Regular physical activity combined with structured exercise training has well described benefits for quality of life and mortality in a range of cardiovascular conditions. For individuals with underlying genetic cardiac myopathies there has been concern that exercise training could trigger a potentially fatal event. Thus, there has been caution with recommending exercise training broadly, especially with respect to vigorous intensity exercise and participation in competitive sports. Current recommendations suggest that intensive exercise and competitive sports maybe reasonable for individuals who no not exhibit overt features of dilated cardiomyopathy (DCM).

DCM is characterised by ventricular enlargement and systolic dysfunction in the absence of other contributors such as valvular, hypertensive, congenital or ischaemic causes. The prevalence of DCM is variable with data from Olmsted county suggesting 1 in 2700 individuals are affected by the disease, while more recent data estimate a frequency as high as 1 in 250 individuals.1 Among these cases it is estimated that up to 10%–20% are due to truncating variants in the sarcomeric protein titin (TTNtv). The titin protein is the largest protein in the human body and has a critical role in both the structure and function of striated muscle tissue, which includes both cardiac and skeletal muscles. Titin …