Andriulli John
University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Cooper University Hospital, Camden, New Jersey, USA.
Am J Cardiol. 2007 May 21;99(10A):23G-8G. doi: 10.1016/j.amjcard.2007.02.039. Epub 2007 Mar 9.
A distinct advantage of implantable device diagnostics is that the data may be made available on a continuous basis, rather than at sporadic intervals associated with clinical testing. Recently, intrathoracic impedance monitoring has also become available in some implantable devices as an index of congestion and thoracic fluid accumulation secondary to decompensated heart failure. Despite the potential advantages, new advances in implantable device diagnostic technology also pose important questions regarding their clinical application. To examine these questions and to generate hypotheses, the relation between daily intrathoracic impedance measurements and other physical measurements or comorbidities was studied. A retrospective review was performed of 25 patients who previously underwent implantation of a cardiac resynchronization therapy/defibrillator device with the capability to continuously monitor intrathoracic impedance. This limited scope analysis demonstrated that daily measurement of intrathoracic impedances might reveal the intrinsic relations between heart failure decompensation and the onset of atrial and ventricular arrhythmias. Abnormal patterns of intrathoracic impedance that has increased and plateaued after implant may indicate worsening heart failure. The severity of congestive heart failure at the time of interrogation may correlate with device-based impedance measurements. Weight, sex, and body index may have a limited impact on impedance, and the lowest impedances may be seen in older patients. Patients with severe pulmonary disease may present with unique daily impedance profiles. Finally, daily impedance may have unpredictable relations with other clinical markers of heart failure. In summary, intrathoracic impedance represents a clinically useful diagnostic tool that can increase our understanding of a dynamic disease state on an individual patient basis.
植入式设备诊断的一个显著优势在于，数据可以持续获取，而非像临床检测那样只能间歇性获取。近来，一些植入式设备中也已具备胸腔内阻抗监测功能，以此作为失代偿性心力衰竭继发的充血和胸腔积液的一个指标。尽管有这些潜在优势，但植入式设备诊断技术的新进展也对其临床应用提出了重要问题。为研究这些问题并提出假设，对每日胸腔内阻抗测量值与其他体格检查指标或合并症之间的关系进行了研究。对25例先前植入了具备持续监测胸腔内阻抗功能的心脏再同步治疗/除颤器设备的患者进行了回顾性分析。这一范围有限的分析表明，每日测量胸腔内阻抗可能会揭示心力衰竭失代偿与房性和室性心律失常发作之间的内在关系。植入后胸腔内阻抗增加并趋于平稳的异常模式可能表明心力衰竭病情恶化。在进行问询时充血性心力衰竭的严重程度可能与基于设备的阻抗测量值相关。体重、性别和身体指数对阻抗的影响可能有限，老年患者的阻抗可能最低。患有严重肺部疾病的患者可能会呈现出独特的每日阻抗曲线。最后，每日阻抗与心力衰竭的其他临床指标之间可能存在不可预测的关系。总之，胸腔内阻抗是一种具有临床实用价值的诊断工具，能够增进我们对个体患者动态疾病状态的了解。
