Symptoms of Myocarditis: What You Need to Know

Myocarditis, an inflammation of the heart muscle, can present with a wide range of symptoms depending on the severity and location of the inflammation. The initial signs can vary based on the underlying cause, but once the heart muscle becomes involved, the symptoms tend to follow a more recognizable pattern.

Mild Myocarditis Symptoms

In mild cases, patients may experience little to no symptoms at all. When symptoms do occur, they are often subtle and can include fatigue, weakness, reduced appetite, and mild heart-related sensations such as palpitations, premature heartbeats, chest tightness, shortness of breath, or difficulty catching one's breath. During a physical examination, a doctor might notice signs like paleness, throat congestion, irregular heart rate, or abnormal heart rhythms such as tachycardia or bradycardia.

Moderate Myocarditis Symptoms

In addition to the symptoms seen in mild cases, moderate myocarditis often includes signs of congestive heart failure. The onset can be sudden, with pronounced fatigue being a key feature. Patients may also experience dizziness, heart palpitations, chest discomfort, heavy sweating, and noticeable paleness—symptoms that closely resemble those of angina. Some individuals may also suffer from abdominal pain, joint pain, muscle aches, restlessness, rapid breathing, and cold extremities.

Severe Myocarditis Symptoms

Severe myocarditis can be life-threatening and typically presents with a rapid, acute onset. Within hours to a couple of days, patients may develop heart failure, heart enlargement, and a significant drop in ejection fraction—a measure of how well the heart pumps blood. Widespread damage to the heart muscle is common, and serious arrhythmias can occur. One particularly dangerous condition associated with myocarditis is Adams-Stokes syndrome, which can lead to fainting, dangerously slow heartbeats, cardiac arrest, atrioventricular block, or ventricular fibrillation.

Heart Arrhythmias and Myocarditis

Arrhythmias caused by myocarditis are a major concern and can lead to sudden cardiac death. Symptoms such as palpitations, low blood pressure, and visual disturbances like "seeing stars" or temporary blindness can be warning signs. In severe cases, these irregular heartbeats can be fatal if not treated promptly.