Research

Post-exercise contractility, diastolic function, and pressure: Operator-independent sensor-based intelligent monitoring for heart failure telemedicine

Tonino Bombardini¹ , Vincenzo Gemignani² , Elisabetta Bianchini² , Emilio Pasanisi¹ , Lorenza Pratali¹ , Mascia Pianelli¹ , Francesco Faita² , Massimo Giannoni² , Giorgio Arpesella³ , Rosa Sicari¹ and Eugenio Picano¹

¹  Department of Echocardiography Lab, Institute of Clinical Physiology, National Council of Research, Pisa, Italy

²  Digital Signal Processing Lab (DSPLAB), Institute of Clinical Physiology, National Council of Research, Pisa, Italy

³  Department of Surgery and Transplants, University of Bologna, Italy

author email corresponding author email

Cardiovascular Ultrasound 2009, 7:21doi:10.1186/1476-7120-7-21

Published:	14 May 2009

Abstract

Background

New sensors for intelligent remote monitoring of the heart should be developed. Recently, a cutaneous force-frequency relation recording system has been validated based on heart sound amplitude and timing variations at increasing heart rates.

Aim

To assess sensor-based post-exercise contractility, diastolic function and pressure in normal and diseased hearts as a model of a wireless telemedicine system.

Methods

We enrolled 150 patients and 22 controls referred for exercise-stress echocardiography, age 55 ± 18 years. The sensor was attached in the precordial region by an ECG electrode. Stress and recovery contractility were derived by first heart sound amplitude vibration changes; diastolic times were acquired continuously. Systemic pressure changes were quantitatively documented by second heart sound recording.

Results

Interpretable sensor recordings were obtained in all patients (feasibility = 100%). Post-exercise contractility overshoot (defined as increase > 10% of recovery contractility vs exercise value) was more frequent in patients than controls (27% vs 8%, p < 0.05). At 100 bpm stress heart rate, systolic/diastolic time ratio (normal, < 1) was > 1 in 20 patients and in none of the controls (p < 0.01); at recovery systolic/diastolic ratio was > 1 in only 3 patients (p < 0.01 vs stress). Post-exercise reduced arterial pressure was sensed.

Conclusion

Post-exercise contractility, diastolic time and pressure changes can be continuously measured by a cutaneous sensor. Heart disease affects not only exercise systolic performance, but also post-exercise recovery, diastolic time intervals and blood pressure changes – in our study, all of these were monitored by a non-invasive wearable sensor.