Gadler F, Linde C, Juhlin-Dannfeldt A, Ribeiro A, Rydén L
Department of Cardiology, Karolinska Hospital, Stockholm, Sweden.
J Am Coll Cardiol. 1996 Apr;27(5):1219-24. doi: 10.1016/0735-1097(95)00573-0.
This study was designed to show the influence of right ventricular pacing site on left ventricular outflow tract obstruction during pacing treatment of patients with hypertrophic obstructive cardiomyopathy.
Atrioventricular synchronous pacing has been reported to reduce left ventricular outflow obstruction and symptoms in patients with hypertrophic obstructive cardiomyopathy. A paradoxic septal movement induced by right ventricular pacing has been implicated as the mechanism behind the reduced left ventricular outflow tract obstruction; however, the importance of pacing site has not been clarified.
Cardiac output, measured invasively, and left ventricular outflow tract gradient, estimated by Doppler echocardiography, were studied in 15 patients with hypertrophic obstructive cardiomyopathy. Measurements were made with the right ventricular electrode in the septal and apical positions during temporary pacing and during sinus rhythm.
Right ventricular apical pacing reduced the outflow tract gradient in all 15 patients to a mean +/- SD of 38 +/- 24 mm Hg from 96 +/- 33 mm Hg during sinus rhythm. During high septal pacing the outflow tract gradient was not reduced, remaining at 93 +/- 44 mm Hg. No significant changes in cardiac output were seen when levels during sinus rhythm (6.4 liters/min), apical pacing (6.4 liters/min) and high septal pacing (5.6 liters/min) were compared.
The right ventricular pacing site is of crucial importance for reducing left ventricular outflow tract obstruction when patients with hypertrophic obstructive cardiomyopathy are treated with pacing. Cardiac output is not reduced by apical pacing.
本研究旨在表明右心室起搏部位对肥厚型梗阻性心肌病患者起搏治疗期间左心室流出道梗阻的影响。
据报道，房室同步起搏可减轻肥厚型梗阻性心肌病患者的左心室流出道梗阻及症状。右心室起搏引起的矛盾性室间隔运动被认为是左心室流出道梗阻减轻的机制；然而，起搏部位的重要性尚未阐明。
对15例肥厚型梗阻性心肌病患者进行了有创测量的心输出量以及通过多普勒超声心动图估算的左心室流出道压差的研究。在临时起搏期间及窦性心律期间，将右心室电极置于间隔和心尖位置进行测量。
15例患者右心室心尖部起搏均使流出道压差从窦性心律时的96±33mmHg降至平均±标准差38±24mmHg。高位间隔起搏时流出道压差未降低，仍为93±44mmHg。比较窦性心律时（6.4升/分钟）、心尖部起搏时（6.4升/分钟）和高位间隔起搏时（5.6升/分钟）的心输出量水平，未见显著变化。
在对肥厚型梗阻性心肌病患者进行起搏治疗时，右心室起搏部位对于减轻左心室流出道梗阻至关重要。心尖部起搏不会降低心输出量。
