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Configuration of linear dynamic cardiomyoplasty for hypoplastic right ventricle
K Morita1, H Kurosawa, S Ishii
1Department of Cardiovascular Surgery, Jikei University School of Medicine, Tokyo, Japan.
Background:
The purpose of this study is to determine feasibility of linear dynamic cardiomyoplasty with a briefly preconditioned latissimus dorsi in the experimental model simulating patch enlargement of the hypoplastic right ventricle.
Methods:
In 8 mongrel dogs, a diminished right ventricular chamber was reconstructed with an extended pericardial patch. A left latissimus dorsi, preconditioned for 2 weeks (2 Hz) after a previous 2-week vascular delay period, was placed on the patch, with the muscle fiber oriented in parallel to the right ventricular long axis.
Results:
Graft pacing with trained-pulses of 25 Hz at a 1:1 ratio showed significant augmentation of pulmonary flow and pressure (158% +/- 21%, 156% +/- 14%, respectively), contributing to restoring right ventricular function comparable with preoperative control, which was also confirmed by the right ventricular function curve and pressure-volume relationship analyzes. Continuous pacing was performed in 4 animals for 7 hours without evidence of muscle fatigue, implying feasibility of "working conditioning" after minimum preconditioning for this type of right heart assist.
Conclusions:
Linear latissimus dorsi myoplasty can restore normal right ventricular performance at a physiologic preload, and may provide a surgical option for the hypoplastic right ventricle.