Biomedical subjects
F Portaluppi
Publications and source records attributed to F Portaluppi.
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. In 10 subjects, cardiac output was also recorded by impedance cardiography. The result of the study was that the first heart sound increased routinely 4-5 times the normal amplitude; in a few subjects the increase was up to 15 times greater. While the extent of increase of S1 was proportional to the severity and duration of the effort and was usually proportional to the increase of other parameters, exceptions were noted as having marked increase of S1 with moderate increase of either blood pressure or heart rate. This was explained by the different receptors activated by the catecholamines and by the complexity of hormonal and neural influences acting on various organs in a stress test. The amplitude of S1 was found to be a reasonably reliable index for following changes of cardiac contractility during exercise, and the suggestion was made that this parameter should be studied in parallel with the others in routine stress tests.
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. The systolic time intervals and the stress tests are briefly discussed. Based on modern experimental studies, the stress test should include both an electro- and a phonocardiogram. In the latter, one would measure the amplitude of the first heart sound as an index of contractility. The conclusion is that combined methods give the best results. They are electrocardiography, phonocardiography, impedance cardiography, and echocardiography. An alternative, dictated by technical problems, is to use at first phonocardiography and impedance plus electrocardiography; then echocardiography plus electrocardiography; and then, if indicated, a stress test might complete the study; the latter should include both an electrocardiogram and a phonocardiogram.
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. In mitral valve prolapse, the contribution to sound production of mitral leaflets and chordae is likely to be minor, as it had been demonstrated for the first heart sound.
Ergometric evaluation of the effects of captopril in hypertensive patients with stable angina.
The antihypertensive and anti-ischaemic effects of methyldopa and captopril were compared in 12 hypertensive patients with coronary artery disease. The antihypertensive effect of alpha-methyldopa (A) and captopril (C) were significant and similar. On the other hand, while methyldopa did not increase the product of systolic pressure and heart rate and did decrease the effort-induced S-T segment depression, C increased the double product (DP) and decreased the ischaemic S-T changes. Captopril might be useful in the treatment of hypertensive patients with coronary artery disease.
Isolated right ventricular infarction followed by posterior left ventricular infarction after a few days.
This report presents a rare case of isolated right ventricular infarction complicated by bilateral occlusive pulmonary embolism apparently due to right ventricular mural thrombus. Only 2 to 3 weeks later an infarct of the posterior wall of the left ventricle finally occurred. The clinical, pathological and electrocardiographic features of the case are discussed. This case shows that right ventricular infarct can occur without a preceding or simultaneous infarct of the left ventricle.
The main heart sounds as vibrations of the cardiohemic system: old controversy and new facts.
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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 0.005). This difference was maximal in the oldest age group and became non significant in the group of children under 12. At slow heart rate, this difference was greater than at a more rapid heart rate. The left ventricular ejection times (LVET), measured on the two pulses, showed a very close correlation (r = 0.96) but the LVET was significantly longer in the SSN tracing, especially in the older subjects. These data reveal that the incisura of the arterial pulse travels more rapidly than the upstroke, especially in older patients and at lower heart rates. The most likely explanation of this fact resides in the frequency-dependent influence of vascular reflections, which is more important with increasing age and slower heart rate. Thus, the transmission velocity along the arterial wall is higher for the higher harmonics of the pulse wave (incisura) than for the lower harmonics (upstroke).
Phonometric study of the human first heart sound.
