Biomedical subjects

M de Scalzi

Publications and source records attributed to M de Scalzi.

4 recordsLinked to original sources

PubMed1989

New indices in the evaluation of clonidine transdermal therapy of hypertension.

Since high blood pressure might be more harmful the higher it is and the more it remains above a determined critical value (140/90 mm Hg - 18.7/12.0 k Pa - in the present study), the hyperbaric impact, a measure of the total load exerted on the arterial walls and the total time during the day when blood pressure is elevated above the critical value, have been evaluated. Ten patients with essential hypertension underwent non-invasive automatic 24-h blood pressure monitoring three times (baseline and after three and seven days from the application on the upper chest of a transdermal self-adhesive patch delivering clonidine). The recorder was programmed to measure blood pressure every 30 min during the day and every 60 min during the night. Significantly lower values of blood pressure, hyperbaric impact and duration of elevated blood pressure have been demonstrated from the third day after the beginning of transdermal therapy.

Administration, Cutaneous↗

PubMed1985

A chronobiologic study on some cardiovascular parameters.

We studied the chronobiologic pattern of heart rate, R and T wave voltage, QT interval, and ST segment displacement. Premature atrial and ventricular beats obtained by dynamic electrocardiography, as well as arterial blood pressure measurements obtained by autometry, have also been studied in 131 untreated subjects (25 with hypertension, 28 with major risk factors for coronary artery disease, 9 with coronary artery disease, 37 presumably healthy and 11 shift workers). Our results show the existence of circadian rhythms in heart rate, in the duration of the QT interval and also in the voltage of R and T waves. Our data for R and T wave voltages do not completely agree with those from other authors. We demonstrated also that smoking may influence the circadian acrophase of the rhythm in R wave voltage while sleeping does not show any relationship with R and T wave voltages although it seems related to the displacement of the ST segment. We could point out only small differences in the chronobiologic behavior of patients with coronary disease and that of normal subjects, unlike the results previously reported by other authors. Our study demonstrated the existence of circadian and ultradian rhythms in premature atrial and ventricular beats as well as circadian and circaseptan rhythms in arterial blood pressure. Further studies are needed to improve our chronobiologic knowledge in order to optimize dosage and time of administration of the drugs used in the long term management of arrhythmias and hypertension.

Adult↗

PubMed1985

Effects of isoproterenol and methoxamine on the electrocardiogram.

The effects of isoproterenal (ISP) and methoxamine (MTX) infusion in 20 asymptomatic subjects with labile T wave were studied. In those treated with ISP the T wave showed an early negative trend and later became clearly positive in 5 subjects. In the majority of the subjects treated with MTX the T wave became positive. T wave changes match variations of both the ventricular gradient and, to a lesser degree, the QRS area. These changes were not related to heart rate or, in the subjects treated with MTX, to the baroreceptorial sensitivity deduced from the slope of the regression equation between R-R internal and systolic arterial pressure. The results of this study confirm the existence of a neurogenic mechanism affecting the electrocardiographic changes in T wave.

Adult↗

PubMed1984

Computerized M-mode echocardiography in the assessment of cardiovascular effects during intravenous administration of amiodarone.

Antianginal and antiarrhythmic long term therapy with amiodarone may be associated with side effects, therefore it should be used mainly in short term treatment of severe arrhythmias and acute coronary insufficiency. It is important to assess if any inotropic effect may be produced after intravenous administration of this drug in commonly accepted therapeutic doses (5 mg/kg body weight). To investigate this possibility we studied the effects of amiodarone on blood pressure (BP), on heart rate (HR) and on the maximal velocity of circumferential fiber shortening (Vcf Max). Simultaneous echocardiogram (UCG), electrocardiogram (lead DII) (ECG) and BP cuff measurement were performed on 12 subjects without cardiomegaly and clinical evidence of heart failure, immediately before a 30 second intravenous injection of amiodarone and every 30 seconds over a period of 6 minutes after drug administration. Amiodarone administration markedly raised HR within the first 30 seconds from the beginning of the injection and concomitantly decreased diastolic BP. No significant lowering of systolic BP was observed. Vcf Max (circ/sec) raised during the test concomitantly with HR increase, showing a significant relationship between left ventricular performance and HR. The same was also true during atrial pacing performed on one subject. No significant changes in any of the parameters studied were demonstrated after placebo (saline solution) administration to two presumable healthy subjects. Amiodarone does not seem to have any positive or negative intrinsic inotropic effect when administered intravenously at a dose of 5 mg/kg body weight.

Adolescent↗