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Biomedical subjects

F Rengo

Publications and source records attributed to F Rengo.

At least 181 records · Page 10Linked to original sources
PubMed1980

Left ventricular function after coronary artery bypass. Non-invasive study by systolic time intervals.

Left ventricular function was evaluated with serial recording of STI intervals in 78 patients with stable angina on effort undergoing coronary and left ventricular cineangiography. On the basis of these data the patients were divided into four groups: OV) nor or mild coronary disease (n. 11); 1V) 70% stenosed vessel; 2V) two significantly affected vessels (n. 32); 3V) three significantly affected vessels (n. 18). Thirty-six patients (9 with one stenosis, 17 with 2, 10 with 3) underwent coronary artery bypass. Thirty-one 8 with one, 15 with 2, 8 with 3) refused the treatment in spite of the same clinical situation and were medically treated. Recordings were performed before medical and surgical treatment and after 6 and 12 months. Initial average values of the patients of 2V and 3V groups showed a shorter LVETI, longer PEPI and higher PEP/LVET ratio than those of 1V and 0V groups. Subjects of 2V group and abnormal left ventricular wall motion showed longer PEPI and higher PEP/LVET than patients of 2V without abnormal wall motion. On first evaluation no differences were observed between surgical and medical groups. The latter did not show any difference after 6 and 12 months. Surgical patients of 2V and 3V showed a longer LVETI, shorter PEPI and a lower PEP/LVET than the medical group. In the surgical group PEPI and PEP/LVET were significantly decreased after surgery while LVETI was prolonged. Our results suggest an improvement of left ventricular performance by coronary artery bypass in patients with coronary artery disease.

Coronary Artery Bypass↗
PubMed1980

Evaluation by multivariate analysis of changes in systolic time intervals during exercise in the supine and upright positions.

In this study multivariate analysis was adopted to establish how simultaneous changes in heart rate (HR), blood pressure (BP) and work load (W) can affect systolic time intervals (STI). Thus, 13 normal volunteers underwent two consecutive exercise stress tests in the supine and upright position on a bicycle ergometer. By multivariate analysis it was shown that, while in the supine position left ventricular ejection time (LVET) is influenced by HR and W (LVET) = 330.6 - 0.76 HR - 0.41 W, F = 224, P is less than 0.001), in the upright position LVET changes are due only to HR variations (LVET = 309 - 0.88 HR, P is less than 0.001). Pre-ejection period (PEP) in both positions is related to HR and W, but this latter has a non-linear influence (supine: PEP = 110.9 - 0.15 HR -0.34 W + 0.0012 W(2), F = 56.4, P is less than 0.001; upright: PEP = 119 - 0.16 HR - 0.5 W + 0.0025 W(2), F = 86.7, P is less than 0.001). Finally, PEP/LVET ratio is correlated both in the supine and upright position with maximal BP, HR and W; however, the influence of HR and BP is different in the two positions (supine: PEP/LVET = 0.259 + 0.00047 BP + 0.00068 HR - 0.00167 W + 0.000013 W(2), F = 5.68, P is less than 0.01; upright: PEP/LVET = 0.201 + 0.0011 HR - 0.00371 W + 0.00016 W(2), F = 4.79, P is less than 0.01).

Adolescent↗
PubMed1980

Long term comparative study of guanfacine and alpha-methyldopa in essential hypertension.

The hypotensive action of guanfacine and alpha-methyldopa has been compared in 30 patients wth moderate essential hypertension. After 2 weeks of placebo treatment, the patients were randomly allocated to a 12 week treatment with either of the two drugs. The treatment was started with guanfacine, 1 mg twice daily p.o., or alpha-methyldopa, 250 mg three time a day p.o. This dose of guanfacine was able to induce a satisfactory control of blood pressure in all patients while the dose of alpha-methyldopa was gradually increased to a predetermined maximum daily dose (2 g) in those patients with unsatisfactory blood pressure control, i.e., systolic blood pressure above 160 mmHg and diastolic above 95 mmHg. Then the two treatments were dicontinued for one week. Both drugs induced a significant reduction of systolic and diastolic blood pressure. However, guanfacine induced a more marked decrease in systolic blood pressure after the 14th day of treatment while the reduction of diastolic blood pressure was significantly higher only at the end of the final wash-out period, thus indicating a longer lasting effect of guanfacine as compared to alpha-methyldopa. Two patients treated with guanfacine developed dryness of the mouth and three of those in the alphamethyldopa group complained of excessive sedation.

