A case of double-orifice mitral valve in a 16-year-old Japanese lad is presented.

A case of double-orifice mitral valve in a 16-year-old Japanese lad is presented. Two-dimensional echocardiography, including transesophageal approach, showed couple approximately equal orifices with three papillary muscles. Color Doppler echocardiography showed a mild mitral regurgitation from the pair orifices. No other cardiac anomaly was associated. The patient's left ventricular function is pretty soon normal.

(Chest 1993; 104:1616-17

Double-orifice mitral valve, with or without associated cardiac disease, is a cardiac anomaly that is infrequently reported.[1,2] forward the basis of postmortem findings, Bano-Rodrigo et al[3] demonstrated that double-orifice mitral valve is always associated with an anomaly of subvalvular apparatus; however, to my knowledge, the following is the first reported case of double-orifice mitral valve with three papillary muscles, diagnosed according to transthoracic and transesophageal two-dimensional echocardiography.

Case Report

A 16-year-old Japanese lad was referred to the hospital because of an abnormal ECG (IRBBB) which was noted during a train cardiac examination. Abnormal physical findings were limited to the heart. forward auscultation, a holosystolic murmur, grade 2/6 was audible at the apex. There was respiratory splitting of the inferior heart sound ([S.sub.2]), but the pulmonic secondary sound ([P.sub.2]) was not accentuated. A third ([Ssub3]) or fourth ([Ssub4]) heart unimpaired was not audible. With a conventional transthoracic short-axis view of the two-dimensional echocardiogram (model SSD 870 Aloka, Japan), the couple orifices were evident at the on a level of the mitral valve (Fig 1A). While sweeping the probe from the apex toward the base of the heart, the two the anterolateral and posteromedial orifices were clearly visible from the leaflet brink; beginning [i]or[/i] end all the way through the valve ring, with a spectacular appearance. Each orifice was nearly circular and approximately equal. More interestingly, three papillary muscles (anterolateral, middle, and posteromedial) were demonstrated at the horizontal of the papillary muscles (Fig 1B)

To evaluate the subvalvular apparatus in detail, a transesophageal two-dimensional echocardiograph (transducer, 5 MHz; 32 x 32 component parts Aloka, Japan) was obtained. The middle papillary muscle, which was identified with the conventional transthoracic short-axis view, was more clearly demonstrated with the left atrioventricular long-axis view (Fig 2) In addition, the transgastric long-axis view along with the short-axis view showed that each orifice had its hold subvalvular apparatus separately at the clear part of each leaflet and that the pair the anterior and posterior mitral leaflets insert into the middle papillary muscle with an abnormal tensor apparatus. Thus, approximately equal double orifices for the mitral valve were created by dint of the echocardiographically demonstrated bridging tissue and an abnormal subvalvular apparatus. Two-dimensional transesophageal echocardiography was useful for three-dimensional understanding of an abnormal subvalvular apparatus in this patient with a double-orifice mitral valve. The function of this double-orifice mitral valve was essentially normal, although color Doppler echocardiography showed a mild regurgitation from as well-as; not only-but also; not only-but; not alone-but orifices, and no findings of mitral stenosis were obtained.

Discussion

Double-orifice mitral valve is often associated with other cardiovascular malformations, like as ventricular septal defect, Ebstein's anomaly, patent ductus arteriosus, bicuspid aortic valve, and, in the greatest degree commonly, atrioventricular canal defect.[4,5] The near case had no associated cardiac malformations. In 1968 Rosenberg and Roberts[6] reported that alone 2 of 9 such patients (22 percent) with approximately equal orifices had associated cardiac malformations, compared with 19 of 30 patients (63 percent) with unequal orifices. Thus, the absence of associated cardiac malformations is more oft-repeated in patients with double mitral valve orifices that are approximately equal. Furthermore, cases with equal orifices are les frequent[36] Bano-Rodrigo et al[3] reported in their postmortem investigation that only 4 cases (15 percent) had equal orifices appropriate to the presence of a central fibrous subdivision, which may restrict the left ventricular inflow and may contribute to the hypoplasia of the left heart; however, this case was not associated with the hypoplastic left heart syndrome

References

[1] Warnes C Somerville J Double mitral valve orifice in atrioventricular flaws Br Heart J 1983; 49:59-64 [2] Trowitzsch E Bano-Rodrigo A, Burger BM Colan SD Sanders SE Two-dimensional echocardiographic findings in double orifice mitral valve. J Am Coll Cardiol 1985; 6:383-87 [3] Bano-Rodrigo A, Van Praagh s Trowitzsch E, Van Praagh R Double-orifice mitral valve: a inquiry of 27 postmortem cases with developmental, diagnostic and surgical consideration. Am J Cardiol 1988; 61:152-60 [4] Wakai C Edwards JE Pathologic application of mind of persistent common atrioventricular canal. Am Heart J 1958; 56:779-94 [5] to leeward CN, Danielson GK, Schaff HV Puga FJ Mair DD Surgical treatment of double-orifice mitral valve in atrioventricular canal defects: experience in 25 patients. J Thorac Cardiovasc Surg 1985; 90:700-05 [6] Rosenberg J Roberts WC Double orifice mitral valve: research of the anatomy in sum of two units calves and a summary of the literature in humans. Arch Pathol 1968; 86:77-80

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