This paper presents a new method to extract the envelope of the fundamental heart sound (S1 and S2) using the logistic function. The sigmoid characteristic of the logistic function is incorporated to segregate S1, and S2 signal intensities from silent or noise interfered systolic and diastolic intervals in a heart sound cycle. This signal intensity transformation brings uniformity to the envelope peak of S1 and S2 sound by inclining the transform intensity distribution towards the upper asymptote of the sigmoid curve. The proposed logistic function based amplitude moderation (LFAM) envelogram method involves finding the critical upper amplitude (xuc) above which the signals will be categorized as loud sound and the critical lower amplitude (xlc) below which the signal will be considered as noise. These critical values are regressively obtained from the signal itself by histogram analysis of intensity distribution. The performance is evaluated on noisy PCG dataset taken from PhysioNet/Computing in Cardiology Challenge 2016. The LFAM envelope yields better hill-valley discrimination of heart sounds from its silent/noisy signal intervals. The enhance heart sound envelope peaks are better than conventional methods. The proposed envelope feature is evaluated for heart sound segmentation using HSMM. There is a significant improvement in segmentation accuracy, especially at a low signal-to-noise ratio. The best average F1 score is 97.73%.

A 71-year-old woman, with the past medical history of heart failure with reduced ejection fraction (EF) and automated implantable cardioverter defibrillator (AICD) placement (for low EF 5-10%) in 2015, presented in February 2017 with the complaint of AICD shocks following an episode of vomiting. She denied any chest pain, abdominal pain, shortness of breath, palpitation, or dizziness. Electrocardiogram (EKG) on admission showed ectopic atrial rhythm with premature ventricular contractions in bigeminies, anterior fascicular block, and left axis deviation. On examination of the cardiovascular system, there was a normal S1 heart sound with a loud A2. There was no jugular venous distention on the neck or pitting edema on the legs. Laboratory studies showed no elevation of cardiac enzymes. Evaluation with chest x-ray showed the right ventricular lead had migrated to the right atrium and the defibrillator generator was flipped with leads coiled around it in transverse axis. AICD interrogation was performed which revealed inappropriate shocks were due to atrial fibrillation with rapid ventricular rate and loss of capture of the right ventricular lead. The diagnosis of Reel syndrome was made, and an electrophysiologist was consulted for replacement of the AICD. Reel syndrome is a variant of Twiddler's syndrome, which is a rare complication of pacemaker implantation. It manifests with the rotation of generator on transverse axis with leads coiling around it. Twiddler's syndrome, on the other hand, is the rotation of the generator on its long axis, which causes damage to the leads by twisting. Reel syndrome is usually observed within months from the placement of the generator compared to Twiddler, which takes years to occur. Twiddler and Reel's syndromes have similar contributing factors, such as female gender, obesity, large pocket, old age, dementia, and deep brain stimulation. Our patient only had two risk factors, namely, the sex and age. We propose that every patient with a pacemaker malfunction and AICD shocks should have a posterior-anterior (PA) chest x-ray and a lateral chest x-ray in addition to AICD interrogation. Twiddler's syndrome is effortlessly observed because of the twisting of dual leads compared to Reel syndrome, which is not straightforward because of the lack tortuosity of the leads.

A 37-year-old man presented with a history of episodic wheeze and breathlessness of 3 years' duration refractory to treatment. Physical examination revealed diffuse expiratory polyphonic rhonchi while the remainder of the examination including the cardiac examination was reported as normal. Pulmonary function testing revealed mild obstruction with bronchodilator reversibility. The patient was discharged on a 6-month course of antitubercular treatment (ATT) as bronchial brush cytology (obtained via bronchoscopy) was positive for acid-fast bacilli. The patient presented after completing 6 months of ATT with persistent symptoms, a loud S1 and a mid-diastolic murmur at the apex. High-resolution CT of the chest showed bilateral dependent ground glass opacities. An echocardiogram revealed a left atrial myxoma, and normal RV size and pressures. The patient underwent successful surgical removal of the same, and made a complete recovery. Refractory wheeze is a very unusual presentation of a left atrial myxoma.