The first heart sound was studied in 20 normal subjects. The phonocardiogram (PCG) was recorded from apical and mid-precordial areas using microphone with a flat response curve from 0.2 to 8,000 Hz. It was stored, together with a simultaneous electrocardiogram, on an FM analog tape recorder (linear frequency response from 0 to 4,000 Hz), fitted with a filter with weighting curve B according to the American National Standard Institute. A linear (SPL) recording was also made. The signal was fed through a digital converter into a minicomputer and the frequency distribution of the first heart sound was analyzed using Fast Fourier Transform. These data were stored and the average spectra were calculated for both B and SPL. The SPL spectra from both apex and mid-precordium showed a maximum intensity of about 80 dB between 12-20 Hz, decreasing progressively to a constant level of 35 dB between 110-120 Hz. The spectra obtained from both areas using filter B showed a maximum intensity of 40-50 dB between 20-60 thereafter. It is important to emphasize that the dB values in B and SPL are absolute, since they refer to a standard reference weighting. It appears that the SPL recording is more valuable in that it allows the study of all components of the PCG signal. The spectra obtained in this study will be used as a standard for future research in various pathological conditions.
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. Special attention was paid to the interval between the 2 main components (Ia and Ib) of the first heart sound, to the amplitude of both Ia and Ib, and to the relationship between carotid upstroke and first heart sound. All intervals between sound components of the patients with ASD were found similar to those of the controls. No increase in amplitude of Ib could be documented. The amplitude of the first heart sound relative to that of the second sound (measured from the ratio I/IIA) was similar to that of the controls, Finally, a slight precedence of aortic valve opening (obtained from the carotid upstroke time minus transmission time) over the second component of the first sound (Ib) was found both in ASD and in controls. In view of these facts, a tricuspid contribution to the mechanism of the b component of the first heart sound appears highly unlikely. On the other hand, this component seems closely related to the dynamic events (blood acceleration and walls deceleration in the aortic root) that follow the aortic valve opening.
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. Nineteen patients with aortic stenosis and four subjects without it were also studied by cardiac catheterization and angiography. The amplitudes of the two components of the second sound were compared, and the ratio of each with the amplitude of the first sound was determined. The ratios of both the aortic and the pulmonic component to that of the first sound were decreased in aortic stenosis, and the decrease of the pulmonic component was comparable to that of the aortic component. These findings could be related to prolongation of the isovolumic relaxation period of both ventricles caused by an influence of the left ventricle on the right, most likely due to functional changes of the interventricular septum.
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. All three components of the first sound were found small and delayed in LBBB; a delay of the arterial pulses was also noted. No additional component that might be attributed to the right heart preceded the delayed first sound. This study confirms that the first heart sound recorded on the chest wall originates only in the left heart and aorta.
Phonometric approach to the analysis of cardiac acoustic phenomena.
The use of phonocardiography is limited by the lack of standardization of acoustical signal pick-up and of the filters. Moreover, quantitative evaluations are not possible. This limits the analysis of acoustic phenomena and makes confrontation between different laboratories impossible. To avoid these drawbacks we have developed a method based on phonometric principles. Heart sounds of twenty for normal subjects were recorded by an air-coupled microphone with the standard 6 ml cavity. The response curve of the microphone is flat from .2 to 8000 Hz. The signal was measured and stored on an analogic tape recorder together with the ECG. For each subject the 3 weighting networks (A, B and C, according to the American National Standard Institute) and the linear recording (SPL) were used and the peak value of every record was written down in dB-peak. The amplitude spectra were obtained through the FFT algorithm. Normal heart sounds reached a high frequency limit of 170 Hz. with a maximum amplitude of 67 dB SPL, 24 dB A, 42 dB B and 59 dB C. Each spectral pattern can provide a useful reference to compare with pathological acoustical findings.
Mechanographic evaluation of left atrial activity in mitral valve prolapse.
Twenty-five patients suffering from mitral valve prolapse were studied to demonstrate any diagnostic modifications of the indirect (esophageal) left atrial pulse (ESO). Valvular prolapse is demostrated on the ESO by a sudden change in slope of the curve after the "x" point, in coincidence with a midsystolic click. Late systolic mitral insufficiency, when associated with prolapse is illustrated on the ESO tracing in two ways: a) an abnormally tall "v" wave; b) a late systolic plateau which begins immediately after the click and continues beyond the second heart sound. After the infusion of methoxamine or isometric exercise the ESO is usually of the a) conformation, while after the inhalation of amyl nitrite the tracing tends to be of the b) type. The "c" wave is at times altered but not always. This alteration is characterized by a greater amplitude and sharper peak. Based on the physiopathogenesis of the alterations of the ESO, it can be stated that they are specific, and sensitive enough to be both qualitative and quantitative.
