Acoustic transmission characteristics of the thorax

Zalter, Rudolf; Hardy, Howard C.; Luisada, Aldo A.

doi:10.1152/jappl.1963.18.2.428

Cited by 19 publications

(5 citation statements)

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“…Baseline force value had an ample range (from 4 to 30 g * 10 -3 ). Cardiac vibrations propagate as mechanical shear waves, and the intervening viscoelastic thoracic tissue attenuates the higher frequencies and introduces a variable propagation delay [ 26 , 27 ]. The absolute force value in the single patient can be related to the transthoracic propagation of cardiac vibrations.…”

Section: Discussionmentioning

confidence: 99%

Cardiac reflections and natural vibrations: Force-frequency relation recording system in the stress echo lab

Bombardini

Gemignani²,

Bianchini³

et al. 2007

Cardiovasc Ultrasound

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BackgroundThe inherent ability of ventricular myocardium to increase its force of contraction in response to an increase in contraction frequency is known as the cardiac force-frequency relation (FFR). This relation can be easily obtained in the stress echo lab, where the force is computed as the systolic pressure/end-systolic volume index ratio, and measured for increasing heart rates during stress. Ideally, the noninvasive, imaging independent, objective assessment of FFR would greatly enhance its practical appeal.Objectives1 – To evaluate the feasibility of the cardiac force measurement by a precordial cutaneous sensor. 2 – To build the curve of force variation as a function of the heart rate. 3 – To compare the standard stress echo results vs. this sensor operator-independent built FFR.MethodsThe transcutaneous force sensor was positioned in the precordial region in 88 consecutive patients referred for exercise, dipyridamole, or pacing stress. The force was measured as the myocardial vibrations amplitude in the isovolumic contraction period. FFR was computed as the curve of force variation as a function of heart rate. Standard echocardiographic FFR measurements were performed.ResultsA consistent FFR was obtained in all patients. Both the sensor built and the echo built FFR identifiy pts with normal or abnormal contractile reserve. The best cut-off value of the sensor built FFR was 15.5 g * 10-3 (Sensitivity = 0.85, Specificity = 0.77). Sensor built FFR slope and shape mirror pressure/volume relation during stress. This approach is extendable to daily physiological exercise and could be potentially attractive in home monitoring systems.

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Section: Discussionmentioning

confidence: 99%

Cardiac reflections and natural vibrations: Force-frequency relation recording system in the stress echo lab

Bombardini

Gemignani²,

Bianchini³

et al. 2007

Cardiovasc Ultrasound

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“…1* ' 20 The Sanborn dynamic microphone used here has a slope of 6 db per octave. 43 It is basically a velocity sensor in contrast to most microphones which have a flat response to displacement (pressure). The energy content or intensity of a sonic vibration is proportional to the frequency squared, times the amplitude squared.…”

mentioning

confidence: 99%

Hemodynamic Determinants of the Amplitude of the First Heart Sound

Sakamoto

Kusukawa

MacCanon

et al. 1965

Circulation Research

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“…The chest wall is a low-pass filter. Cardiac vibrations propagate as mechanical shear waves, and the intervening viscoelastic thoracic tissue attenuates the higher frequencies and introduces a variable propagation delay [ 22 , 23 ].…”

Section: Discussionmentioning

confidence: 99%