Intensity Of Heart Sounds Research Articles

Unveiling the Impact of Respiratory Event-Related Hypoxia on Heart Sound Intensity During Sleep Using Novel Wearable Technology.

Cardiovascular disorders are the leading cause of mortality worldwide with obstructive sleep apnea (OSA) as the independent risk factor. Heart sounds are strong modalities to obtain clinically relevant information regarding the functioning of the heart valves and blood flow. The objective of this study was to use a small wearable device to record and investigate the changes in heart sounds during respiratory events (reduction and cessation of breathings) and their association with oxyhemoglobin desaturation (hypoxemia). Sleep assessment and tracheal respiratory and heart sounds were recorded simultaneously from 58 individuals who were suspected of having OSA. Sleep assessment was performed using in-laboratory polysomnography. Tracheal respiratory and heart sounds were recorded over the suprasternal notch using a small device with embedded microphone and accelerometer called the Patch. Heart sounds were extracted from bandpass filtered tracheal sounds using smoothed Hilbert envelope on decomposed signal. For each individual, data from 20 obstructive events during Non-Rapid Eye Movement stage-2 of sleep were randomly selected for analysis. A significant increase in heart sounds' intensities from before to after the termination of respiratory events was observed. Also, there was a significant positive correlation between the magnitude of hypoxemia and the increase in heart sounds' intensities (r>0.82, p<0.001). In addition, the changes in heart sounds were significantly correlated with heart rate and blood pressure. Our results indicate that heart sound analysis can be used as an alternative modality for assessing the cardiovascular burden of sleep apnea, which may indicate the risk of cardiovascular disorders.

Diagnostic utility of echocardiography and ultrasonography in buffaloes suffering from pericarditis

Pericarditis remains a serious problem faced by bovine producers in the developing countries. This study was designed to evaluate the echocardiographic and ultrasonographic changes in dairy buffaloes affected with pericarditis presented to Large Animal Clinic, Teaching Veterinary Hospital of Guru Angad Dev Veterinary and Animal Sciences University (GADVASU), Ludhiana, India. 49 buffaloes were included and selected on the basis one or more of the clinical signs viz., brisket edema, dyspnoea, muffled heart sounds and distended jugular veins. Animals were subjected to clinical examination, thoracic and abdominal ultrasonography and M- mode echocardiography. The CVS examination revealed normal intensity of heart sounds in 17 and muffled in 32 cases with splashing/pericardial rub in 9 cases. Ultrasonography revealed spleenic congestion, liver was congested in majority of the cases with visible dilatation of the caudal vena cava. Heart was normal in 7 and visibly compressed in 42 cases due to the pericardial fluid. Massive pleural fluid was seen in 28 cases. Buffaloes in our study had pericardial effusions (n=49), pleural and pericardial effusions (n=45) and pleural, pericardial and peritoneal effusions (n=19). The predominant echocardiographic findings were significantly decreased dimensions of the heart chambers in both systole and diastole. The left ventricular contractility indices (FS% and EF%) were significantly high. The clinical findings alone do not allow a definitive diagnosis of pericarditis as characteristic signs were not present in all the cases. The combined use of ultrasonography and echocardiography provides a comprehensive idea about such cases and aids in early diagnosis of pericarditis.

Changes in brain function and heart sound in acute sleep deprivation individuals

AimsSleep deprivation (SD) has become a health problem in modern society due to its adverse effects on different aspects. However, the relationship between sleep and cardiovascular system function remains unclear. Here we explored the changes occurring in the brain and the heart sounds after SD. MethodsNinety healthy adult men were recruited and subjected to 36 h of Sleep Deprivation (SD). They participated in a number of tests, including measurements of the heart sound, blood oxygen, and heart rate every 2 h. By using of principal component analysis to reduced the dimensionality of heart sound data. While the ALFF and ReHo indexes were measured via fMRI before and after SD. Correlation and regression analyses were used to reveal the relationship between fMRI and heart sound changes due to SD. ResultsIn this study, there were no abnormal values in the heart rate and blood oxygen during 36 h of SD, whereas the intensity of heart sounds fluctuated significantly increased and decreased. The ALFF was increased in bilateral pericalcarine(Calcarine), left anterior cuneus, (Precuneus_L), right superior temporal gyrus(Temporal_Sup_R), left supplementary motor area (Supp_Motor_Area_L); However, it was reduced in the right medial superior frontal gyrus (Frontal_Sup_Medial_R), right dorsolateral superior frontal gyrus (Frontal_Sup_R) and left medial frontal gyrus (Frontal_Mid_L). The regression analysis uncovered that the intensity of the heart sound in the systole, s1, and s2 phase could be explained by Calcarine_L changes. ConclusionAcute sleep deprivation affects cardiac-brain axis and the specific brain regions. Calcarine_L changes during sleep deprivation are involved in regulating heart contractions.

