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Biomedical subjects

F Rengo

Publications and source records attributed to F Rengo.

At least 91 records · Page 5Linked to original sources
PubMed1993

Acute effects of nifedipine, diltiazem and their combination in patients with chronic stable angina: a double-blind, randomized, cross-over, placebo-controlled study.

We evaluated the acute therapeutic effects of the oral administration of nifedipine (10 mg) and diltiazem (120 mg) alone and in combination in 16 patients with effort angina. The 16 patients (13 men and three women; mean age 59 +/- 7 years) performed a symptom-limited bicycle exercise stress test 3 h after placebo or active substance administration. Maximal work load, exercise duration and time to 1 mm ST segment depression were significantly increased and ST depression at peak exercise was significantly decreased by the combination of drugs. Nifedipine and diltiazem alone similarly improved exercise duration as markedly as their combination. One patient stopped the test after all three treatments for angina associated with ST depression > 2 mm. The combination of drugs yielded the best symptomatic effect: only four patients complained of angina in comparison to eight and seven patients after diltiazem and nifedipine, respectively. Nifedipine and diltiazem are effective and safe antianginal drugs. Some patients respond better to one drug than to the other. Patients who remain symptomatic in spite of maximal doses of a single drug may derive some benefit from combination therapy.

Aged↗
PubMed1993

Age-related changes of antianginal effects of verapamil in patients with stable effort angina. A medium term randomized double-blind placebo controlled trial.

Our study evaluated the effects of verapamil in elderly patients with stable effort angina using a medium-term double-blind placebo-controlled protocol. Thirty-nine consecutive patients, 23 middle-age patients (50 +/- 6 years; range 38-60 years) and 16 elderly patients (66 +/- 2 years; range 65-70 years) with exertional angina were chosen. After a run-in period, both groups received treatment with either placebo or verapamil--360 mg daily--for 4 weeks. During treatment, weekly angina frequency and nitroglycerin consumption were significantly reduced in both groups. Verapamil significantly decreased the rate-pressure product at rest in elderly patients and in both groups at submaximal exercise, due to a reduction in heart rate in both groups and to a more marked decrease in arterial pressure in older patients. At peak exercise, the rate-pressure product was unchanged in both groups after verapamil, while exercise capacity showed a significant improvement in the middle-aged, and ST segment depression was reduced in both groups. After verapamil, 30% of middle-aged patients and 44% of elderly patients had to stop exercising because of angina. Side effects were rare and no drop-out was recorded. Verapamil exerted its antianginal action by means of a decrease in myocardial oxygen consumption at rest and at submaximal exercise in the elderly, while only at submaximal exercise in the middle-aged. Therefore verapamil at the dose of 360 mg daily proved an effective antianginal drug with a safe effect profile also in elderly patients.

Adult↗
PubMed1993

Left ventricular diastolic filling in elderly hypertensive patients.

OBJECTIVE: To evaluate the effects of mild to moderate hypertension and of LVH on diastolic filling and other Doppler indices in the elderly. DESIGN: Survey with a control group. SUBJECTS: Seventy-one hypertensives (34 men, 37 women) referred for echocardiograms and 32 age- and sex-matched normotensive volunteers. Thirty-six of the hypertensives had LVH; 34 did not. SETTING: Echocardiographic laboratory. MEASUREMENTS: M-mode, two-dimensional, and pulsed Doppler echocardiograms. A wide variety of Doppler-derived indices of diastolic function were assessed. RESULTS: All Doppler derived indices of left ventricular diastolic filling (peak E, peak A, their ratio, EF slope, time-velocity integrals, atrial filling fraction, and isovolumic relaxation time) were similar among the three groups. CONCLUSION: Elderly mild to moderate hypertensives with or without LVH have LV diastolic filling that is normal for age. The identification of pathological diastolic dysfunction requires comparison to age-matched controls, since aging, a major factor influencing diastolic filling, can mask the effect of hypertension.

Age Factors↗
PubMed1993

Echocardiographic vs hemodynamic monitoring during isometric exercise in patients with coronary artery disease.

