Normal Mitral Valve Function Research Articles

The mitral plication suture: A new technique of mitral valve repair

During 1975, 67 patients underwent attempted repair of mixed mitral valve disease by use of the new mitral plication suture (MPS) technique. Ninety per cent had successful repair and 10 par cent required valve replacement. The MPS is a double, semicircular, buttressed annuloplasty suture that constricts the enlarged mitral annulus to correct mitral regurgitation (MR), supports mitral subunit repair procedures, and yet maintains the flexibility of the mitral annulus. The hospital mortality rate was 6 per cent. There were no late deaths during 10.4 months of follow-up. Six per cent of the patients who had valve repair required subsequent MVR. Their repair operations are considered late failures. Echocardiography, a useful technique for assessing the status of the patients postoperatively, demonstrated normal mitral valve and left ventricular function in the majority of patients; comparisons with replacement valves are documented. Death and morbidity was less frequent than in patients with MVR, both in the hospital and during follow-up. The aggressive policy of mitral valve repair has reduced the number of MVR's from 95 during 1974 to 52 in 1975. Although follow-up is short, we conclude that the new MPS is a valid surgical adjunct to the complete repair of the mitral valve.

The Papillary Muscle Syndrome

Normal mitral valve function is dependent upon several structures other than the valve leaflets alone. These structures are in anatomic continuity from the atrial muscle to the ventricular muscle and, in addition to the leaflets, include the valve ring, the chordae tendineae, conduction tissue, and the papillary muscles. For perfectly normal valve function, each of these structures must be (1) anatomically and functionally intact, (2) in appropriate spatial interrelationship, and (3) operative in correct temporal sequence with respect to related structures. Obviously, normal mitral valve function is dependent upon a rather complex and finely coordinated system. In the past, of all the structures in this system, the papillary muscles have received the least interest and study. Yet they are of paramount importance, and disturbances of their function are a common cause of mitral valve incompetence. <h3>Pathophysiology</h3> Causes of papillary muscle dysfunction may be outlined as follows: Circulatory insufficiency (ischemia) Angina

PERSISTENT COMMON ATRIOVENTRICULAR CANAL. ANATOMY AND FUNCTION IN RELATION TO SURGICAL REPAIR.

The mitral valve anatomy of endocardial cushion defects is reviewed and compared with the anatomic requirements for normal mitral valve function. It is shown that very often mitral valve anatomy is such that function should be not at all or only minimally affected. Evidence is quoted that this is indeed so. The potential harm that may result from indiscriminate suturing of mitral valve clefts and careless repair of the septal defects is described. Principles for the repair of the mitral valve in these cases are enunciated. A small series of cases that have had preoperative and 1-year postoperative assessments of mitral valve function is presented to illustrate some of these points.

EVALUATION OF FUNCTION OF MITRAL VALVE AFTER HOMOTRANSPLANTATION IN THE DOG

SUMMARY AND CONCLUSIONS Nine dogs were studied 3 to 8 months after total orthotopic homotransplantation of the mitral valve. Another dog, which had mitral insufficiency of 3 years’ duration, was studied before and 6 weeks after replacement of the anterior leaflet. Two dogs were found to have completely normally functioning valves, 1 had pure mitral stenosis, 2 had mild mitral stenosis and associated mild mitral insufficiency, and 3 had mild or moderate mitral insufficiency. One animal had severe mitral insufficiency, and the dog with transplantation of the anterior leaflet had normal mitral valve function. One dog, restudied 16 months postoperatively, shows no deterioration of the good results displayed early after surgery. Its ability to increase the cardiac output nearly threefold above the resting value in response to exercise demonstrates the excellent function of the left ventricle and transplanted valve. In normal dogs, minimal “mitral regurgitation” is usual. This factor and the problem of nonrepresentative sampling from the left atrium render the upstream-sampling dye method for quantitation of regurgitation of limited reliability.