Increases in the intensity of heart sounds at the termination of respiratory events are positively correlated with the magnitude of hypoxia

Increases in the intensity of heart sounds at the termination of respiratory events are positively correlated with the magnitude of hypoxia

Use of acoustic cardiography immediately following electrical cardioversion to predict relapse of atrial fibrillation.

Predicting atrial fibrillation (AF) recurrence after successful electrical cardioversion (ECV) is difficult. The main aim of this study was to investigate whether acoustic cardiography (AUDICOR® 200) immediately post-ECV might provide indices for AF relapse following cardioversion. Acoustic cardiography parameters included Electromechanical Activation Time (EMAT), Left Ventricular Systolic Time (LVST), QRS duration, heart rate and third heart sound intensity (S3 Strength). We analysed data from 140 patients who underwent successful cardioversion and in whom AUDICOR results and echocardiographic measurements immediately after (baseline) ECV were available. Patients were prospectively followed-up at 4-6 weeks, 3 and 12 months post-ECV, and sinus rhythm maintenance was evaluated using acoustic cardiography and Holter electrocardiography. The effect of each baseline AUDICOR parameter on the hazard of AF relapse was investigated using Cox proportional hazards (PH) models. Fifty patients (35.7%) had AF relapse. Of all the AUDICOR parameters, only S3 Strength exhibited consistent predictive value. Increasing S3 Strength increased the hazard of relapse in a univariable Cox PH model (HR=2.52, p=0.003), and in two multivariable Cox PH model constructions (Model 1 excluded heart rate and Model II excluded EMAT/RR, LVST and LVST/RR) both of which included the parameters as continuous variables (Model I: HR=1.15, p=0.042; Model II: HR=1.14, p=0.045) or the parameters dichotomized according to suggested cut-points (Model I: HR=2.5, p=0.007; Model II: HR=2.09, p=0.031). In conclusion, this study suggests that acoustic cardiography may be a simple inexpensive and quantitative bedside method to assist in prediction of AF recurrence after ECV.

Identification of Staphylococcus pseudintermedius in canine infective endocarditis using PCR-RFLP analysis

A 5-year-old, 8.95 kg, female Schnauzer presented anorexia with a 3-day history and increased heart sound intensity. Based on the clinical and echocardiographic findings along with the positive blood culture result, the dog was diagnosed with infective endocarditis (IE). Using proper antibiotics treatment, clinical signs were improved within 3 days and resolved within 1 week. For exact identification of the causative agent, multiplex polymerase chain reaction (PCR) and PCR-restriction fragment length polymorphism (RFLP) methods were performed. The etiological agent was confirmed as Staphylococcus pseudintermedius with antibiotics resistance genes such as β-lactamase (blaZ) and methicilline resistance (mecA). The bacterial virulence factors included pyogenic toxin genes such as staphylococcal enterotoxins A, B, C, D, and E and toxic shock syndrome toxin 1. Diagnosis of IE is challenging due to a variety of non-specific clinical presentations, rapid disease progression, and lack of a confirmative diagnostic technique. This report demonstrated that such molecular diagnostics could be very useful for diagnosing and identifying characteristics of the causative organism for prediction of prognosis and proper treatment. To our knowledge, this is the first report on the isolation of S. pseudintermedius using molecular diagnostics from a clinical case of canine IE.

Time-domain analysis of heart sound intensity in children with and without pulmonary artery hypertension: a pilot study using a digital stethoscope.

We studied digital stethoscope recordings in children undergoing simultaneous catheterization of the pulmonary artery (PA) to determine whether time-domain analysis of heart sound intensity would aid in the diagnosis of PA hypertension (PAH). Heart sounds were recorded and stored in .wav mono audio format. We performed recordings for 20 seconds with sampling frequencies of 4,000 Hz at the second left intercostal space and the cardiac apex. We used programs written in the MATLAB 2010b environment to analyze signals. We annotated events representing the first (S1) and second (S2) heart sounds and the aortic (A2) and pulmonary (P2) components of S2. We calculated the intensity (I) of the extracted event area (x) as [Formula: see text], where n is the total number of heart sound samples in the extracted event and k is A2, P2, S1, or S2. We defined PAH as mean PA pressure (mPAp) of at least 25 mmHg with PA wedge pressure of less than 15 mmHg. We studied 22 subjects (median age: 6 years [range: 0.25-19 years], 13 female), 11 with PAH (median mPAp: 55 mmHg [range: 25-97 mmHg]) and 11 without PAH (median mPAp: 15 mmHg [range: 8-24 mmHg]). The P2∶A2 (P = .0001) and P2∶S2 (P = .0001) intensity ratios were significantly different between subjects with and those without PAH. There was a linear correlation (r > 0.7) between the P2∶S2 and P2∶A2 intensity ratios and mPAp. We found that the P2∶A2 and P2∶S2 intensity ratios discriminated between children with and those without PAH. These findings may be useful for developing an acoustic device to diagnose PAH.

