Atrial cardiomyoplasty after Fontan-type procedures.

The purpose of right atrial cardiomyoplasty is to increase atrial-pulmonary flow in patients undergoing Fontan-type procedures. We developed two surgical techniques to bypass the right ventricle, followed by right atrial cardiomyoplasty with a stimulated latissimus dorsi muscle flap (LDMF). In 10 goats, the left LDMF was transferred into the chest by removal of the second rib. After sternotomy, the right atrial appendages of five goats (group 1) were connected to the distal main pulmonary artery with polytetrafluoroethylene tubing and the proximal pulmonary trunks were ligated. In the other five goats (group 2), under cardiopulmonary bypass, bioprosthetic valves were implanted into the inferior venae cavae. The tricuspid orifice was closed, and the atriopulmonary connection was performed. The left LDMF was sutured over the right atrium and stimulated using synchronous 30-Hz bursts of impulses delivered by a Medtronic Cardiomyostimulator. Hemodynamic studies were performed in the acute phase. Right atrial, pulmonary arterial, and aortic pressures were assessed. Cardiac output was measured using ultrasonic flow studies. LDMF stimulation restored pulsatile pressure patterns in the pulmonary artery and increased the cardiac output. These observations were more evident in the model with caval valvular implant. This functional "ventricularization" of the right atrium could improve long-term results after Fontan-type procedures and extend operative indications. Chronic experimental studies are necessary to evaluate the diastolic and systolic functions of the neo-right ventricle.