Inflammatory cardiomyopathy: A review and meta-analysis of pathophysiology, diagnosis and clinical management

Inflammatory cardiomyopathy (ICM) is a serious long-term sequelae of myocarditis (MC), defined as the inflammation of the heart muscle accompanied by cardiac dysfunction. Definitive diagnosis of ICM remains a challenge due to the lack of pathognomonic clinical signs and symptoms, as well as the disease mimics a variety of other non-inflammatory myocardial diseases. The disease has multiple aetiologies including infectious, autoimmune, drugs and toxins. Diagnosis relies on histological, immunological, immunohistochemical and molecular findings of infectious causes and the evidence of cardiac dysfunction. Whereas endomyocardial biopsy is the diagnostic gold standard for MC and ICM as well as distinguishes aetiological forms, its use in routine clinical setting is infrequent. The result is the lack of certainty in the epidemiological impact and the natural history of ICM. Moreover, ICM may resolve spontaneously, recur or become chronic leading to death or the need for cardiac transplantation. Traditional diagnosis based on the Dallas Criteria considered MC a relatively rare cause of ICM, HF and sudden cardiac death. However, the recent use of highly sensitive immunohistochemical and molecular tools applied to EMB together with advances in non-invasive imaging modalities suggest the prevalence of the MC and ICM could be much higher than previously estimated. Therefore, the present study reviews published literature on the epidemiology, aetiology, pathophysiology, diagnosis and clinical management to broaden understanding of this potentially treatable but life-threatening disease entity.