A case of atrial fibrillation in a horse: clinical and electrocardiographic features

Atrial fibrillation (AF) was detected as an incidental finding in a 14 years old brood mare horse which was maintained for student education in the teaching hospital, Faculty of Veterinary Medicine, Mashhad. Irregular heart rhythm, variable intensity of heart sounds and f waves were revealed in clinical examination and electrocardiography. Hematology showed normal values and hyponutremia was observed in serum biochemical analysis. Treatment of the horse was done with oral administration of uinidine sulfate (200 mg tabs). Normal rhythm was appeared after 24 hours of treatment. Herein, we have discussed the etiology and the treatment procedure of this dysrhythmia.

Clinical and pathological study of experimentally- induced yew (Taxus baccata) poisoning in sheep

Acute yew (Taxus baccata) intoxication was induced in 7 adult sheep by oral administration of the plant materials at the dose of 2.5g/kg body weight. Blood samples for hematology and serum biochemistry were collected before and after the induced intoxication.Electrocardiography was performed using a base-apex lead. Intoxicated animals displayed lethargy, depression, bradycardia and varying intensity of heart sounds. The ECGs of intoxicated sheep showed a variety of arrhythmias and abnormalities including multifocal ventricular tachycardia, idioventricular and idiojunctinal rhythm and QRS and T widening. Four sheep died within 4-16 hours after yew administration. Significant increase of white blood cells, total neutrophil counts and serum sodium concentration were observed. Post mortem examination and histological evaluation were done with special regards on tissue changes of the myocardium and conduction system. There were hyperemia, focal hemorrhage and multifocal nonsuppurative interstitial myocarditis with mild focal cardiac muscle cell degeneration and necrosis in the affected hearts which appeared more prominent in the right atrium. Histopathological examination of cardiac conduction system also revealed moderate to severe interstitial edema with inflammation of the SA-node, AV-node, the bundle branches and His-bundle in all cases which was most severe in the AV-node and the His-bundle. Oral administration of dried leaves of T. baccata, at the dose of 2.5g/kg can induce acute toxicity, manifested clinically by a variety of cardiac arrhythmia and myocardial lesions including special conduction system in pathology.

Importance of haemodynamic monitoring in cardiac tamponade

A55-year-old man presented to the emergency room (ER) with complaints of anorexia, feelings of being unwell and anuria from the previous day. He denied any chest pain, palpitations, dyspnoea on exertion or fever. He was recovering from a recent throat infection and had a past medical history of diabetes mellitus, hypertension and hypercholesterolaemia. He was pale-looking and his physical examination revealed hypotension (90/60 mmHg) and tachycardia. He appeared in mild respiratory distress. Examination of neck veins showed raised jugular venous pressure of 6 cm above the sternal angle. His chest was clear on auscultation and the intensity of heart sounds were diminished with no added sounds. He had a measured pulsus-paradoxus of 20 mmHg. His electrocardiogram showed diffuse low-voltage complexes with no evidence of electrical alternans. There were ST segment elevations in lateral leads with tall T-waves in anterior precordial leads suggestive of posterolateral myocardial infarction (Figure 1). Posterior changes were confirmed on a posterior electrocardiogram (Figure 2). Right-sided electrocardiogram failed to reveal any ST-T abnormalities suggestive of right ventricular infarction. The initial set of laboratory tests done in ER revealed high blood urea nitrogen (9.64 mmol/litre) and serum creatinine (150.28 μmol/litre). The first set of cardiac enzymes revealed high troponin I (23.05 μg/litre) with normal myoglobin and creatine kinase. An arterial line was placed that revealed pulsus-paradoxus of 20 mmHg. A Swan–Ganz catheter was placed and showed: right ventricle of 53/33 mmHg; right atrium of 28 mmHg; pulmonary artery of 50/32 mmHg; pulmonary capillary wedge pressure of 30 mmHg. The central venous pressure tracing showed complete obliteration of ‘y’ descent. Dopplerechocardiography was done. It showed mild-to-moderate pericardial effusion with possible thrombus overlying the right ventricular wall. Posterior and lateral walls were found to be hypokinetic. The patient underwent coronary angiography before emergency pericardiocentesis. Angiography revealed complete occlusion of the first obtuse marginal. Aortic-pulse tracing is shown in Figure 3. These pressure tracings were consistent with cardiac tamponade with a demonstrable pulsus-paradoxus of about 20 mmHg. Ventriculography was not performed because of a suspected subacute rupture of the myocardial wall. A cautious pericardiocentesis was performed. Examination of the pericardial cavity revealed 300 cm3 of blood clots. In the absence of an ongoing leak, a pericardial window was created and a drain was left in situ. The patient was dialysed once after the procedure. His haemodynamics improved significantly after surgery. He remained stable through the course of his stay in the hospital and was discharged 3 days after pericardiocentesis.

