Diastolic time - frequency relation in the stress echo lab: filling timing and flow at different heart rates.
A cutaneous force-frequency relation recording system based on first heart sound amplitude vibrations has been recently validated. Second heart sound can be simultaneously recorded in order to quantify both systole and diastole duration.


OBJECTIVE
1- To assess the feasibility and extra-value of operator-independent, force sensor-based, diastolic time recording during stress.


METHODS
We enrolled 161 patients referred for stress echocardiography (exercise 115, dipyridamole 40, pacing 6 patients).The sensor was fastened in the precordial region by a standard ECG electrode. The acceleration signal was converted into digital and recorded together with ECG signal. Both systolic and diastolic times were acquired continuously during stress and were displayed by plotting times vs. heart rate. Diastolic filling rate was calculated as echo-measured mitral filling volume/sensor-monitored diastolic time.


RESULTS
Diastolic time decreased during stress more markedly than systolic time. At peak stress 62 of the 161 pts showed reversal of the systolic/diastolic ratio with the duration of systole longer than diastole. In the exercise group, at 100 bpm HR, systolic/diastolic time ratio was lower in the 17 controls (0.74 +/- 0.12) than in patients (0.86 +/- 0.10, p < 0.05 vs. controls). Diastolic filling rate increased from 101 +/- 36 (rest) to 219 +/- 92 ml/m2* s-1 at peak stress (p < 0.5 vs. rest).


CONCLUSIONS
Cardiological systolic and diastolic duration can be monitored during stress by using an acceleration force sensor. Simultaneous calculation of stroke volume allows monitoring diastolic filling rate.Stress-induced "systolic-diastolic mismatch" can be easily quantified and is associated to several cardiac diseases, possibly expanding the spectrum of information obtainable during stress.
Bombardini
Tonino
T
Department of Echocardiography, Institute of Clinical Physiology, National Council of Research, Pisa, Italy. tbombardini@yahoo.it
Gemignani
Vincenzo
V
Bianchini
Elisabetta
E
Venneri
Lucia
L
Petersen
Christina
C
Pasanisi
Emilio
E
Pratali
Lorenza
L
Alonso-Rodriguez
David
D
Pianelli
Mascia
M
Faita
Francesco
F
Giannoni
Massimo
M
Arpesella
Giorgio
G
Picano
Eugenio
E
D003198:Computer Simulation; D003326:Coronary Circulation; D003971:Diastole; D005080:Exercise Test; D005260:Female; D006326:Heart Auscultation / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008955:Models, Cardiovascular; D013223:Statistics as Topic; D013318:Stroke Volume; D018487:Ventricular Dysfunction, Left / Q000503:physiopathology*