Heart Beat August 2011 Issue

Heart Beat: August 2011


Angiotensin receptor blockers (ARBs), a commonly used class of blood pressure medications, do not increase cancer risk, according to a one-year safety review conducted by the U.S. Food and Drug Administration (FDA). The FDA, prompted by a 2010 study that suggested a small risk associated with ARBs, analyzed the data from more than 155,000 patients in 31 randomized clinical trials. ARBs are primarily used to treat hypertension, but also heart failure, cardiovascular risk reduction and diabetic kidney disease. ARBs include valsartan (Diovan), losartan (Cozaar), and irbesartan (Avapro). The FDA, in addition to ruling out an increased cancer risk associated with ARBs, also reminded patients not to stop taking their anti-hypertensive medications without first consulting with their doctors. ARBs work by reducing the presence of a chemical that causes the muscles around blood vessels to constrict, thus narrowing the vessels and increasing blood pressure. ARBs are commonly used to treat hypertension in patients with heart failure and kidney disease, as well as patients with an enlarged heart.


Open-heart aortic valve replacement surgery and a less invasive catheter-based procedure have similar one-year survival rates in high-risk patients. A study presented June 5 at the Transcatheter Valve Therapies meeting found that a ballon-expandable transcatheter valve replacement procedure in patients at high risk for surgery is just as safe and effective as surgery that requires opening up the chest. Transcatheter valve procedures take about 90 minutes, while open heart surgery can take four to six hours. Patients may be classified as high risk for surgery if they are especially frail or have other medical conditions that would put them at great risk if they were on a heart-lung machine. Aortic valve replacement treats severe aortic stenosis, a condition in which the valve restricts blood flow into the bodyís largest artery.


Many patients with hypertension require multiple medications to lower their blood pressure. In some, however, no number of medications does the trick. For these patients, a solution might lie in a small device that emits electrical impulses, tricking the body into thinking blood pressure has spiked and rallying its forces to lower it. In a study of 265 patients with blood pressure readings of 160/80 mm Hg and higher despite three or more hypertension medications, the device produced systolic pressures of 140 mm Hg or less in 41 percent after six months and in 54 percent after 12 months. At the annual meeting of the American College of Cardiology in April 2011, the researchers explained that 88 percent of study participants responded to the device, which produced a 35 mm Hg drop in blood pressure and, they noted, a decrease in the size of the left ventricle, indicating reduced risk of heart failure.


A program of regular exercise proved superior to beta blockers in treating and even curing an unusual heart condition called Postural Orthostatic Tachycardia Syndrome (POTS). The condition, in which a patientís heart is smaller than it should be, is also known as "Grinch Syndrome" after the Dr. Seuss story "The Grinch Who Stole Christmas," which featured a character whose heart was "two sizes too small." A study comparing the effects of exercise and beta blockers was published in the June issue of Hypertension: Journal of the American Heart Association. POTS is characterized by a rapidly increasing heartbeat, particularly when a patient moves from a prone position to standing upright. Lightheadedness can also accompany this condition, which primarily affects women. The exercise program in the study initially had patients exercising in seated position, such as rowing or using a recumbent bike. From there, patients gradually started exercising in an upright position. Researchers noted that regular exercise would have to be maintained by POTS patients for the improved heart function to continue through life.