Laser myoplasty for hypertrophic cardiomyopathy: In vitro experience in human postmortem hearts and in vivo experience in a canine model (transarteriai) and human patient (intraoperative)

The feasibility of performing a myotomy/myectomy for hypertrophic cardiomyopathy (HC) by means of laser phototherapy was evaluated experimentally in vitro and in vivo, and the procedure then applied to a patient intraoperatively. In vitro experience revealed that the beam of an argon laser, delivered directly or via an optical fiber, could both cut and vaporize myocardium, producing a myotomy/ myectomy morphologically similar to that produced by the conventional blade technique. In vivo experiments, in which the beam of an argon laser was delivered via an optical fiber to the ventricular septum of a canine heart, confirmed that a laser myoplasty could be achieved in 4 of 5 dogs by a transarterial approach. Finally, laser myoplasty was performed intraoperatively in a patient with HC, using a 200-μ fiber interfaced with an argon laser. Measured laser power was 1.5 W; cumulative exposure was less than 4 minutes; the myoplasty was 4 × 1 × 0.5 cm. These investigations establish the feasibility of using laser therapy to create a myoplasty trough that is similar in appearance to that typically achieved by the conventional blade technique. Illumination of the intraventricular operative field and precise modeling of the myoplasty trough constitute the principal advantages of laser myoplasty for HC.