From the Guidelines
Myocarditis can indeed cause acute mitral regurgitation (MR) through several mechanisms, including inflammation of the myocardium leading to left ventricular dilation and dysfunction, papillary muscle dysfunction, or direct involvement of the mitral valve apparatus. The relationship between myocarditis and acute MR is well-documented in numerous published case reports and studies, with viral myocarditis (particularly from coxsackievirus, influenza, and more recently COVID-19) being associated with acute MR 1. Some key points to consider in the management of myocarditis-induced acute MR include:
- The pathophysiology typically involves either papillary muscle dysfunction due to inflammation of the supporting myocardium, ventricular dilation causing mitral annular enlargement, or direct inflammatory damage to the valve leaflets.
- Diagnosis typically requires echocardiography to assess valve function, cardiac MRI to evaluate for myocardial inflammation, and sometimes endomyocardial biopsy for definitive diagnosis.
- Treatment focuses on addressing the underlying myocarditis with anti-inflammatory medications, supportive care, and in severe cases, surgical intervention may be necessary to repair or replace the mitral valve, as seen in cases of severe MR secondary to acute myocardial infarction 1. The most recent and highest quality study on mitral regurgitation management, a systematic review of clinical practice guidelines and recommendations, highlights the importance of timely intervention in patients with MR, particularly those with symptoms or features predictive of deterioration 1. In the context of myocarditis-induced acute MR, it is essential to prioritize morbidity, mortality, and quality of life as outcomes, and to consider the latest evidence-based recommendations for management, including the potential need for surgical intervention in severe cases 1.
From the Research
Myocarditis and Acute Mitral Regurgitation
- Myocarditis is a condition where the heart muscle becomes inflamed, and it can lead to various complications, including acute mitral regurgitation (MR) 2.
- Acute MR can occur due to papillary muscle rupture, which can be caused by myocarditis, infections, or trauma 2.
- A case report described a patient with spontaneous papillary muscle rupture resulting in severe mitral regurgitation with refractory heart failure, where myocarditis was considered a possible cause 2.
Mechanisms and Prevalence
- Mitral regurgitation can occur due to primary (organic) or secondary (functional) mechanisms, and identification of the causative mechanism is crucial for management strategy and outcome 3.
- The prevalence of MR varies, and it has been observed in over one-quarter of patients after acute myocardial infarction, with a significant impact on survival 4.
Treatment and Management
- There is currently no effective medical treatment for chronic MR, and careful follow-up is essential to accomplish timely surgical intervention 3.
- Mitral valve repair is preferable to valve replacement, and percutaneous valve interventions have shown promising results, although longer-term evaluation is needed to assess efficacy, durability, and safety 3.
- The use of ACE inhibitors and angiotensin receptor blockers (ACE-I/ARB) has been associated with improved clinical outcomes in patients with moderate-to-severe MR and preserved to mildly reduced left-ventricular ejection fraction 5.