Data_Sheet_1_Cardiovascular Autonomic Dysfunction Is the Most Common Cause of Syncope in Paced Patients.docx

Introduction: Syncope and orthostatic intolerance in paced patients constitute a common clinical dilemma. We, thus, aimed to determine the etiology of syncope and/or symptoms of orthostatic intolerance in paced patients.Methods: Among 1,705 patients with unexplained syncope and/or orthostatic intolerance that were investigated by cardiovascular autonomic tests, including Valsalva maneuver, active standing, carotid sinus massage, and tilt-testing, 39 patients (2.3%; age 65.6 years; 39% women) had a cardiac implantable electronic device (CIED). We explored past medical history, diagnoses found during cardiovascular autonomic tests, and the further clinical workup, in case of negative initial evaluation.Results: An etiology was identified during cardiovascular autonomic tests in 36 of the 39 patients. Orthostatic hypotension (n = 16; 41%) and vasovagal syncope (n = 12; 31%) were the most common diagnoses. There were no cases of pacemaker dysfunction. The original pacing indications followed guidelines (sick-sinus-syndrome in 16, atrioventricular block in 16, atrial fibrillation with bradycardia in five). Twenty-two of the 39 patients (56%) had experienced syncope prior to the original CIED implantation. Orthostatic hypotension was diagnosed in seven (32%) and vasovagal syncope in nine (41%) of these patients. Of the 17 patients that had not experienced syncope prior to the original CIED implantation, nine patients (53%) were diagnosed with orthostatic hypotension and vasovagal syncope was diagnosed in three (18%). Of the 39 patients, two had implantable cardioverter-defibrillators to treat malignant ventricular arrhythmias diagnosed after syncopal episodes.Conclusion: Cardiovascular autonomic tests reveal the etiology of syncope and/or orthostatic intolerance in the majority of paced patients. The most common diagnosis was orthostatic hypotension (40%) followed by vasovagal syncope (30%), whereas there were no cases of pacemaker dysfunction. Our results emphasize the importance of a complete diagnostic work-up, including cardiovascular autonomic tests, in paced patients that present with syncope and/or orthostatic intolerance.

引言：在起搏患者中，晕厥和直立性不耐受构成了一种常见的临床难题。因此，本研究旨在确定起搏患者晕厥及/或直立性不耐受的病因。方法：在1,705名经心血管自主神经功能测试（包括Valsalva动作、主动站立、颈动脉窦按摩和倾斜试验）检查出的不明原因晕厥和/或直立性不耐受的患者中，共有39名患者（占2.3%；平均年龄65.6岁；女性占39%）安装了心脏植入式电子装置（CIED）。我们对患者的既往病史、心血管自主神经功能测试中发现的诊断以及初步评估结果为阴性时的进一步临床检查进行了探究。结果：在39名患者中，有36名患者在心血管自主神经功能测试中确定了病因。其中，直立性低血压（n = 16；占41%）和血管迷走性晕厥（n = 12；占31%）是最常见的诊断。未发现起搏器功能障碍。原发性的起搏适应症遵循了指南（16例为病态窦房结综合征，16例为房室传导阻滞，5例为伴有心动过缓的房颤）。在39名患者中，有22名（占56%）在原发CIED植入前经历过晕厥。其中，7名（占32%）被诊断为直立性低血压，9名（占41%）被诊断为血管迷走性晕厥。在原发CIED植入前未曾经历晕厥的17名患者中，有9名（占53%）被诊断为直立性低血压，3名（占18%）被诊断为血管迷走性晕厥。在39名患者中，有2名在晕厥发作后诊断为恶性室性心律失常，并安装了植入式心脏除颤器。结论：心血管自主神经功能测试揭示了大多数起搏患者晕厥及/或直立性不耐受的病因。最常见的诊断是直立性低血压（占40%），其次是血管迷走性晕厥（占30%），且未发现起搏器功能障碍。我们的研究结果强调了在出现晕厥和/或直立性不耐受的起搏患者中进行全面诊断检查的重要性，包括心血管自主神经功能测试。