BACKGROUND: Isometric exercise is able to induce myocardial asynergies in patients with coronary artery disease as demonstrated by noninvasive monitoring performed during stimulation. AIMS OF THE STUDY: In the present study, a combined echocardiographic and hemodynamic monitoring of left ventricular contractility has been conducted in order to verify, with invasive and noninvasive techniques, the ability of isometric exercise in inducing transient myocardial ischemic phenomena. METHODS: The study population was composed of 20 patients with angiographic evidence of significant coronary stenosis (> or = 50%), and 10 subjects with normal coronary angiograms. All 30 subjects admitted to the study underwent an isometric exercise stress during echocardiographic and hemodynamic monitoring of left ventricular contractility. RESULTS: Nine out of 20 patients with coronary disease showed regional asynergy during the test (Group I). The remaining 11 patients showed normal myocardial contractility (Group II). None of the 10 control subjects showed mechanical signs of ischemia during the test. Left ventricular end diastolic pressure significantly increased in both Group I (10 +/- 2 to 24 +/- 4 mmHg) and Group II (12 +/- 3 to 26 +/- 3 mmHg) (p < 0.01) while it remained unchanged in the control group (9 +/- 2 to 13 +/- 2 mmHg; p = NS); dp/dt increase (% basal) was significantly higher in the control group (45 +/- 6%) than in either Group I (25 +/- 3%) or Group II (26 +/- 3%) (p < 0.01). CONCLUSIONS: Isometric exercise was able to induce left ventricular asynergies due to regional myocardial ischemia. Hemodynamic contractility monitoring easily distinguished the control subjects from the patients with coronary disease but was not able to discriminate patients with handgrip-induced regional asynergy. Thus, the echocardiographic technique offers more detailed information about regional myocardial function than do the common hemodynamic contractility indexes.

Adult↗
PubMed1992

Effect of beta-adrenoceptor blockade on dipyridamole-induced myocardial asynergies in coronary artery disease.

Twenty-one patients with angiographic evidence of significant coronary artery disease, and positive dipyridamole echocardiographic test results at basal condition and after 7 days of placebo treatment were prospectively studied to see whether beta blockade modifies the effects of dipyridamole echocardiographic testing on regional myocardial contractility. Patients were randomized to propranolol (120 mg/day) or placebo treatment in 3 divided doses for 7 days, after which each patient crossed over to the alternate regimen. Dipyridamole-echocardiographic testing was repeated at the end of each treatment. Propranolol abolished new mechanical signs of transient dipyridamole-induced ischemia (new wall motion abnormalities or an increase in degree of basal asynergies, or both) in 13 of 21 patients. The remaining 8 patients had positive results on dipyridamole echocardiographic testing after the propranolol treatment period. At basal conditions both heart rate and rate-pressure product were significantly reduced with propranolol; there was also a significant decrease in these parameters at peak dipyridamole infusion. At peak dipyridamole infusion heart rate and rate-pressure product were significantly lower in patients with negative than in those with positive echocardiographic test results after propranolol. Our data show that administration of beta blockade significantly reduces the development of transient dipyridamole-induced myocardial asynergies, the earliest markers of acute myocardial ischemia, detected with 2-dimensional echocardiography.

Adrenergic beta-Antagonists↗
PubMed1992

Age-related effects of ischemia, lidocaine and verapamil on overdrive-induced suppression of ventricular pacemakers in isolated rat heart.

The effect of age on ventricular automaticity in the isolated perfused rat heart was determined under different conditions. When the ventricle is electrically stimulated at a faster rate, drive cessation is followed by a temporary suppression of ventricular automaticity (overdrive suppression). The effects of ischemia, lidocaine and verapamil on overdrive suppression were studied in isolated perfused adult and senescent rat hearts with complete atrio-ventricular block, by monitoring ventricular escape rate and escape rhythm recovery time after 1 minute of overdrive at a constant multiple (x3) of the spontaneous rate. The results demonstrated that: 1) lidocaine decreases ventricular automaticity especially in senescent hearts; 2) verapamil does not modify ventricular automaticity in basal conditions in either adult or senescent hearts; 3) myocardial ischemia causes a reduction in ventricular automaticity and more markedly in senescent hearts; and 4) lidocaine exaggerates the effect of ischemia, while verapamil seems to antagonize its depressant effect more in adult than in senescent hearts.

Aging↗
PubMed1992

Age-related effects of platelet activating factor (PAF) in the isolated perfused rat heart.