Age Factors↗
PubMed1980

[Clinical evaluation of a new antianginal drug: droprenylamine].

In this study the antianginal action of droprenylamine, a cycloaliphatic derivative of prenylamine, was evaluated. Forty patients were included in three groups: in the first group a double blind study was carried out, while in the other two groups, both treated with droprenylamine for a 12 weeks period, were evaluated the effects on workload tolerance or the efficacy in reducing the number of angina pectoris episodes per week and the assumption of nitroglycerine. The double blind study shows that droprenylamine is able to reduce significantly the nitroglycerine assumption. Furthermore, during the 12 week treatment with droprenylamine we can observe a significant reduction of the ST segment depression, at comparable workloads, a significantly increased tolerance to stress test and an early and significant reduction of the angina attacks and, subsequently, of the assumption of nitroglycerine. In conclusion, this drug, which appears free of side effects, may be useful in the treatment of angina pectoris; in particular, the possible association with other antianginal drugs should be evaluated.

Adult↗
PubMed1980

Disopyramide and mexiletine: which is the agent of choice in the long term-oral treatment of lidocaine-responsive arrhythmias? Efficacy comparison in a randomized trial.

Forty patients with serious lidocaine-responsive ventricular arrhythmias were randomly assigned to treatment with either oral disopyramide (100 mg 4 times daily) or mexiletine (200 mg 4 times daily) for 3 weeks. A satisfactory arrhythmias control (greater than 75 % reduction of premature ventricular complexes per minute as compared to the control period prior to lidocaine administration) was achieved in 19 patients in the mexiletine group and in 16 in the disopyramide treated patients. Furthermore, disopyramide failed to maintain the reduction of the number of ventricular extrasystoles per minute obtained with lidocaine, while mexiletine succeeded. Finally, the number of ventricular extrasystoles per minute in the mexiletine treated group was significantly lower than in the other group. Gastrointestinal disturbances were more frequent during mexiletine administration.

Arrhythmias, Cardiac↗
PubMed1980

[Correlations between angiocardiography and changes of R wave amplitude during effort in patients with coronary heart disease (author's transl)].

The Authors studied correlations between angiocardiography and changes of R wave amplitude (delta R) during effort in 113 patients. They showed coronarographic evidence: 69 with stenosis greater than or equal to 70% of at least one major coronary vessel and 44 with no significant lesions. delta R values greater or equal than 0 were considered as pathologic. delta R appeared greater than or equal to 0 in 8 of 14 patients (57%) with single stenosis, 4 (28%) with abnormal wall motion (AWM). delta R increase or unchanged in 26 of 31 (84%) patients with double stenoses, 25 of them (81%) with AWM. delta R was greater than or equal to 0 in 22 of 24 (92%) with triple stenoses. In subjects with milk coronary artery disease (CAD) R wave increased or unchanged in 47% (19/44). Pathologic changes of R wave are highly frequent in CAD patients, especially in those with severe impairment. These changes, however, are not specific or costant because they appeared enough frequently in subjects with normal doronary vessels, and, moreover, R wave may decrease also in CAD patients with severe impairment. The Authors consider that evidence of delta R values greater than or equal to 0 may not be considered as a sign of CAD, but it must be evaluated with the other data showed by ergometric tests.

Adult↗
PubMed1980

[Diagnostic availability of R wave changes during effort test for a diagnosis of coronary artery disease (author's transl)].

New ecgraphic criteria has been proposed to improve diagnostic availability of R wave changes (delta R) and algebra summation of delta R and ST segment depression (delta RST) in comparison to the criterion of ST depression (ST). The AA. considered as a positive test for a diagnosis of coronary artery disease (CAD): delta R and delta RST values greater than or equal to 0. In 69 patients with stenosis, 75% of at least one major coronary vessel, delta RST showed correct diagnosis in 87% of cases, R in 81% and ST in 73%. RST sensitivity was better than that of ST (P = 0,02). In 44 patients with normal coronaries delta RST was able to correct diagnosis in 52% of cases, delta R in 57% and ST in 73%. ST specificity was better than that of delta RST (P = 0,04). Predictive accuracy was comparable for the three criteria. In normal healthy subjects everyone with an exercise test negative for CAD, with ST analysis, delta R and delta RST was 0 in 16% of cases. New ecgraphic criteria, also showing a better sensitivity in comparison with ST segment analysis, have a worsened specificity. The Authors do not consider these methods a significant improvement in ecgrahic evaluation of exercise test.

