[The effect of calypsol, thiopental sodium and fentanyl on the functional status of the sinoatrial node and the heart conduction system in patients with paroxysmal arrhythmias].

64 patients with paroxysmal arrhythmias caused in 44 cases by collateral atrioventricular pathways have been studied. Endocardial programmed electrical cardiostimulation was applied. It has been established that calypsol at a dose of 2 mg/kg significantly improves the functional state of the sinoatrial node, atrioventricular conduction and conduction in collateral atrioventricular pathways functioning both anterogradely and retrogradely. Fentanyl, already at a dose of 2.5 micrograms/kg inhibits considerably the functional state of the sinoatrial node, without affecting conduction in the normal AV system and in collateral atrioventricular pathways. Thiopental sodium at a dose of 7 mg/kg improves slightly the functional state of the sinoatrial node.