A 36-year old man developed exertional dyspnea and fatigue of 2 months duration. There was no history of orthopnea or paroxysmal nocturnal dyspnea. Physical examination revealed a well-built man with supine right upper arm blood pressure of 135/76 mmHg, regular pulse rate of 88 beats/min, and no evidence of heart failure. Precordial examination showed normal heart sounds, a 3/6 diastolic rumble murmur. No opening snap or third sound was audible. An electrocardiogram revealed sinus rhythm with a heart rate of 86beats/min, left atrial overload and normal atrio-ventricular conduction. The chest skiagram showed mild left atrial prominence. Routine Laboratory tests showed no anaemia, liver dysfunction or renal dysfunction. He underwent detailed transthoracic echocardiographic examination.
Echocardiogram revealed dilated left atrium, normal left ventricle and normal left ventricular function. Mitral valve area by planimetry and the pressure half-time method was 1.02 cm2 with a trans-mitral peak and mean gradient of 9 and 5 mmHg respectively. Abnormal chordae tendineae with reticular structures attached to a solitary papillary muscle originating from the posteromedial wall was detected (Fig. 1 a, b, c). A small muscular ridge or trabecula was present at the location of anterolateral papillary muscle without any chordal attachment (Fig. 1c). An additional movie file shows this in more detail [see Additional file 1]. No other congenital heart anomalies were identified. A 3D transesophageal echocardiography was performed. Reticular chordae tendineae with scattered holes among them was confirmed (Fig. 1d). An additional movie file shows this in more detail [see Additional file 2]. Thus, the final diagnosis was isolated parachute mitral valve with reticular chordae tendineae and severe mitral stenosis, without any other congenital heart anomalies.
The patient was referred for surgery. The operation was performed through a minimally invasive right thoracotomy with the use of cardiopulmonary bypass. Through an interatrial approach, the mitral annulus, leaflets, chordae tendinae, and papillary muscles were exposed. Valve analysis showed two thickened mitral valve leaflets and commissures, but all the chordae tendinae merged into a solitary papillary muscle. It presented as a funnel-type structure. The chordae tendinae were lengthy and thick. A distinctive reticular fibrous diaphragm with scattered holes obstructing the valvular orifice was found on mitral valve apparatus as the chordae tendinae intermixed each other (Fig. 2). An additional movie file shows this in more detail [see Additional file 3]. The valve naturally was deformed. These anomalies, coupled with their convergent papillary insertion, resulted in restricted leaflet mobility, thus creating a stenotic mitral valve as the leaflets were closely apposed, greatly reducing the effective mitral orifice area. It was seen that the only functional communication between the left atrium and the left ventricular was through the reticular spaces. These spaces did not allow free outflow of blood from the left atrium. The patient was implanted with a #27 St Jude’s prosthesis in mitral position.
The postoperative recovery was uneventful. The patient was discharged 7 days after surgery. At the 5-year follow-up examination, the patient was in good health.
