MITRAL VALVE DISEASE By Magdi A Ghareeb MD

MITRAL VALVE DISEASE By Magdi A. Ghareeb MD, FECC Professor of cardiology

Mitral Stenosis Ø Definition Ø Mitral stenosis leads to an obstruction of blood between the left atrium (LA) and the left ventricle (LV), caused by abnormal mitral valve function Ø The mitral valve area in a healthy individual measures 4 -6 cm 2

Etiology 1 -Rheumatic carditis. Ø 2 - Non rheumatic stenosis is rare in adult. In infants and children resulting from Dysplasia of the valve or from the parachute deformity or supra valvular ring in the left atrium. In adults: Ø -Atrial myxomobacterial vegetations. Ø -Calcification of the valvular ring in the elderly. Ø

Pathophysiology: Ø Ø Ø Obstruction of flow during the diastolic filling period of the left ventricle creates a pressure gradient between the left atrium and the left ventricle. This pressure gradient is related to orifice size and diastolic flow though the mitral valve Obstruction to flow increases left atrial pressure and volume which is reflected to the pulmonary veins, capillaries and eventually to the pulmonary arteries and right ventricle and atrium. Chronic elevation of left atrial pressure will cause hyperplasia and hypertrophy of the pulmonary vessels, veins, capillaries and arteries. RV hypertrophy results from chronic pulmonary hypertension.

Clinical manifestations: History: Ø 50% of patients with recognized mitral stenosis have a history of acute rheumatic fever. Symptomatic patients complain from: Ø Dyspnea Ø Fatigue Ø Palpitation Ø Hemoptysis Ø Hoarseness of voice Ø Chest pain Ø Cerebrovascular accident from an embolus may be the initial symptom.

Clinical manifestations: Physical examination: General signs: Ø Resting tachycardia or atrial fibrillation. Ø Mitral facies with malar flush and peripheral cyanosis. Ø The neck veins may be distended if right ventricular failure is present. Ø Systolic pulsation of the deep jugular veins indicates tricuspid regurgitation and a prominent wave suggests concomitant tricuspid stenosis.

Cardiac signs: The typical auscultatory findings are: Accentuated first heart sound (S 1). Ø Opening snap. Ø Diastolic rumbling murmur at the apex. Ø If pulmonary hypertension and right ventricular hypertrophy have developed, a right ventricular lift can be palpated along the left sternal border. Ø With severe mitral stenosis, it is often possible to palpate an accentuated first heart sound (S 1) and the vibrations of the diastolic rumble at the cardiac apex. Ø

Accentuated first heart sound: => Is due to sudden cessation of the upward motion of the valve that has been depressed in the left ventricular chamber during the diastolic filling period. => The mobility of valve leaflets, the diastolic gradient across the valve and PR interval of the ECG all contribute to the intensity of the first heart sound. => When the mobility of the mitral valve is diminished due to calcification as well as associated mitral regurgitation, the S 1 diminishes in intensity. => Shortening of PR interval by tachycardia, fever or thyrotoxicosis can all accentuate S 1

The opening Snap (OS): => It is produced during maximum excursion of the anterior leaflet of the mitral valve. => The OS can occur 0. 03 to 0. 14 sec after the second heart sound (S 2). => The higher the left atrial pressure, the shorter the interval between the aortic valve closure (S 2) and the opening snap (S 2 -OS time). => Critical mitral stenosis produces a S 2 OS time of less than 0. 08 sec.

Diastolic rumbling murmur: => The murmur is low -pitched; best heard with the bell of the stethoscope and becomes accentuated in the latter phase of diastole with atrial contraction. => Although the presystolic component of the rumble is augmented by atrial contraction, rarely this phase of the murmur will increase with atrial fibrillation

Diastolic rumbling murmur: The diastolic murmur may be localized to a small area of the apex and become audible only after the patient turns to the left lateral decubitus position. Ø The intensity of the murmur does not necessarily relate to the severity of mitral stenosis. Ø A rumble starting with the opening snap and continuing to the first sound suggest more severe impairment. Ø The rumble may distinguish or disappear in the late stages of the disease when the cardiac output declines. Ø

Diastolic rumbling murmur: Other conditions associated with a mitral diastolic rumble include: Ø Left atrial myxoma Ø Atrial septal defect Ø Patent ductus arteriosus. Ø Calcification of the mitral annulus. Ø Carey coomb 's murmur in acute rheumatic fever. Ø Austin flint murmur due to aortic regurgitation.

Electrocardiogram: The characteristic ECG finding in MS is the broad, notched P wave most prominent in lead II with a negative terminal deflection in lead V 1. Atrial fibrillation is common. It develops in any condition associated with left atrial enlargement. When pulmonary hypertension develops right ventricular hypertrophy manifest.

