Neuromuscular relaxants in non-cardiac surgery after cardiomyoplasty

Dynamic cardiomyoplasty is a therapeutic alternative to heart transplantation in irreversible cardiac insufficiency. Little information exists about the use of muscle relaxants in patients with cardiomyoplasty. In particular, it is not clear if the muscle flap is responsive to neuromuscular blockers. The purpose of this report is to describe the safe use of vecuronium in a patient with cardiomyoplasty.

A 59-yr-old man, after cardiomyoplasty for dilated cardiomyopathy two years earlier, underwent general anaesthesia with fentanyl, propofol and vecuronium during surgery for intestinal ischaemia. Intraoperative transthoracic echocardiography showed that vecuronium did not affect muscle flap motion. Two days after surgery he died in septic shock. Post-mortem histological and immunohistochemical examination showed nervous degeneration of the flap probably as a result of the chronic low frequency pacing. There was also an increase in extrajunctional receptors and an alteration in junctional receptors, as demonstrated by the negative reaction to anti-synaptophysin antibodies, used to identify the neuromuscular plate.

In patients undergoing non-cardiac surgery after previous cardiomyoplasty, muscle relaxants, such as vecuronium, may be used safely. Depolarising agents, such as succinylcholine, should probably be avoided because of the possible exaggerated actions on extrajunctional receptors.