[Role of the increased cholinergic activity in prevention of reperfusion-induced arrhythmia in dog experiments].
Explore the source record for details and available documents.
Animals↗
Biomedical subjects
V Canonico
Publications and source records attributed to V Canonico.
Effect of nifedipine on dipyridamole thallium-201 myocardial scintigraphy.
The effect of a calcium antagonist drug, nifedipine, on dipyridamole thallium-201 images was assessed in 10 angina patients with positive dipyridamole test. Two dipyridamole thallium-201 tests were performed, the first in basal conditions, the second after administration of 20 mg nifedipine. After dipyridamole, heart rate and double product increased respectively from 68.0 +/- 8.2 to 94.7 +/- 11.5 beats/min (p less than 0.01) and from 9459.5 +/- 1800.2 to 12,770.0 +/- 1864.7 mmHg X beats/min (p less than 0.01). Dipyridamole when infused after nifedipine induced an increase in heart rate from 74.2 +/- 7.16 to 88.8 +/- 5.6 beats/min (p less than 0.01) and in double product from 9650.5 +/- 1348.0 to 11,399.0 +/- 1146 mmHg X beats/min (p less than 0.05). Systolic and diastolic blood pressures were unmodified during the two studies. Segment scores were comparable before and after nifedipine. Thus, nifedipine does not worsen thallium-201 myocardial images obtained during dipyridamole infusion, therefore, this test could provide an alternative to exercise thallium-201 in patients receiving calcium antagonist drugs.
Coronary Circulation↗
[Beneficial effects of diltiazem in exertion stable angina. Evaluation of coronary hemodynamics during cardiac pacing].
We evaluated the protective effect of Diltiazem from pacing-induced myocardial ischemia in 9 patients (pts) with coronary heart disease (CAD) and stable effort angina by studying the changes in systemic and coronary hemodynamics during pacing. Hemodynamic parameters were evaluated at baseline and at peak pacing before and after Diltiazem, 25 mg i.v. Diltiazem prevented angina in 6 of 7 pts who presented angina in the control pacing. This beneficial effect was accompanied at peak pacing rate by a significant fall in ST depression, arterial pressure, rate-pressure product and left ventricular (LV) end-diastolic pressure, while no significant changes were observed in LV dp/dt max, coronary blood flow and coronary vascular resistance. Therefore, Diltiazem exerts a protective effect from pacing-induced myocardial ischemia in pts with CAD and stable effort angina, without impairing LV function. This beneficial effect is due to a reduction in myocardial metabolic requirements, rather than to an improvement of blood supply to the ischemic myocardium.
Aged↗
Effect of mexiletine on reperfusion-induced ventricular arrhythmias: comparison with lidocaine.
Thirty mongrel dogs underwent proximal occlusion of the left anterior descending coronary artery to evaluate the comparative action of mexiletine and lidocaine on ventricular arrhythmias during myocardial reperfusion. Heart rate, arterial blood pressure, left ventricular end-diastolic pressure and dp/dt max were evaluated before and at the 20th and 25th min after coronary occlusion; at the 25th min coronary occlusion was removed. Dogs were randomly assigned to one of the following groups of 10: 1) control group; 2) dogs given i.v. mexiletine; 3) dogs given i.v. lidocaine. As expected, during ischemia, myocardial contractility decreased after mexiletine or lidocaine administration more than in the control group. Ventricular arrhythmias during myocardial reperfusion occurred in 9 dogs of the control group (ventricular tachycardia in 2 cases and ventricular fibrillation in 7 cases). Among dogs given mexiletine only 1 had ventricular fibrillation (p less than 0.001 vs control). Six of the 10 dogs given lidocaine had ventricular arrhythmias (ventricular tachycardia in 5 cases and ventricular fibrillation in 1 case) (p = ns vs control group; p less than 0.05 vs mexiletine group). Thus mexiletine and lidocaine had similar effects on cardiac function during myocardial ischemia and only mexiletine showed a protective effect against reperfusion ventricular arrhythmias.
Animals↗
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↗
Efficacy of a new antihypertensive agent (indenolol) assessed by ambulatory blood pressure monitoring.
The effects of two-week treatment periods with indenolol (I) and metoprolol (M) were examined by 24-hour mean blood pressure (BP) monitoring in control conditions and during exercise stress test in 7 patients with essential hypertension, using the Oxford method. Both drugs induced a significant reduction in mean BP and heart rate (HR) as compared to pretreatment values (mean BP: from 117 +/- 3 mmHg to 106 +/- 4 after I, p less than 0.05 and to 102 +/- 3 after M, p less than 0.01; HR: from 78 +/- 2 bpm to 66 +/- 2 after I, p less than 0.01 and to 67 +/- 2 after M, p less than 0.01). I and M induced a significant reduction in systolic and diastolic BP throughout the day and most of the night. During bicycle ergometer the basal and peak values of systolic and diastolic BP were significantly lower after both treatments as compared to the pretreatment values (both p less than 0.01). Our data suggest that I once a day possesses a substantial and consistent antihypertensive action, effective over most of the 24 hours.
Adrenergic beta-Antagonists↗
Hemodynamics of the splanchnic and systemic circulation after hypotonic water load-comparison between normal subjects and patients with congestive heart failure.
