Bupivacaine hastens the ischemia-induced decrease of the electrical ventricular fibrillation threshold
| Autor: | Georges Faucon, M. Freysz, L. Bertrix, Quadiri Timour, Joseph Loufoua, Jean F Aupetit |
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| Rok vydání: | 1995 |
| Předmět: |
Tachycardia
Male medicine.medical_specialty medicine.drug_class Swine Ischemia Myocardial Ischemia Action Potentials Blood Pressure Heart Conduction System Internal medicine Heart rate medicine Animals Fibrillation Bupivacaine business.industry Local anesthetic Cardiac Pacing Artificial Heart medicine.disease Anesthesiology and Pain Medicine Coronary occlusion Anesthesia Ventricular fibrillation Ventricular Fibrillation Cardiology Female medicine.symptom business medicine.drug |
| Zdroj: | Anesthesia and analgesia. 80(4) |
| ISSN: | 0003-2999 |
| Popis: | Myocardial ischemia sensitizes the cardiotoxic effects of bupivacaine, especially the propensity to ventricular fibrillation. To investigate this sensitization and to elucidate its mechanism, the influence of bupivacaine alone, or associated with ischemia, was studied on electrical fibrillation threshold in anesthetized, open chest pigs. Determination of fibrillation threshold was performed with impulses of 100 ms duration at the rate of 180 bpm, in the absence of ischemia and at the end of increasing periods of ischemia (30, 60, 120, 180 s) obtained by complete occlusion of the left anterior descending coronary artery close to its origin. The effect of bupivacaine (1.00 mg/kg initial dose plus 0.04 mg.kg-1.min-1 over 25 min) was compared to the control in the same animals. This effect corresponded to 1.4-1.8 micrograms/mL plasma concentrations likely to be observed in humans after regional anesthesia. Bupivacaine significantly increased the fibrillation threshold before coronary occlusion from approximately 7.0 to 9.5 mA. In contrast, during ischemia the fibrillation threshold was shifted to the left and down, with a hastening of spontaneous fibrillation. Recording of monophasic action potentials in the ischemic area revealed that conduction time was prolonged by more than 100% under the combined influence of ischemia and bupivacaine, whereas the major enhancement of excitability due to ischemia was not attenuated by bupivacine. Therefore, bupivacaine should be used with caution in the condition of ischemia, especially if heart rate is rapid. In the present experiments, tachycardia is another factor in the enhancement of bupivacaine effects on conduction. |
| Databáze: | OpenAIRE |
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