Dr. Upasana Tayal
Dilated cardiomyopathy is a heart muscle disease whereby the main pumping chamber of the heart (the left ventricle) becomes bigger and weaker. It affects 1 in 250 people. In the vast majority of cases we don’t know why the heart becomes damaged in the first place. Research has found that abnormalities in a giant gene, called titin, are found in approximately 10-20% of people with the condition.
In research we recently published in the Journal of the American College of Cardiology, we found that these abnormalities in the titin gene are associated with an increased risk of abnormal heart beats (arrhythmias) in patients with dilated cardiomyopathy.
We studied 572 patients with dilated cardiomyopathy who had all had genetic sequencing (to study the titin gene) and MRI scans of the heart (to get detailed information about the structure of their hearts). We also looked at their medical records leading up to the time of their diagnosis.
We found that patients with the abnormal titin gene have a 2.90 fold increased risk of abnormal heart rhythms either before their diagnosis or in the early stages of disease (atrial fibrillation – from the top chamber of the heart or ventricular tachycardia- from the bottom chamber of the heart). Crucially, this was after taking into account all the usual factors that cause abnormal heart rhythms such as being male, being older, or having a more damaged heart to start with.
Going forwards, we now need to figure out if patients with the abnormal titin gene have a higher risk of dangerous heart rhythms in the longer term. If so, we need to know if the risk is of abnormal top chamber (atrial) or bottom chamber (ventricular) arrhythmias, or both. Finally, we also need to understand how the titin gene is linked to the electrical system of the heart. Plenty of questions to keep researchers in this area busy!