From the Guidelines
Acute mitral regurgitation is primarily caused by conditions that suddenly disrupt the normal function of the mitral valve apparatus, with the most common cause being acute myocardial infarction, particularly involving the inferior or posterior wall of the left ventricle, which can lead to papillary muscle dysfunction or rupture, as noted in 1 and further supported by 1. The causes of acute mitral regurgitation can be categorized into several key areas, including:
- Acute myocardial infarction, which can lead to mitral valve annulus dilatation due to left ventricular dilatation and dysfunction, papillary muscle dysfunction, or papillary muscle rupture, as described in 1
- Infective endocarditis, where bacterial infection damages the valve leaflets or chordae tendineae, as mentioned in 1
- Trauma to the chest, resulting in damage to the valve apparatus or papillary muscles
- Spontaneous chordal rupture, often associated with myxomatous degeneration or mitral valve prolapse, as noted in 1
- Prosthetic valve dysfunction, including paravalvular leaks or structural valve deterioration, as mentioned in 1 It is essential to promptly identify the cause of acute mitral regurgitation, as it can lead to rapid hemodynamic deterioration, pulmonary edema, and cardiogenic shock due to the sudden volume overload on a left ventricle that hasn't had time to compensate, unlike in chronic mitral regurgitation where adaptive mechanisms develop gradually, as supported by the findings in 1 and 1.
From the Research
Causes of Acute Mitral Regurgitation
The causes of acute mitral regurgitation (mitral valve insufficiency) can be classified into several categories, including:
- Chordae tendineae (CT) rupture, which is the most common etiology of acute severe mitral regurgitation today, especially in patients with floppy mitral valve/mitral valve prolapse 2
- Papillary muscle (PM) rupture, often associated with myocardial infarction (AMI) 2, 3, 4, 5
- Infective endocarditis (IE), which can cause native or prosthetic valve damage, including leaflet perforation, ring detachment, and CT or PM rupture 2, 6
- Mitral valve prosthesis dysfunction, which can be biological or mechanical 6
- Trauma, such as percutaneous valvuloplasty 6
Mechanisms and Clinical Presentation
The mechanisms of acute mitral regurgitation can be classified into four categories:
- Mutilating valve lesions
- Rupture of chordae tendineae
- Papillary muscle lesions
- Biological or mechanical valve prosthesis dysfunction The clinical presentation and prognosis of acute mitral regurgitation depend on the volume of regurgitation, left ventricular function, and left atrial compliance 6
Diagnosis and Treatment
Diagnosis of acute mitral regurgitation can be confirmed by Doppler ultrasound, which defines the mechanism and sometimes eliminates the need for an invasive investigation 2, 6 Treatment of acute mitral regurgitation depends on the aetiology, volume of regurgitation, left ventricular function, and treatment implemented, and may include: