[Non-invasive assessment of coronary reperfusion]. / Valutazione incruenta della riperfusione coronarica.

The patency of the infarct-related coronary artery seems to be an important prognostic factor after an acute myocardial infarction. Coronary angiography has been used until now to assess coronary patency. However, as it is an invasive procedure and its optimal timing after fibrinolytic treatment has not been established, a noninvasive marker is most desirable. There are a number of methods currently used to document coronary reperfusion non-invasively. This review discusses the advantages and disadvantages of the classic non-invasive methods, like resolution of chest pain, reperfusion arrhythmias, normalization of ST segment elevation, and enzymatic determinations. The imaging methods, especially echocardiography but also magnetic resonance imaging, offer interesting possibilities for the future.

[The frequency of early coronary reperfusion assessed by electrocardiographic criteria in relation to the timing of thrombolytic therapy in acute myocardial infarct]. / Frequenza della riperfusione coronarica precoce valutata con criteri elettrocardiografici in rapporto al tempo del trattamento trombolitico nell'infarto miocardico acuto.

This study was aimed at assessing coronary reperfusion in patients with acute myocardial infarction (AMI) undergoing systemic thrombolysis with SK and rtPA. The occurrence of reperfusion was related to the time of treatment. The evaluation of reperfusion was performed by monitoring ST segment changes. 56 patients with AMI were studied. 22 out of these (39.2%) showed a significant decrease (greater than 50%) in ST segment sum (sigma ST) at 100 minutes from the beginning of the treatment. Analysis of the relationship between reperfusion and elapsed time between the onset of symptoms and the treatment, reveals that the reperfusion is less frequent (p less than 0.05) in patients treated at 180 minutes or later. The standard electrocardiogram appears as the most useful method to evaluate indirectly coronary reperfusion in acute myocardial infarction. A further refinement of this method is desirable to recommend its widespread clinical use. The assessment of reperfusion by means of ECG in large series of patients will permit the evaluation of the benefits of reperfusion, in terms of survival, complications and incidence of ventricular dysfunction.

Standing-up test in young borderline hypertensives.

Seventeen normals (mean age, 34 +/- 4.31 years) and thirteen borderline hypertensives (BH) (mean age, 33 +/- 4.6), immune from any other pathology, were tested (standing-up test) in order to assess possible parasympathetic dysfunctions in young BH, not preselected as hyperkinetic subjects. Curves of heart rate (HR) variations were monitored by electrocardiogram during the test with an exhaustive analysis carried out to obtain indexes showing the whole trend as well as the 30 degrees/15 degrees ratio. No significant difference emerges between the two groups when mean values of such parameters are compared. It is concluded that parasympathetic dysfunctions do not occur in BH patients.

[Functional relationships between plasma renin activity and hemodynamic indices in essential arterial hypertension]. / Correlazioni funzionali tra attivita' reninica del plasma e indici emodinamici nell'ipertensione arteriosa essenziale.

Vasoconstriction-volume analysis postulates that arteriolar vasoconstriction is the mechanism of blood pressure elevation in patients with "high-renin" essential hypertension while a volume expanded state with relatively dilated arterioles sustains "low renin" essential hypertension. To test this hypothesis we carried out hemodynamic and PRA studies in 43 essential hypertensives. Cardiac index was directly related to PRA (r=0,41; p less than 0,01), by contrast, peripheral vascular resistances and plasma volume were unrelated to PRA. The data do not support the bipolar hypothesis since vasoconstriction and volume expansion are associated with unpredictable changes in PRA. The direct relationship between CI and PRA may be interpreted as the result of a common factor (presumably sympathetic nervous system) governing both functions.

[Cardiac output and pulmonary blood volume in arterial hypertension of chronic uremia]. / La portata cardiaca e il volume di sangue polmonare nell'ipertensione arteriosa dell'uremia cronica.

To investigate the mechanisms that sustains arterial hypertension in chronic uremia we performed hemodynamic studies in 13 dialysed uremics by means selective radiocardiography (Donato-Giuntini method). The 5 dialysed patients with dialysis controllable hypertension (GROUP B) had higher cardiac indexes (CI) respect to the 8 dialysed normotensive controls (GROUP A) (CI: Group B 4,250 l/min/m2, Group A 3,610 l/min/m2; p less than 0,05). The higher CI in group B appeared independent from the degree of anemia because the two groups had comparable hematocrit values (Hct:Group B 26,2% Group A 26,4%); On the other hand the slight blood volume expansion we observed in group B (7%) respect to group A hardly explains the observed difference in CI. It is interesting that pulmonary blood volume/total blood volume ratio (PBV/TBV) was significantly higher in dialysed hypertensives (PBV/TBV: Group B 14,26%, Group A 11,15%; p less than 0,05) The higher PBV/TBV can be the result of a decrease in venous compliance and could explain the higher CI in group B; further studies however are warranted to elucidate this point.