Ribeiro Antonio Luiz P, Ferreira Lídia Magda, Oliveira Enilce de, Cruzeiro Paulo C F, Torres Rosália Moraes, Rocha Manoel Otávio Costa
Internal Medicine Department, Medical School of the UFMG, Belo Horizonte, MG, Brazil.
Arq Bras Cardiol. 2004 Jul;83(1):40-4; 35-9. doi: 10.1590/s0066-782x2004001300004. Epub 2004 Aug 18.
To assess the use of the active orthostatic stress test for detecting vagal dysfunction in patients with Chagas' disease with preserved overall systolic function, and to compare it with the respiratory sinus arrhythmia test.
Sixty-one chagasic patients (Ch) and 38 nonchagasic (NCh) patients with no significant evidence of heart disease or systemic diseases underwent Doppler echocardiography and autonomic function tests. The respiratory sinus arrhythmia test was performed through electrocardiographic recording during deep breathing, at 6 ripm, calculating the E:I ratio (mean ratio between the longest expiratory RR interval and the shortest inspiratory RR interval at each cycle). The electrocardiogram was recorded during the act of standing and during the following 30 seconds (active orthostatic stress test), and the max RR/min RR ratio (the longest and shortest RR intervals right after change in posture) was calculated. The indices were adjusted for significant covariables.
The max RR/min RR ratio (NCh: 1.52 [1.44-1.74] x Ch: 1.43 [1.33-1.51], P < 0.001) and the E:I ratio (NCh: 1.38 +/- 0.02 x Ch: 1.25 +/- 0.02, P<0.001) were lower among chagasic patients. A high correlation was observed between the adjusted max RR/min RR ratio and E:I ratio (r = 0.628, P < 0.001), but neither significantly correlated with left ventricular ejection fraction.
Chagasic patients with preserved left ventricular overall systolic function showed a significant reduction in the vagal indices obtained on short-lasting tests, as compared with normal controls. The active orthostatic stress test that, showed a good correlation with the respiratory sinus arrhythmia maneuver, constituted a valid option for the outpatient care assessment of vagal control.
评估主动直立应激试验在检测整体收缩功能保留的恰加斯病患者迷走神经功能障碍中的应用，并将其与呼吸性窦性心律不齐试验进行比较。
61例恰加斯病患者（Ch组）和38例无明显心脏病或全身性疾病证据的非恰加斯病患者（NCh组）接受了多普勒超声心动图和自主神经功能测试。呼吸性窦性心律不齐试验通过在深呼吸时以每分钟6次呼吸的频率进行心电图记录来完成，计算E:I比值（每个周期中最长呼气RR间期与最短吸气RR间期的平均比值）。在站立过程中及随后30秒记录心电图（主动直立应激试验），并计算最大RR/最小RR比值（姿势改变后立即出现的最长和最短RR间期）。对这些指标进行显著协变量调整。
恰加斯病患者的最大RR/最小RR比值（NCh组：1.52[1.44 - 1.74]×Ch组：1.43[1.33 - 1.51]，P < 0.001）和E:I比值（NCh组：1.38±0.02×Ch组：1.25±0.02，P<0.001）较低。调整后的最大RR/最小RR比值与E:I比值之间存在高度相关性（r = 0.628，P < 0.001），但两者均与左心室射血分数无显著相关性。
与正常对照组相比，整体左心室收缩功能保留的恰加斯病患者在短期测试中获得的迷走神经指标显著降低。主动直立应激试验与呼吸性窦性心律不齐操作显示出良好的相关性，是门诊评估迷走神经控制的有效选择。
