Myocarditis and pericarditis are defined by abnormal inflammation in the myocardium or pericardium, respectively. The inflammation may be secondary to a number of causes, ranging from viral (most common) to autoimmune (less common). The disease can present on a spectrum of clinical severity, ranging from mild chest pain to acute heart failure and sudden death. In some cases, the disease can lead to chronic dilated cardiomyopathy. Each etiology may respond differently to treatment options, so thorough history-taking, physical examination, and laboratory/imaging evaluation are essential for evaluation and management.