Intravenous administration of 10 mg verapamil significantly prolonged the AH interval from 99 to 150 msec and increased the effective and functional refractory periods of the AV node.
Observational (n=8)
No
Does intravenous verapamil alter electrophysiological properties in a concentration-dependent manner in patients with paroxysmal supraventricular tachycardia?
Intravenous verapamil prolongs AV nodal conduction and refractoriness in a concentration-dependent manner, providing a pharmacokinetic and electrophysiological basis for its efficacy in terminating paroxysmal supraventricular tachycardia.
Absolute Event Rate: 150% vs 99%
p-value: p=<0.01
Ten mg of verapamil was administered intravenously to eight patients with paroxysmal supraventricular tachycardia. After drug administration, investigation of the pharmacokinetics of verapamil was carried out, and the relationship between plasma verapamil concentration and its electrophysiological effects was studied. After verapamil administration, pharmacokinetic parameters were calculated using a two-compartment open model. Biological half-life ranged from 2.91 to 4.55 hours and apparent volume of distribution ranged from 1.28 to 3.18 L/kg. Total body clearance ranged from 216 to 733 ml/min.Verapamil significantly prolonged the AH interval but did not prolong the HV interval. The effective and the functional refractory period of the AV node (ERPAVN and FRPAVN) were also prolonged after verapamil administration. The antegrade echo zone and the supraventricular tachycardia zone were also narrowed in most patients. A concentration-dependent relationship between plasma verapamil andpercent increase of both ERPAVN and AH interval was observed.
Koike et al. (Sat,) conducted a observational in Paroxysmal supraventricular tachycardia (n=8). Verapamil vs. Pretreatment baseline was evaluated on AH interval at 15 minutes (p=<0.01). Intravenous administration of 10 mg verapamil significantly prolonged the AH interval from 99 to 150 msec and increased the effective and functional refractory periods of the AV node.