Primary myocardial involvement in systemic sclerosis: evidence for a microvascular origin.

Systemic sclerosis (SSc) is a connective tissue disease characterised by widespread vascular lesions and fibrosis of the skin and internal organs. Cardiac involvement is recognised as a poor prognostic factor when clinically evident. Primary myocardial involvement is common in SSc. Increasing evidence strongly suggests that myocardial involvement is related to repeated focal ischaemia leading to myocardial fibrosis with irreversible lesions. Reproducible data have shown that this relates to microcirculation impairment with abnormal vasoreactivity, with or without associated structural vascular abnormalities. Consistently, atherosclerosis and macrovascular coronary lesions do not seem to be increased in SSc. Myocardial involvement leads to abnormal systolic and diastolic left ventricular dysfunction and right ventricular dysfunction. Sensitive and quantitative methods have demonstrated the ability of vasodilators, including calcium channel blockers and angiotensin converting enzyme inhibitors, to improve both perfusion and function abnormalities further emphasising the critical role of microcirculation impairment. Recent quantitative methods such as tissue Doppler echocardiography and magnetic resonance imaging have underlined these results.