Effect of magnesium on ventricular fibrillation due to hypothermia.

Ventricular fibrillation in hypothermia develops at an oesophageal temperature of about 27°C. During heart surgery performed under cardiopulmonary bypass, fibrillation at this temperature is noted as a rule. Under such circumstances, however, this otherwise fatal irregularity, in fact, facilitates the work of the surgeon, since the operation can be performed on an immobile heart. Electrical defibrillation used during rewarming of the patient generally does not present difficulties. In certain cases, as in major myocardial injury accompanied by disorders of acidbase balance, and disturbances of the coronary circulation, defibrillation may be achieved with difficulty, and may be successful only after several attempts or may even sometimes be impossible. In an attempt to facilitate defibrillation, we put to trial the well-known anti-arrhythmogenic effect of magnesium in ventricular fibrillation (Antaloczy, 1965; Enselber, Simmonds and Mintz, 1950; Loeb et al., 1963; Surawitz, 1966; Szekeres, 1954).