PubMed Health⌕ Search

Biomedical subjects

G Brevetti

Publications and source records attributed to G Brevetti.

At least 37 records · Page 2Linked to original sources
PubMed1985

24-hour blood pressure recording in patients with orthostatic hypotension.

Continuous intra-arterial blood pressure measurement and electrocardiograms were obtained in two ambulatory patients with orthostatic hypotension due to autonomic dysfunction. Systolic and diastolic arterial pressure presented marked variations which took place mainly during the day and were related to several physical activities; however, marked falls in blood pressure were also observed during sleep and at the moment of arousal. A peak incidence of hypotensive events was found in the afternoon, mainly in the hours following the afternoon meal. Recording was repeated after 3 weeks of treatment with propranolol, 40 mg t.i.d. In patient 1, beta blockade drastically reduced the number and severity of hypotensive episodes, while propranolol failed to control blood pressure in patient 2, who experienced a higher number of hypotensive events during treatment. Findings of this study may be relevant to the management of patients with orthostatic hypotension and should contribute to a more accurate characterization of blood pressure profile in autonomic dysfunction.

Blood Pressure↗
PubMed1984

Long-term protection of ischaemic myocardium by nitroglycerin ointment.

To assess whether the reduction in ischaemic injury during acute myocardial infarction induced by nitroglycerin (NTG) results in a decrease in tissue necrosis, 96 rats were assigned to two groups. The first group (n = 34) was sham-operated. The second group of 62 rats was randomised in a ratio of 2:1 into control (n = 43) and treated (n = 19) subgroups following coronary artery occlusion. Treated animals received an application of 2% NTG ointment every 8 h immediately post-occlusion. All rats were killed 48 h after coronary artery occlusion and total creatine kinase activity (CK) of the left ventricle (LV) was measured. Infarct size calculated by CK depletion was 65.2 +/- 14.3% (mean +/- SD) of LV in control rats, and 51.6 +/- 14.0% of LV in NTG-treated (p less than 0.02). In a further series of 46 rats with coronary occlusion, the area of infarcted myocardium 21 days post-occlusion was assessed by planimetry on histological sections. In rats with control occlusion (n = 22), the extent of infarction was 30.6 +/- 4.8% of LV, and in NTG-treated rats (n = 24) it was 16.2 +/- 5.8% of LV (p less than 0.001). The amount of scar tissue in the infarcted myocardium 21 days post-occlusion was also determined by measuring LV hydroxyproline and collagen content in an additional 32 rats randomly assigned to a control (n = 11), a NTG-treated (n = 9) and a sham-operated group (n = 12).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1983

Dilazep-induced reduction of ischemic necrosis in rats with coronary artery occlusion.

To assess whether dilazep reduces myocardial necrosis we assigned 72 rats that survived coronary artery occlusion to 3 groups. The first control group (n = 26) received coronary occlusion and was untreated. The second group (n = 21) received coronary occlusion and was treated with dilazep (150 micrograms/kg s.c.) every 8 hours for 48 hours. The third group (n = 25) was sham-operated. Forty-eight hours later the creatine-kinase activity of the left ventricle was measured. The calculated left ventricular fraction that survived the occlusion was larger in dilazep-treated rats (44.5 +/- 4.1% of left ventricle) than in controls (31.2 +/- 3.2%; P less than 0.05). Twenty-six more rats also underwent coronary occlusion; 12 were controls and the remaining 14 were treated with dilazep at the same time and dose as before and killed 21 days after occlusion. Infarct size was evaluated on histological sections of the hearts by planimetry. The amount of left ventricle preserved from necrosis was larger in dilazep-treated rats, 82.1 +/- 0.9%, compared to controls 69.5 +/- 1.4% (P less than 0.05). Dilazep seems effective in preserving myocardial tissue from ischemic necrosis, and its beneficial effects are long-lasting, producing permanent reduction of infarct size.

Animals↗
PubMed1983

Beneficial effect of papaverine plus raubasine in peripheral arterial insufficiency.

It has been demonstrated that, in most arteriopathic patients, vasodilators induce the vascular steal phenomenon, i.e. the shunting of blood from the ischemic to the normally perfused areas. It is conceivable, therefore, that vasoconstrictors may improve in the opposite way, reducing the blood flow to the normal zones and increasing it to the ischemic. A "reverse vascular steal" caused by the simultaneous IV injection of a vasodilator and a beta-blocker has been previously shown; however, the chronic treatment of arteriopathic patients with beta-adrenoceptor blocking drugs often results in increased evidence of peripheral arterial insufficiency; therefore, the combination of a vasodilating drug with a beta-blocker is limited in the clinical practice. The aim of this study was to investigate the efficacy of the combination of the vasodilator papaverine hydrochloride with a drug having vasoconstrictive action without the undesirable side effects of beta-blockers. Accordingly, raubasine (40 mg) was given p.o. associated with papaverine (300 mg) in 10 arteriopathic patients, who presented a significant reduction of blood flow in the affected limb after the administration of 300 mg p.o. of papaverine alone. The measurements of blood flow were performed by impedance plethysmographic recordings to evaluate papaverine plasma concentrations. Data obtained by this study indicate that papaverine alone induces a significant reduction of blood flow starting from the time of its maximal plasma concentration. Raubasine alone does not induce any change in blood flow, while the combination of the 2 drugs significantly increases the blood supply to the affected limb. These favorable results, probably related to the ability of raubasine to induce a reverse vascular steal, suggest that the combination of this drug with a vasodilator such as papaverine may represent a new approach in the treatment of peripheral arterial insufficiency.

