MECHANISM AND BEHAVIOR OF SYMPTOMATIC TACHYCARDIA

杜克大学医学中心临床药理学和心脏病学部门的研究人员使用兰金综合临床研究中心研究房颤和其他常见心律失常患者。房颤是最常见的心律失常，需要抗心律失常药物治疗，占美国所有心律失常住院治疗的三分之一以上。房颤患者通常正常的心律被快速、不规则的心脏跳动所取代，这可能会导致胸部重击感、呼吸急促、胸痛、头晕或意识丧失。这些时期可能持续几分钟或几小时，或者可能无限期地持续，除非医生给予紧急治疗。在兰金综合临床研究中心进行的研究集中于阐明房颤和心律相关疾病的机制、临床病程和最佳治疗。这些研究集中于测量房颤和阵发性室上性心动过速的自发发生频率。在150例停用抗心律失常药物治疗的患者中，一半患者在约3周内出现自发性症状复发;事实上，约1/5的患者在不到1天内出现心律失常症状复发。房颤患者复发期间的平均心率为132次/min，阵发性室上性心动过速患者为198次/min。在房颤患者中，约1/9的患者发生了第二次心律失常，房扑，与房颤一起沿着记录。无症状性心律失常的发生率约为有症状性心律失常发生率的12倍。奇怪的是，生活质量并不受心律失常发生频率的影响。类似的方法被用于研究植入心律转复除颤器（ICD）的室性心动过速患者。该人群中ICD电击的频率提供了室性心动过速发生率的估计值。约1/3的患者在1个月内发生室性心动过速。这些研究结果对设计慢性抗抑郁药物治疗的临床试验具有重要意义。

Investigators in the Divisions of Clinical Pharmacology and Cardiology at Duke University Medical Center have used the Rankin General Clinical Research Center to study patients with atrial fibrillation and other common disorders of the heart rhythm. Atrial fibrillation is the most common disorder of the heart rhythm requiring treatment with antiarrhythmic drugs, and it accounts for over one-third of all U.S. hospitalizations for arrhythmias. Patients with atrial fibrillation have their usually normal heart rhythm replaced by periods of rapid, irregular heart beating that may cause a sense of pounding in the chest, shortness of breath, chest pain, dizziness, or loss of consciousness. These periods may last for minutes or hours, or they may last indefinitely unless acute treatment is given by a physician. Studies conducted on the Rankin General Clinical Research Center have concentrated on elucidating the mechanism, clinical course, and optimal treatment of atrial fibrillation and related disorders of the heart rhythm. These studies have focused on measuring the frequency of spontaneous occurrence of atrial fibrillation and paroxysmal supraventricular tachycardia. Among 150 patients studied who had their antiarrhythmic drug therapy withdrawn, one-half had a spontaneous, symptomatic recurrence in about 3 weeks; in fact, about 1 in 5 had a symptomatic recurrence of their arrhythmia in less than 1 day. The average heart rate during recurrences was 132 beats/min for patients with atrial fibrillation and 198 beats/min for patients with paroxysmal supraventricular tachycardia. Among the patients with atrial fibrillation, about 1 in 9 had a second arrhythmia, atrial flutter, recorded along with fibrillation. The frequency of asymptomatic arrhythmias was approximately 12 times the rate of symptomatic arrhythmias. Curiously, quality of life was not affected by the frequency of arrhythmia occurrence. Similar methods were used to study patients with ventricular tachycardia who had an implanted cardioverter defibrillator (ICD). The frequency of ICD shocks in this population provided an estimate of the occurrence of ventricular tachycardia. About 1/3 of the patients had an episode of ventricular tachycardia within 1 month. Results of these studies are important for designing clinical trials of chronic antiarrhythmic drug therapy.