Protein Discovery Explains Why Sudden Cardiac Arrest Tends To Occur In The Morning

Sudden cardiac arrest -- when your heart stops functioning because of an electrical disturbance, which can lead to death if not treated immediately with CPR or defibrillation -- is known to occur more often between the hours of 6 a.m. and 10 a.m. But why?

According to new research, it could have something to do with levels of a protein called KLF15, which regulates electrical activity in the heart.

Dr. Mukesh Jain, M.D., of Case Western Reserve University, and colleagues found that people with heart failure tend to have low levels of this protein. Plus, they found in mice that this protein seems to be the link between circadian rhythm -- the body's internal clock -- and sudden cardiac arrest.

"Sudden cardiac death due to this electrical instability causes an estimated 325,000 deaths annually in the United States alone," Jain said in a statement. "That includes the three out of four heart disease deaths in people aged 35-44. In all too many cases, there is no second chance. The first event is the last event. Our research points the way toward possible ways of easing that toll -- new drugs that could reduce that risk, for example."

The research was presented at the annual meeting of the American Chemical Society; because it has yet to be published in a peer-reviewed journal, the findings should be considered preliminary.

Now, Jain is looking for a potential drug that could raise levels of KLF15, to see if doing so could help to prevent sudden cardiac arrest.

Right now, preventive options for sudden cardiac arrest include lifestyle changes (like eating a nutritious diet, exercising, and not smoking or drinking excessively) and taking doctor-recommended medications for heart risk factors like high cholesterol. Anti-arrhythmic drugs or an implantable cardioverter-defibrillator may also be recommended as a preventive measure for people known to be at high risk for the condition, according to the Mayo Clinic.

Once sudden cardiac arrest occurs, it can kill in just minutes if CPR or a defibrillator -- which shocks the heart back into rhythm -- are not used, the National Heart, Lung and Blood Institute reported.