Does chamber dilation occur in acute myocarditis (inflammation of the heart muscle) as seen on an echocardiogram (ultrasound of the heart)?

Chamber Dilation in Acute Myocarditis on Echocardiogram

Chamber dilation is not a typical finding in acute myocarditis on echocardiogram, though it may develop in more severe or fulminant cases, particularly as the disease progresses. 1

Echocardiographic Findings in Acute Myocarditis

Common Findings

• Left ventricular systolic and diastolic dysfunction 1
• Resting regional wall motion abnormalities that don't correspond to coronary territories 1
• Exercise-induced wall motion abnormalities due to microvascular dysfunction 1
• Non-specific changes in myocardial texture 1
• Intracardiac thrombi in severe cases 1
• Secondary mitral and/or tricuspid regurgitation 1
• Co-existent pericardial involvement 1

Wall Thickness Changes

• Acute myocarditis typically presents with thickened ventricular walls rather than dilation, especially in fulminant forms 1
• This wall thickening is due to myocardial interstitial edema from the inflammatory process 1, 2
• Echocardiography cannot accurately differentiate between myocardial edema and true wall hypertrophy 1

Progression to Dilated Cardiomyopathy

• Chamber dilation may develop as myocarditis progresses to inflammatory cardiomyopathy 3
• Myocarditis is recognized as a major cause of dilated cardiomyopathy when inflammation persists 4, 5
• The transition from acute myocarditis to dilated cardiomyopathy can occur over weeks to months 1
• Fulminant myocarditis may present with normal end-diastolic diameter with mildly thickened walls rather than dilation 1

Advanced Echocardiographic Techniques

• Speckle tracking imaging can help identify areas of inflammation in patients with normal standard echocardiographic parameters 1
• Reduction in global systolic longitudinal strain and strain rate correlates with intramyocardial inflammation 1
• Real-time, low-mechanical-index myocardial contrast echocardiography can identify perfusion defects that don't match coronary territories, suggesting myocarditis 1

Diagnostic Approach

• Echocardiography is recommended in all patients with clinically suspected myocarditis (Level of Evidence C) 1
• Cardiac MRI provides superior diagnostic accuracy compared to echocardiography for myocarditis 6
• The pattern of late gadolinium enhancement on cardiac MRI in myocarditis is typically epicardial or midwall, unlike the endocardial pattern seen in ischemic disease 1, 6
• Endomyocardial biopsy remains the gold standard for confirming myocarditis diagnosis 4

Clinical Implications

• The presence of chamber dilation may indicate a more severe or chronic inflammatory process 3
• Cases with myocardial edema without late gadolinium enhancement on cardiac MRI have been associated with improved recovery and outcomes 1
• A QRS width >120 ms on ECG predicts a higher risk of death or transplantation in myocarditis patients 1, 7
• Recurrent episodes of myocarditis can cause reversible cardiomyopathy with return to normal cardiac function 8

Monitoring Considerations

• Serial echocardiography is valuable to monitor for development of chamber dilation, which may indicate progression to inflammatory cardiomyopathy 3
• Patients with myocarditis should avoid competitive sports for 3-6 months after diagnosis 1
• Reassessment with clinical evaluation and functional testing is indicated before resuming competitive sports 1