Biomedical subjects

C Lirato

Publications and source records attributed to C Lirato.

10 recordsLinked to original sources

PubMed2001

Left ventricular geometry and arterial function in hypercholesterolemia.

AIMS: To investigate the effect of hypercholesterolemia on total arterial compliance and left ventricular (LV) geometry in the absence of arterial hypertension and diabetes. METHODS: One hundred and fifty-two normotensive, non-diabetic patients (109 men) aged 52 +/- 10 years with plasma cholesterol > 240 mg/100 mL, and 282 normotensive controls (154 men) aged 42 +/- 10 years (p < 0.0001) with plasma cholesterol < 200 mg/100 mL were studied by means of echocardiography. The stroke volume/pulse pressure ratio as a percentage of the value predicted by individual age, body weight and heart rate was used as a prognostically-validated index of total arterial compliance. Central pulse pressure (PP) was estimated using a regression equation obtained in a non-overlapping population. RESULTS: Although within the "normal" range, systolic pressure, PP and estimated central PP were higher in the hypercholesterolemic patients even after controlling for differences in age, body mass index (BMI) and race (all p < 0.0001). After controlling for differences in systolic pressure, age, BMI and race, LV mass and the prevalence of hypertrophy were comparable between the two groups, whereas relative diastolic wall thickness was greater (0.36 + 0.06 vs 0.33 + 0.05) and percent SV/PP (stroke volume/PP) lower in the hypercholesterolemic patients (96 +/- 19% vs 102 +/- 18%; both p < 0.005). After considering the covariates, there was still an independent negative correlation between relative wall thickness and percent SV/PP (r = -0.37, p < 0.0001). CONCLUSIONS: Hypercholesterolemia in normotensive non-diabetic adults is independently associated with a mildly concentric LV geometry and a reduced index of total arterial compliance.

Adult↗

PubMed1997

Effect of dietary versus pharmacological correction of hypertriglyceridemia on red blood cell membrane sodium/lithium countertransport activity.

An elevated red blood cell Na/Li countertransport (Na/Li CT) is often associated with high blood pressure and metabolic abnormalities. Recent studies suggested that a reduction in serum TG levels is associated with a decrease in Na/Li CT activity. However, it is still unclear if this phenomenon could be originated from systemic metabolic alterations or from modifications of the membrane dynamic properties. Aim of the present study was to investigate whether dietary or pharmacological TG lowering therapy might have a different effect on Na/Li CT activity and related metabolic parameters. Twenty normotensive hyper-TG patients were recruited from the Lipid outpatient Clinic: they had a baseline Na/Li CT activity significantly higher compared with age- and BMI-matched normolipidemic controls (386+/-33 vs 274+/-39 umol/l RBC/h, p<0.05). The patients were randomly prescribed one of the following two-months treatment: Group 1)-triglyceride lowering diet; Group 2)-lipid lowering drug (Gemfibrozil 600 mg b.i.d.). Na/Li CT and metabolic and anthropometric variables were measured at baseline and after 1 and 2 months of treatment. At the end of intervention, there was in both groups a significant and comparable fall in plasma triglyceride (group 1: -2.61+/-0.73 mmol/l p<0.01; group 2: -4.29+/-1.20 mmol/l p<0.01). In the diet-treated group there were, in addition small but significant reductions in body weight (-3.7+/-0.8 kg p<0.01), fasting glucose (-0.36+/-0.14 mmol/l p<0.05) and insulin levels (-2.1+/-0.5 mU/l, p<0.01), while no such changes were observed in the fibrate treated patients. Na/Li CT activity was significantly and comparably reduced at the end of treatment in both groups (group 1: -97+/-28 umol/l cell/h, p<0.01; group 2: -89+/-30 umol/l cell/h, p<0.01). In conclusion, these results indicate that the decrease in Na/Li CT associated with both dietary and drug treatment of hypertriglyceridemia is to be traced to a direct effect of plasma TG concentration on this transport system (probably as a result of modification in the membrane lipid environment) rather than to changes in plasma insulin levels or insulin resistance.

