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KMID : 0377519840090040541
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Chung-Ang Journal of Medicine
1984 Volume.9 No. 4 p.541 ~ p.547
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Effect of Antiarrhytmic Agents on Action Potential and Contractility of Rabbit Papillary Muscle
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Ahn Yong-Jin
Lee Chung-Soo
Lee Kwang-Soo
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Abstract
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In papillary muscles of rabbit right ventricle, The effect of antiarrhythmic agents on the transmembrane action potential and isometric tension were investigated. The change of pattern of action potential and isometric tension following the administration of several antiarrhythmic agents in concentrations from 10^-8-10^-4 mole/L was recorded. The resting membrane potential, amplitude of action potential, amplitude of overshoot potential, duration of action potential and maximal rate of depolarization were recorded during exposure to antiarrhythmic agents. The following results were obtained. 1. Lidocaine, procaineamide, propranolol and diltiazem depressed myocardial contractility in a dose dependent manner. 2. Lidocaine significantly shortened the duration of action potential, however quinidine and procaineamide increased the duration of action potential. 3. Propranolol, procaineamide and quinidine decreased the peak maximal rate of phase 0 depolarization (Vmax) in a dose dependent manner, but lidocaine decreased the Vmax in only high concentrations. The above results indicate that antiarrhythmic agents alter the electrophysiologic character of cardiac muscle cell differently. This suggests that procaineamide and quinidine may act through the similar mechanism which not shared by lidocaine.
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