Clinical cardiac involvement in idiopathic inflammatory myopathies: a systematic review

Background: Idiopathic inflammatory myopathies (IIM) presenting with diffuse skeletal muscular inflammation and cardiac involvement is one of the major causes of clinical deterioration. Our purpose was to observe the frequency of various reported clinical cardiac afflictions, cardiovascular mortality and its most important contributors in the IIM population.

Methods: MEDLINE database was searched from 1977 through 2009. Articles reporting objective evidence of cardiac involvement were assessed. Patients were included if they satisfied Bohan and Peter criteria for definite or probable diagnosis of IIM. The review conforms to the criteria of the new PRISMA statement of preferred reporting items for systematic reviews and meta-analyses.

Results: Thirty-three out of 90 articles reported cardiac data. Twelve were case reports, while 21 articles were either cohort studies or case series. Angina was reported in 7% of cumulative prospective cohort. Dysrhythmias were seen in 31.8% of electrocardiograms. Diastolic dysfunction was the most common echocardiographic finding. Congestive heart failure was reported in 5.6% of the prospective cohort and was the most common cause of death accounting for 21% of total cardiac mortality. Myocarditis was the most common feature in reported pathology literature (38%), followed by focal myocardial fibrosis (22%).

Conclusion: Cardiac involvement is an important cause of morbidity and mortality in patients with IIM. Myocardial fibrosis puts the patient at risk for systolic or diastolic heart failure and dysrhythmias. This review, therefore, suggests the importance of early and comprehensive cardiac evaluation in IIM population. Confirmation of these findings will require prospective studies of consecutive patients with long-term follow-up.