de Micheli A, Medrano G A, Casanova J M
Departamento de Farmacología del Instituto Nacional de Cardiología Ignacio Chávez, México.
Arch Inst Cardiol Mex. 1995 Nov-Dec;65(6):484-95.
Experimental ventricular tachycardias (VT) were provoked in dog hearts with minute crystals of aconitine introduced into the periphery of an infarcted area, produced by intramural injection of 1-1.5 ml of phenol. The response of these tachycardias to verapamil was studied. Leads II, aVL, intraventricular right and left unipolar records, as well as one on the superior vena cava were registered under control conditions, with VT and after the injection of the antiarrhythmic agent. This injection was infused into superior vena cava over 15-20 minutes. Records were obtained with constant intervals, waiting for the recovery of sinus rhythm (SR) and the posterior reappearance of ventricular tachycardia. The experiments were performed 6 to 8 hs with continuous infusion of Hartmann's solutions. Throughout these periods, the variations of systemic systolic pressure were registered. Of the 75 dogs treated with 0.2 mg/kg of verapamil, SR was recovered transiently in 30 (40%), while it exerted no antiarrhytmic effect in 19 (25%). Arterial systolic pressure fell importantly in 10 animals (13%). In 3 other groups, of 15 dogs each, comparative administration of verapamil vs lidocaine (I), vs mexiletine (II) and vs propafenone (III), was tried. In Group I, verapamil reestablished transient SR in 73% and lidocaine in only 7%; in II, SR resulted from verapamil in 33% and from mexiletine in 7%; in III, SR reappeared in 21% with verapamil and in 28% with propafenone. The repeated positive effect of verapamil was found in 33% of 15 experiments. This drug is effective in certain experimental ventricular tachycardias, probably related to calcium-dependent potentials.
通过向由壁内注射1 - 1.5毫升苯酚产生的梗死区域周边引入乌头碱微晶，在犬心脏中诱发实验性室性心动过速（VT）。研究了这些室性心动过速对维拉帕米的反应。在对照条件下、出现室性心动过速时以及注射抗心律失常药物后，记录II导联、aVL导联、心室内右和左单极记录以及上腔静脉的一个记录。该注射剂在15 - 20分钟内注入上腔静脉。以恒定间隔获取记录，等待窦性心律（SR）恢复以及室性心动过速再次出现。实验持续6至8小时，持续输注哈特曼溶液。在此期间，记录体循环收缩压的变化。在75只接受0.2毫克/千克维拉帕米治疗的犬中，30只（40%）窦性心律短暂恢复，而19只（25%）未产生抗心律失常作用。10只动物（13%）动脉收缩压显著下降。在另外3组中，每组15只犬，尝试比较维拉帕米与利多卡因（I组）、与美西律（II组）以及与普罗帕酮（III组）的给药效果。在I组中，维拉帕米使73%的犬窦性心律短暂恢复，而利多卡因仅使7%的犬恢复；在II组中，维拉帕米使33%的犬恢复窦性心律，美西律使7%的犬恢复；在III组中，维拉帕米使21%的犬窦性心律再次出现，普罗帕酮使28%的犬出现。在15次实验中的33%发现维拉帕米有反复的阳性作用。该药物在某些实验性室性心动过速中有效，可能与钙依赖性电位有关。
