Miranda Cláudia Madeira, Silva Rose Mary Ferreira Lisboa da
Serviço de Cardiologia, Hospital Madre Teresa, Belo Horizonte, MG, Brazil.
Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil.
Arq Bras Cardiol. 2016 Dec;107(6):568-575. doi: 10.5935/abc.20160177.
Cardioinhibitory vasovagal response is uncommon during the tilt test (TT). Heart rate variability (HRV) by use of spectral analysis can distinguish patients with that response.
To compare the HRV in patients with cardioinhibitory vasovagal syncope (case group - G1) with that in patients without syncope and with negative response to TT (control group - G2).
64 patients were evaluated (mean age, 36.2 years; 35 men) and submitted to TT at 70 degrees, under digital Holter monitoring. The groups were paired for age and sex (G1, 40 patients; G2, 24).
In G1, 21 patients had a type 2A response and 19 had type 2B, with mean TT duration of 20.4 minutes. There was a greater low frequency (LF) component (11,6 versus 4,5 ms2, p=0.001) and a lower low/high frequency ratio in the supine position (3,9 versus 4,5 ms2, p=0.008) in G1, with no difference during TT between the groups. Applying the receiver operating characteristic curve for cardioinhibitory response, the area under the curve was 0.74 for the LF component in the supine position (p = 0.001). The following were observed for the cutoff point of 0.35 ms(2) for the LF component: sensitivity, 97.4%; specificity, 83.3%; positive predictive value, 85.3%; negative predictive value, 96.9%; and positive likelihood ratio, 5.8.
HRV in the supine position allowed identifying patients with syncope and cardioinhibitory response with a high negative predictive value and likelihood ratio of 5.8.
在倾斜试验（TT）期间，心脏抑制性血管迷走反应并不常见。使用频谱分析的心率变异性（HRV）可以区分有该反应的患者。
比较心脏抑制性血管迷走性晕厥患者（病例组 - G1）与无晕厥且TT反应阴性的患者（对照组 - G2）的HRV。
对64例患者（平均年龄36.2岁；35名男性）进行评估，并在数字动态心电图监测下于70度进行TT。根据年龄和性别对两组进行配对（G1组40例患者；G2组24例）。
在G1组中，21例患者有2A型反应，19例有2B型反应，平均TT持续时间为20.4分钟。G1组在仰卧位时低频（LF）成分更大（11.6对4.5 ms²，p = 0.001），仰卧位时低/高频比值更低（3.9对4.5 ms²，p = 0.008），两组在TT期间无差异。应用心脏抑制反应的受试者工作特征曲线，仰卧位时LF成分的曲线下面积为0.74（p = 0.001）。对于LF成分的截断点为0.35 ms²，观察到以下结果：敏感性为97.4%；特异性为83.3%；阳性预测值为85.3%；阴性预测值为96.9%；阳性似然比为5.8。
仰卧位时的HRV能够识别出有晕厥和心脏抑制反应的患者，其具有较高的阴性预测值和5.8的似然比。
