Tomasi Luca, Zanotto Gabriele, Zanolla Luisa, Golia Giorgio, Ometto Renato, Bonanno Carlo, Vergara Giuseppe, Maines Massimiliano, Lonardi Gabriele, Visentin Emanuela, Rauhe Werner, Latina Loredana, Perrone Cosimo, Varbaro Annamaria, DE Santo Tiziana
Divisione Clinicizzata di Cardiologia, Azienda Ospedaliera Istituti Ospitalieri di Verona, Verona, Italy.
Pacing Clin Electrophysiol. 2011 Apr;34(4):407-13. doi: 10.1111/j.1540-8159.2010.02979.x. Epub 2010 Nov 22.
Increased plasma levels of amino-terminal fraction of brain natriuretic peptide (NT-proBNP) and alterations of diastolic filling as described by Doppler transmitral flow pattern are well-known markers of decompensated heart failure (HF). Recently, some implantable defibrillators have allowed monitoring of intrathoracic impedance, which is related to lung water content, potentially indicating HF deterioration. The aim of this study was to assess the correlation between intrathoracic impedance and NT-proBNP and echo-Doppler transmitral flow indexes.
Data were collected from 111 HF patients, in six Italian centers. All patients were on optimal medical therapy. Device diagnostics, echographic data, NT-proBNP determination, and clinical status as assessed by the Heart Failure Score (HFS) were registered at baseline, at bimonthly visits, and at unscheduled examinations due to HF decompensation or device alerts.
Over a median follow-up of 413 days, 955 examinations were performed. Intrathoracic impedance was significantly correlated with NT-proBNP (P = 0.013) and with mitral E-wave deceleration time (DtE) (P = 0.017), but not with HFS. At the time of confirmed alert events, NT-proBNP was significantly higher than during confirmed nonalert event examinations; DtE did not differ, whereas impedance was significantly lower.
A decrease in intrathoracic impedance is inversely correlated with NT-proBNP and directly correlated with DtE. Intrathoracic impedance monitoring therefore has the physiologic basis for being a useful tool to identify early HF decompensation.
脑钠肽氨基末端片段（NT-proBNP）血浆水平升高以及多普勒二尖瓣血流模式所描述的舒张期充盈改变是失代偿性心力衰竭（HF）的众所周知的标志物。最近，一些植入式除颤器能够监测与肺含水量相关的胸腔内阻抗，这可能预示着HF的恶化。本研究的目的是评估胸腔内阻抗与NT-proBNP以及超声多普勒二尖瓣血流指标之间的相关性。
从意大利六个中心的111例HF患者收集数据。所有患者均接受最佳药物治疗。在基线、每两个月随访时以及因HF失代偿或设备警报而进行的不定期检查时，记录设备诊断、超声心动图数据、NT-proBNP测定以及通过心力衰竭评分（HFS）评估的临床状态。
在中位随访413天期间，共进行了955次检查。胸腔内阻抗与NT-proBNP（P = 0.013）和二尖瓣E波减速时间（DtE）（P = 0.017）显著相关，但与HFS无关。在确认警报事件时，NT-proBNP显著高于确认非警报事件检查期间；DtE无差异，而阻抗显著降低。
胸腔内阻抗降低与NT-proBNP呈负相关，与DtE呈正相关。因此，胸腔内阻抗监测有作为识别早期HF失代偿有用工具的生理基础。
