A woman who suffers sudden cardiac arrest is significantly less likely than a man to exhibit the decrease in the heart's pumping ability that is widely recognized as a precursor, says a new study in the Nov. 24 Journal of the American College of Cardiology.
The lack of left ventricular dysfunction could mean that fewer women meet current medical guidelines for implantable cardiac defibrillators that can prevent sudden cardiac arrest, says the study's lead researcher.
"If 100 men have a sudden death heart attack, 40 of them will show a critical decrease in their heart's pumping function prior to their heart attack," said Sumeet S. Chugh, M.D., associate director of the Cedars-Sinai Heart Institute and holder of The Pauline and Harold Price Chair in Cardiac Electrophysiology Research. "But only 20 women of 100 will have that critically reduced pumping ability. We are able to predict sudden cardiac death in men much better than women, and for a condition that has a 95 percent chance of instantaneous death, prediction is everything."
The study also found that among sudden cardiac arrest victims, far fewer women than men had an established diagnosis of coronary artery disease. The reasons remain to be clarified, but coronary artery disease is the condition most commonly associated with sudden cardiac arrest, and symptoms of heart disease often prompt patients to see their doctors and initiate testing and therapy. The authors suggest, therefore, that the lower prevalence of recognized coronary artery disease may be another barrier impeding women from discovering their risk of sudden cardiac arrest and taking preventive steps.
"Men and women have been treated identically for the prevention of sudden cardiac death," Chugh said. "We cannot continue to do that. We need to find novel ways of predicting sudden cardiac death in women because the predictors used so far are more applicable to men."
Unlike heart attacks (myocardial infarction), which are typically caused by clogged coronary arteries reducing blood flow to the heart muscle, sudden cardiac arrest is the result of defective electrical activity of the heart. Patients may have little or no warning, and the disorder usually causes nearly instantaneous death.
Chugh leads the Oregon Sudden Unexpected Death Study, a comprehensive, 16-hospital, multi-year assessment of cardiac deaths in the 1 million population Portland, Ore. metropolitan area. Funded in part by the National Heart Lung and Blood Institute, the study's goal is to shed light on the risk factors, triggers and genetic defects associated with sudden cardiac death.