Evaluation of left ventricular diastolic function in insulin dependent diabetic children by M-mode and Doppler echocardiography.

To evaluate the presence of diabetic cardiomyopathy, we measured various parameters of left ventricular systolic and diastolic function by means of M-mode and Doppler echocardiography in 50 IDDM children (mean age 13 +/- 3 years; mean IDDM duration 5.9 +/- 4.1 years) free of cardiovascular symptoms. As compared to age-matched healthy control subjects, diabetic children evidenced a significant increase in mean values of pressure half time (PHT), an index of the early diastolic phase (53.7 +/- 10.2 msec vs 44.5 +/- 9, p < 0.002). When the patients were subdivided on the basis of IDDM duration, metabolic control and the presence of retinal microangiopathic abnormalities, those with longer IDDM duration and poor glycemic balance had higher PHT values. These data indicate that an early diastolic dysfunction, expressed by reduced left ventricular compliance, can be found in children with Type 1 diabetes mellitus of relatively short duration. Doppler echocardiography is a reliable non-invasive means to assess early impairment of cardiac function in IDDM patients.

The effect of pure right ventricular ischemia on right and left ventricular performance in the anesthetized dog.

This study was planned to investigate the effect of ischemic dysfunction of the free wall of the right ventricle on right and left ventricular performance in the presence of a normally contracting interventricular septum. The experiments were performed in 6 anesthetized dogs in which echocardiogram, electrocardiogram, aortic blood pressure and left and right ventricular pressure were recorded. In the dog, the contractility of the septum is not affected by the occlusion of the right coronary artery which does not perfuse this part of the myocardium. Complete occlusion of the major individual ventricular branches and partial occlusion of the main right coronary artery did not impair right ventricular performance. Only complete occlusion of the main artery affected right and left ventricular function as revealed by echocardiogram. Reduced output by the ischemic right ventricle caused a reduction in left ventricular diastolic and systolic dimensions and in left ventricular developed pressure without any effect on left ventricular end-diastolic pressure.

Coronary response to transient increases in transmural pressure.

Previous studies have shown that transient increases in aortic blood pressure obtained by occlusion of the descending thoracic aorta, in anesthetized dogs with beta-blockade and vagal section, did not affect coronary vascular resistance apart from a non-significant increase just after release of the constriction. The present study examined whether this response also occurred in the normally innervated heart. Experiments were carried out in six anesthetized dogs, in which pressure in the aortic root and in the left ventricle, as well as flow in the left circumflex coronary artery, were recorded. Coronary vascular resistance was calculated as the ratio of the difference between aortic pressure and left ventricular pressure to coronary circumflex flow during the slow inflow phase. Before occlusion coronary vascular resistance was significantly lower than during the same period in the previous studies using animals with beta-blockade and vagal section. During the occlusion, in contrast with the previous investigation, the increase in aortic pressure caused a significant increase in coronary vascular resistance 10 seconds after the beginning of the occlusion. Coronary vascular resistance was further increased immediately after release of the occlusion, concomitantly with the decrease in aortic pressure, which fell abruptly below the control level. The increase immediately after the release of the constriction was qualitatively similar, but greater in extent, to that observed in the animals with vagal section and beta-blockade. These differences are assumed to depend on a lower vasomotor tone in the normally innervated hearts.(ABSTRACT TRUNCATED AT 250 WORDS)

[Mitral valve bioprosthesis from bovine pericardium. Color Doppler echographic study and long-term follow up]. / Bioprotesi valvolari mitraliche di pericardio bovino. Studio ecocardiografico e color Doppler e follow-up a lungo termine.

Pericardial heart valve bioprostheses have been utilized for 20 years. In spite of encouraging initial results, long-term follow-up showed a higher incidence of structural failures and primary tissue failures than porcine bioprostheses. Pericarbon represents the newest generation of bovine pericardial bioprostheses. Aim of this study is the long-term evaluation with echocardiographic and color Doppler technique of an innovative bioprostheses, in particular, its morfological and functional characteristics. From 1985 to 1989, 78 consecutive patients (21 males, 57 females, mean age 56.5 +/- 8.16 years) underwent mitral valve replacement with Pericarbon 29, by the same operator, who preserved the mitral posterior leaflet. One month after operation, 21 of these patients underwent echo-color Doppler evaluation, in normalized hemodynamic conditions (normality ranges). In 1995, at the end of the followup, 30 of the remaining 54 patients underwent new echo-color Doppler evaluation and these data were compared with normality ranges values. Leaflets' thickness increased from 0.98 +/- 0.09 to 2.87 +/- 0.73 mm (anterior leaflet; p < 0.0001) and from 1.02 +/- 0.08 to 2.71 +/- 0.45 mm (posterior leaflet; p < 0.0001) 43.3% of anterior leaflet and 53.3% of posterior leaflet showed fibrocalcic lesions. Mean transvalvular gradient increased from 3.4 +/- 0.2 to 6.6 +/- 3.4 mmHg (p < 0.0001); also functional area decreased (p < 0.0001). We have found no paraprosthetic regurgitation and a very low number of central prosthetic regurgitation. Left ventricular function, evaluated by ejection fraction and regional kinesis, remained substantially preserved.