[Ketamine anesthesia for definitive implantation of a cardiac pace maker (author's transl)]

An hemodynamic study has been performed in eight patients (age 68 +/- 7) suffering from complete atrioventricular block. They had to undergo the definitive implantation of a cardiac pace maker under general anesthesia. The fixed cardiac frequency may help to understand the effect of the anesthetic agent used on the cardiac muscle function. Ketamine is the only agent used directly at an initial intravenous dose of 3 mg.kg-1 followed by a perfusion in a constant rate of 0.20 mg.kg-1. min-1. Hemodynamic data (arterial pressure, pulmonary pressures, thermodilution cardiac output) are performed before induction, then every 5 minutes after induction for a 20 minute period. The absence of respiratory depression (PaCO2: 38 +/- 3 mm Hg) shows that hemodynamic changes are entirely due to ketamine. The peak of these changes takes place after 5 minutes (significant rise (p < 0.05) in systemic and pulmonary resistances, in systemic arterial pressure and in pulmonary arterial pressure). Stroke index decreases moderately. After 20 minutes all the parameters have returned to control values. Use of ketamine is not desirable for two reasons: 1 degree The rise of the afterload may alter the hemodynamic state which can be previously deteriorated in patients suffering from atrio-ventricular block. 2 degree Post-anesthetic agitation can displace the right ventricular electrode.