心外膜原発悪性中皮腫の牛1例

Clinical examination of a Holstein cow (aged 7 years and 3 months) with cyanosis, jugular-vein distention, and non-inflammatory edema in the brisket and ventral abdomen revealed decreased intensity of heart sounds, marked hydropericardium, and increased serum γ-globulin values. Gross solid opaline masses were found over the epicardium, and the pericardial fluid was distinctly blood-like. Histopathologic examination resulted in a diagnosis of the neoplastic masses as malignant mesothelioma.

Bruit Alternans

Alternation of the amplitude of the pulse at regular intervals (pulsus alternans) has been associated with left ventricular failure of several causes.1 While “auditory alternans,” characterized by regular variation in the intensity of heart sounds and murmurs, is well described,1-5 alternation of the intensity of peripheral arterial bruits has not been commonly appreciated. This report describes a patient with atherosclerotic disease involving the heart and peripheral arteries in whom alternation of a femoral bruit was noted in association with pulsus alternans.

MEASUREMENT OF INTENSITY OF HEART SOUNDS AND MURMURS

MEASUREMENT OF INTENSITY OF HEART SOUNDS AND MURMURS

The first heart sound in left bundle branch block: an echophonocardiographic study.

To examine the nature of the first heart sound in left bundle branch block (LBBB), 26 patients with LBBB were studied using echophonocardiography. Apexcardiograms and systolic time intervals were also obtained from these patients and the results were compared with 20 normal subjects. Mitral closure preceded tricuspid closure by 0.02-0.04 second in 19 of the 20 normal subjects. In contrast, in subjects with LBBB there was a variable delay in mitral closure so that in seven subjects the sequence of mitral and tricuspid closure was normal, in 11 it was reversed compared wih the normal group, and in eight closure of both valves was simultaneous. The interval from the onset of ventricular depolarization to mitral closure was 0.074 +/- 0.019 (mean +/- SD) for the patients with LBBB and 0.057 +/- 0.008 second for the normal group (p < 0.001). With LBBB the first sound tended to be of reduced intensity and separate mitral and tricuspid components could not be identified. Systolic time intervals and the apexcardiograms demonstrated a delayed onset of left ventricular contraction and an increased isometric contraction time in the LBBB group, both of which would contribute to a delayed mitral valve closure and decreased first heart sound intensity.

Method and apparatus for discrimination and detection of heart sounds

A method and apparatus for transposition of heart sounds to a range easily detectable by the human ear and suitable for transmission, for discrimination of low intensity or brief sounds, and for display of the heart sounds on conventional recording devices involve steps of and means for, respectively, converting the heart sounds to electrical signals having given frequency components, providing an audio frequency carrier having further frequency components, generating a transposed output representing a sum and a difference of the frequency components and the further frequency components, filtering the transposed output to remove the difference of the frequency components and further frequency components, and generating an audible representation of the heart sounds and/or displaying a visual representation thereof. As a further feature, the inventive method and apparatus provide for detection of an envelope of heart sound intensity, and provision of a visual indication of whether or not electrical signals corresponding to heart sounds are of proper signal amplitude for consistent measurement of heart sound intensity.

Study of respiratory influence on the intensity of heart sound in normal subjects.

The amplitudes of the first and second heart sounds were recorded during quiet natural breathing in 31 normal subjects. A total of 3,656 and 3,016 heart beats were available at the apex and pulmonic areas respectively. The intensities of the first and second heart sounds were found to be increased during expiration. This respiratory tendency in the heart sounds was less prominent during the transitional phase between expiration and inspiration. Therefore we suggest that respiratory changes in heart sounds should be evaluated with a heart beat located at or close to the center of each inspiration and expiration. Respiratory alteration in the intensity of heart sounds is one of the commonest auscultatory pitfalls. Auscultatory evaluation of the intensity of heart sounds should thus be performed carefully, with the respiratory changes kept in mind.

