Heart disease is the leading killer of Americans, but many are still able to survive heart attacks. What determines who is able to overcome an attack and who succumbs? A team of researchers from the Wake Forest Baptist Medical Center report in the British Medical Journal’s Health that they may have an answer. They identified a common set of risk factors that separate those who experience sudden cardiac death from those who have heart attacks.
Sudden cardiac death occurs when the heart suddenly and unexpectedly stops beating, which in turn prevents blood from flowing to the brain and essential organs, causing death within minutes. It differs slightly from a heart attack, during which blood flow to part of the heart is blocked.
“Since sudden cardiac death usually occurs before patients ever make it to the hospital, there is very little that can be done to save them,” said Dr. Elsayed Z. Soliman said. “Identifying specific predictors that separate the risk of sudden cardiac death from that of non-fatal or not immediately fatal heart attacks would be the first step to address this problem, which was the basis for our study.”
Heart attack and heart disease are both risk factors for sudden cardiac death, but now researchers have identified some additional characteristics that will help doctors to know which people are at greater risk of dying suddenly from heart problems. Using data culled from 18,497 participants in two longitudinal studies, the ARIC (Atherosclerosis Risk in Communities) and the CHS (Cardiovascular Health Study), the scientists found several correlations that helped predict risk of sudden cardiac death — and others that helped predict the likelihood of coronary heart disease. It’s important to remember these associations are not causal — meaning their presence doesn’t mean cardiac death is inevitable, nor does it mean that people without the risk factors are protected from dying suddenly of heart failure. Many of the risk factors could be markers for other, hidden factors like overall lifestyle, access to health care and health insurance or chronic illness.
Still, the factors may help doctors and patients to identify those who might be at higher risk of dying from heart events, and motivate them to pay special attention to keeping their hearts healthy. Here’s what the researcher found:
Ethnicity Black patients were more likely than non-black patients to die of a heart attack before reaching hospital, but they were less likely to have heart disease.
Blood Pressure Having high blood pressure, or hypertension along with an increased heart rate were strong predictors of sudden death.
Body Mass Index (BMI) An extremely high BMI or a low one — being morbidly obese or significantly underweight — was associated with a bigger risk of sudden death, but not an increased risk of coronary heart disease.
ECG Report. Several measures of heart health such as the heart’s beating rhythm can be assessed using an electrocardiograph (ECG) test. Abnormal results on this test were among the strongest predictors of sudden cardiac death, including aberrantly inverted T-waves.
The good news is that many of these risk factors, such as weight and blood pressure, can be changed. So the researchers said that their next step will be to study whether or not modifying these factors by having patients lose weight or lower their blood pressure, will have a preventative effect.
“We need to know if lowering hypertension, BMI or resting heart rate would reduce the risk of dying suddenly,” Soliman said. If that’s true, the combination of the risk profile his group found along with treatments to address them could save many of the estimated 230,000 and 325,000 people who die of sudden cardiac death each year.
