiac arrest, resuscitation or shock.

"Preserving heart function is critical to optimal cardiac outcomes," said George W Vetrovec, MD, chair of cardiology at the VCU Pauley Heart Center.

"These agents have significant potential to enhance patient outcomes, particularly in high risk circumstances, such as acute heart attacks," Vetrovec added.

For several years, Kukreja and his colleagues have studied a class of erectile dysfunction drugs known as phosphodiesterase-5 inhibitors as part of ongoing research into heart protection. The team first investigated sildenafil, and then vardenafil, and found that both compounds were protective when given before a heart attack under experimental conditions.