The authors investigated the changes in cardiovascular and splanchnic hemodynamic, diuresis and urinary and hepatic veins osmolarity induced by hypotonic water load in five normal subjects and in five patients with congestive heart failure (CHF). Pulmonary wedge pressure increased significantly only in CHF patients while cardiac index, total pulmonary resistances and peripheral vascular resistances remained unchanged in both groups. Hepatic blood flow increased significantly in control group while in CHF showed a significant reduction 15 and 30 minutes after water load. Hepatic veins osmolarity decreased significantly in control group only at the 45th minute. Diuresis was significantly higher in normals which eliminated water load with a lower urinary osmolarity. The authors conclude that: water loading is particularly interesting in so much it resembles the physiological conditions of the absorption of the alimentary hypotonic bolus; the failing heart responds to the water load on a depressed function curve; the hepatic blood flow is reduced in CHF patients and is probably responsible for some humoral abnormalities found in these subjects; CHF patients eliminate a water load slower than a normal subject and with a higher osmolarity.
Aged↗
[Effectiveness of the aorto-coronary by-pass procedure in elderly patients].
This study was undertaken to evaluate the efficacy of coronary artery by-pass grafting (CABG) in elderly patients with coronary artery disease. A consecutive series of 79 patients, 65 years of age and older, who underwent CABG from 1975 to 1981 was analysed and their follow up status ascertained. This group was compared with a consecutive series of 397 patients under the age of 65 who underwent CABG during the same period. The patients aged 65 years or greater had a higher incidence of unstable angina pectoris (p less than 0.05). Coronary angiographic and left ventriculographic features were comparable in both age groups; also comparable were the number of saphenous veins graft utilized and the number of left ventricular aneurysmectomies and mitral valve replacements performed. The hospital mortality rate for patients aged 65 years and older was 12.6%, for those aged less than 65, it was 8.3%; if the other cardiac procedures are excluded mortality rates become 12.5% and 6.0% respectively (n.s.). Survival at 6 years was 92% for patients in both age groups. However, the symptomatic status was less favourable in older patients, compared with that obtained in younger patients (p less than 0.05).
Aged↗
Comparison of the antihypertensive activities of xipamide and chlorthalidone: a double-blind, randomized, crossover trial.
The effectiveness of a new potent diuretic, xipamide, was evaluated in the treatment of patients with mild to moderate essential hypertension. The effects of daily doses of 40 mg xipamide were compared with those of 100 mg chlorthalidone with respect to systolic and diastolic blood pressure, using a double-blind crossover design. Patients received each drug for 6 weeks, the order of treatments being at random and the periods being separated by a 'washout' period of 7 days. The results showed that xipamide was as effective as chlorthalidone in controlling blood pressure, both in the upright and supine positions, and when administered after chlorthalidone produced a further reduction. No such further reduction occurred when chlorthalidone was given after xipamide. Serum electrolyte changes induced by the two diuretics were comparable. Both drugs were well tolerated and caused few side-effects.
Adult↗
[The hemodynamic effects of reproterol in patients with chronic obstructive lung disease (author's transl)].
Our study was undertaken in order to evaluate hemodynamic effects of intravenous administration of Reproterol in patients with chronic obstructive lung disease (COLD). Reproterol is a monomulecolar combination of catecholamine and theophilline. Diastolic pulmonary pressure and wedge pressure decreased 20 minutes after Reproterol while total pulmonary resistances were reduced 10 minutes after drug administration; sistolic pulmonary pressure and cardiac index increased only after 10 minutes; heart rate increased until 15th minute. Reproterol, as a catecholamine-theophylline combination, has an additional site of action over and above the pure catecholamine effect owing to inhibition of phosphodiesterase; so an increase in cAMP content is achieved either by increasing the synthesis or by blocking the breakdown. Our results assess that Reproterol has a beneficial effect on pulmonary hemodynamics in COLD.
Adult↗
Evaluation of the efficacy of slow-release nifedipine in systemic hypertension by ambulatory intraarterial blood pressure monitoring.
We assessed the effect on blood pressure of administration of slow-release nifedipine tablets (20 mg) by continuous intraarterial blood pressure monitoring (Oxford system) in 10 patients with untreated essential hypertension. Blood pressure was recorded under control conditions and during nifedipine therapy. During each monitoring period patients were instructed to perform various types of exercise. The initial dose of nifedipine was 20 mg twice a day (8:00 a.m. and 8:00 p.m.). For patients in whom arterial pressure control was not achieved, the dose of the drug was increased at weekly intervals, first to 40 mg in the morning and 20 mg at night and then to 40 mg twice a day. The average daily dose was 52 mg. Nifedipine twice a day significantly reduced systolic and diastolic blood pressures both during the day and during the night. The rise in blood pressure due to dynamic or isometric exercise or to mental testing was blunted. Heart rate did not change. Orthostatic hypotension was not observed, and there were only minor side effects, which did not require withdrawal of the patient from the trial. Bioavailability of nifedipine from this preparation was satisfactory, as shown by plasma concentrations which remained constantly in the therapeutic range. Thus, slow-release nifedipine given twice a day represents an effective treatment in patients with essential arterial hypertension. The reduced frequency of administration required may improve patient compliance with this treatment.
Adult↗
[Efficacy and tolerance of aniracetam in elderly patients with primary or secondary mental deterioration].
The study was carried out on 60 patients (mean age 69.9 +/- 10.3 years) suffering from slight-moderate brain pathology primary or secondary to vascular forms. Patients were treated with 1500 mg/day per os of Aniracetam or placebo. Drug efficiency evaluation was performed utilizing the following psychometric tests: Blessed Scale, figures repetition test, Benton test, Corsi test, Rey test, Pieron test, phrases construction test, verbal fluency test. They were carried out during basal visit after two and four month treatment. In Aniracetam treated group the score showed a significant improving during the first and second control. In placebo treated group no change statistically considerable happened in any test. Aniracetam has proved to be a useful drug in slight-moderate brain decay treatment of the elderly.
Aged↗