Intravenous tetrandrine in terminating acute episodes of paroxysmal supraventricular tachycardia.

The use of intravenous tetrandrine on paroxysmal supraventricular tachycardia (PSVT) in 32 episodes of 27 cases were studied. The single blind test was done by injecting normal saline as placebo for self-control. Ambulatory ECG was recorded continuously. The dose of tetrandrine ranged from 0.12 to 0.21 g. The success rates of conversion of the placebo and tetrandrine were 3.1% and 83.9% respectively, being statistically significant (P less than 0.001). The efficacy of tetrandrine was comparable to that of verapamil (85%). In 4 cases of WPW syndrome one was converted by the placebo, the other 3 by tetrandrine. Those who did not respond to tetrandrine were mostly suffering from organic heart disease and were supposed to have automatic atrial tachycardia. The time needed for conversion ranged from immediacy after intravenous injection to 20 minutes, with an average of 4.6 minutes. The ECG changes of the termination of PSVT were similar to that of verapamil and can be explained as the effect of slow channel antagonists. Tetrandrine may be an alternative to verapamil in the treatment of PSVT.