Pulmonary Vascular Hemodynamic data.

<p>Abbreviations: LAp = Left atrial pressure, L/min/m² = Liters per minute per meter squared, PAp = Pulmonary arterial pressure, PAWp = pulmonary artery wedge pressure, PVRI = pulmonary vascular resistance index, QPI = Pulmonary blood flow index, WUm² = Wood Units x meter squared, Note PVRI calculated from pressures at the time of QPI measurement not acoustic recording</p><p>Subjects #1–11 with Pulmonary arterial hypertension (mean pulmonary arterial pressure ≥25 mmHg).</p

Pseudocode of Method V.

<p>The function that detects the first heart sound (S1) and the second heart sound (S2) waves has five inputs: the heart sound signal (HS_signal), event-related durations <i>W</i>₁, <i>W</i>₂, anticipated block width (BlockSize), and the offset (<i>β</i>). Daubechies 'db6' wavelet is used for filtering the signal and the wavelet detail <i>D</i>₆ represents the heart sounds in the analysis.</p

Flowcharts for five methods to detect S1 and S2 waves in heart sounds.

<p>(a) Method I, (b) Method II, (c) Method III, (d) Method IV, (e) Method V.</p

Pulmonary arterial hypertension: Subjects #1–11 with pulmonary arterial hypertension (mean pulmonary arterial pressure ≥ 25 mmHg).

<p>Abbreviations: BMI = Body Mass Index, BSA = Body Surface Area, CDH = Congenital Diaphragmatic Hernia, CHD = Congenital Heart Disease, F = Female, M = Male, m = meters, IPAH = Idiopathic Pulmonary Hypertension, kg = kilograms,</p><p>Pulmonary arterial hypertension: Subjects #1–11 with pulmonary arterial hypertension (mean pulmonary arterial pressure ≥ 25 mmHg).</p

Power spectrum of ‘db6’ wavelet for details (top) and approximations (bottom) at scales <i>a</i> = 2^<i>j</i>, <i>j</i> = 1, .., 6.

<p>Note, the sampling frequency of the heart sounds is 4000 Hz.</p

Behavior of the ‘db6’ wavelet dealing with different morphologies of S1 and S2.

<p>(a) Wavelet details for heart sounds with low S1 amplitude measured at the second intercostal space for a subject with mean PAp < 25 mmHg, (b) Wavelet approximations for the same heart sounds used in (a), (c) Wavelet details for heart sounds with low S2 amplitude measured at apex for a subject with mean PAp ≥ 25 mmHg, and (d) Wavelet approximations for the same heart sounds used in (c).</p

Power spectrum of S1 and S2 segments compared to the power spectrum of wavelet details used in all methods at the second intercostal space (left) and apex (right).

<p>A total of 284 heart beats used in this analysis for subjects with mean PAp > = and < 25 mmHg. Note, the sampling frequency of the heart sounds is 4000 Hz.</p

A rigorous optimization over all parameters of Method V: event-related durations <i>W</i>₁, <i>W</i>₂, anticipated block width (BlockSize), and the offset (<i>β</i>).

<p>All possible combinations of parameters (46,376 iterations) have been investigated and sorted in descending order according to their overall accuracy. The data used in this training phase was heart sounds measured at apex for all subjects with mean PAp ≥ 25 mmHg. The overall accuracy is the average value of SE and +P.</p

Features output.

<p>(a) Original heart sound signal from a subject with mean pulmonary arterial pressure of 20 mmHg (b) second-order Shannon energy of <i>D</i>₅ wavelet in Method I (c) second-order Shannon energy of <i>D</i>₆ wavelet in Method II (d) third-order Shannon energy in Method III (e) wavelet approximation <i>A</i>₆ in Method IV (f) generating blocks of interest in Method V.</p

Demarcation of the 1st (S1) and 2nd (S2) heart sounds.

<p>The normalized amplitude (<i>y</i>-axis) is plotted against time in seconds (<i>x</i>-axis). Time zero second depicts the annotated peaks for S1 and S2 events.</p