Adult↗
PubMed1980

[The effects of the stellate ganglion electrostimulation on the coronary circulation of the dog (author's transl)].

In this study we have investigated the effects of the stellate ganglion electrostimulation on the perfusion pressure of coronary vascular bed perfused at constant flow. We always observed systemic hypertension and two kinds of response in the coronary district: vasodilatation or vasoconstriction. These responses were blocked by propranolol and phentolamine i.a. administration respectively, while both the phenomena were blocked by i.v. infection of guanethidine. These results seem to suggest that nervous sympathetic stimulation induces catecholamines release by means of either pregangliar adrenergic fibers directed to coronary vessels either postgangliar adrenergic fibres directed to the myocardium. The occurrence of vasodilatation or vasoconstriction could be explained by the prevalent stimulation of myocardial or coronary adrenoceptors.

Animals↗
PubMed1980

[Effects of metoprolol on myocardial performance in hypertensive patients during exercise (author's transl)].

In this study the effects of metoprolol administration (200 mg daily per os) to 20 hypertensive subjects (WHO stage I and II), as a 20-days course, on heart rate (HR), systolic blood pressure (BP) and myocardial performance evaluated by systolic time intervals, were studied both at rest and during exercise. This treatment was able to reduce significantly HR and BP in all the patients, both at rest and during exercise. After the 20 days treatment, the left ventricular ejection time corrected for HR (LVETc) did not show any significant change both at rest and during exercise. On the other hand, the pre-ejection period (PEP) changed at rest in all the subjects studied after metoprolol treatment, but increased significantly during exercise only in patients in the I WHO class and only at the highest work load (at 70 watts, from 63 +/- 2 to 78 +/- 7 msec, P ¿ 0.05). Furthermore, in the same group of patients the maximal work load increased significantly after metoprolol treatment (from 67.5 +/- 6 to 85 +/- 8 watts, P < 0.05).

Adult↗
PubMed1979

Effect of furosemide on plasma concentration and beta-blockade by propranolol.

Although propranolol and furosemide are used together for hypertension, the effects of furosemide on plasma levels and beta-blocking action of propranolol are not known. Ten healthy subjects received propranolol 40 mg orally; the mean plasma propranolol levels in 60, 90, 180, and 300 min were 85 +/- 16, 90 +/- 7, 82 +/- 8, and 58 +/- 8 ng/ml. Propranolol was then given together with furosemide (25 mg orally) and the propranolol blood level was measured. Mean propranolol plasma levels were 106 +/- 11 ng/ml at 60 min, 120 +/- 12 ng/ml at 90 min (p less than 0.01), 102 +/- 8 ng/ml at 180 min (p less than 0.05), and 78 +/- 8 ng/ml at 300 min (p less than 0.01). Six additional subjects were given an infusion of 1 microgram/min isoproterenol increased by 0.5 microgram/min every 2 min until the heart rate rose by 25% after oral administration of furosemide 25 mg. This procedure was repeated after propranolol (40 mg orally) and propranolol with furosemide (25 mg orally). The amount of isoproterenol which raised the heart rate by 25% was 2.6 +/- 0.3 micrograms after furosemide alone and 17.7 +/- 2 micrograms after propranolol (p less than 0.01). After propranolol with furosemide the dose of isoproterenol required to elevate heart rate by 25% was 109 +/- 15 micrograms (p less than 0.001).

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↗
PubMed1979

Potassium sparing effect of amiloride in patients receiving diuretics: a quantitative study.

This study was undertaken in order to assess the K+ sparing ability of amiloride. Thirty patients with liver cirrhosis and ascites or congestive heart failure were divided into three groups and treated with amiloride (Group A), hydrochlorothiazide (Group B) and amiloride plus hydrochlorothiazide (Group C) for 15 days. In all groups there was an increased diuresis while only in group A and C there was a statistically significant rise of K+ serum levels and a slight increment of K+ urinary loss. Total body K+ evaluated by 42K increased in group A and C while decreased in group B. Our results seem to confirm that amiloride has a mild diuretic action with a powerful K+ sparing capacity; amiloride is also able to counterbalance and reverse hydrochlorthiazide induced K+ urinary loss.

Adult↗