Can Myocarditis Occur with a Normal Echocardiogram?
Yes, myocarditis can absolutely occur with a completely normal standard echocardiogram, particularly in less severe forms of the disease. 1
Why Standard Echocardiography Often Misses Myocarditis
The European Society of Cardiology explicitly states that 2D echocardiography has played a limited role in diagnosing acute myocarditis due to lack of specific diagnostic features and apparently normal examinations encountered in less severe forms. 1
Key Limitations:
Non-specific findings: When abnormalities are present, they may include LV systolic/diastolic dysfunction, regional wall motion abnormalities, or unspecific texture changes—none of which are diagnostic of myocarditis specifically 1
Cannot differentiate edema from hypertrophy: Even when myocardial interstitial edema causes wall thickening (especially in fulminant forms), standard echocardiography cannot accurately distinguish this from true wall hypertrophy 1
Mild cases appear normal: Less severe presentations frequently show completely normal standard echocardiographic parameters 1
Clinical Implications for Diagnosis
Do not rule out myocarditis based on a normal echocardiogram alone. The diagnosis requires integration of multiple modalities:
Essential Diagnostic Approach:
Clinical presentation: 82-95% of adults present with chest pain, 19-49% with dyspnea, 5-7% with syncope 2
Biomarkers: Elevated troponins are present in the majority of cases 2, 3
ECG changes: ST-segment abnormalities and T-wave inversions are common 4, 2
Cardiac MRI is the gold standard: Provides superior diagnostic accuracy compared to echocardiography, with typical epicardial or midwall late gadolinium enhancement patterns 5, 6
Advanced Echocardiographic Techniques That May Help
When standard echo is normal but clinical suspicion remains high:
Speckle Tracking Imaging:
Can detect subclinical inflammation: Reduction in global systolic longitudinal strain (LV-GLS) and strain rate correlates with intramyocardial inflammation on endomyocardial biopsies, even when standard parameters appear normal 1, 7
Important caveat: Cannot differentiate inflammation-induced strain reduction from other causes (subendocardial ischemia, infiltrative disease, toxin-related damage) 1
Myocardial Contrast Echocardiography:
- Identifies perfusion defects: Areas of necrosis and inflammation create perfusion defects that don't match coronary distribution territories, raising suspicion for myocarditis 1, 7
Role of Serial Echocardiography
Even with an initially normal echocardiogram, the American College of Cardiology recommends serial echocardiography to monitor for development of ventricular dysfunction or pericardial effusion. 4
What to Monitor:
- Significant changes in wall motion during disease course 7
- Development of complications: intracardiac thrombi, pericardial effusion 7
- Secondary valvular regurgitation (mitral/tricuspid) 1
Common Pitfall to Avoid
The most critical error is dismissing myocarditis as a diagnosis because the echocardiogram is normal. This is particularly dangerous given that:
- Approximately 75% of admitted myocarditis patients have uncomplicated courses with near 0% mortality 2
- However, 2-9% develop hemodynamic instability requiring mechanical support, with 28% mortality at 60 days 2
- Patients require continuous cardiac monitoring to detect life-threatening arrhythmias 4
If clinical suspicion for myocarditis exists (chest pain, elevated troponins, ECG changes), proceed with cardiac MRI regardless of normal echocardiographic findings. 5, 7, 6