Jan, 2011
Deep Anesthesia Suppresses Ventricular Tachyarrhythmias in Rabbit Model of the Acquired Long QT Syndrome
CIRCULATION JOURNAL
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- Volume
- 75
- Number
- 1
- First page
- 89
- Last page
- 93
- Language
- English
- Publishing type
- Research paper (scientific journal)
- DOI
- 10.1253/circj.CJ-10-0478
- Publisher
- JAPANESE CIRCULATION SOC
Background: Anesthesia sometimes suppresses ventricular tachyarrhythmias (VT) resistant to conventional pharmacological treatment.
Methods and Results: To know (1) whether deep anesthesia inhibits abnormal repolarization-related VT and (2) if alpha 2-adrenoreceptor (AR) agonistic action is associated with the antiarrhythmic effect of anesthetics, the incidence of VT in a rabbit model of acquired long QT syndrome using different anesthetic regimen was assessed. In Study 1 (n=30), 15 rabbits were lightly anesthetized with ketamine (123 +/- 46 mg/kg) and an alpha 2-AR agonist, xylazine (9.4 +/- 3.0 mg/kg), while combination of these anesthetics at high doses were used in the other 15 rabbits (343 +/- 78 mg/kg and 38.9 +/- 3.0 mg/kg). Administration of alpha 1-AR stimulant, methoxamine and nifekalant (Ikr blocker) caused VT in all lightly anesthetized rabbits. In contrast, VT was observed only in 1 of the 15 deeply anesthetized rabbits (P<0.01). In Study 2 (n=15), 10 rabbits were anesthetized with high-dose ketamine and low-dose xylazine. In the other 5 rabbits, low-dose ketamine and high-dose xylazine were used. QTc interval in the latter was longer than that of the former (399 +/- 56 ms vs. 494 +/- 57 ms, P<0.01). Although no VT appeared in high/low-rabbits, VT occurred in 3 out of 5 low/high-rabbits (P<0.05).
Conclusions: These results suggest that (1) deep anesthesia suppresses abnormal repolarization-related VT and (2) antiarrhythmic effect of anesthesia on this type of VT is not dependent on a2-AR agonistic action. (Circ J 2011; 75: 89-93)
Methods and Results: To know (1) whether deep anesthesia inhibits abnormal repolarization-related VT and (2) if alpha 2-adrenoreceptor (AR) agonistic action is associated with the antiarrhythmic effect of anesthetics, the incidence of VT in a rabbit model of acquired long QT syndrome using different anesthetic regimen was assessed. In Study 1 (n=30), 15 rabbits were lightly anesthetized with ketamine (123 +/- 46 mg/kg) and an alpha 2-AR agonist, xylazine (9.4 +/- 3.0 mg/kg), while combination of these anesthetics at high doses were used in the other 15 rabbits (343 +/- 78 mg/kg and 38.9 +/- 3.0 mg/kg). Administration of alpha 1-AR stimulant, methoxamine and nifekalant (Ikr blocker) caused VT in all lightly anesthetized rabbits. In contrast, VT was observed only in 1 of the 15 deeply anesthetized rabbits (P<0.01). In Study 2 (n=15), 10 rabbits were anesthetized with high-dose ketamine and low-dose xylazine. In the other 5 rabbits, low-dose ketamine and high-dose xylazine were used. QTc interval in the latter was longer than that of the former (399 +/- 56 ms vs. 494 +/- 57 ms, P<0.01). Although no VT appeared in high/low-rabbits, VT occurred in 3 out of 5 low/high-rabbits (P<0.05).
Conclusions: These results suggest that (1) deep anesthesia suppresses abnormal repolarization-related VT and (2) antiarrhythmic effect of anesthesia on this type of VT is not dependent on a2-AR agonistic action. (Circ J 2011; 75: 89-93)
- Link information
- ID information
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- DOI : 10.1253/circj.CJ-10-0478
- ISSN : 1346-9843
- Web of Science ID : WOS:000285814300016