Myocarditis Diagnosis Criteria

Myocarditis refers to the inflammation of the heart muscle, with viral myocarditis being the most common type. The diagnosis is primarily based on several key factors that help identify the condition accurately.

Medical History of Infection

Patients suffering from viral myocarditis often have a history of upper respiratory tract infection 1 to 3 weeks before the onset of symptoms. This may include signs such as fever, runny nose, sore throat, and cough, which are indicative of a prior viral infection that could lead to myocardial inflammation.

Clinical Symptoms

The symptoms of myocarditis can vary widely in severity. Mild cases may present with subtle signs like palpitations, shortness of breath, and chest discomfort. However, more severe cases can lead to life-threatening complications including heart failure, malignant arrhythmias, cardiogenic shock, and even sudden cardiac death. These symptoms necessitate prompt medical evaluation and intervention.

Diagnostic Tests

Several diagnostic tools are essential in confirming myocarditis and assessing its impact on heart function.

Blood Tests

Cardiac biomarkers such as troponin and creatine kinase-MB (CK-MB) are frequently elevated in cases of myocardial injury. These markers are crucial in supporting the diagnosis of myocarditis and ruling out other potential causes of cardiac symptoms.

Electrocardiogram (ECG)

An ECG can reveal important changes such as ST-segment elevation or depression, T-wave abnormalities, or the presence of arrhythmias like premature beats. These findings are not specific to myocarditis but can indicate myocardial damage or electrical instability.

Echocardiogram

An echocardiogram may show reduced left ventricular function or abnormal wall motion, both of which suggest impaired heart muscle performance. This imaging technique is non-invasive and provides valuable insights into the structural and functional status of the heart.

Endomyocardial Biopsy

While endomyocardial biopsy remains the gold standard for diagnosing myocarditis, it is an invasive procedure and not routinely performed. It is typically reserved for cases where the diagnosis remains uncertain despite other testing or when specific treatment decisions depend on histological confirmation.

Additional Laboratory Tests

Other supportive tests may include serological testing for viral antibodies in the blood or throat swabs to identify the presence of specific pathogens. These tests help establish a link between a recent infection and the development of myocarditis.