Intensity of Heart Sounds in the Evaluation of Patients following Myocardial Infarction

The amplitude and intensity of heart sounds were measured at the chest wall in 25 patients with acute myocardial infarction in order to determine what meaningful clinical information can be derived from observing the intensity of the heart sounds. During the early period after infarction, the first heart sound (S₁), the aortic component of the second heart sound (A₂), and the pulmonary component of the second heart sound (P₂) each were lower (P < 0.001) than the respective heart sounds of 23 normal subjects. Measurable reductions of sounds frequently occurred in the absence of a third heart sound or rales. Prolongation of the ratio of the preejection period over the left ventricular ejection time (PEP/LVET) (P < 0.001) and a reduced rate of isovolumic relaxation (P < 0.001) accompanied the reduced heart sounds. During the course of recovery, the average intensity of A₂ increased in 19 of 25 patients. Among the 19 patients who showed an increase in A₂, the PEP/LVET decreased (improved) (P < 0.02), and the rate of isovolumic relaxation increased (P < 0.001). Blood pressure did not change. The diminished A₂, as shown by recently described mechanisms of production of the second heart sound, is due to a reduction of left ventricular isovolumic relaxation. Similarly, the reduced P₂ implies that right ventricular isovolumic relaxation also was affected by the infarction. Variations of S₁ seem to relate to variations of the left ventricular contractile state. The results of this study indicate that the intensity of heart sounds at the chest wall in patients with normal valves and normal transmission of sound is measurably diminished in patients following myocardial infarction. Noticeable ausculatory variations of the intensity of heart sounds can serve as a meaningful guide to the evaluation of ventricular performance at the bedside.

Mitral valve closure in atrial flutter.

12 patients who had atrial flutter without clinical, echocardiographic or angiographic evidence of aortic insufficiency were studied with simultaneous echo- and phonocardiograms. In patients with high-grade atrioventricular (AV) block, the mitral valve opened and closed with each flutter wave. Of seven patients, two had persistent and five had intermittent early mitral valve closure before QRS inscription. In five patients (three with 2:1 AV block) the mitral valve closed on time. In one patient with a mitral valve prosthesis, echocardiography and cinefluorography demonstrated closure during mid-diastole, with reopening in late diastole after a flutter wave. Final valve closure occurred before the onset of the QRS, and each closure was associated with a click. Simultaneous phonocardiographic analysis in these patients demonstrated that the first heart sound intensity was inversely related to the degree of mitral valve preclosure. This relationship was independent of the length of the RR interval. Thus, atrial flutter independent of any other cause of abnormal hemodynamics may produce early mitral valve closure. The echocardiographic finding of premature mitral arrhythmias, may not have the same diagnostic or prognostic significance previously described in patients with sinus rhythm and normal AV conduction.

Accentuation of heart sounds in anemia: an effect of blood viscosity.

The effect of blood viscosity on the intensity of heart sounds was investigated in 25 anemic patients and 41 control subjects. Calibrated phonocardiograms showed that in anemic patients, the aortic component of the second sound was of greater amplitude (54 +/- 3 vs. 33 +/- 3 dyn/cm2) (P less than 0.001). The pulmonary component of the second sound and the first sound were also of higher amplitude in anemic patients (both P less than 0.001). The viscosity of blood of anemic patients was lower (0.029 +/- 0.001 vs. 0.045 +/- 0.001 poise) (P less than 0.001). Blood pressure was comparable among the two groups. Sound produced by closure of a normal porcine valve in an in vitro flow system also showed an accentuated sound with liquids of lower viscosity. Augmented diastolic vibrations of the closed valve, shown by high-speed motion pictures, accompanied the accentuated sound. These observations suggest that the accentuated second sound in anemic patients results from the lower blood viscosity, which reduces the damping forces that act upon the semilunar valve as it vibrates after closure. The reduced damping would allow augmented vibrations that result in an accentuated sound.

Digital Spectrum Analysis of the First and Second Heart Sounds

Abstract : An application of spectrum analysis in phonocardiography is described. The authors propose that separate spectra be computed for the first and second heart sounds, and suggest how the spectra can be used in both experimental and clinical investigations. The computational procedure is described, an example is presented, and a FORTRAN subroutine is provided that can be used to compute the spectrum estimates. The results presented represent a first step in the data analytic process, and provide a method of exposing and summarizing the 'information' in the data. The method has potential application in both the diagnosis of cardiovascular disease and the monitoring of critically ill patients. To illustrate the latter point it is proposed that the heart sound spectra could be used to construct an index of relative heart sound intensity that has potential application in monitoring the depth of anesthesia during surgery. (Modified author abstract)