Obesity cuts risk of sudden cardiac death--study

A surprising new study shows that excess weight has a protective effect on obese patients with heart failure and they fare better than the leaner ones.

Researchers of University of Rochester Medical Center found normal and underweight patients exhibited an astounding 99 percent increase in risk for sudden cardiac death compared to those who were grossly overweight.

Lead author of the study, Ilan Goldenberg, research associate professor of Medicine in the Cardiology Division declared, “This study is important because it not only answers questions regarding the risk of sudden cardiac death in different types of heart failure patients, but poses several new questions that need to be explored.

“Why do obese heart failure patients see a risk advantage? Why do normal weight patients have a significantly different risk profile than those who are slightly overweight? These are important questions that may have treatment implications in the future.”

Link between weight and risk of sudden cardiac death assessed
The researchers at the university’s Heart Research Follow-Up Program conducted a study to investigate the link between weight and risk of sudden cardiac death.

Using advanced analysis methods, the scientists studied the risk death from acute heart failure in 1,231 patients.

All the participants had suffered at least one previous heart attack and were diagnosed with a low ejection fraction, a measure of how much blood is pumped from the heart with each beat.

The researchers found that obesity appeared to protect patients from the risk of sudden cardiac death.

Undoubtedly, obesity is a risk factor for heart disease but once severe heart failure sets in, a paradox occurs by which the overweight heart failure patients fare better than their leaner counterparts.

Bonnie Choy, co-lead author and second year medical student said, “When we started this study we were hoping the data would disprove the obesity paradox.

“Our study is the first to create and analyze subcategories within non-obese patients, looking at overweight, normal and underweight patients, but even with this advanced analysis we still the saw an inverse relationship between BMI and sudden cardiac death.”

Effect of BMI on benefits of implantable cardioverter defibrillator
Additionally, the researchers also assessed the effect of body mass index (BMI) on the potential benefits of implantable cardioverter defibrillator (ICD).

ICD is a small medical device implanted in the chest that detects irregular and potentially fatal heart rhythms (arrhythmias), which often lead to sudden cardiac death, and shocks the heart back into a normal rhythm.

The researchers found ICD therapy is more beneficial in thinner patients who were at higher risk for sudden cardiac death.

Reasons for obesity as protective factor ambiguous
It is not clear why excess weight is a protective factor in heart failure. The researchers speculate that maybe weight problems lead people to earlier diagnosis and better care.

Or it may be that obesity confers some kind of 'metabolic reserve' that helps the heart failure patients.

Eric Hansen, co-lead author said, “Obese patients are hard on their bodies; many don’t eat right, don’t exercise, and many smoke. If their bodies are surviving this bad treatment then perhaps they are better equipped, from a genetic standpoint, to live with heart failure.”

The results were presented at the American College of Cardiology Annual Scientific Session in Atlanta.