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


OBJECTIVE
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.


CONCLUSIONS
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.
Bombardini
Tonino
T
Department of Echocardiography Lab, Institute of Clinical Physiology, National Council of Research, Pisa, Italy. tbombardini@yahoo.it
Gemignani
Vincenzo
V
Bianchini
Elisabetta
E
Pasanisi
Emilio
E
Pratali
Lorenza
L
Pianelli
Mascia
M
Faita
Francesco
F
Giannoni
Massimo
M
Arpesella
Giorgio
G
Sicari
Rosa
R
Picano
Eugenio
E
D000054:Acceleration; D001794:Blood Pressure; D001795:Blood Pressure Determination / Q000379:methods*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005080:Exercise Test; D005260:Female; D006326:Heart Auscultation / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009200:Myocardial Contraction; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013314:Stress, Mechanical; D017216:Telemedicine / Q000379:methods*; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000503:physiopathology*