Spectral analysis of heart sounds: Relationships between some physical characteristics and frequency spectra of first and second heart sounds in normals and hypertensives

Noninvasive blood pressure and the second heart sound analysis

“…These methods are uncomfortable and inadequate for long term monitoring, and several techniques to substitute the current standard are being explored for the continuous noninvasive BP estimation, with as little apparatus as possible, applying different physiological properties of the cardiovascular system, such as the Pulse Transit Time (PTT) [1], vascular transit time (VTT) [3], and the heart sound [4], [5], [6]. Since increased BP leads to an increase in amplitude and frequency of the second heart sound [7], we propose to explore heart sound as a noninvasive BP correlate.…”

Changes in Amplitude Characteristics of Heart Sound Signals during External:cuff:inflation Procedure: A Pilot Study

“…An existing study reported that amplitude of S2 from hypertensive patients was higher than that from normotensive [2]. Increased BP also led to an increase in frequency of S2 [3], [4]. The relation between S2 and the arterial BPs from both systemic and pulmonary circulations has been confirmed in [5], [6], [7].…”

Separating Heart Sound from Lung Sound Using LabVIEW

“…Though peak frequencies of heart sounds have been shown to be much lower than those of lung sounds [11], comparisons between lung sound recordings acquired over the anterior right upper lobe containing and excluding heart sounds show that PSD in both cases is maximal below 150 Hz.…”

“…The BIC penalizes excess model order more severely than the AIC does. For the BIC, an optimal model is the one that minimizes the following equation: (11) Final Prediction Error Criterion: The Final Prediction Error Criterion (FPE) estimates the model-fitting error when the model uses to predict new outputs. For the FPE, an optimal model is the one that minimizes the following equation:…”