Aged↗
PubMed1982

Effects of combined alpha- and beta-blockade by labetalol in patients with coronary artery disease.

1 The effect of labetalol 100 mg orally twice daily on exercise tolerance has been compared with placebo in 19 normotensive subjects with angiographic evidence of coronary artery disease. 2 Labetalol, at the same work load as during placebo exercise, significantly reduced systolic and diastolic blood pressures, as well as heart rate and rate-pressure product. 3 Similarly, ST segment depression was reduced by labetalol from 2.0 +/- 0.4 to 1.36 +/- 0.6 mm (P less than 0.001), thus enabling an increase in exercise tolerance from a control value of 83.7 +/- 18 to 95.3 +/- 19 W (P less than 0.005). 4 In seven other patients, also with coronary artery disease, the haemodynamic effects of a single 0.6 mg/kg intravenous dose of the drug was evaluated during exercise. 5 Compared with conditions during control exercise, labetalol induced a significant reduction in rate-pressure product from 17228 +/- 2375 to 13445 +/- 2404 mmHg/min (P less than 0.005) and in peripheral vascular resistance from 612.0 +/- 61.2 to 512.7 +/- 36.2 dyn cm-5 m-2 (P less than 0.0025). These events were not accompanied by any change in cardiac index and in dP/dT left ventricular end-diastolic pressure (LVEDP) ratio. 6 These data suggest that labetalol may induce reduction in myocardial oxygen consumption, thereby increasing exercise tolerance in patients with coronary artery disease, without impairment of left ventricular performance.

Adult↗
PubMed1980

Three hundred and fifty-three consecutive patients with permanent transvenous pacemakers.

The safety and convenience of the transvenous approach to long-term endocardial pacing are well established, but its principal drawback is electrode displacement. The reported incidence of this complication varies between 3.0% to 36.7%, and is highest in the early post-implantation period before endocardial fixation of the electrode tip. Recently Brewster and Evans determined that the electrode displacement rate in 21 published series averaged 14.3%. However, the Inter Society Committee on Heart Diseases (ICHD) report on pacemakers states that a rate of early displacement greater than 5% calls for a critical review of results. The training and expertise of the persons inserting the pacemaker electrodes undoubtedly are major factors which determine the proper transvenous placement of permanent cardiac electrodes. This paper deals with our clinical experience of 353 patients who received permanent transvenous pacemakers during the period September 1, 1974 through March 1, 1979, with emphasis on problems and complications encountered and overall results.

Adolescent↗
PubMed1979

Effects of propranolol in a case of orthostatic hypotension.

In a hypertensive patient with orthostatic hypotension, the changes in several haemodynamic indices with respect to posture were evaluated. In the upright position, systemic blood pressure was reduced as compared with the supine position, and peripheral vasodilation was present, as shown by an increase in Jantsch's index of the impedance plethysmographic tracings. Systolic time intervals remained unchanged with changes in posture. Propranolol 10 mg intravenously brought the response to normal. In fact, after beta-blockade in the standing position the blood pressure remained unchanged and normal peripheral vasoconstriction was observed. Similar results were seen during atrial pacing at a constant heart rate of 130 beats/minute. In this patient, propranolol appears to normalise the response to the posture change, by restoring normal vasoconstriction in the upright position.

Blood Pressure↗
PubMed1979

Protective effects of propranolol on the exercise-induced reduction of blood flow in arteriopathic patients.

The vascular steal phenomenow, that is, the shunting of blood from ischemic to normally perfused areas, is commonly observed during exercise in the affected limbs of patients with peripheral arterial insufficiency. Propranolol was administered to 18 arteriopathic patients before the exercise to ascertain whether the reverse situation can be induced. The results indicate that before propranolol administration, Jantsch's index (used to quantify the plethysmographic waves) decreased from 0.53 +/- 0.05 to 0.33 +/- 0.04 (P less than 0.001) at 1 minute, and to 0.38 +/- 0.04 (P less than 0.001) at 5 minutes after the end of the exercise. When the exercise was repeated after propranolol, Jantsch's index did not change. These findings indicate that propranolol can inhibit exercise-induced vascular steal.

Arterial Occlusive Diseases↗
PubMed1977

Reduction of blood flow following ischemia in arteriopathic patients: reversion of the phenomenon induced by propranolol.

In most arteriopathic patients, the release of a transitory ischemia in the affected limb reduces blood flow, instead of increasing it as in normal subjects. In this study the effects of propranolol administration on this paradoxical response have been investigated. After rheographic tracings were recorded in 14 arteriopathic patients in the basal condition and in the postischemic period, 10 mg of propranolol was administered IV and the protocol was then repeated. The blood flow in the affected area, measured as Jantsch's index of the rheographic tracings, was 0.63 +/- 0.04 in the basal condition and was reduced to 0.51 +/- 0.05 (P less than 0.001) in the postischemic period. When the ischemia was repeated after propranolol administration, Jantsch's index rose from 0.57 +/- 0.04 to 0.85 +/- 0.09 (P less than 0.01). The reversion of the paradoxical response to the ischemia induced by propranolol administration suggests that the beta-adrenergic blockade can increase blood flow to the ischemic area, probably through a constrictive action on arterovenous connections.

Arteriosclerosis↗