Brignole M, Gianfranchi L, Menozzi C, Raviele A, Oddone D, Lolli G, Bottoni N
Laboratory of Electrophysiology and Pacing, Ospedali Riuniti, Lavagna, Italy.
J Am Coll Cardiol. 1993 Oct;22(4):1123-9. doi: 10.1016/0735-1097(93)90426-2.
The purpose of this study was to evaluate the role of autonomic reflexes in the genesis of syncope associated with the onset of paroxysmal atrial fibrillation.
Syncope associated with paroxysmal atrial fibrillation has been interpreted as an ominous finding predictive of rapid ventricular rates. However, various mechanisms may be involved when heart rate is not particularly high.
Forty patients (age 60 +/- 14 years, 20 men, 20 women) with syncope and atrial fibrillation were compared with atrial fibrillation without syncope. Carotid sinus massage and head-up tilt testing (at 60 degrees for 60 min at baseline and during isoproterenol infusion) were performed during sinus rhythm. A positive response was defined as the induction of syncope. Atrial fibrillation was also induced on a tilt table at 60 degrees by means of short bursts of atrial pacing.
Results of carotid sinus massage were positive in 15 (37%) of 40 patients but in no control subjects (p = 0.002). Head-up tilt test findings were positive in 25 (66%) of 38 patients and in 2 (12%) of 16 control subjects (p = 0.0004). The induction of atrial fibrillation in the upright position elicited syncope in 16 (42%) of 38 patients but in none of 16 control subjects (p = 0.001). At the beginning of atrial fibrillation, systolic blood pressure was lower in patients than in control subjects (88 +/- 32 vs. 127 +/- 32 mm Hg), whereas mean heart rate was similar (142 +/- 35 vs. 134 +/- 25 beats/min). The correlation between heart rate and systolic blood pressure was weak (r = 0.35), and in five patients syncope occurred at a heart rate < or = 130 beats/min. At the time of syncope, heart rate decreased (-12 +/- 21 beats/min) in patients with induced syncope, whereas it remained unchanged in patients without induced syncope (+1 +/- 17 beats/min, p = 0.04) or slightly increased in control subjects (+9 +/- 21 beats/min, p = 0.009).
Patients with syncope associated with paroxysmal atrial fibrillation are predisposed to an abnormal neural response during both sinus rhythm and arrhythmia. In some patients the onset of atrial fibrillation triggers vasovagal syncope.
本研究旨在评估自主神经反射在阵发性心房颤动发作相关晕厥发生机制中的作用。
与阵发性心房颤动相关的晕厥被认为是预测快速心室率的不祥征兆。然而，当心率并非特别高时，可能涉及多种机制。
将40例伴有晕厥和心房颤动的患者（年龄60±14岁，男性20例，女性20例）与无晕厥的心房颤动患者进行比较。在窦性心律期间进行颈动脉窦按摩和头高位倾斜试验（基线时60度持续60分钟以及在输注异丙肾上腺素期间）。阳性反应定义为诱发晕厥。还通过短阵心房起搏在60度倾斜台上诱发心房颤动。
40例患者中有15例（37%）颈动脉窦按摩结果为阳性，而对照组无1例阳性（p = 0.002）。38例患者中有25例（66%）头高位倾斜试验结果为阳性，16例对照组中有2例（12%）阳性（p = 0.0004）。在直立位诱发心房颤动时，38例患者中有16例（42%）出现晕厥，而16例对照组中无一例出现晕厥（p = 0.001）。在心房颤动开始时，患者的收缩压低于对照组（88±32 vs. 127±32 mmHg），而平均心率相似（142±35 vs. 134±25次/分钟）。心率与收缩压之间的相关性较弱（r = 0.35），5例患者在心率≤130次/分钟时发生晕厥。在晕厥时，诱发晕厥的患者心率下降（-12±21次/分钟），而未诱发晕厥的患者心率保持不变（+1±17次/分钟，p = 0.04）或对照组心率略有增加（+9±21次/分钟，p = 0.009）。
伴有阵发性心房颤动相关晕厥的患者在窦性心律和心律失常期间均易发生异常神经反应。在一些患者中，心房颤动的发作会触发血管迷走性晕厥。