Platelet Activating Factor (PAF) is a phospholipid that has been implicated as an important mediator of anaphylactic cardiac dysfunction and involved in the toxic effects of the ischaemia-reperfusion process. In the elderly, these phenomena are thought to be exaggerated by the age-related changes in response to several chemical factors and myocardial ischaemia. We evaluated the effects of PAF (acetyl-o-alkyl-l-phosphatidylcholine) on left ventricular systolic (LVSP) and diastolic (LVDP) pressure, coronary flow rate (CFR) and heart rate (HR) in adult (6 months, AH) and senescent (24 months, SH) rat hearts. The perfusion of PAF (10(-8), 10(-7) and 10(-6) M) induced a concentration-related reduction of LVSP, CFR and HR and a linear increase in LVDP. Contractile modifications were more pronounced in senescent hearts: LVSP decreased (P < 0.01) and LVDP increased with respect to younger animals (P < 0.01 vs. AH). This negative inotropic effect was also present in electrically paced hearts. PAF produced conduction arrhythmias ranging from second-degree atrio-ventricular conduction block to cardiac standstill both in adult and senescent hearts; at a higher dose (10(-6) M), cardiac standstill appeared after 96.5 +/- 15.3 s in adult hearts and after 45.5 +/- 17.6 s in senescent hearts (P < 0.01). Lyso-PAF did not modify while specific PAF antagonist compounds CV-3988 inhibited all electromechanical responses both in adult and senescent hearts. These data suggest that age influences the effect of PAF on contractile parameters, coronary flow and conduction arrhythmias by acting on receptors, whose function is unaffected by age.

Aging↗
PubMed1992

Early manifestations of dementing illness: treatment with glycosaminoglycan polysulfate.

1. In a multicenter, placebo-controlled, double-blind clinical trial in 156 elderly patients with psychopathologic symptoms, glycosaminoglycan polysulfate was found to be a therapeutically effective agent in the treatment of the earliest manifestations of a dementing process. 2. Treatment with glycosaminoglycan polysulfate in the daily dosage of 600 LRU, administered on the basis of a divided dosage schedule for 24 weeks, was significantly superior to an inactive placebo on several outcome measures including the SCAG Total and factor scores (i.e., Cognitive Dysfunction, Withdrawal, Agitation/Irritability and Depression), the NOWLIS Total and Fatiguability factor scores, the MMSE, the HAM-D Total and Vegetative Symptoms factor score and the CGI Severity of Illness and Global Improvement. 3. The drug was well tolerated; vital signs and laboratory measures did not show clinically significant changes within the experimental period.

Affect↗
PubMed1992

Controlled study on the therapeutic efficacy of propionyl-L-carnitine in patients with congestive heart failure.

A double-blind phase II study of propionyl-L-carnitine (CAS 17298-37-2) versus placebo was carried out on a group of 60 patients with mild to moderate (II and III NYHA class) congestive heart failure. The group was made up of men and women aged between 48 and 73 years in chronic treatment with digitalis and diuretics for at least 3 months and who still displayed symptoms. Thirty of these patients were chosen randomly and for 180 days, 500 mg of propionyl-L-carnitine was orally administered, 3 times a day in addition to their usual treatment. At basal conditions and after 30, 90 and 180 days the maximum exercise time was evaluated using an exercise tolerance test performed on an ergometer bicycle and the left ventricular ejection fraction was tested by means of bidimensional echocardiography. After one month of treatment, the patients treated with propionyl-L-carnitine, compared to the control group, showed significant increases in the values of both tests, increases which became even more evident after 90 and 180 days. At the stated times the increases in the maximum exercise time were 16.4%, 22.9%, and 25.9%, respectively. The ventricular ejection fraction increased by 8.4%, 11.6% and 13.6%, respectively. On the basis of these results, having studied the particular mechanism of action of propionyl-L-carnitine the authors conclude that it represents a drug of undoubted therapeutic interest in patients with congestive heart failure, in whom it could be efficaciously administered along with a standard pharmacological therapy.

Aged↗
PubMed1992

Evaluation of the therapeutic efficacy and tolerability of levocarnitine propionyl in the treatment of chronic obstructive arteriopathies of the lower extremities: a multicentre controlled study vs. placebo.

