Comparative pharmacodynamics of intravenous lidocaine in patients with acute and chronic ventricular arrhythmias.
OBJECTIVE
To evaluate the pharmacodynamics of intravenous lidocaine in patients with acute-onset and chronic ventricular arrhythmias.


METHODS
Open-label, pharmacodynamic evaluation.


METHODS
Private, university-affiliated, hospital coronary-care unit.


METHODS
Twenty cardiac patients with acute-onset ventricular ectopy and 20 with chronic ventricular ectopy.


METHODS
Intravenous lidocaine was administered to all patients as a 1-mg/kg bolus, a 0.5-mg/kg bolus, and a 2.8-mg/min constant infusion for 48 hours.


METHODS
Changes in ventricular premature beat (VPB) frequency against total treatment period frequency and by an hour-to-hour assessment of changes in VPB frequency compared with total baseline frequencies. Response was defined as greater than or equal to 80 percent total VPB reduction, greater than or equal to 90 percent paired VPB reduction, and total abolition of nonsustained ventricular tachycardia events.


RESULTS
A statistically significant difference in the pharmacodynamic effects of lidocaine were observed during the first eight hours of treatment in patients with acute-onset and chronic VPBs. The number of patients with acute-onset VPBs who responded to lidocaine in the first hour of treatment did not change significantly over the remaining hours of treatment. Response to lidocaine was less in patients with chronic VPBs than in patients with acute-onset VPBs. The response rate to lidocaine was significantly less during the first eight hours in patients with chronic VPBs than in patients with acute-onset VPBs. Following eight hours of treatment, the response rates between acute-onset and chronic VPB patients were not significantly different. Mean lidocaine plasma concentrations were not different between the groups. In addition, there were no significant differences in the incidence of adverse effects between the two groups.


CONCLUSIONS
The onset of antiarrhythmic effect as measured by suppression of ventricular ectopy is delayed in patients with chronic VPBs compared with patients with acute-onset VPBs. Decisions about lidocaine response in patients with chronic VPBs cannot be made accurately in the first eight hours of therapy.
Hilleman
D E
DE
Creighton University Cardiac Center, Omaha, NE 68131.
Mohiuddin
S M
SM
Mooss
A N
AN
Hunter
C B
CB
Destache
C J
CJ
Sketch
M H
MH
D000208:Acute Disease; D000368:Aged; D001145:Arrhythmias, Cardiac / Q000188:drug therapy / Q000503:physiopathology*; D002908:Chronic Disease; D005260:Female; D006352:Heart Ventricles; D006801:Humans; D007262:Infusions, Intravenous; D008012:Lidocaine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D008991:Monitoring, Physiologic; D013997:Time Factors
D008012:Lidocaine