Malfatto Gabriella, Caravita Sergio, Giglio Alessia, Rossi Jessica, Perego Giovanni B, Facchini Mario, Parati Gianfranco
Divisione di Cardiologia, Ospedale San Luca, Istituto Auxologico Italiano IRCCS, Milano, Italy (G.M., S.C., A.G., J.R., G.B.P., M.F., G.P.).
Divisione di Cardiologia, Ospedale San Luca, Istituto Auxologico Italiano IRCCS, Milano, Italy (G.M., S.C., A.G., J.R., G.B.P., M.F., G.P.) Dipartimento di Medicina Clinica, Prevenzione e Biotecnologie Sanitarie, Università di Milano-Bicocca, Milano, Italy (S.C., G.P.).
J Am Heart Assoc. 2015 May 5;4(5):e001678. doi: 10.1161/JAHA.114.001678.
In patients with chronic heart failure, abnormal ventilation at cardiopulmonary testing (expressed by minute ventilation-to-carbon dioxide production, or VE/VCO2 slope, and resting end-tidal CO2 pressure) may derive either from abnormal autonomic or chemoreflex regulation or from lung dysfunction induced by pulmonary congestion. The latter hypothesis is supported by measurement of pulmonary capillary wedge pressure, which cannot be obtained routinely but may be estimated noninvasively by measuring transthoracic conductance (thoracic fluid content 1/kΩ) with impedance cardiography.
Preliminarily, in 9 patients undergoing invasive hemodynamics during cardiopulmonary testing, we demonstrated a significant relationship between VE/VCO2 slope and resting end-tidal CO2 pressure with baseline and peak pulmonary capillary wedge pressure. Later, noninvasive hemodynamic evaluation by impedance cardiography was performed before cardiopulmonary testing in 190 patients with chronic systolic heart failure and normal lung function (aged 67±3 years, 71% with ischemia, ejection fraction 32±7%, 69% with implantable cardioverter-defibrillator or cardiac resynchronization therapy). In this group, we determined the relationship between abnormal ventilation (VE/VCO2 slope and resting end-tidal CO2 pressure) and transthoracic conductance. In the whole population, thoracic fluid content values were significantly related to VE/VCO2 slope (R=0.63, P<0.0001) and to resting end-tidal CO2 pressure (R=-0.44, P<0.001).
In patients with chronic heart failure, abnormal ventilation during exercise may be related in part to pulmonary congestion, as detected by resting baseline impedance cardiography.
在慢性心力衰竭患者中，心肺测试时的异常通气（以分钟通气量与二氧化碳产生量之比，即VE/VCO2斜率，以及静息呼气末二氧化碳分压表示）可能源于自主神经或化学反射调节异常，也可能源于肺充血引起的肺功能障碍。后一种假设得到了肺毛细血管楔压测量的支持，肺毛细血管楔压无法常规获取，但可通过阻抗心动图测量经胸电导（胸液含量1/kΩ）进行无创估计。
首先，在9例心肺测试期间接受有创血流动力学检查的患者中，我们证明了VE/VCO2斜率和静息呼气末二氧化碳分压与基线和峰值肺毛细血管楔压之间存在显著关系。随后，在190例慢性收缩性心力衰竭且肺功能正常的患者（年龄67±3岁，71%有缺血，射血分数32±7%，69%有植入式心脏复律除颤器或心脏再同步治疗）进行心肺测试前，通过阻抗心动图进行无创血流动力学评估。在该组中，我们确定了异常通气（VE/VCO2斜率和静息呼气末二氧化碳分压）与经胸电导之间的关系。在整个研究人群中，胸液含量值与VE/VCO2斜率（R=0.63，P<0.0001）和静息呼气末二氧化碳分压（R=-0.44，P<0.001）显著相关。
在慢性心力衰竭患者中，运动时的异常通气可能部分与肺充血有关，这可通过静息基线阻抗心动图检测到。
