Electrophysiologic Effects of Procaine Amide in Patients with Intraventricular Conduction Delay

Abstract

In 16 patients with intraventricular conduction delay (IVCD) and cardiac arrhythmias, procaine amide (PA) was infused intravenously at rates of 30-40 mg/min until a maximum dose of 750-1,000 mg was administered. His bundle electrograms and plasma PA levels were obtained every 5 min during infusion and for 25 min thereafter. The mean peak PA level (10.2 3.4 ,ug/ml) was achieved at the end of infusion. Mean control A-V nodal conduction times (A-H: 99.5 -+-34 msec) and A-H at peak PA levels (90 + 15.3) did not differ significantly. However, the mean infranodal conduction time (H-Q) at peak PA (68.1 + 14.8 msec) was significantly higher than control measurements (57.6 13 msec) (P < 0.001), with a mean percent increase of 18% (11 msec), and maximal prolongation of H-Q occurred at peak PA blood levels. There was no statistically significant correlation between maximum absolute or percent change in H-Q and control H-Q, control QRS duration, or peak PA levels. One patient with sinus bradyeardia had further decreases in rate and a junctional rhythm after PA. Intravenous administration of PA appears safe and effective for patients with IVCD in terms of arrhythmia control and absence of high degree A-V

Relationship between the pharmacokinetics and pharmacodynamics of procainamide

“…The data from a number of studies of both PCA and quinidine (in which measurements have been made sufficiently soon after a dose) suggest that pharmacologic effects of both drugs are somewhat delayed relative to the time-course of plasma concentrations. 7,10,11,17,25,32 We have been able to quantitate the degree of such delay. It is characterized by a half-time of approximately 7 min.…”

Task Force on Sudden Cardiac Death of the European Society of Cardiology

“…Conflicting data exist concerning the value of HV prolongation to predict the risk of SCD due to bradyarrhythmias in these patients and it is commonly agreed that a prolonged HV interval (>75 ms) is poorly predictive of major events. On the other hand, some experienced authors indicate an HV interval exceeding 100 ms identifies a subgroup of extremely high-risk patients, in whom permanent pacing is essential [474][475][476] . The significance of bundle branch block as an independent marker for SCD is also controversial.…”

Lithium‐Associated Mobitz II Block: Case Series and Review of the Literature

“…Consistent with this hypothesis, the Na + channel blocker procainamide has been shown to prolong His-ventricular conduction times in patients with underlying intraventricular conduction delay. 13 It is therefore possible that Na + channel blockade by lithium could induce infra-Hisian block in patients with a predisposition for conduction disease.…”