A 33 - year old woman presented to our cardiology service with signs and symptoms of congestive heart failure.
Her medical history was unremarkable, however a year ago and soon after her third child delivery, she had been admitted in another hospital for acute pulmonary oedema after labor.
Cor triatriatum with obstructive behavior causing pulmonary hypertension had bee diagnosed, while the left ventricle was structurally and functionally intact.
The patient at that time denied surgey and had been discharged on medical therapy.
At present admission the patient presented with NYHA functional class III, symptoms of heart failure and palpittions as a result of persistent atrial flutter.
On physical examination a loud pulmonary component of the 2nd heart sound and a diastolic murmur was heard in the mitral area.
Signs of right-sided heart failure were absent.
A transthoracic echocardiography revealed a moderately dilated left ventricle (LV), globally hypokinetic, with severely impaired systolic function (EF estimated ≥30%).
Left atrium (LA) was dilated, with a mobile, membrane-like echogenic structure into it.
Transesophageal echocardiogram (TEE) documented a fibromuscular membrane across the LA, dividing it into two compartments, a proximal one receiving the pulmonary venous flow and a distal one containing the left atrial appendage (LAA).
The two chambers communicated via a non-restrictive orifice, but the membrane prolapsed towards the mitral valve inflow causing severe obstruction.
Mitral valve appeared normal, with mild regurgitation.
Patent foramen ovale (PFO), atrial septal defect (ASD) and anomalous venous connections were ruled out and the diagnosis of cor triatriatum was reconfirmed.
Magnetic resonance imaging ( MRI) of the heart also revealed the fibromuscular septum into the left atrium and the low left ventricular ejection fraction [(LVEF) 30%, cardiac index 1,6 L/min/m2, cardiac output 2,7 L/min] (figure ​1).
Coronary angiography showed normal coronary arteries.
With these findings the patient was scheduled for surgery.
Anesthetic induction was achieved with standard technique including administration of sodium pentothal, sevofluorane, fentanyl and muscle relaxant.
Invasive monitoring included the use of right radial arterial lines, a pulmonary artery catheter and a foley catheter with temperature probe to measure bladder temperature as an indicator of core body temperature.
Transesophageal echocardiography (TEE) was also instituted.
Surgery was performed through a median sternotomy.
Connection to cardiopulmonary bypass (CPB) was achieved by standard ascending aorta and bicaval cannulation.
Mildly hypothermic (32°C) CPB was established.
Cold blood cardioplegia was administered in an antegrade fashion through the aortic root after clamping the aorta.
The interatrial groove was developed and the common pulmonary venous chamber of the left atrium was opened through a vertical incision anterior to the right pulmonary veins, exactly as for mitral valve surgery.
After insertion of a self-retaining retractor to facilitate exposure, the diaphragm was exposed and the central hole in it was identified.
A preliminary incision out from the hole improved exposure for the definitive excision.
Orifices of the pulmonary veins on both sides were located.
Position of the atrial septum was also identified by a small opening in the right atrium and by inserting a curved clamp to displace the septum into the common pulmonary venous chamber of the left atrium.
There was no atrial septal defect or patent foramen ovale.
The diaphragm was then easily completely excised exposing the mitral valve (figure ​2).
The left atrial appendage was closed from inside the left atrium using a running 3-0 polypropylene suture to prevent future thrombus formation.
The atriotomy incisions were closed, the heart having been filled with blood before the last few sutures were placed.
The patient was rewarmed, the aortic cross-clamp was removed and additional de-airing was carried out in the usual manner.
CPB was terminated with minimal inotropic support, involving milrinone and levophed with good hemodynamics.
The postoperative course was uneventful and the patient was extubated after 12 hours and discharged from the hospital on the fifth postoperative day.
At 3 months follow-up, the patient was asymptomatic (NYHA class I), in sinus rhythm.
TTE and MRI revealed a mildly dilated LV with great improvement in systolic function and an estimated LVEF of 50%.