Adult↗

PubMed1997

Influence of autonomic tone on QT interval duration.

The autonomic tone has been shown to influence the duration of the QT interval, however the independent contribution of sympathetic and parasympathetic tone is not fully elucidated. The influence of autonomic tone on QT duration was studied in 10 young healthy volunteers by evaluating the changes in QT and RR duration induced by i.v. isoproterenol infusion and by standing before and after i.v. administration of propranolol or atropine. Furthermore, the relationship between RR interval and QT duration was evaluated during nocturnal sinus arrhythmia and submaximal exercise test. Low doses of isoproterenol reduced RR (p < 0.01) but not QT interval duration, while higher doses influenced both RR (p < 0.0001) and QT (p < 0.001) duration. Propranolol did not influence standing-induced shortening of RR and QT intervals; on the contrary, atropine administration abolished standing-induced QT interval shortening, without influencing RR changes. QT duration resulted significantly related to preceding RR interval at peak exercise (r = 0.87, p < 0.001) and during nocturnal sinus arrhythmia (r = 0.73, p < 0.0005), however, the regression lines showing the correlation between QT and preceding RR interval were different. Both sympathetic and parasympathetic tone appear to contribute to heart rate-independent changes in QT duration. In the basal state parasympathetic more than sympathetic tone influences the relation QT-heart rate. Major increases of sympathetic nervous system activity may change the relation QT-heart rate. Thus, in case of abrupt autonomic changes, any proposed formula for heart rate correction of QT may result inappropriate, also in the normal range of heart rate.

Autonomic Nervous System↗

PubMed1995

Effects of age and hypertension on adrenoceptor-sensitivity evaluated with CD25 and QT/QS2.

BACKGROUND: We studied the effects of age and hypertension on responses to chronotropic dose (CD25) and standing-induced changes in the ratio of electrical systole (QT) to electromechanical systole (QS2) in order to identify their role on beta adrenoceptor sensitivity and to verify the value of QT/QS2 ratio as a noninvasive parameter of beta-adrenoceptor sensitivity. METHODS: We enrolled 33 normal subjects and 37 hypertensive patients (WHO stage I and II) (age range 21-82 years). RESULTS: CD25 was significantly age-related in normotensive and hypertensive subjects, whereas standing-induced QT/QS2 changes were age-related in normotensive subjects only When we divided subjects into three age groups, beta-adrenoceptor sensitivity was found to be lower in hypertensives than normotensives in the two groups under age 60, but was not affected in those over age 60. This suggests that hypertension influences beta-adrenoceptor sensitivity in younger subjects, but not in elderly patients, whose beta-adrenoceptor sensitivity is already reduced. CONCLUSIONS: CD25 does not predict standing-induced QT/QS2 ratio changes; therefore, during autonomic stimulation, QT/QS2 ratio seems not to be significantly related to beta adrenergic sensitivity.

Adult↗

PubMed1994

Regression of left ventricular hypertrophy and improvement of renal hemodynamics in hypertensive patients treated with quinapril.

Of 17 patients with mild to moderate essential hypertension, 8 showed echocardiographic evidence of left ventricular hypertrophy. Cardiac and renal function evaluated by glomerular filtration rate (GFR) were studied in all patients before and after 20 weeks of quinapril treatment. Systolic pressure decreased from 174.7 +/- 16.7 to 131.7 +/- 7.7 mmHg (p < .0001) and diastolic pressure decreased from 101.8 +/- 9.8 to 80 +/- 4.3 mmHg (p < .0001). Left ventricular mass index decreased in the eight patients with left ventricular hypertrophy (p < .01). Basal values of GFR were lower than normal in 41% of all patients; GFR increased significantly after 20 weeks of treatment (from 96.5 +/- 32.3 to 108.6 +/- 31.12 ml/min, p < .01); it decreased in only one patient. Patients reported few adverse effects to quinapril, and no important clinical laboratory abnormality was observed. Quinapril not only lowered arterial pressure, but it had a distinct effect on regression of left ventricular hypertrophy and favorable effects on renal function.

