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R Zannoli

Publications and source records attributed to R Zannoli.

51 records · Page 3Linked to original sources
PubMed1979

[Left ventricular volume measurement; the accuracy of the measurement].

Volume angiography is a widely diffused technique in hemodynamic laboratories despite several factors which limit the validity of the method. We have evaluated three of these factors: a) indefiniteness in the identification of the contour of the left ventricular cavity on the projected image; b) indefiniteness due to the reproducibility in tracing the contour of the left ventricular cavity by the same operator; c) indefiniteness related to the geometrical assumption (ellipsoid of revolution). The indefiniteness, given as per cent variation from the mean value, has been determined for the diastolic as well as systolic phase. The maximal possible indefiniteness, for diastole and systole, in contours identification in 15 cases has been found to be +/- 11.3% and +/- 24% of the mean volume. Intra observer reproducibility evaluated outlining 30 times the left ventricular contour has been equal to a mean difference from the mean volume of +/- 1.2% for diastole and +/- 4% for systole. The mean difference of the mean volume calculated with the area-lenght method (ellipsoid geometry) from the volume calculated with the Simpson rule has been, on 15 cases, equal to 4% in diastole and 11% in systole. This high level of indefiniteness, mainly for the systolic phase, must be considered before giving a value excessively precise to the volume data obtained with angiography. On the other hand, the method retains an orientative meaning extremely useful in clinical evaluation.

Angiocardiography↗
PubMed1978

[Hemodynamic effects of disopyramide and procainamide in open-chest animals].

Hemodynamic effects of two antiarrhythmic agents, disopyramide and procainamide, have been evaluated in anesthetized open-chest healthy pigs after random administration. At therapeutic plasma concentrations none of these agents proved to have deleterious hemodynamic effects. The most important action was observed after disopyramide infusion and consisted in significant bradycardia which confirmed the known effect on sinus node automaticity of the drug. Left ventricular dp/dt, an index of cardiac contractility, was unchanged after infusion of both drugs. On the ECG intervals, only procainamide provoked a significant prolongation of QTc. It is concluded that at therapeutic dosage disopyramide does not present deleterious hemodynamic effects in animals and proves to be a valid alternative to other traditional antiarrhythmic agents.

Animals↗
PubMed1978

[Evaluation of the radiological exposure for medical terms involved in haemodynamic examinations (author's transl)].

The radiation exposure of the medical team involved in 35 consecutive cardiac catheterisation procedures performed at the Istituto di Malattie dell'Apparato Cardiovascolare, University of Bologna, was calculated. A mapping of the iso-exposure lines and the values of radiation exposure of each component of the team were determined for each procedure. With these parameters the total amount of radiation for a normal diagnostic activity coul be calculated. The mean values obtained (150-250 mR/week) were in the range of the maximal values permitted to medical teams professionally exposed to the risk of radiation (3R/13 weeks). Rotation of the components of the team granted a continuing diagnostic activity within the limits of radiation exposure imposed by the law. An evaluation of the different procedures and techniques indicated coronary arteriography as the procedure with a higher risk of radiation (M = 50 mR/procedure) and pointed out the mechanism involved in order to obtain a considerable reduction of radiation exposure.

Cardiac Catheterization↗
PubMed1977

[Study of the precision and limitations in measuring left ventricular pressure and its first time-derivative (author's transl)].

The precision in measuring left ventricular pressure and its first time-derivative has been evaluated with the study of the physical caracteristics of a system currently used for pressure wave sampling. Besides the different catheters, the set-up tested consists of a nylon connector (110 cm) and of two three way stopcocks. Amplitude and phase response, from 1 to 60 Hz, have been obtained testing the system with sinusoidal pressure waves generated by an hydraulic oscillator. Despite mild differences dependent on the different catheters, the system amplifiers remarkably at frequencies above 5 Hz. Above this limit the harmonic content of the left ventricular pressure wave is negligible and can be ignored in defining the basic morphology and the absolute values of the curve. Similary, the amplification of these high frequency harmonics operated by the system does not affect appreciably pressure measurements. In the case of the pressure time-derivative the significant harmonic content is shifted toward higher frequencies. For this reason a reliable dp/dt cannot be obtained with this hydraulic set-up. A maximal hypothetic error, utilizing a Cook 5.2 F 105 cm catheter, of 8-9% and 28-31% has been estimated for pressure and time-derivative measurments respectively.

Cardiac Catheterization↗
PubMedDate not supplied

Haemodynamic effects of prenalterol in acute myocardial ischaemia in open chest pigs.

The haemodynamic effects of prenalterol, a new sympathomimetic agent, have been studied in anaesthetized open-chest pigs with acute myocardial ischaemia provoked by left anterior descending coronary artery ligation. A group of eight animals was infused with saline and served as control (C). In both groups the ligation of the left anterior descending coronary artery determined a significant (P less than 0.05) reduction of aortic flow, maximum left ventricular (LV) dp/dt with no changes in heart rate. The infusion of a first dose of 30 micrograms/kg of prenalterol restored the depressed haemodynamics but increased significantly the heart rate in the prenalterol group while the saline infused group did not show any significant changes. The haemodynamic effects of prenalterol were still evident 25 min after the infusion. The subsequent administration of a second dose of 60 micrograms/kg of prenalterol resulted in a further improvement of the aortic flow, LV dp/dt and heart rate which reached values higher than in the basal condition. The positive inotropic effect was not associated with changes in stroke volume, therefore the increase in aortic flow was essentially due to an increase of the heart rate. It is concluded that prenalterol is a powerful inotropic agent in acutely infarcted animals. Its action on aortic flow appears to be related to an increase in heart rate in contrast to some previous observations.

Animals↗