Mitral regurgitation is a defective closure of mitral valve of the heart. Mitral valve opens in diastole to promote blood flow from the left atrium into the left ventricle, blood coming from the pulmonary veins and that in turn is ejected into the aorta in systole. During systole, the mitral valve must be closed to ensure an increase of pressure in the left ventricle and pump the blood into the aorta. In mitral regurgitation, during systole some blood to be ejected into the aorta returns to the left atrium. Regurgitation dilates the left atrium, the pressure increases in pulmonary veins, lung and right heart.
The forms of acute mitral regurgitation can produce pulmonary edema by extravasation of blood from the pulmonary capillaries with increased pressure. Mitral insufficiency may occur in an inferior myocardial infarction, in chronic ischemia which causes pillars fibrosis, in thoracic trauma, infective endocarditis, or in a degeneration of cordage finished with its rupture.
In the compensatory mechanisms, occurs a dilation of the left ventricle to cope with the diastolic overload (normal flow and the previous jet regurgitation).
Causes of mitral regurgitation
Mitral regurgitation is most often associated with older adults due to a degeneration of the mitral valve. It can also occur in an acute rheumatic valvular damage, mitral valve prolapse, in major deficiency of vitamin C in young women, or within rare diseases as Marfan syndrome, hypertrophic cardiomyopathy, lupus erythematosus, scleroderma.
Signs and symptoms of mitral regurgitation
Common symptoms are related with complications and failure degree. A dilated left atrium may cause atrial fibrillation felt by the patient as palpitations. If lungs are affected it can appear hemoptysis (rarely) or dyspnea (difficulty to breath and is a gravity sign in pulmonary edema), or in the stage of heart failure, predominant signs of right heart failure ( swelling of legs, liver pain, dyspnea, distended jugular veins).
Depending on the cause, it can be differentiated the following symptoms: chest pain if mitral regurgitation is associated and / or due to ischemia, fever in case of endocarditis.
Clinician can detect in most cases during auscultation with a stethoscope: mitral systolic murmur that radiates to the axilla and has the character of a jet of steam.
Diagnosis of mitral regurgitation
Diagnosis in mitral regurgitation is suspected based on clinical data (signs and symptoms of the patient and clinical exam) and laboratory data to confirm the diagnosis: ECG, chest X-ray, transthoracic Doppler echocardiography and other complementary exams depending of the case particularities: transesophageal echocardiography, Holter ECG, coronary x-ray, respiratory functional tests.
Treatment of mitral regurgitation
Treatment has several stages: etiologic – where the cause can be treated (mitral regurgitation caused by rheumatic fever, infective endocarditis, ischemia), treatment of the complications in cases where they were installed (treatment of heart failure or atrial fibrillation and anticoagulation in patients at risk). For severe symptomatic mitral regurgitation or with increased impact on lung function there is recommended cardiac surgery: mitral valve replacement with mechanical or biological valve prosthesis.