Ypenburg Claudia, Bax Jeroen J, van der Wall Ernst E, Schalij Martin J, van Erven Lieselot
Department of Cardiology, Leiden University Medical Center, Leiden, The Netherlands.
Am J Cardiol. 2007 Feb 15;99(4):554-7. doi: 10.1016/j.amjcard.2006.08.066. Epub 2007 Jan 2.
Intrathoracic impedance measurement has been introduced in the InSync Sentry biventricular implantable cardioverter-defibrillator and may permit the early identification of pulmonary fluid accumulation secondary to left-sided heart failure (HF). An audible alarm (the OptiVol alert) can be triggered when the impedance index increases to greater than a predefined level of 60 Omega . day. The aim of this study was to evaluate the clinical value of the OptiVol alert and its prediction for decompensated HF. One hundred fifteen consecutive patients (mean New York Heart Association class 2.8 +/- 0.5, mean left ventricular ejection fraction 26 +/- 8%) who received InSync Sentry biventricular implantable cardioverter-defibrillators were included. When presenting with the OptiVol alert, current hemodynamic status was evaluated. During follow-up (mean 9 +/- 5 months), there were 45 presentations with the OptiVol alert in 30 patients. Clinical signs and symptoms of HF were present in only 15 patients (33%), whereas in the remaining patients, clinical signs of HF were absent (p <0.05). Receiver-operating characteristic curve analysis showed that increasing the threshold for the OptiVol alert provided a substantial increase in specificity for the detection of HF, with the optimal cut-off value identified at 120 Omega . day, yielding sensitivity of 60% and specificity of 73%. In conclusion, intrathoracic impedance measurement as present in the InSync Sentry biventricular implantable cardioverter-defibrillator may be a useful tool for monitoring pulmonary fluid status. The proposed threshold for the OptiVol alert of 60 Omega. day is very sensitive but not specific for the assessment of HF; adjustment of threshold settings may yield a superior balance between sensitivity and specificity.
胸内阻抗测量已被应用于InSync Sentry双心室植入式心脏复律除颤器中，它可能有助于早期识别继发于左心衰竭（HF）的肺液积聚。当阻抗指数增加到大于预先设定的60Ω·天的水平时，可触发听觉警报（OptiVol警报）。本研究的目的是评估OptiVol警报的临床价值及其对失代偿性HF的预测能力。纳入了115例连续接受InSync Sentry双心室植入式心脏复律除颤器的患者（平均纽约心脏协会心功能分级为2.8±0.5，平均左心室射血分数为26±8%）。出现OptiVol警报时，评估当前的血流动力学状态。在随访期间（平均9±5个月），30例患者中有45次出现OptiVol警报。只有15例患者（33%）出现HF的临床体征和症状，而其余患者没有HF的临床体征（p<0.05）。受试者工作特征曲线分析表明，提高OptiVol警报的阈值可显著提高检测HF的特异性，最佳截断值确定为120Ω·天，敏感性为60%，特异性为73%。总之，InSync Sentry双心室植入式心脏复律除颤器中的胸内阻抗测量可能是监测肺液状态的有用工具。提议的OptiVol警报阈值60Ω·天对HF评估非常敏感但不具有特异性；调整阈值设置可能会在敏感性和特异性之间产生更好的平衡。
