Phonocardiography as a monitor of cardiac performance during anesthesia.

The usefulness of phonocardiography as a monitor of cardiac performance during anesthesia was investigated in six dogs. Anesthetic depression by halothane, isoflurane and nitrous oxide was demonstrated by the phonocardiogram. Likewise, the stimulating effect of dopamine clearly showed in the recordings.

The first heart sound in normal and pathological conditions.

Considerations of the physical basis of cardiac contraction and sound generation explain the mechanism of the first sound. Older theories examining this sound as the result of valve closure or stiffening are refuted. It has been demonstrated that the normal first sound originates in the left ventricle alone and that accelerations and decelerations, "timed" by mitral and aortic valves events, are its cause.

New index of cardiac contractility during stress testing with treadmill.

Experimental demonstration that the external phonocardiogram is similar to the third derivative (rate of acceleration) of LV pressure, and that catecholamines cause a similar increase of the early systolic wave of the first derivative of LV pressure and of S1 prompted a study of the first sound during stress testing. Following a previous study with different types of ergometers, the present investigation was based on records of 10 normal, young volunteers, taken during treadmill exercise while a phonocardiogram was recorded at the apex. The first heart sound increased in all of them averaging an eightfold increase during maximal stress.

Noninvasive index of cardiac contractility during stress testing: a collaborative study.

The present study was conducted in parallel in three different institutions with a similar purpose but using different technical setups. Based on the experimental demonstration that the external phonocardiogram is similar to the rate of acceleration (d3P/d3t) of the left ventricular pressure, and that catecholamines in a similar way increase the early positive wave of the left ventricular pressure and the first heart sound (S1) of the external phonocardiogram; knowing that exercise causes secretion of catecholamines and sympathetic reflexes, we have studied the S1 changes as a result of exertion in 34 normal young subjects. Blood pressure, heart rate, electrocardiograph, and phonocardiograph recordings of each subject were taken.

Various types of systolic clicks in patients with muscular subaortic stenosis.

Four clinical cases of subaortic hypertrophic muscular stenosis are discussed. All four, in addition to a loud systolic murmur, had a loud systolic click. However, the timing of the click and its relationship to the phase of the carotid pulse were different in each case varying from close to medium and to distant (or midsystolic).

Assessment of left ventricular function by noninvasive methods.

The possibility of evaluating left ventricular function by noninvasive methods is discussed in detail. The methods that are considered are electrocardiograph, phonocardiography, apex cardiography, sphygmography, impedance cardiography, electrokymography, and echocardiography. Following a brief section of 'definitions', each method is described in detail including technical problems, difficulties, and results.

Considerations on the mechanism of the systolic click of mitral valve prolapse.

The Authors briefly discuss the mechanism of production of the systolic click of mitral valve prolapse. A "valvular" mechanism seems inadequate to explain the genesis of vibrations that can be recorded, not only in the external phonocardiogram, but also in the intraventricular pressure tracing, in the apex cardiogram, and even in the left atrial pulse (esophagus). It seems more logical to postulate that the force of deceleration created by the sudden eversion of a mitral leaflet set the whole cardiohemic system (blood, myocardial walls, and the mitral apparatus) into vibration, thus producing the click.

Diagnosis of tricuspid insufficiency by non invasive methods.

The diagnosis of tricuspid insufficiency was first made at the end of last century, based on clinical signs. Graphic tracings of the venous system were soon recorded and were demonstrated useful in the forties and fifties. New methods involving invasive procedure or expensive instrumentation have been described in the last twenty years.

The jugular and hepatic tracings in normal subjects and in conduction defects.

The present study is a revision of the patterns of the jugular and hepatic tracings, two non-invasive tracings of the venous system. The study was performed in 40 subjects; 30 of them were normal while 10 had minor conditions affecting the left heart. The time of onset and peak of the various waves was statistically evaluated in this series.

Transmission delays of different portions of the arterial pulse. A comparison between the indirect aortic and carotid pulse tracings.

The transmission delays of the upstroke and incisura of the arterial pulse were measured in 128 normal subjects, divided in three groups of increasing age, by comparing the timing of the indirect aortic arch pulse (recorded at the suprasternal notch) (SSN) and the indirect, right carotid tracing (CAR). In the total group, the mean delay of the upstroke was 24.4 msec while the mean delay of the incisura was 19 msec (P less than 0.

First heart sound in atrial septal defect.

This is a retrospective study of 25 patients with secundum-type of ASD, confirmed by catheterization and angiocardiography. As controls, 25 normal subjects of matching age were studied. The phonocardiograms and carotid pulses of the 2 groups were recorded and compared.

Peculiarities of the first heart sound in bundle branch blocks. A new interpretation based on graphic analysis.

A phonocardiographic study in a medium frequency range was made over various areas of the precordium in 27 cases of right bundle branch block (RBBB), 28 cases of left bundle branch block (LBBB), and 30 normal subjects of the same age. The various components of the first heart sound plus the pulses at the suprasternal notch and the right carotid artery were studied in regard to timing, relationship with the ECG and the arterial pulses, intervals between components, and amplitude. The timing and intervals of the three components of the first sound were found normal in RBBB and so were the arterial pulses; apparent wide splitting was occasionally noted, due to recording of the first (a) and third (c) components, the latter being larger, as frequently observed in old age.

The pulmonary component of the second heart sound in acquired aortic stenosis.

The amplitude of the pulmonic component of the second sound in aortic stenosis was studied in 49 patients with this lesion. As controls, 50 normal subjects were also studied. Both groups were investigated by phonocardiography, apex cardiography and arterial tracings.

Abnormal left ventricular contraction revealed by impedance cardiograms and arterial tracings in bundle branch blocks and old myocardial infarcts.

Following the observation of an unusual pattern of the first derivative of the impedance cardiogram in cases of bundle branch block, a systematic study was performed both in normal controls and clinical cases. This graphic study was supplemented by the simultaneous recording of the first derivative of an arterial tracing, preferably the indirect aortic pulse at the suprasternal notch. These studies were performed in 70 subjects: 30 normal subjects, 14 cases of right bundle branch block, 14 cases of left bundle branch block, and 12 cases of old infarcts.

Changes of cardiac output caused by aging: an impedance cardiographic study.

The various parameters of cardiac output were studied in 132 healthy subjects from 20 to 89 years of age by impedance cardiography. This noninvasive method supplied data that were similar to those found by others by dye dilution methods. All parameters of cardiac output decrease with age.

Sounds and pulses as aids to cardiac diagnosis.

Areas of auscultation are reviewed. Heart sounds, clicks, snaps, and murmurs are discussed as they appear in various cardiac problems, particularly with respect to their usefulness in differential diagnosis.