Exercise-induced right ventricular cardiomyopathy in an endurance cyclist: a case report

Background

The wide-ranging benefits of frequent and moderate exercise are well recorded in the literature. Chronic deleterious remodelling in response to exercise is less well described. We describe an amateur endurance cyclist who, in addition to developing a heart failure syndrome and electrocardiographic evidence of arrhythmia, also developed severe functional tricuspid regurgitation.

Case summary

After developing palpitations during long distance cycle rides as part of his fitness regimen, a 69-year-old male presented to emergency services but was discharged. While continuing to enjoy long-distance cycling, he began to develop peripheral swelling and presented for a second time to hospital. Subsequent investigation found he had a dilated right heart, exercise-induced arrhythmia, and mid-wall myocardial fibrosis. A diagnosis of exercise-induced cardiomyopathy was made. He was managed with diuretics and immediate cessation of exercise. His symptoms improved and he remains symptom free.

Discussion

The volume of blood passing through the right heart increases during exercise. In vulnerable individuals undertaking frequent endurance exercise, this can promote structural remodelling and fibrotic change. It is unclear if cessation of exercise can reverse the remodelled heart. There are some early advances in predictive biomarkers and imaging techniques in categorizing those in the population who would be at risk of developing this cardiomyopathy, and those who can undergo intense exercise regimens without concern. If those at risk of developing an exercise-induced cardiomyopathy can be accurately identified, the next dilemma is how can their risk of heart failure or sudden death be acceptably minimized.

Acute and Chronic Response to Exercise in Athletes: The "Supernormal Heart"

During last decades, most studies have examined the exercise-induced remodeling defined as "athlete's heart". During exercise, there is an increased cardiac output that causes morphological, functional, and electrical modification of the cardiac chambers. The cardiac remodeling depends also on the type of training, age, sex, ethnicity, genetic factors, and body size. The two main categories of exercise, endurance and strength, determine different effects on the cardiac remodeling. Even if most sport comprise both strength and endurance exercise, determining different scenarios of cardiac adaptation to the exercise. The aim of this paper is to assemble the current knowledge about physiologic and pathophysiologic response of both the left and the right heart in highly trained athletes.

Relationship between arrhythmogenic right ventricular dysplasia and exercise

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is rare cardiomyopathy associated with life-threatening arrhythmias and increased risk of sudden cardiac death. In addition to mutations in desmosomal genes, environmental factors such as exercise have been implicated in the pathogenesis of the disease. Recent studies have shown that exercise may be associated with adverse outcomes in ARVD/C patients. Based on current evidence, ARVD/C patients are recommended to limit exercise irrespective of their mutation status. In addition, some studies have suggested the presence of an entirely acquired form of the disease caused by exercise that has been dubbed exercise-induced ARVD/C.