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Year
2007 |
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Viagra good for treating heart ailment
July 12, 2007
Researchers in Edmonton have discovered that Viagra
could save the lives of people with a certain type of heart ailment.
The pill, taken by millions of men for erectile
dysfunction, has now been shown to improve the performance of
diseased right ventricles of the heart. While therapies exist to
treat trouble in the left ventricle, which pumps blood around the
body, there were no treatments for the right side of the heart,
which pumps blood only into the lungs.
"It's weird that medicine, as advanced as it is, has completely
ignored the right chambers," said Evangelos Michelakis, a University
of Alberta Hospital cardiologist and Canada Research Chair specialist
in high blood pressure in the lung.
When the arteries of the lung constrict, the pressure of the blood
inside goes up and puts a strain on the right ventricle of the heart.
Patients experience shortness of breath and fatigue, and their risk
of dying prematurely rises.
"Someone with high blood pressure can live 30 or 40 more years,
but someone with pulmonary hypertension, which is the same but in
the lungs, can only live three to five years."
In a study to be published next week in Circulation, a journal
of the American Heart Association, the U of A Hospital researchers
report on the beneficial impact of Viagra
on the right ventricle, which could add years to patients' lives.
Viagra targets an enzyme called phosphodiesterase Type 5. It is
known to constrict the arteries in the lungs, causing breathing
difficulties, and in the penis, causing impotence. It's now known
that the constricting enzyme can also show up in the right chambers
of the heart, spelling trouble for the patient.
"In a normal heart (the enzyme) is not there, but all of a
sudden it appears once it becomes diseased," said Jayan Nagendran,
a cardiac surgery resident at the U of A. Viagra relaxes the arteries
in the lung, which brings down the blood pressure while the right
chamber of the heart has a chance to strengthen.
Viagra, whose proper name is sildenafil, has been shown to be dangerous
for patients who take nitroglycerine or other forms of nitrates
to treat coronary artery disease. Both Viagra and nitrates dilate
the blood vessels and, in combination, the two drugs can cause extreme
drops in blood pressure.
Research published by the Edmonton team in 2002 found that Viagra
helps to lower blood pressure in the lungs. The drug is now routinely
prescribed to treat this condition, called pulmonary hypertension.
Source : Canada
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