Gauss A, Hübner C, Radermacher P, Georgieff M, Schütz W
Department of Anesthesiology, University of Ulm, Germany.
Anesthesiology. 1998 Mar;88(3):679-87. doi: 10.1097/00000542-199803000-00019.
The incidence of perioperative bradyarrhythmias in patients with bifascicular or left bundle branch block (LBBB) and the influence of an additional first-degree atrioventricular (A-V) block has not been evaluated with 24-h Holter electrocardiographic monitoring. Therefore the authors assessed the rate of block progression and bradyarrhythmia in these patients.
Patients (n = 106) with asymptomatic bifascicular block or LBBB with or without an additional first-degree A-V block scheduled for surgery under general or regional anesthesia were enrolled prospectively. Three patients were excluded. Of the 103 remaining, 56 had a normal P-R interval and 47 had a prolonged one. Holter monitoring (CM2, CM5) was applied to each patient just before induction of anesthesia and was performed for 24 h. The primary endpoint of the study was the occurrence of block progression. As secondary endpoints, bradycardias < 40 beats/min with hemodynamic compromise (systolic blood pressure < 90 mmHg) or asystoles > 5 s were defined.
Block progression to second-degree A-V block and consecutive cardiac arrest occurred in one case of LBBB without a prolonged P-R interval Severe bradyarrhythmias with hypotension developed in another eight patients: asystoles > 5 s occurred in two cases and six patients had bradycardias < 40/min. Pharmacotherapy was successful in these eight patients. There was no significant difference for severe bradyarrhythmias associated with hemodynamic compromise between patients with and without P-R prolongation (P = 1.00).
In patients with chronic bifascicular block or LBBB, perioperative progression to complete heart block is rare. However, the rate of bradyarrhythmias with hemodynamic compromise proved to be relevant. Because an additional first-degree A-V block did not increase the incidence of severe bradyarrhythmias and pharmacotherapy by itself was successful in nearly all cases, routine prophylactic insertion of a temporary pacemaker in such patients should be questioned.
双分支或左束支传导阻滞（LBBB）患者围手术期缓慢性心律失常的发生率以及额外一度房室（A-V）传导阻滞的影响尚未通过24小时动态心电图监测进行评估。因此，作者评估了这些患者的传导阻滞进展率和缓慢性心律失常情况。
前瞻性纳入计划在全身或区域麻醉下进行手术的无症状双分支阻滞或LBBB患者（n = 106），伴有或不伴有额外一度A-V传导阻滞。排除3例患者。其余103例中，56例P-R间期正常，47例P-R间期延长。在麻醉诱导前对每位患者应用动态心电图监测（CM2、CM5），并持续监测24小时。研究的主要终点是传导阻滞进展的发生情况。作为次要终点，定义了心率<40次/分钟且伴有血流动力学障碍（收缩压<90 mmHg）的心动过缓或停搏>5秒。
1例P-R间期未延长的LBBB患者发生了传导阻滞进展至二度A-V传导阻滞并连续心脏骤停。另外8例患者出现了伴有低血压的严重缓慢性心律失常：2例发生停搏>5秒，6例患者心率<40次/分钟。这8例患者药物治疗成功。P-R间期延长和未延长的患者之间，伴有血流动力学障碍的严重缓慢性心律失常发生率无显著差异（P = 1.00）。
慢性双分支阻滞或LBBB患者围手术期进展为完全性心脏传导阻滞的情况罕见。然而，伴有血流动力学障碍的缓慢性心律失常发生率被证明是相关的。由于额外的一度A-V传导阻滞并未增加严重缓慢性心律失常的发生率，且几乎在所有情况下药物治疗本身都很成功，因此对此类患者常规预防性插入临时起搏器应受到质疑。