The treatment of symptomatic chronic obstructive peripheral arteriopathies is a difficult task since it requires the prolonged administration of drugs which are often unable to correct the various pathogenetic factors reponsible for the disability. The authors, on the basis of recent studies demonstrating the rheological and vasoactive as well as metabolic activities of levocarnitine propionyl, have decided to use this substance in the treatment of arteriopathics affected by intermittent claudication. Levocarnitine propionyl administered orally to 142 arteriopathics affected by intermittent claudication was responsible for a marked increase in initial as well as absolute walking distances. It is particularly important to note that these clinical results were obtained primarily due to the metabolic activities of levocarnitine propionyl.

Administration, Oral↗
PubMed1991

Exercise induced increase in diastolic blood pressure. Is it an indicator of coronary artery disease?

It has been previously reported that an increase in diastolic blood pressure greater than 15 mmHg comparing values at rest with those on treadmill exercise, with or without ST changes, enhances the probability of coronary artery disease. To investigate whether the diastolic blood pressure variation keeps its diagnostic value during upright bicycle exercise, we evaluated the diastolic blood pressure variations in 111 patients with angiographically documented coronary artery disease without previous myocardial infarction and in 53 patients with normal coronary arteries undergoing maximal stress testing on a bicycle ergometer. The sensitivity of diastolic blood pressure (DBP) variations to detect coronary artery disease was 66%, the specificity 32%, the positive predictive value 67%, the negative predictive value 31% and the predictive accuracy 55%. The respective values for ST depression were 83% (P less than 0.001 vs DBP variations), 53% (P less than 0.05 vs DBP variations), 64% (P less than 0.05 vs DBP variations) and 75% (P less than 0.001 vs DBP variations). Forty-nine of the 75 patients with multivessel coronary artery disease and 60 of the 89 patients without coronary artery disease or with single vessel disease had abnormal DBP variations (sensitivity 65; specificity 33%). The sensitivity of ST segment depression in predicting multivessel disease was 91% (P less than 0.001 vs DBP variations), and the specificity 42%. Thus, for bicycle ergometer exercise testing, ST segment depression seems to be more accurate than DBP variations in the diagnosis of coronary artery disease.

Adult↗
PubMed1991

Effects of intracoronary gallopamil on coronary hemodynamics and myocardial oxygen consumption in humans.

The response of coronary hemodynamics to the intracoronary (i.c.) bolus administration of gallopamil, 1.5 and 3.0 micrograms/kg, was evaluated in 14 patients with normal coronary arteries. Gallopamil, 3.0 micrograms/kg, induced a small and transient decrease in systolic and mean arterial pressure and a small increase in the preejection period. Coronary sinus blood flow increased significantly at 30 s (p less than 0.01) and returned to baseline 10 min after gallopamil administration. Coronary vascular resistance was still reduced at 10 min and returned to baseline at 15 min. Myocardial O2 consumption and extraction decreased significantly (p less than 0.01) at 30 s. While myocardial O2 consumption returned to baseline 15 min after gallopamil administration, myocardial O2 extraction was still significantly reduced at this time. Milder and more transient changes were observed after i.c. administration of the lower dose (1.5 micrograms/kg), and no significant changes were found after i.c. administration of saline. These data show that i.c. gallopamil, in patients with normal coronary arteries, induces direct, transient, and dose-related peripheral coronary vasodilation. The reduction of myocardial O2 consumption and extraction suggests a direct negative inotropic and metabolic effect of gallopamil.

Adult↗
PubMed1991

Mechanisms of lidocaine actions on normal and abnormal rhythms in canine cardiac tissues in vivo and in vitro.

