Obesity has long been identified as a risk factor for cardiovascular disease and heart failure. But, a new study conducted by researchers at the University of Rochester Medical Center found to be the contrary.

Non-obese heart failure patients - including overweight, normal and underweight patients - had a 76 percent increase in risk of sudden cardiac death compared to obese heart failure patients.

Normal and underweight patients showed a startling 99 percent increase in risk for sudden cardiac death compared to obese patients.

The researchers at the University's Heart Research Follow-Up Program in their analysis found that decreased BMI or body mass index was associated with a large increase in the risk of sudden cardiac death. These findings reaffirm the obesity paradox, a phenomenon long recognized by cardiologists that, once afflicted, obese heart failure patients fare better than their slimmer counterparts.

In addition to evaluating the relationship between BMI and sudden cardiac death, researchers assessed the effect of BMI on the benefit of implantable cardioverter defibrillator (ICD) therapy.

An implantable cardioverter defibrillator is a medical device about the size of a pager that is surgically implanted in the chest under local anesthesia. The device detects irregular and potentially fatal heart rhythms (arrhythmias), which often lead to sudden cardiac death, and shocks the heart back into a normal rhythm.

Researchers found that implantable cardioverter defibrillator therapy was more effective in the non-obese patients with lower BMI values who were at higher risk for sudden cardiac death. These findings may help identify patients who would get the most benefit from an ICD - patients with a lower BMI.

Sudden cardiac death claims up to 330,000 American lives every year, accounting for about half of all cardiac deaths. Sudden cardiac arrest, a condition in which the heart suddenly and unexpectedly stops beating, leads to sudden cardiac death if it is not treated within minutes. Most cases of sudden cardiac arrest are due to abnormal heart rhythms that can result from blockage of coronary arteries or scarring from a prior heart attack. Certain drugs can also trigger abnormal rhythms and death.

Medicine