The study's findings have been presented today by lead author Dr Rajeev Pathak, speaking at the American College of Cardiology’s 64th Annual Scientific Session in San Diego.
"This study is the first to track the long-term effects of weight loss and the degree of weight fluctuation on atrial fibrillation," says Dr Pathak, a cardiologist and electrophysiology fellow at the University of Adelaide and PhD student under Professor Prash Sanders in the Centre for Heart Rhythm Disorders.
"Patients who lost more weight and maintained a more stable weight over four years showed marked reductions in atrial fibrillation burden and severity, the study’s primary endpoints," he says.
"In a key finding, obese patients who lost at least 10% of their body weight were six times as likely to achieve long-term freedom from atrial fibrillation compared to those who did not lose weight."
Dr Pathak says weight loss also led to favourable changes in cardiovascular risk factors, such as improvements in blood pressure and the structure and function of the heart, and reductions in obstructive sleep apnoea and diabetes.
Weight and impact on heart rhythm was followed in more than 350 obese patients with atrial fibrillation, with researchers tracking their health annually for an average of four years. To encourage weight loss, the patients' clinic used a motivational, goal-directed approach that initially included in-person visits every three months, detailed dietary guidance, low-intensity exercise, counseling support, and a daily diet and physical activity diary.
After an average of four years, 45% of patients who lost 10% or more of their body weight, and 22% of patients who lost 3-9% of their weight, achieved freedom from atrial fibrillation symptoms without the use of any atrial fibrillation surgery or medication.
"Even with the use of surgery or medication, those who lost more weight were substantially more likely to be cured of atrial fibrillation," Dr Pathak says.
This study is also published today in the Journal of the American College of Cardiology. The investigators have been supported by the National Health and Medical Research Council (NHMRC) and the National Heart Foundation of Australia.