Chest Roentgenogram: Left atrial hypertension, which results in left atrial enlargement, prominence of pulmonary arteries. Ø Right ventricular enlargement. Ø Left atrial enlargement appears as a straightening of the left cardiac border on the standard post-ant chest film. Ø Large left atrium may elevate the left main branches and produce posterior elevation of the barium filled oesophagus. Ø

Chest Roentgenogram: When the pulmonary capillary pressure exceeds the oncotic pressure of plasma proteins (normal = 20 -25 mm. Hg) fluid accumulates in the interstitial space of the lungs. Ø The interlobular septal changes and the linear shadows are perpendicular to the pleura at the bases of lungs and known as Kerley's B lines Ø Acute elevation of pulmonary venous pressure will cause pulmonary edema with alveolar extravasation of fluid. Ø Right ventricular dilatation and hypertrophy is recognized on the lateral chest roentgenogram. Ø

Echocardiography Ø Two-dimensional echocardiography can display the orifice size and area. Ø Doppler readings can provide accurate estimates of diastolic gradient and serve a basis for evaluation of mitral valve area. Ø Information on left atrial dimensions, right ventricular enlargement and left ventricular size can be obtained from the echocardiogram.

Cardiac Catheterization Cardiac catheterization can be used to: Ø Determine the gradient across the mitral valve. Ø Provide data for calculation of the mitral valve area. Ø Identify other valve lesions. Ø Assess ventricular function. Ø Determine the status of the coronary arteries. Ø The normal mitral valve area is 4 to 6 cm 2. Ø The hemodynamic abnormalities develop when the valve is <2 cm 2 and with a mitral valve area < I cm 2, dyspnea, fatigue, pulmonary hypertension, right ventricular failure and reduced cardiac output are generally present.

Natural history and prognosis of MS Ø Ø The average of onset of rheumatic fever is 12 years with latent period of about 19 years from the acute episode to the detection of murmur of MS. Dyspnea and fatigue are the most common symptoms and can be due to pulmonary hypertension and right ventricular failure. Atrial fibrillation, fever, emotional stress or pregnancy can increase the COP and abruptly elevate the pulmonary capillary pressure with the development of pulmonary edema. Severe pulmonary hypertension will reduce the COP and the pressure load will lead to dilatation of the right ventricle.

Natural history and prognosis of MS Ø Right sided heart failure followed with neck vein distension, hepatic enlargement ascitis, and peripheral edema. Ø Atrial fibrillation develops in 40 to 50 % of patients with mitral stenosis particularly in those over the age of 40 years. Ø The onset of atrial fibrillation may lead to further dilatation of the left atrium.

Natural history and prognosis of MS Ø Ø Ø Atrial fibrillation may be paroxysmal or respond to pharmacological agents or cardioversion. As the atrial fibrillation becomes more chronic, resistance to cardioversion develops. A serious complication of mitral stenosis is systemic embolization. A history of atrial fibrillation as well as the age of the patient appears associated with a higher incidence of systemic embolization. Bacterial endocarditis is infrequent in isolated mitral stenosis, but prolonged fever should always raise this possibility.

Treatment Medical: In mitral stenosis efforts are directed at prevention of recurrent rheumatic fever and bacterial endocarditis. Ø Rheumatic fever prophylaxis should continue until the age of 35 years. For endocarditis prophylaxis: § In dental and bronchoscopy: 2 gm of penicillin orally 1 hour before the dental and then 1 and 6 hours after the procedure. Ø

Treatment For genitourinary, gastrointestinal procedures: 2 gm ampicillin should be given IM or IV + gentamycin 1. 5 mg/Kg IM or IV 1 hour before the procedure then 8 hours later. § For minor procedures: 3 gm amoxicillin orally 1 hour before the procedure and 11/2 gm 6 hours later. §

Treatment Digitalis should be used in patients with atrial fibrillation to slow the ventricular rate. Digitalis may be useful in preventing paroxysmal atrial fibrillation. Ø Anticoagulation should be used in patients with mitral stenosis who have chronic atrial fibrillation or paroxysmal atrial fibrillation unless there is a contraindication to the use of the drug. Ø Systemic embolization requires anticoagulation for an indefinite period. Ø If the embolus is to an extremity or in the mesenteric system, surgery should be planned. Ø

Percutaneous balloon mitral valvuloplasty was proved to be successful in patients with symptomatic mitral stenosis. Ø This procedure is carried out when the patient's valve area is < 1. 5 cm 2 Ø Transesophgeal echocardiography is mandatory prior to the procedure for screening of the left atrium and more importantly the left atrial appendage which is not visualized by transthoracic echocardiography. Ø In patients with left atrium or left atrial appendage thrombus PBMV is contraindicated. Those patients are referred to surgery.

