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Biomedical subjects

B Magnani

Publications and source records attributed to B Magnani.

At least 235 records · Page 13Linked to original sources
PubMed1983

Electrophysiologic properties of prenalterol.

We assessed the electrophysiological properties of prenalterol, a new beta-selective agonist, in 10 patients with normal and 10 patients with delayed atrioventricular (A-V) conduction times. We evaluated sinus node function, A-V conduction times, refractory periods, atrial or ventricular arrhythmias, spontaneous or induced by the single extrastimulus technique during basal conditions, 5 minutes after a first dose of 20 micrograms/kg of prenalterol, and 5, 15 and 30 minutes after a second injection of the same dose. Prenalterol increased heart rate about 20%, with statistically significant shortening of right atrial refractory periods, A-V nodal functional and effective refractory periods and A-H interval in both groups after the first dose. In the 6 patients with sick sinus syndrome, prenalterol increased heart rate significantly and decreased maximum sinus node recovery time which reached a statistically significant value (P less than 0.05) 5 and 30 minutes after the second dose. At the highest dose, prenalterol seemed to increase the number of ventricular and/or atrial arrhythmias only in those patients with the arrhythmias before treatment. Prenalterol increases heart rate and decreases A-V node conduction times. The shortening of maximum sinus node recovery time in patients with the sick sinus syndrome, especially if confirmed after oral administration, could indicate a specific use of this drug in patients with sinus bradycardia or atrial fibrillation with a slow ventricular response.

Adrenergic beta-Agonists↗
PubMed1983

Propranolol v. verapamil in the treatment of unstable angina. A double-blind cross-over study.

A double-blind, cross-over study was performed in 23 consecutive patients with unstable angina at rest in order to compare the efficacy of verapamil (480 mg/day) and propranolol (240 mg/day) in reducing the number of anginal crises and nitroglycerin (NTG) consumption. Twenty patients, 15 men and five women, mean age 59.7 (range 45-68) years completed the study. The mean daily number of attacks was 3.1 in the two-day run-in period and 2.9 in a subsequent two-day placebo period immediately preceding the treatment periods. Propranolol reduced the number of attacks to 1.6 (P less than 0.01 compared to the run-in and placebo periods). Verapamil reduced the crises to 0.2/day (P less than 0.01 compared to the run-in placebo and propranolol periods). The NTG consumption behaved in a similar way. Adverse reactions to verapamil were observed in two patients. Although there are objective difficulties in performing correct trials in these kinds of patients, the results of this study indicate the efficacy of verapamil in preventing anginal pains during the "warm phase' of the unstable form and stress the superiority of this calcium antagonist when compared to propranolol.

Aged↗
PubMed1983

Prenalterol in primary dilated cardiomyopathy: hemodynamic and angiographic evaluation.

The hemodynamic effects of an acute infusion of prenalterol (PN), a new inotropic beta-adrenoceptor agonist, have been evaluated by cardiac catheterization in 10 patients with primary dilated (congestive) cardiomyopathy. A single dose of 20 micrograms/kg was administered over 5 min after basal hemodynamic and angiographic measurements. The administration of prenalterol caused a significant increase in mean cardiac index, from 2.3 to 3.3 l/min/m2 (P less than 0.01) and mean stroke volume, from 47 to 62 ml (P less than 0.01) without a change in heart rate. Mean left ventricular end-diastolic pressure was reduced from 19 to 13 mm Hg (P less than 0.05) and left ventricular dp/dt rose from 902 to 1089 mm Hg/s (P less than 0.01). Stroke work index increased from 27 to 40 g m/m2 (P less than 0.01) and ejection fraction from 31 to 36% (P less than 0.05). Mean blood pressure did not change and the systemic vascular resistance decreased from 24 to 17 RU (P less than 0.01). The favorable effect of prenalterol on left ventricular relaxation was shown by an increase of peak negative left ventricular dp/dt from 946 to 1159 mm Hg/s and by a decrease of the time constant of left ventricular pressure fall from 49 to 39 s. These results demonstrated a positive inotropic effect of prenalterol on patients with diffuse and severely reduced contractility.

Cardiac Output↗
PubMed1983

[Extension of necrosis in the acute phase of myocardial infarct. Clinical picture and prognosis].