1. The actions of lidocaine on cardiac pacemaker rhythms were studied in anaesthetized dogs and in Purkinje fibres from hearts of the same animals. 2. In vivo, lidocaine (1 mg/kg, intravenously) slowed the sino-atrial (SA) node rhythm (-5.0%), and (during vagal stimulation) prolonged ventricular standstill by +25.1% and slowed the idioventricular rhythm (-16.7%). A higher dose (4 mg/kg) had more pronounced effects. 3. Propranolol also slowed sinus (-26.2%) and idioventricular (-27.2%) rhythms, and prolonged ventricular standstill (+36.8%). In the presence of propranolol, the effects of lidocaine on idioventricular rhythm were exaggerated. 4. In Purkinje fibres driven in vitro, lidocaine (10 mumol/L) decreased contractile force (-47.9%) and (during the interruption of drive) prolonged the suppression of (+53.2%) and slowed the escape rhythm (-67.0%). 5. In the presence of lidocaine the threshold potential was shifted to less negative values and diastolic depolarization slope was decreased (-23.6%). 6. Lidocaine slowed spontaneously active Purkinje fibres, abolished early afterdepolarizations in low [K]o and slow responses in high [K]o (by shifting the threshold to less negative values), and antagonized strophanthidin arrhythmias. 7. TTX reduced the hyperpolarization by lidocaine in low [K]o and vice versa. 8. We conclude that lidocaine enhances vagally-induced ventricular standstill by depressing the idioventricular rhythm far more than the sinus rhythm, an action enhanced by beta-blockade. Furthermore, lidocaine depresses normal and different types of abnormal automaticity through direct and indirect effects of the blockade of the fast sodium channel.

Animals↗
PubMed1991

Dipyridamole echocardiography as a useful and safe test in the assessment of coronary artery disease in the elderly.

We prospectively studied the sensitivity, specificity, feasibility, and safety of high-dose dipyridamole echocardiography, compared to exercise electrocardiography in 130 subjects (67 younger and 63 elderly patients) referred for angiographic evaluation of suspected or proven coronary artery disease. Sensitivity, specificity, and feasibility of dipyridamole echocardiography were respectively 75.5%, 100%, and 88.0% in younger patients and 82.9%, 100%, and 79.4% in elderly patients (P = NS). The sensitivity of exercise electrocardiography was 72.7% in young and 66.6% in elderly patients (P = NS); specificity 66.0% vs 60.0% (P = NS); feasibility 83.6 vs 63.5 (P = 0.05). Forty-nine younger and 38 elderly patients performed both tests. Sensitivity of dipyridamole echocardiography compared to exercise electrocardiography was 76.2% vs 73.8% in young patients and 83.3% vs 70% in the older group (P = NS). The feasibility of the two tests was significantly different in the elderly group only (dipyridamole echocardiography 79.4% vs exercise electrocardiography 63.5%; P less than 0.01). The incidence of side effects during dipyridamole echocardiography was similar in the two groups, except for dyspnea which was observed in 20% of older and 5% of younger patients (P less than 0.05). Our data demonstrate that the dipyridamole test combined with echocardiographic monitoring of regional myocardial contractility may be considered a valid non-invasive method for evaluating coronary artery disease in the elderly and that this test is a satisfactory alternative to the exercise stress test.

Aged↗
PubMed1991

The hypothetical role of potassium conductance on the genesis of R-wave amplitude increase during ischemia in the isolated rat heart.

The effect of increased potassium conductance on the genesis of R-wave amplitude increase during acute myocardial ischemia has been studied in the isolated perfused rat heart by simultaneously recording the R-wave amplitude of epicardial electrograms (VEE), heart rate (HR), coronary flow rate (CFR), left ventricular diastolic pressure (LVDP), and left ventricular systolic pressure (LVSP). The experiments were performed during basal and partial or total ischemic conditions at spontaneous or fixed HR. In some experiments, potassium conductance was increased by means of high-calcium (8 mM) or acetylcholine chloride (10(-6) M) perfusion. In the control experiments, partial ischemic perfusion produced an increase in VEE and LVDP and a decrease in HR, CFR, and LVSP; total ischemic perfusion exaggerated these variations. High-calcium perfusion provoked an increase in VEE and LVDP and a decrease in HR, CFR, and LVSP during basal conditions (p less than 0.01 vs. control experiment); these modifications increased progressively during partial ischemic perfusion (p less than 0.01 vs. control experiment) and during total ischemic perfusion (p less than 0.01 vs. control experiment). Perfusion with acetylcholine chloride produced variations similar to those observed in high-calcium solution except that LVDP under basal conditions remained unchanged from control. When the HR was maintained at a constant value by means of atrial pacing the results were similar to those observed in the unpaced hearts. In conclusion, in the isolated perfused rat heart, increasing potassium conductance may influence the genesis of R-wave amplitude increasing during acute myocardial ischemia.

Acetylcholine↗