TY - JOUR
T1 - Interaction of metoprolol and lidocaine on the ventricular fibrillation threshold in the anesthetized dog
AU - de Langen, Cees D.J.
AU - William Balke, C.
AU - Spear, Joseph F.
AU - Levine, Joseph H.
AU - Neil Moore, E.
PY - 1988/12
Y1 - 1988/12
N2 - In the present study, we evaluated the antiarrhythmic interaction (s) of metoprolol and lidocaine in 16 dogs using the ventricular fibrillation threshold(VFT) method. The right ventricle was stimulated with a 100 Hz train of 12, 4 ms pulses delivered after every eighth atrial paced beat at a basic cycle length of 300 ms. Lidocaine dosage was 2 mg/kg followed by a 70 μg/kg/min infusion and metoprolol dosage was a 75 μg/kg bolus. In Group 1. lidocaine was followed by metoprolol; in Group 2. first lidocaine then metoprolol and again lidocaine were given: And in Group 3, dogs received first metoprolol. then lidocaine. and subsequently metoprolol. Drug dose intervals were 45 min. In Group I. lidocaine elevated the VFT to 149% ± 20% and metoprolol to 204% ± 30% of control. (p < 0.01). In group 2. the VFT remained elevated after the second lidocaine administration (p < 0.05 vs. Group 1). In Group 3. the VFT was increased by metoprolol to 227%; ± 30% of control (p < 0.01). Interestingly, defibrillation induced by the combination of metoprolol and lidocaine occurred after 3.2 ± 0.5 s in four out of 16 animals (p < 0.05). This chemical'" defibrillation never occurred when only metoprolol or lidocaine alone was administered. Fibrillation was often more organized in the presence of the combination of metoprolol plus lidocaine, which might relate to the observed defibrillation associated with metoprolol plus lidocaine. In conclusion. the combination of metoprolol and lidocaine has no proarrhythmic effects and may enhance the electrical stability of the ventricles as measured by the VFT method
AB - In the present study, we evaluated the antiarrhythmic interaction (s) of metoprolol and lidocaine in 16 dogs using the ventricular fibrillation threshold(VFT) method. The right ventricle was stimulated with a 100 Hz train of 12, 4 ms pulses delivered after every eighth atrial paced beat at a basic cycle length of 300 ms. Lidocaine dosage was 2 mg/kg followed by a 70 μg/kg/min infusion and metoprolol dosage was a 75 μg/kg bolus. In Group 1. lidocaine was followed by metoprolol; in Group 2. first lidocaine then metoprolol and again lidocaine were given: And in Group 3, dogs received first metoprolol. then lidocaine. and subsequently metoprolol. Drug dose intervals were 45 min. In Group I. lidocaine elevated the VFT to 149% ± 20% and metoprolol to 204% ± 30% of control. (p < 0.01). In group 2. the VFT remained elevated after the second lidocaine administration (p < 0.05 vs. Group 1). In Group 3. the VFT was increased by metoprolol to 227%; ± 30% of control (p < 0.01). Interestingly, defibrillation induced by the combination of metoprolol and lidocaine occurred after 3.2 ± 0.5 s in four out of 16 animals (p < 0.05). This chemical'" defibrillation never occurred when only metoprolol or lidocaine alone was administered. Fibrillation was often more organized in the presence of the combination of metoprolol plus lidocaine, which might relate to the observed defibrillation associated with metoprolol plus lidocaine. In conclusion. the combination of metoprolol and lidocaine has no proarrhythmic effects and may enhance the electrical stability of the ventricles as measured by the VFT method
KW - Antiarrhythmic activity
KW - Antifibrillatory activity
KW - Combined drug therapy
KW - Lidocaine
KW - Metoprolol
KW - Ventricular fibrillation
UR - http://www.scopus.com/inward/record.url?scp=0023804198&partnerID=8YFLogxK
U2 - 10.1097/00005344-198812000-00010
DO - 10.1097/00005344-198812000-00010
M3 - Article
C2 - 2467087
AN - SCOPUS:0023804198
VL - 12
SP - 683
EP - 688
JO - Journal of Cardiovascular Pharmacology
JF - Journal of Cardiovascular Pharmacology
SN - 0160-2446
IS - 6
ER -