[Different cardiovascular and hormonal consequences of A-V fistula in uremic patients (author's transl)].
The Authors studied 11 uremic patients for whom it was necessary to make an arterio-venous (A-V) fistula for dialysis purposes. Before and after creation of the fistula, the following parameters were determined: arterial pressure (PA) heart rate (HR), peripheral vascular resistances (PVR), renin, adrenalin and nor-adrenalin blood levels. The patients were divided in two groups according to the increase of the systolic output (SO) and o the cardiac index (CI) after the fistula (1st group of 5 patients: less than 30% increase of these values as compared to those before the fistula; 2nd group: more than 30% increase. By using Wilcoxon distribution free test it was possible to demonstrate the existence of a different condition, statistically significant in the two groups. In the 1st group of older patients (P < 0.05) where the systolic pressure values were greater (P < 0.05) and the indexes of the mechanical events of the left ventricle were altered, there was an increase of heart rate (P < 0.05), a moderate reduction of PVR (P < 0.01) and a very small increase of the systolic output and cardiac index (P < 0.01). Furthermore, in the 1st group, a left ventricular hypertrophy was observed, except in one case whereas this condition was constantly absent in the patients of the 2nd group. Patients of the 1st group had high nor-adrenalin blood levels, which did not change after the significantly after the creation of the fistula. In conclusion, an A-V fistula provokes two different hemodynamic behaviours which are related to age, pressure values, myocardial performance, presence of a left ventricular hypertrophy, PVR variations, and renin and nor-adrenalin blood levels.
[Spectral analysis of a "sea gull cry" murmur (author's transl)].
"Precordial honk" is a loud, high pitched, musical and usually intermittent systolic noise. The concept of extracardiac origin and "inocence" of this finding is superseded and today its valvular origin during mitral prolapse, mitral or tricuspidal insufficiency - due to rheumatic or ischaemic disease - or during cardiomiopathy is demonstrated. The acoustic characterization of this finding was based on phonocardiographic registration. All the authors describe the "precordial honk" as a high frequency murmur without specifying the acoustic characteristics of the phenomenon. A spectral analysis technique applied to the acoustic cardiac signal (Fourier analysis) has been employed in order to study the "precordial honk" of a 15-year-old boy with mitral valve prolapse. This made possible to show that this sound had only one fundamental frequency at 300 Hz. without harmonics; a "sea gull cry" murmur (as the cry of many birds is) justifying the name given by clinicians. The spectral analysis of phonocardiography signal allow to study, more precisely, the cardiac acoustic phenomenon.
[Spectral analysis of cardiac acoustic phenomena].
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The fast Fourier transform in the analysis of the normal phonocardiogram.
The present study is focused on spectrum analysis as a useful method of processing the PCG in order to obtain the frequency spectral distribution of normal heart sounds. Thirty normal subjects aged from 17 to 34 were studied. PCG was recorded on the fourth intercostal space at the left sternal border using a sound level meter coupled with a standard 6 ml cavity. The microphone had a linear response from 0.2 to 8,000 Hz. The signal was filtered with the standard B network according to the ANSI specifications and was registered on a four track FM tape recorder. A four channel analyzer with a microprocessor for off-line elaborations was used with 10 KHz sampling frequency. The PCG signal was triggered by a QRS detector on the R wave of the simultaneously recorded ECG. Fast Fourier transform was performed employing either a four channel analyzer with a microprocessor, or an A/D converter with a computer. Finally the results of the analysis were statistically elaborated. The described procedures permit to obtain a direct and exact tracing of the acoustic features of the heart, thus representing an attempt to come closer to the standardization and automatic analysis of the phonocardiographic technique.