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Biomedical subjects

M Zanella

Publications and source records attributed to M Zanella.

3 recordsLinked to original sources
PubMed1992

[A critical review of the stable changes in ventricular repolarization in ischemic cardiopathy. A correlation with the angiographic findings].

Unknown is the significance of the abnormalities of repolarization observed at rest in patients with coronary artery disease (CAD) demonstrated by coronary angiography, except for ischemic episodes, myocardial infarction, left ventricular hypertrophy, electrolyte changes or pharmacological interactions. The chronic T wave inversion and ST segment depression are usually considered as an alteration due to ischemia ("chronic myocardial ischemia"); this definition is, in our opinion, erroneous, because myocardial ischemia is an acute episode caused by a sudden lack of balance between demand and availability of myocardial oxygen, corresponding to transient electrocardiographic alterations. Thus, the definition of "chronic myocardial ischemia" referred to stable abnormalities of repolarization is incorrect, because a "chronic" lack of balance between MVO2 and O2 availability would produce necessarily irreversible myocardial damage (necrosis). To contribute to the comprehension of the stable ECG changes at rest, we have selected a group of patients with CAD demonstrated by coronary angiography, presenting stable T wave alterations and ST depression at rest. We have studied the main and regional left ventricular function through radionuclide angiocardiography (ACS). Comparing the abnormalities of repolarization (ECG) on the one hand with angio, EFR and VER on the other, we have obtained different positive correlations, according to the functional parameters considered (EFR and VER). In our study, the lowest positive correlation has been noticed comparing ECG versus angio, VER and EFR (37.5%), while the highest correlation was obtained when ECG was considered versus angio and VER (56.25%). Evaluating ECG versus angio and EFR we have obtained a positive correlation equal to 43.75%. So we have deduced that VER is the functional parameter that better relates to angio and ECG.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

Circadian rhythms of atrial natriuretic peptide, renin, aldosterone, cortisol, blood pressure and heart rate in normal and hypertensive subjects.

The occurrence and extent of a circadian rhythm in the circulating concentrations of atrial natriuretic peptide (ANP) are still matters of controversy. Only a few data are available in humans relating the time structure of plasma ANP levels with the circadian patterns of other hormones and cardiovascular variables. In a group of hospitalized normal volunteers (six men and four women, 16-76 years old), and in a group of hospitalized hypertensives (seven men and three women, 18-76 years old), we investigated the circadian variability of ANP and its temporal relationship with the circadian rhythms of blood pressure (BP) and heart rate (HR), and plasma renin activity (PRA), plasma aldosterone (PA) and plasma cortisol (PC) levels, by using a chronobiological inferential statistic method. At the end of a synchronizing period of 1 week (the diet and daily schedule were standardized), the subjects underwent automatic BP and HR monitoring, and blood sampling for 24 h. A statistically significant mean circadian rhythm was demonstrated for ANP, BP, HR, PRA, PA and PC in both normal and hypertensive subjects. The mean circadian acrophase of ANP (calculated to occur at around 04.00 h) anticipated the corresponding acrophases of the other hormones; BP and HR rhythms appeared to be in antiphase with ANP rhythm, i.e. the peak of BP and HR rhythms more or less coincided with the trough in ANP rhythm. A significant increase in the daily levels (assessed by the circadian mesor) of ANP was present in hypertensive subjects when compared with normal controls. In essential hypertension the circadian rhythm of ANP was set at higher circulating levels, but otherwise it was similar to the circadian rhythm found in normals. ANP mesors correlated significantly with renin and aldosterone mesors in normal subjects but not in hypertensive patients. ANP appears to anticipate awakening in its circadian periodic rise. On the basis of the considerable acrophase asynchronism, it seems possible to exclude any causal relations between the periodic changes of ANP and the rhythmic fluctuations of the other hormones that we studied. In contrast, important relations may be hypothesized between ANP levels and BP and HR values, on the basis of their antiphase rhythms.

Aldosterone↗