Clinical Investigation in the ED

In the ED an ECG, chest radiograph (CXR) and echocardiography should be performed at an early stage.

Learning bite

There is no single diagnostic test in the ED that will confirm a diagnosis of myocarditis but several investigations will aid in making a clinical diagnosis.

ECG

The ECG most commonly demonstrates a sinus tachycardia with or without non- specific ST segment and T wave changes. A finding of an unexplained sinus tachycardia with no other likely cause should prompt consideration of a diagnosis of myocarditis. In contrast to ECG changes in acute coronary syndromes, changes associated with myocarditis do not follow a coronary artery territorial distribution.

Possible abnormalities

• ST segment depression or elevation
• Atrioventricular or intraventricular block
• non-specific T wave changes
• Q-T prolongation
• P-R segment depression

Click on the ECGs to enlarge.

Fig 1a: ECG showing acute pericarditis: widespread p-r depression and saddle-shaped ST elevation	Fig 1b: ECG showing left bundle branch block

 CXR

A CXR may be normal.

It may show cardiomegaly or features of cardiac failure.
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Fig 2: CXR showing acute pulmonary oedema

Possible abnormalities

• Normal
• Pulmonary oedema
• Cardiomegaly
• Pleural or pericardial effusions

Echocardiography

Transthoracic echocardiography is currently recommended in the initial evaluation of all patients with suspected myocarditis.

Echocardiographic findings can be varied and are Non-specific [6]. Retrospective review of echocardiograms performed in patients with biopsy proven myocarditis demonstrated left ventricular dysfunction in 69% of patients but left ventricular cavity enlargement was less common [7]. Right ventricular dysfunction was demonstrated in 23% of these patients.

Fig 3: Echocariogram from an infant with myocarditis showing multichamber dilation

Possible abnormalities

• Decreased left ventricular ejection fraction
• Right ventricular dysfunction
• Multichamber dilatation
• Pericardial effusion
• Focal or global wall motion abnormality