A genetic cause of increased heart rate has been found

Scientists have found genetic variants linked to cardiovascular disease.

Northwestern Medicine researchers have identified 68 previously unknown genetic variants that contribute to increased resting heart rate (RHR). They did a full-genome meta-analysis of 99 studies covering 835,365 people from the UK Biobank and the International Consortium for Resting Heart Rate (IC-RHR) datasets.

"This is the largest study of its kind to date," said Marilyn Cornelis, study co-author and assistant professor of preventive medicine at Northwestern University.

Overall, the researchers found 493 genetic variants at 352 loci, with cardiovascular tissue being the primary site of variant effects on gene expression. Expression of the HR gene was highest in ventricular and atrial cardiomyocytes, the transverse striated muscle cells of the heart that are responsible for cardiac contractions.

A meta-analysis linked genetic high HR to a higher risk of dilated cardiomyopathy, in which enlarged heart chambers lose their ability to contract. This can lead to blood clots, arrhythmias and chronic heart failure.

However, the study also showed an inverse association between high HR and other cardiovascular diseases such as atrial fibrillation, ischemic stroke and cardioembolic stroke.

The researchers also found no association between genetic variants and increased mortality.

According to the American Heart Association, a "normal" heart rate is 60-100 beats per minute, with anything above that level increasing the risk of cardiovascular disease.

The study was published in the journal Nature Communications.