Abstract
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.Aims1- To assess the feasibility and extra-value of operator-independent, force sensor-based, diastolic time recording during stress.MethodsWe 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.ResultsDiastolic 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).ConclusionCardiological 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.
Highlights
Physiologists and cardiologists are keenly aware of heart rate (HR) dependence of physiological indexes used to assess cardiac function
Cardiological systolic and diastolic duration can be monitored during stress by using an acceleration force sensor
Diastolic blood pressure increased in the exercise, decreased in the dipyridamole, while unchanged in the pacing group; the response was heterogeneous at the individual level. (Table 3)
Summary
Physiologists and cardiologists are keenly aware of heart rate (HR) dependence of physiological indexes used to assess cardiac function. Prior work concerning diastolic duration has been motivated primarily by consideration of diastolic myocardial perfusion time rather than the duration of mechanical events and has been used to assess the HR-dependent effects of pharmacological agents [7,8,9] Recent studies utilizing both exercise radionuclide angiography time activity curve [10] or Doppler echocardiography [11,12] assessed that cardiac performance may be characterized in terms of the relative duration of systole and diastole. Physiological systole lasts from the start of isovolumic contraction to the peak of the ejection phase, so that physiological diastole commences as the LV pressure starts to fall. This concept fits well with the standard pressure-volume curve [13]. Second heart sound can be simultaneously recorded by the same
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