Non-invasive Assessment of Pulmonary Hypertension Using a Small Portable Device Measuring Cardiac Intervals: Design for Telemonitoring

Abstract

Background Pulmonary hypertension is a condition that pulmonary artery pressure iselevated. The diagnosis and monitoring of pulmonary artery pressure oftenrequiring invasive procedures. HEMOTAG, is a small portable device that usesmicro-sensors to capture cardiac vibrations and electrocardiogram, transducedvia thoracic electrodes. It is a viable option to measure cardiac timeintervals (CTIs), surrogate markers of intracardiac pressure. In this study,mitral valve closure (MVC) and isovolumetric contraction time (IVCT) wereassessed as valid markers for pulmonary artery pressure, compared againstintracardiac pressures measured simultaneously at the time of right heartcatheterization. Methods In 37 patients, mean pulmonary artery pressure (mPAP) was measured duringcardiac catheterization. Simultaneously, Hemotag analyzed CTIs: MVC and IVCT.The predictability value of non-invasively HEMOTAG-derived CTIs- MVC and IVCT -were assessed to determine elevated mPAP. Linear correlation analysisbetween CTIs and mPAP was performed. Sensitivity, specificity, positive, andnegative predictive values were calculated. Results Mean age was 65.40 ± 12.42years, mean ejection fraction was 54.61 ± 14.24%,48% were women, 55.2% had left valvular disease, 27.6% had systolicdysfunction, and mean mPAP was 16.10 ± 5.40 mmHg. With a paired dichotomous interpretation,sensitivity of 81% was noted for MVC and specificity of 100% was observed withIVCT. A receiver operator characteristic curve was employed to assessperformance with an AUC of 0.71 and 0.64 for MVC and IVCT, respectively. Therewere no strong correlations observed between mPAP and CTIs (Table 1). Conclusions HEMOTAG detected elevated mPAPwith good sensitivity and high specificity. This preliminary study hasdemonstrated the feasibility of estimating mPAP using a portable, non-invasivedevice that empowers patients to transmit such data from home instantaneouslyto providers. Further studies are required to validate HEMOTAG as apoint-of-care non-invasive assessment for pulmonary hypertension patients.