Search

The extensive use of ultrasound imaging in cardiology has greatly contributed to expand both its diagnostic possibilities and its utility in the interpretation of physiopathologic mechanisms. Conventional echocardiography is the more specific technique for the diagnosis of myocardial hypertrophy which, in turn, is one of the most important cardiovascular risk factors. The improvement of ultrasound technology may expand the possibility of noninvasive characterization of left ventricular hypertrophy by adding to the already known information about left ventricular mass and function, and that relative to the degree of hypertrophy-related fibrosis. In the present paper the authors reviewed the knowledge about biological and hemodynamic factors which contribute to the development and regression of myocardial hypertrophy. The possible role of new ultrasonic technology in the tissue characterization of myocardial hypertrophy is also discussed.

Four patients on regular dialysis were studied by echocardiographic method during ultrafiltration sequential dialysis performed according to two different protocols: procedure 1: ultrafiltration alone (1 hour) followed by diffusive dialysis (3 hours); procedure 2: dialysis (3 hours) followed by ultrafiltration alone (1 hour). Blood pressure, heart rate, cardiac output, stroke volume, systolic and diastolic dimension of the left ventricle, systolic and diastolic volumes of the left ventricle, ejection fraction, shortening fraction and total peripheral vascular resistance index were measured. During ultrafiltration there is an increase of the total peripheral vascular resistance index. Myocardial contractility improves only during dialysis. Physiographic and therapeutic implications are discussed.

Echocardiographic indices of left ventricular volume and mass and electrocardiographic indices of left ventricular hypertrophy have evaluated in 25 patients with chronic aortic regurgitation and in 10 normal subjects. When the patients with aortic regurgitation were subdivided in three groups with increasing evidence of left ventricular hypertrophy, the echocardiographic measures of left ventricular dimension and mass were also found to be increased, with statistically significant differences between patients and controls and among the three groups of patients as well. A specially constructed cumulative electrocardiographic index of left ventricular hypertrophy (Sokolow and Lyon's index plus Lewis' index plus strain pattern) is correlated with the left ventricular end-diastolic diameter (r = 0.65; P less than 0.001), cross-sectional area (r = 0.65; p less than 0.001) and mass (r = 0.75; p less than 0.001) better than the isolated electrocardiographic indexes.

Cardiovascular complications are very common in uraemic patients on regular dialytic treatment and are often the cause of death. In these patients many echocardiographic studies have been carried out to establish the presence of cardiac alterations. In particular some M-mode echocardiographic investigating have shown a significant incidence of asymmetric septal hypertrophy (ASH), but often the patients had associated cardiomegaly or arterial hypertension. In the present paper M-mode echocardiogram and carotid pulse tracing were recorded after dialysis in 23 normotensive long-term hemodialyzed patients. The aim of the study was to detect the incidence of ASH and to assess the functional behaviour of the left ventricle in relation to the presence of the septal abnormality. ASH as ratio of interventricular septal to posterior wall thickness (IVS/PWT) of 1.3 or greater, without systolic anterior motion of anterior mitral leaflet (SAM), was found in 52.1% of patients. The group with ASH showed an obvious reduction of the cardiac index (CI), after dialysis, due to reduction of left ventricular size and to the abnormal septal function. CI was normal in patients without ASH. On the other hand the presence of ASH did not significantly influence the percentage of fractional shortening (FS%), the velocity of circumferential fiber shortening (Vcf) and the ejection fraction (EF%) which were similar in both groups of patients. A long-term echocardiographic follow-up of these patients may be important to outline the natural history of ASH and to evaluate its relation to chronic renal failure on hemodialytic treatment.

The aim of the present study is to analyze variations of external cardiac work and of indices of myocardial oxygen consumption induced by upright tilting and hand-grip in volley-ball athletes (group A) in comparison with a group of normal subjects (group N). For this purpose we have used impedance cardiography, a simple, reproducible and non invasive technique, which is very reliable in evaluating both systolic time intervals and hemodynamic parameters such as stroke volume and cardiac output. No significant differences, of external cardiac work, double and triple product were observed between group A and N upon upright tilting. Hand-grip test, on the other hand, can differentiate the myocardial behaviour of trained people from that of the control group. The double product was significantly reduced in group A in comparison with group N (P less than 0.001 and the end of the test, P less than 0.05 after 30", P less than 0.001 after 1' and 3"). The triple product was significantly reduced in group A in comparison with group N at the end of the test (P less than 0.005). External cardiac work was always higher in group A in comparison with group N (P less than 0.02, at the stop P less than 0.05 after 30", P less than 0.01 after 1', P less than 0.0001 after 3'). Therefore in volleyball athletes the myocardium exhibits better mechanical performance than in normal subjects.

Sympathetic-adrenergic activity has been evaluated in 23 chronic uremic, normotensive patients on regular hemodialysis, 7 of which (30.4%) with M-mode and bidimensional echocardiographic finding of asymmetric septal hypertrophy. The sympathetic function has been assessed by measuring arterial plasma norepinephrine and epinephrine levels before and after postural activation, just before and after dialysis. After dialysis, standing caused a significant increase of plasma norepinephrine levels in patients with asymmetric septal hypertrophy in comparison with patients without asymmetric septal hypertrophy and with the control non uremic group. Moreover, a significant decrease in blood pressure and a sharp heart rate increase were noted in the patients without asymmetric septal hypertrophy, whereas mean blood pressure and heart rate were unchanged in the patients with asymmetric septal hypertrophy. These results suggest that increased plasma norepinephrine concentration may have a role in the development of interventricular septal hypertrophy.