AIMS Diagnostic criteria for ambulatory blood pressure monitoring (ABPM) in patients with suspected reflex syncope are lacking. The study hypothesis was that patients with reflex syncope have a higher prevalence of systolic blood pressure (SBP) drops on ABPM. METHODS AND RESULTS ABPM data from reflex syncope patients and controls, matched by average 24 h SBP, age, sex, and hypertension were compared. Patients with constitutional hypotension, orthostatic hypotension, and predominant cardioinhibition during carotid sinus massage or prolonged electrocardiogram monitoring or competing causes of syncope were excluded. Daytime and nighttime SBP drops (<110, 100, 90, 80 mmHg) were assessed. Findings were validated in an independent sample. In the derivation sample, daytime SBP drops were significantly more common in 158 syncope patients than 329 controls. One or more daytime drops <90 mmHg achieved 91% specificity and 32% sensitivity [odds ratio (OR) 4.6, P < 0.001]. Two or more daytime drops <100 mmHg achieved 84% specificity and 40% sensitivity (OR 3.5, P = 0.001). Results were confirmed in the validation sample of 164 syncope patients and 164 controls: one or more daytime SBP drops <90 mmHg achieved 94% specificity and 29% sensitivity (OR 6.2, P < 0.001), while two or more daytime SBP drops <100 mmHg achieved 83% specificity and 35% sensitivity (OR 2.6, P < 0.001). CONCLUSION SBP drops during ABPM are more common in reflex syncope patients than in controls. Cut-off values that may be applied in clinical practice are defined. This study expands the current indications for ABPM to patients with reflex syncope.

中文翻译：

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24 小时动态血压监测期间的低血压与反射性晕厥之间的关联：SynABPM 1 研究。

AIMS 缺乏对疑似反射性晕厥患者动态血压监测 (ABPM) 的诊断标准。研究假设是反射性晕厥患者在 ABPM 时收缩压 (SBP) 下降的患病率较高。方法和结果 比较反射性晕厥患者和对照组的 ABPM 数据，与平均 24 小时 SBP、年龄、性别和高血压相匹配。排除有全身性低血压、体位性低血压和颈动脉窦按摩或长时间心电图监测期间主要心脏抑制或晕厥的竞争原因的患者。评估了白天和夜间 SBP 下降 (<110, 100, 90, 80 mmHg)。调查结果在独立样本中得到验证。在推导样本中，158 名晕厥患者的日间 SBP 下降明显高于 329 名对照组。一次或多次日间滴注 <90 mmHg 的特异性为 91%，敏感性为 32% [优势比 (OR) 4.6，P < 0.001]。两次或多次日间滴剂 <100 mmHg 的特异性和敏感性分别为 84% 和 40%（OR 3.5，P = 0.001）。结果在 164 名晕厥患者和 164 名对照的验证样本中得到证实：一次或多次日间 SBP 下降 <90 mmHg 达到 94% 的特异性和 29% 的敏感性（OR 6.2，P < 0.001），而两次或多次日间 SBP 下降 <100 mmHg 的特异性为 83%，敏感性为 35%（OR 2.6，P < 0.001）。结论 ABPM 期间 SBP 下降在反射性晕厥患者中比在对照组中更常见。定义了可用于临床实践的临界值。