Ingemansson M P, Holm M, Olsson S B
Department of Cardiology, University Hospital, Lund, Sweden.
Heart. 1998 Jul;80(1):71-6. doi: 10.1136/hrt.80.1.71.
To determine the effects of upright posture compared with supine position on the dominant atrial cycle length (DACL) in patients with chronic atrial fibrillation.
The power/frequency spectrum of QRST suppressed lead V1 ECG was studied in 14 patients in the supine position and during the head up tilt table test. The DACL changes were compared with changes in heart rate and blood pressure.
Compared with the supine position, the upright position reduced the DACL from 160 to 150 ms (p < 0.01). The DACL was increased after returning to the supine position from the upright position, from 147 to 154 ms (p < 0.01). Heart rate increased from 91 beats/min in the supine position to 106 in the upright position (p < 0.01). There was a decrease in heart rate from 109 beats/min in the upright position to 93 after returning to the supine position (p < 0.01). No significant changes were seen in systolic or diastolic blood pressure. There were indications of an inverse relation between DACL and heart rate when comparing the supine position before and after tilt with the upright position (p < 0.001).
The sympathetic stimulation and vagal withdrawal induced by rising to upright body position are associated with a decrease in DACL during chronic atrial fibrillation. Thus a reflex increase in sympathetic discharge after induction of atrial fibrillation could favour the persistence of the arrhythmia.
确定慢性心房颤动患者直立姿势与仰卧位相比对主导心房周期长度（DACL）的影响。
对14例患者在仰卧位及头高位倾斜试验期间的QRST压低的V1导联心电图的功率/频率谱进行研究。将DACL的变化与心率和血压的变化进行比较。
与仰卧位相比，直立位使DACL从160毫秒降至150毫秒（p<0.01）。从直立位恢复到仰卧位后，DACL从147毫秒增加到154毫秒（p<0.01）。心率从仰卧位的91次/分钟增加到直立位的106次/分钟（p<0.01）。从直立位恢复到仰卧位后，心率从109次/分钟降至93次/分钟（p<0.01）。收缩压和舒张压未见明显变化。比较倾斜前后的仰卧位与直立位时，DACL与心率之间存在负相关趋势（p<0.001）。
慢性心房颤动期间，起身至直立位引起的交感神经刺激和迷走神经撤离与DACL降低有关。因此，心房颤动诱发后交感神经放电的反射性增加可能有利于心律失常的持续存在。
