Paparella N, Cappato R, Alboni P
Divisione di Cardiologia, Ospedale Civile-Cento.
G Ital Cardiol. 1993 Jan;23(1):29-37.
The influences of the sympathetic tone on the conduction in the Kent bundle have been widely investigated; on the contrary, very little is known about the effects of the vagal tone on such a bypass. Vagal influences on Kent bundle can be adequately investigated only after sympathetic blockade.
An electrophysiological study was performed in 12 subjects with Wolff-Parkinson-White syndrome (7 F and 5 M, age: 30 +/- 17 years) during basal state, after beta-blockade (propranolol 0.2 mg/Kg iv) and after atropine (0.04 mg/Kg iv).
In no subject were signs of organic heart disease present. The anterograde effective refractory period of the bypass significantly lengthened after propranolol (291 +/- 65 ms vs 313 +/- 52 ms, p < .01), and shortened after atropine (313 +/- 52 ms vs 290 +/- 46 ms, p < .01). This parameter showed no significant differences in the basal state nor after complete autonomic blockade. The longest pacing atrial cycle length for a second degree atrio-ventricular block in the bypass significantly lengthened after propranolol (322 +/- 55 ms vs 383 +/- 44 ms, p < .01) and shortened after atropine, even if the variation was not statistically significant (383 +/- 44 ms vs 368 +/- 39 ms, p: NS); such a parameter was significantly more prolonged after complete autonomic blockade than in the basal state (p < .05). The retrograde conduction in the bypass showed a similar behaviour: the retrograde effective refractory period and the longest ventricular pacing cycle length for a second degree ventriculo-atrial block significantly lengthened after propranolol (434 +/- 133 ms vs 532 +/- 188 ms, p < .01 and 398 +/- 150 ms vs 492 +/- 179 ms, p < .01, respectively) and shortened after atropine (532 +/- 188 ms vs 464 +/- 157 ms, p < .01, and 492 +/- 179 ms vs 431 +/- 158 ms, p < .05, respectively). These parameters were more prolonged after complete autonomic blockade than in the basal state (p < .05).
These data evidence a vagal influence on the conduction in the resting Kent bundle; the vagal effect appears, however, less marked than the sympathetic one.
交感神经张力对肯特束传导的影响已得到广泛研究；相反，关于迷走神经张力对这种旁路的影响却知之甚少。只有在交感神经阻滞之后，才能充分研究迷走神经对肯特束的影响。
对12例预激综合征患者（7例女性，5例男性，年龄：30±17岁）在基础状态、β受体阻滞剂（静脉注射普萘洛尔0.2mg/kg）后及阿托品（静脉注射0.04mg/kg）后进行电生理研究。
所有患者均无器质性心脏病体征。普萘洛尔治疗后旁路的前向有效不应期显著延长（291±65ms对313±52ms，p<.01），阿托品治疗后缩短（313±52ms对290±46ms，p<.01）。该参数在基础状态及完全自主神经阻滞后无显著差异。旁路中二度房室传导阻滞的最长起搏心房周期长度在普萘洛尔治疗后显著延长（322±55ms对383±44ms，p<.01），阿托品治疗后缩短，尽管差异无统计学意义（383±44ms对368±39ms，p：无显著性差异）；该参数在完全自主神经阻滞后比基础状态下显著延长（p<.05）。旁路的逆向传导表现出类似的行为：普萘洛尔治疗后逆向有效不应期及二度室房传导阻滞的最长心室起搏周期长度显著延长（分别为434±133ms对532±188ms，p<.01及398±150ms对492±179ms，p<.01），阿托品治疗后缩短（分别为532±188ms对464±157ms，p<.01及492±179ms对431±158ms，p<.05）。这些参数在完全自主神经阻滞后比基础状态下延长更明显（p<.05）。
这些数据证明迷走神经对静息肯特束的传导有影响；然而，迷走神经的作用似乎不如交感神经的作用明显。
