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T Toselli

Publications and source records attributed to T Toselli.

36 records · Page 2Linked to original sources
PubMed1982

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.

Adolescent↗
PubMed1981

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.

Adolescent↗
PubMed1980

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.

Electrocardiography↗
PubMed1980

[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.

Adolescent↗
PubMed1979

Diagnosis of mitral valve diseases using indirect (esophageal) left atrial pulse.

The diagnostic usefulness of the indirect (esophageal) left atrial pulse (ESO) has been analyzed in: 1) 25 patients (pts) with mitral insufficiency (MI), 2) 18 pts with mitral stenosis, 3) 29 pts with combined valvular disease, 4) 10 normal subjects. In addition, in 1) and 4), the ESO was recorded under the following dynamic conditions: a) during isometric exercise (handgrip), b) after inhalation of amyl nitrite, c) after intravenous infusion of methoxamine. The ESO tracing demonstrated estimates of the severity of the disease. Under dynamic conditions no modification from the resting morphology was obtained in the control group, whereas in MI the following modifications were observed: a) increased, progressive, positive elevation of the systolic phase of the ESO during the handgrip and the administration of the methoxamine; b) tendency to return to normal morphology after amyl nitrite.

Heart Atria↗
PubMed1979

[Technical and methodological aspects concerning the application of Fourier's analysis to phonocardiography (author's transl)].

The frequency spectrum analysis (Fourier's analysis) has recently been applied to phonocardiography. Using this mathematical approach instead of the current empirical analysis, it is possible to obtain -- on a less subjective basis -- more precise pathophysiological and diagnostic information from the acoustic cardiac phenomena. On the other hand, this refinement of the method of analysis stresses the need for better technical and methodological solutions, in order to reach the standardization of both the transduction and the recording of the acoustic signal at higher level of sensibility, fidelity and reproducibility. With this in mind, and on the basis of their experience, the Authors suggest the adoption of devices with specific technical characteristics, and propose a suitable method of application of Fourier's analysis to the phonocardiogram.

Fourier Analysis↗
PubMed1979

Cardiomechanical effect of k-strophanthoside administered to healthy volunteers by the rectal route.

Eight healthy volunteers were given k-strophanthoside (Strofopan) 1 mg rectally in order to evaluate changes in the cardiac function. Cardiomechanical measurements were performed by the polygraphic method before administering the drug and 1, 2, 3, 4, 5 and 6 h later. Three of the eight subjects continued to receive k-strophanthoside 1 mg daily for a further 6 days. Similar evaluations were made at the same times on day 3 and on day 7 of treatment. All indices considered varied to a statistically significant extent and showed the maximum effect at about the 4th h. The most evident changes were observed in the ICT and the PEP/LVET ratio. Here, the maximum variations were 46.3% and 29.5%, respectively, as compared with baseline values (P less than 0.01). When treatment was given for 7 days, the baseline values measured on day 3 and day 7 before administration showed a moderate and constant decrease in all parameters as compared with the first baseline value. This proves that k-strophanthoside administered rectally possesses steady-state activity with time. From a comparison of the changes in the same parameters as observed in a previous investigation after administering digoxin 0.50 mg orally there is reason to conclude that the effects obtained after administering k-strophanthoside 1 mg rectally were of the same magnitude.

Adult↗