Central Double Orifice Mitral Valve

Palpitations of 1 week’s duration prompted a previously healthy 29-year-old woman to seek medical attention. She had no other symptoms. Physical examination, ECG, and 24-hour Holter monitoring results were normal. An echocardiogram (shown here) revealed a central double orifice mitral valve (DOMV) with equally divided orifices attached to 2 papillary muscles. A central bridge connected both leaflets. No significant regurgitation, stenosis, or other structural abnormalities were noted. The systolic and diastolic functions were also normal.

Fewer than 100 cases of DOMV have been described.^1-3 The lesion is usually diagnosed during early childhood and is associated with other congenital heart malformations, mainly atrioventricular septal defect (AVSD). Other less frequent associated lesions are ventricular septal defect, coarctation of the aorta, subaortic stenosis, patent ductus arteriosus, and primum atrial septal defect.¹ Other anomalies of the valve apparatus include accessory papillary muscles and cleft leaflets.² DOMV is associated with mitral regurgitation in 25% of cases, mitral stenosis in 13%, and mixed defect (regurgitation and stenosis) in 6%.³

There are two types of DOMV:

•Eccentric or hole type.

•Central or bridge type.

The eccentric type accounts for 85% to 90% of cases and is characterized by a larger main orifice beside a small accessory orifice. An AVSD is usually present when the smaller orifice is located at the posteromedial commissure.^1-3

The central or bridge type is seen in 10% of cases. A central bridge of fibrous tissue connects the two leaflets of the mitral valve. The two openings may be equal or unequal. The chordae tendineae surrounding each orifice usually insert into more than two papillary muscles. Fewer than 10 cases have been reported; the other cases had an associated malformation (AVSD, ventricular septal defect, or coarctation of aorta) and were diagnosed in children.^1-3

This case is unusual because it features a central DOMV with two papillary muscles and no other structural problem. Besides transient palpitation, the anomaly has not provoked any symptom or cardiac dysfunction. Although there is no specific recommendation for this disorder when asymptomatic, this patient has been followed up with yearly echocardiograms for early detection of potential functional abnormality. She was advised to continue her usual life activities. No medication has been started thus far.