Is myocarditis serious? In fact, myocarditis is an inflammatory disease of the myocardium. Patients with myocarditis may experience symptoms such as fatigue, palpitations, shortness of breath, discomfort or pain in the precordial area, nausea, vomiting, abdominal pain, diarrhea, etc. During examinations, we often see slight enlargement of the heart, arrhythmias, gallop rhythm, and other manifestations of heart dysfunction. In severe cases, myocarditis can lead to fulminant myocarditis, such as severe heart failure or cardiogenic shock, often accompanied by arrhythmias. Even with timely and standard treatment, death may occur due to the severity of the condition. Even if patients with myocarditis recover, they may still have some sequelae on the electrocardiogram, such as atrioventricular block, bundle branch block, premature beats, or junctional rhythm.