Surgery PBMV now replaced closed mitral commissurotomy which was used to be performed in the past. Ø Open mitral commissurotomy is used in selected patients e. g. patients with left atrial thrombus. Ø Mitral valve replacement is used in patients with heavily calcific and severely deformed valves. Ø The artificial valve used in Egypt is the mechanical tilting disc bileaflet valve. Ø

Mitral Regurgitation Definition: Mitral regurgitation occurs when contraction of the left ventricle ejects blood into the left atrium as a result of abnormalities in the mitral valve apparatus

Etiology: A- Chronic Regurgitation: 1 -Rheumatic fever. 2 - Prolapse of the mitral valve. 3 - Coronary artery disease. 4 - Left ventricular dilatation. 5 - Calcific mitral annulus. 6 - Papillary muscle dysfunction (infarction). 7 -Congenital heart disease. 8 - Systemic lupus erythematosus.

B- Acute Regurgitation: 1 -Rupture of chordae tendinae (myxomatous, endocarditis, trauma) 2 - Rupture of papillary muscle (infarction, trauma) 3 -Perforation of leaflets ( endocarditis). The abrupt hemodynamic alterations produce marked elevation of the left ventricular enddiastolic pressure, left atrial pressure and pulmonary capillary pressure.

Clinical manifestations Symptoms: Ø Chronic mitral regurgitation can be tolerated for many years without clinical evidence of a reduction in cardiac reserve. Ø Fatigue and dyspnea are initial symptoms which can gradually progress to orthopnea, paroxysmal nocturnal dyspnea and peripheral edema. Ø In acute mitral regurgitation from sudden disruption of mitral valve apparatus, the symptoms are those of congestive heart failure or acute pulmonary edema.

Physical examination: In chronic mitral regurgitation: Displacement of the cardiac apex impulse with a hyperdynamic motion over a diffuse area. Ø By auscultation, there is high pitched holosystolic murmur beginning with the 1 st heart sound and extending to the 2 nd heart sound. It is heard at the cardiac apex and radiates to the left. Ø The 1 st heart sound is diminished and the duration of systolic is shortened. Ø A ventricular gallop sound is fre audible at the apex. Ø

In acute mitral regurgitation: Ø The physical findings are often those of acute pulmonary edema and left ventricular failure. Ø The heart size may be normal with hyperactive apical motion. Ø In acute regurgitation which is often due to rupture of the chordae tendineae, the holosystolic murmur is harsh and can be heard over the back of the neck, vertebrae and sacrum.

Electrocardiogram Ø Left atrium or left ventricular enlargement. Ø Atrial fibrillation can develop. Ø When coronary artery disease is the mechanism for mitral regurgitation, Q wave abnormalities of a previous infarction are frequently present.

Chest Roentgenogram Ø Left ventricular and left atrial enlargement develop in long standing mitral regurgitation. Ø In coronary artery disease, heart size can range from normal to significant dilatation of both the left ventricle and left atrium. Ø Acute mitral regurgitation can manifest with acute mitral regurgitation on a normal cardiac size.

Echocardiogram In rheumatic disease echocardiogram can be used to evaluate: Ø Valve motion Ø Thickness Ø Calcification of the mitral valve apparatus. In acute mitral regurgitation echocardiogram can detect: Ø Ruptured chordae. Ø Ruptured papillary muscle. Ø Perforated valve leaflet.

Cardiac catheterization Ø Cardiac catheterization can confirm the diagnosis of mitral regurgitation, assess ventricular function. Ø Recognize other underlying cardiac lesions. Ø Can delineate the anatomy of coronary arteries.

Pathophysiology Chronic mitral regurgitation causes a volume overload on the left ventricle and left atrium. Ø The compensatory mechanism of the left ventricle to chronic mitral regurgitation is dilatation of the chamber. Ø Dilatation of the left ventricle is accompanied by an increase in wall thickness and hypertrophy to maintain mechanical function. Ø In acute mitral regurgitation hemodynamics differ from chronic form because the valvular regurgitation is often abruptly imposed on a normal ventricle Ø

Natural history and prognosis The prognosis will depend on the underlying etiology and the state of the left ventricular function Ø Ø In chronic mitral regurgitation volume overload may be tolerated for many years before symptoms of heart failure develop Left atrial enlargement predisposes to left atrial fibrillation which Can be complicated by embolization. Infective endocarditis can develop In acute mitral regurgitation the clinical course is often complicated by acute pulmonary edema and sometimes cardiogenic shock.