In a consecutive series of 297 patients prospectively evaluated at the time of admission for an acute myocardial infarction, the extension of necrosis was found to occur in 16,4% of the cases. The electrocardiographic site of extension was the same as during the initial episode in over 75% of cases suggesting the possibility of a similar pathogenetic mechanism and the involvement of the same coronary district. Patients in Killip class I were respectively 61% and 45% before and after the extension, in class II 33% and 14%, in class III 6% and 14%, in class IV 0 and 27% (p less than 0,001). In-hospital mortality was 16,1% without and 38,8% with extension (p less than 0,001). The peak level of CPK-MB was an average of 110 +/- 45 U/1 before and 96 +/- 34 after the extension (p = N.S.). It was not possible to recognize the patients at risk of extension according to the traditional clinical parameters (age, sex, site of necrosis, transmural involvement, residual angina, Norris index and Killip class before the extension). It is concluded that the protection of the myocardium at risk is of primary importance in the setting of acute myocardial infarction, regardless of the possibility of saving areas already compromised at the time of admission or the hypothetical "border zone".

Humans↗
PubMed1983

Intrahospital prognosis of acute myocardial infarction by means of discriminant analysis: methodological aspects and clinical results.

Discriminant analysis was carried out in 83 patients with acute myocardial infarction who underwent hemodynamic monitoring, to obtain a prognostic index. The classification rate was satisfactory in over 80% of the patients both in a subset used to construct the prognostic index and in a pilot group in which the validity of the index was assessed. In decreasing order of importance the parameters in the function were: age, history of angina, pulmonary artery end-diastolic pressure, diastolic systemic pressure, sum of ST segment elevation, pulmonary vascular resistance, heart rate, history of hypertension and site of necrosis. A much less satisfactory classification rate was obtained using two well-established indexes, perhaps because of sampling, methodological and chronological differences. It thus seems desirable for each hospital to use prognostic indexes obtained from its own population. Such indexes should be updated whenever necessary.

Adult↗
PubMed1982

Renal haemodynamics after chronic treatment with labetalol and propranolol.

1 Effective renal plasma flow (ERPF) and glomerular filtration rate (GFR) were measured in two groups of 12 patients both at rest and during sub-maximal cycloergometer exercise while on placebo and after 3 months of treatment with either labetalol or propranolol. 2 ERPF increased and renal vascular resistance decreased both at rest and during exercise after labetalol treatment, compared with placebo; the opposite was observed after propranolol treatment. 3 GFR increased after labetalol and decreased after propranolol both at rest and during exercise, compared with placebo, but these changes were not statistically significant. 4 Labetalol and propranolol resulted in the same decrease in blood pressure and a comparable incidence of side effects.

Adult↗
PubMed1982

[Precapillary pulmonary hypertension: effect of Captopril].

The immediate and sustained haemodynamic effects of Captopril (CPT), an oral inhibitor of angiotensin converting enzyme, were studied in six patients (pts) with severe pulmonary hypertension (PH) (pulmonary artery pressure: mean +/- SD value = 57 +/- 20 mmHg). Two pts had primary PH, 2 embolic PH and 2 Eisenmenger Physiology (EP). Administration of 100 mg of CPT in a single oral dose produced a significant decrease only in systemic arterial pressure (SAP) (p less than 0.025) and systemic vascular resistance (SVR) (p less than 0.05) in 5 of 6 pts. Heart rate (HR), cardiac index (CI), pulmonary vascular resistance (PVR), pulmonary arterial (PAP), pulmonary wedge (PWP) and right atrial pressure (RAP) did not change significantly. These results were confirmed in a repeat haemodynamic study after 4 months of long-term treatment with 50 or 100 mg of CPT 3 times daily. In 1 pt with EP and severe congestive heart failure (CHF) the same chronic treatment produced a marked decrease in HR (from 114 to 88 b/min), RAP (from 10 to 1 mmHg), PWP (from 15 to 6 mmHg), PVR (from 41 to 30 UR), SVR (from 58 to 43 UR). Systemic CI increased from 1.68 to 2.60 l/min/m2 and pulmonary CI from 1.64 to 2.5 l/min/m2; no changes were seen in PAP and SAP. These data suggest that CPT is not effective on pulmonary haemodynamics in pts with precapillary PH and normal CI whereas the drug seems to influence favourably the pulmonary circulation in pts with PH secondary to or associated with left ventricular failure. The necessity of evaluating not only PVR but PAP as well, in studying the effect of vasodilators especially in pts with precapillary PH and normal CI, is discussed. In fact a reduction of PAR without decrease of PAP, as frequently seen in previous reports, is probably due to a primary increase of CI induced by the drug.

Adolescent↗