Adult↗

PubMed1993

[Treatment of hyperlipidemia in patients with ischemic heart disease].

Do patients with coronary heart disease benefit from lipid lowering treatment? In the last 20 years clinical research has addressed this question considering 3 different endpoints: clinical events, progression and regression of atherosclerotic plaque, and vascular tone. Eight major secondary prevention trials showed that a 10% reduction in serum cholesterol led to reduction of 15% in the number of all myocardial infarctions. Seven secondary prevention trials based on coronary angiography showed that a 20% serum cholesterol reduction can induce regression and/or reduce progression of plaques in as short as 2 years. In vivo experiments have also shown that coronary spasms are the most common response to various stimulations in hypercholesterolemic individuals; vasodilation is the most common coronary response in subjects with low cholesterol levels.

Cholesterol↗

PubMed1993

[Acute effects of propranolol and its association with nifedipine in aged patients with effort stable angina. Randomized double-blind crossover study, under placebo control].

Calcium-antagonist and B-blockers are effective in improving exercise tolerance in patients with effort angina. We studied the short effects of oral administration of nifedipine (10 mg) and propranolol (80 mg) alone and in combination in 15 elderly patients with chronic exertional angina pectoris in a double-blind, randomized, cross-over study. The 15 patients (13 men and 2 women, mean age 69 years) performed symptoms-limits bicycle exercise stress test 3 h after placebo or active substance administration. Maximal work load, exercise duration, real time to 1 mm ST segment depression were significantly increased and ST depression at peak exercise was significantly decreased by drug alone and in combination. Propranolol and nifedipine improved exercise duration in combination; however, a different response to the three pharmacologic interventions was found in patients treated with single drug. The improvement in exercises tolerance was associated with rate-pressure product values at peak exercise tolerance was associated with rate-pressure product values at peak exercise, unchanged after placebo and significantly reduced after both propranolol alone and in combination. After placebo all patients had exercise-induced angina, in 50% and in 40% after propranolol and the combination of the two drugs, respectively. In aging patients nifedipine and propranolol are effective in the treatment of effort angina and they are superior in patients who show poor response to mono therapy, although this combination will be conditioned by different patient sensibility to the three pharmacologic interventions and then therapeutic choice would be evaluated and verified individually.

Age Factors↗

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↗

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↗

PubMed1989

[Efficacy of diltiazem in elderly patients with stable effort angina].

The antianginal effects of 360 mg/day of diltiazem were evaluated, using intrapatient comparisons, in a double/blind, randomized, placebo/controlled trial in 24 young patients (50 +/- 7 years) and in 16 elderly patients (67 +/- 3 years) with stable effort angina. All patients had angiographic documentation of significant coronary artery disease. An open-labelled, randomized, crossover design was employed. For 1 week prior to beginning the study, the patient was on no medication except sublingual nitrates. The study consisted of an initial 2-week single-blind placebo run-in period followed by a 4-week randomized double-blind crossover between diltiazem, 120 mg t.i.d., and placebo. A diary of chest pain and nitroglycerin usage was kept during this period and run-in. Exercise tests were carried out during the run-in period (2 tests) and at the end of the 4-week treatment. After diltiazem 12 of the 24 young patients stopped the exercise test because of angina. A similar number (9/16) of elderly patients stopped the exercise test because of angina. During diltiazem treatment, weekly angina frequency was significantly reduced in the young patients (1.25 +/- 0.67 vs 3.87 +/- 1.19-run-in, 4.08 +/- 1.24-placebo; p less than 0.01) and in the elderly patients (0.87 +/- 0.71 vs 4.06 +/- 1.48-run-in, 4.12 +/- 1.5-placebo; p less than 0.01). Weekly TNT consumption significantly decreased in both groups of patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