Fujino H, Fujiseki Y, Shimada M
Department of Pediatrics, Shiga University of Medical Science, Otsu.
J Cardiol. 1989 Mar;19(1):307-15.
Calcium channel blockers (diltiazem or verapamil) were administered in 17 pediatric patients with supraventricular tachycardia to evaluate their drug effects on electrophysiologic properties and the tachycardia zone. Using electrophysiologic technique, 10 patients were diagnosed as having orthodromic reciprocating tachycardia (ORT), including three patients with concealed atrioventricular bypass tracts. Four patients were diagnosed as having atrioventricular nodal re-entrant tachycardia (AVNRT) of the slow-fast type and three patients were diagnosed as having intra-atrial re-entrant tachycardia (IART). Diltiazem was given to 10 patients; verapamil, to eight patients at doses of 0.15-0.2 mg/kg intravenously. Electrophysiologic properties and the tachycardia zone were then evaluated before and after the administration of calcium channel blockers. Diltiazem and verapamil produced no significant changes in the sinus node and atrial functions including basic sinus cycle length, sinoatrial conduction time, maximum sinus node recovery time and the effective atrial refractory period. Although sinus cycle length was shortened after verapamil in half the cases, it was due to increased sympathetic tone secondary to hypotension rather than to direct action of verapamil. Calcium channel blockers, however, prolonged the PR interval and significantly increased the effective refractory period of the atrioventricular node. Properties of the atrioventricular bypass tracts were not affected by calcium channel blockers. Diltiazem and verapamil were markedly effective in ORT and AVNRT. Their re-entrant circuits, including the atrioventricular node and the tachycardia zones, were shortened or resolved. However, IART showed no significant change in the tachycardia zone after the administration of calcium channel blockers, because the re-entrant circuit was not present within the atrioventricular node.(ABSTRACT TRUNCATED AT 250 WORDS)
对17例室上性心动过速患儿使用钙通道阻滞剂（地尔硫䓬或维拉帕米），以评估其对电生理特性及心动过速区域的药物作用。采用电生理技术，10例患者被诊断为顺向型房室折返性心动过速（ORT），其中3例有隐匿性房室旁路。4例患者被诊断为慢快型房室结折返性心动过速（AVNRT），3例患者被诊断为房内折返性心动过速（IART）。10例患者给予地尔硫䓬；8例患者给予维拉帕米，静脉注射剂量为0.15 - 0.2mg/kg。然后在给予钙通道阻滞剂前后评估电生理特性及心动过速区域。地尔硫䓬和维拉帕米对窦房结和心房功能无显著影响，包括基础窦性周期长度、窦房传导时间、最大窦房结恢复时间及有效心房不应期。虽然半数病例在使用维拉帕米后窦性周期长度缩短，但这是由于低血压继发交感神经张力增加，而非维拉帕米的直接作用。然而，钙通道阻滞剂延长了PR间期，并显著增加了房室结的有效不应期。房室旁路的特性不受钙通道阻滞剂影响。地尔硫䓬和维拉帕米对ORT和AVNRT显著有效。其折返环路，包括房室结和心动过速区域，缩短或消失。然而，IART在给予钙通道阻滞剂后心动过速区域无显著变化，因为折返环路不在房室结内。（摘要截选至250字）
