Reiter M J, Mann D E
Department of Medicine, University of Colorado Health Sciences Center, Denver 80262.
Am J Cardiol. 1990 Mar 1;65(9):623-7. doi: 10.1016/0002-9149(90)91041-4.
The electrophysiologic effects of 45 degrees head-up tilt were studied in 19 patients with atrioventricular accessory pathways. Upright posture enhanced both anterograde and retrograde accessory pathway conduction when compared to the supine position: the anterograde block cycle length decreased from 374 +/- 52 ms (mean +/- standard error) (supine) to 303 +/- 33 ms (tilt) (p less than 0.05); anterograde effective refractory period decreased from 286 +/- 17 to 249 +/- 10 ms (p less than 0.05); retrograde block cycle length shortened from 331 +/- 36 to 291 +/- 35 ms (p less than 0.05); retrograde effective refractory period decreased from 312 +/- 26 ms to 274 +/- 15 ms (p less than 0.05). During induced atrial fibrillation the mean RR interval and the shortest RR interval between preexcited beats decreased approximately 10% with head-up tilt. During orthodromic reciprocating tachycardia, tachycardia cycle length shortened 15%. Tachycardia rate during electrophysiologic study in the head-up position more closely approximated the rate of clinical tachycardia than did the rate in the supine position. Head-up tilt significantly enhances anterograde and retrograde accessory pathway conduction, increases the rate of arrhythmias using an accessory pathway and may be clinically useful in the assessment of patients with an accessory pathway.
对19例患有房室旁道的患者研究了45度头高位倾斜的电生理效应。与仰卧位相比，直立姿势增强了顺行和逆行旁道传导：顺行阻滞周期长度从374±52毫秒（平均值±标准误）（仰卧位）降至303±33毫秒（倾斜位）（p<0.05）；顺行有效不应期从286±17毫秒降至249±10毫秒（p<0.05）；逆行阻滞周期长度从331±36毫秒缩短至291±35毫秒（p<0.05）；逆行有效不应期从312±26毫秒降至274±15毫秒（p<0.05）。在诱发房颤期间，头高位倾斜时平均RR间期和预激搏动之间的最短RR间期减少约10%。在顺向折返性心动过速期间，心动过速周期长度缩短15%。与仰卧位时的心率相比，头高位时电生理研究期间的心动过速心率更接近临床心动过速的心率。头高位倾斜显著增强顺行和逆行旁道传导，增加使用旁道的心律失常发生率，可能在评估有旁道的患者时具有临床应用价值。
