Myocarditis and Chronic Inflammatory Cardiomyopathy, from Acute Inflammation to Chronic Inflammatory Damage: An Update on Pathophysiology and Diagnosis

Abstract

Acute myocarditis covers a wide spectrum of clinical presentations, from uncomplicated myocarditis to severe forms complicated by hemodynamic instability and ventricular arrhythmias; however, all these forms are characterized by acute myocardial inflammation. The term “chronic inflammatory cardiomyopathy” describes a persistent/chronic inflammatory condition with a clinical phenotype of dilated and/or hypokinetic cardiomyopathy associated with symptoms of heart failure and increased risk for arrhythmias. A continuum can be identified between these two conditions. The importance of early diagnosis has grown markedly in the contemporary era with various diagnostic tools available. While cardiac magnetic resonance (CMR) is valid for diagnosis and follow-up, endomyocardial biopsy (EMB) should be considered as a first-line diagnostic modality in all unexplained acute cardiomyopathies complicated by hemodynamic instability and ventricular arrhythmias, considering the local expertise. Genetic counseling should be recommended in those cases where a genotype–phenotype association is suspected, as this has significant implications for patients’ and their family members’ prognoses. Recognition of the pathophysiological pathway and clinical “red flags” and an early diagnosis may help us understand mechanisms of progression, tailor long-term preventive and therapeutic strategies for this complex disease, and ultimately improve clinical outcomes.

A Unique Case of Goodpasture’s Syndrome-Induced Cardiorenal Syndrome

“…Myocarditis can have a variety of clinical manifestations such as chest pain, new or worsening heart failure, chronic heart failure, life-threatening hemodynamic compromise (i.e., fulminant myocarditis, with cardiogenic shock and severely reduced LVEF), life-threatening arrhythmias, or conduction disturbances [ 15 ]. Diagnostic tools used when myocarditis is suspected include cardiac MRI, which has the highest sensitivity if performed two to three weeks after the initial clinical presentation, endomyocardial biopsy, which remains the gold-standard technique to diagnose acute myocarditis [ 16 ] and reveals an inflammatory infiltrate with necrosis or degeneration of adjacent myocytes, markers of myocyte injury and inflammation such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) although not specific and not necessarily increased in myocarditis, high sensitivity troponins, brain natriuretic peptide (BNP) and NT-proBNP (useful but not specific) [ 15 ]. Ten months after the initial presentation, the patient presented with new-onset heart failure in the setting of fluid overload with failed peritoneal dialysis two months prior (eight months after the initial presentation).…”