Department of Cardiovascular, Neural and Metabolic Sciences, IRCCS, Istituto Auxologico Italiano, Faint & Fall Programme, S. Luca Hospital, Piazzale Brescia 2, 20149 Milan, Italy.
Department of Cardiology, Arrhythmologic Centre, Ospedali del Tigullio, Lavagna, Italy.
Europace. 2022 Jul 21;24(7):1164-1170. doi: 10.1093/europace/euab300.
Syncope without prodromes in subjects with normal heart and normal electrocardiogram (ECG) is classified as non-classical neurally mediated syncope and is characterized by low adenosine plasma levels (APLs) and frequent asystolic syncope. We assessed the efficacy of theophylline, a non-selective adenosine receptor antagonist, in preventing syncopal events.
Participants received an implantable cardiac monitor, underwent APL measurement, and received oral theophylline at maximum tolerated dose (starting dose 300 mg b.i.d.). They were compared with a historical cohort of untreated patients with implantable cardiac monitor who had the same inclusion criteria and were balanced with the propensity score (PS) method as regard age, sex, lifetime syncopal episodes, APL, and antihypertensive drugs. Primary endpoint was time to first syncopal recurrence at 24 months. There were 76 patients in the theophylline group and 58 in the control group. Syncope recurred in 25 (33%) patients in the theophylline group and in 27 (47%) patients in the control group, with an estimated 2-year recurrence rate of 33% and 60%, respectively, and a hazard ratio of 0.53 [95% confidence interval (CI), 0.30-0.95; P = 0.034]. Most of the benefit of theophylline is derived from reduction of syncope due to asystolic atrioventricular (AV) block (hazard ratio of 0.13; 95% CI, 0.03-0.58; P = 0.008). Thirty (39%) patients discontinued theophylline after a median of 6.4 (interquartile range 1.7-13.8) months due to side effects.
Theophylline was effective in preventing recurrences in patients with syncope without prodromes, normal heart, and normal ECG. The benefit was greater in patients with syncope due to asystolic AV block.
CLINICALTRIALS.GOV IDENTIFIER: NCT03803215.
在心脏正常且心电图（ECG）正常的患者中，无先兆晕厥被归类为非经典神经介导性晕厥，其特征为低腺苷血浆水平（APL）和频繁的停搏性晕厥。我们评估了茶碱（一种非选择性腺苷受体拮抗剂）预防晕厥事件的疗效。
参与者接受了植入式心脏监测仪，进行了 APL 测量，并接受了最大耐受剂量的口服茶碱（起始剂量 300mg 每日两次）。他们与接受植入式心脏监测仪治疗的未治疗患者的历史队列进行了比较，并使用倾向评分（PS）方法根据年龄、性别、终生晕厥发作次数、APL 和抗高血压药物进行了平衡。主要终点是在 24 个月时首次复发性晕厥的时间。茶碱组有 76 例患者，对照组有 58 例患者。茶碱组有 25 例（33%）患者发生晕厥复发，对照组有 27 例（47%）患者发生晕厥复发，估计 2 年复发率分别为 33%和 60%，风险比为 0.53 [95%置信区间（CI），0.30-0.95；P=0.034]。茶碱的大部分益处来自于减少因房室（AV）阻滞引起的晕厥（风险比为 0.13；95%CI，0.03-0.58；P=0.008）。由于副作用，30 例（39%）患者在中位数为 6.4 个月（四分位距 1.7-13.8）后停用了茶碱。
茶碱可有效预防无先兆、心脏正常和心电图正常的晕厥患者的复发。对于因停搏性 AV 阻滞引起的晕厥患者，获益更大。
临床试验.gov 标识符：NCT03803215。