The ability of clinicians, ie, 10 veterinary students, 10 general practitioners, and 10 board certified internists, to describe and interpret common normal and abnormal heart sounds was assessed. Recordings of heart sounds from 7 horses with a variety of normal and abnormal rhythms, heart sounds, and murmurs were analyzed by digital sonography. The perception of the presence or absence of the heart sounds S1, S2, and S4 was similar for clinicians irrespective of their level of training and was in agreement with the sonographic interpretation on 89, 82, and 78% of occasions, respectively. However, practitioners were less likely to correctly describe the presence of S3. The heart rhythm was correctly described as being regular or irregular on 89% of occasions, and this outcome was not affected by level of training. Differentiation of the type of irregularity was less reliable. The perception of the intensity of a heart murmur was accurate and correlated with the grade assigned in the living horses, R2 = .68, and with sonographic measurements of the murmur's intensity, R2 = .69. Clinicians overestimated the duration of cardiac murmurs, particularly that of the loud systolic murmur. Only diplomates could reliably differentiate systolic from diastolic murmurs. The ability to diagnose the underlying cardiac problem was significantly affected by training; diplomates, practitioners, and undergraduates made the correct diagnosis on 53, 33, and 29% of occasions, respectively. The poor diagnostic ability of practitioners and the lack of improvement in diagnostic skill after the 2nd year of veterinary school emphasizes the need for better teaching of these skills. Digital sonograms that combine sound files with synchronous visual interpretations may be useful in this regard.

Infarction of the central nervous system secondary to embolism from a left atrial myxoma is a recognized phenomenon. However, a myxoma as the source of an embolus may be overlooked, if, during the evaluation of a patient with a stroke of unknown etiology, an index of suspicion is not present. We report a case of a 57-year old woman presenting three episodes of cerebral infarction always in the same brain territory, suggesting a carotid pathology. The physical examination of the patient only showed a loud S1 with no other sounds and neurologic alterations, namely, right hemiparesia and aphasia. Diagnosis was made by two-dimensional echocardiography and better delineation was obtained by magnetic resonance imaging (MRI). The patient subsequently received a successful ressection of the myxoma. Eighteen months later the patient was well.

The salient phonoechocardiographic features of patients having hypertrophic cardiomyopathy (HCM) with or without left ventricular outflow tract (LVOT) gradients are reviewed. Intracardiac sound and pressure recordings from high fidelity catheter-tipped micromanometers have documented that the precordial murmur is the summation of both the systolic ejection murmur (SEM) arising from the LVOT, as well as the mitral regurgitant murmur recorded from the left atrium. The intensity of the precordial murmur varies directly with the LVOT gradient, which in turn is determined primarily by the contractility and loading conditions of the left ventricle. Reversed splitting of the second heart sound (S2) with paradoxical respiratory movement is a common finding in HCM, and when present, almost always denotes a significant LVOT gradient. It is due to marked lengthening of the left ventricular ejection time secondary to prolongation of the contraction and relaxation phases of left ventricular systole. The presence of a fourth heart sound (S4) is the rule in HCM when normal sinus rhythm is present, and is a reflection of a forceful left atrial contraction into a hypertrophied noncompliant left ventricle. A third heart sound (S3) is also common in HCM, and often the initial vibrations occur before the 0 point of the apexcardiogram (ACG) and continue giving the auscultatory impression of a diastolic rumble. When associated with a loud S1, which is frequently present, the clinical presentation may mimic mitral stenosis. This is particularly true when the patient has chronic atrial fibrillation. Careful attention to evidence of marked left ventricular hypertrophy as well as the typical echocardiographic findings of HCM preclude this diagnosis. In conclusion, phonoechocardiography is a simple non-invasive technique which almost always makes the definitive diagnosis of HCM.

A case of partial atrioventricular block with Wenckebach periods and a loud first heart sound (S1) associated with the longest P-R interval of the cardiac cycles is described. Although the surface electrocardiogram provided no clues to this paradoxical behavior, the intraatrial electrogram revealed that the long P-R interval with the loud S1 was accompanied by atrial echoes (reciprocal atrial beats). The loud S1 with a very long P-R interval was always caused by an atrial contraction synchronous with the QRS complex.