Supernormal left ventricular diastolic function in triathletes.

We studied the structural and functional heart adaptations of 52 male triathletes compared with those of 22 active, nonathletic men, by 2-dimensional Doppler echocardiography. Left ventricular diastolic function was evaluated by recording transmitral flow velocities. To exclude the influences of preload, left atrial pressure, and aortic pressure, left ventricular diastolic function was also evaluated by pulsed Doppler tissue imaging. Significant differences in cardiac structure and function were observed between the 2 groups. In the triathletes, the left ventricular diastolic function was completely normal, despite signs of mixed eccentric and concentric left ventricular hypertrophy, and this function was better than that in the control group. We measured 2 aspects of the late passive diastolic filling period in the triathletes: ASEAC value (the amplitude of excursion of the interventricular septal endocardium at the end of left ventricular diastole just after atrial contraction); and the time between onset of the P wave on the electrocardiographic tracing and onset of systolic septal movement on M-mode echocardiography. Pulsed Doppler tissue imaging confirmed these results. The E/A ratios (peak early left ventricular diastolic motion velocity divided by the peak atrial systolic motion velocity), measured by pulsed Doppler tissue imaging, yielded even more evidence for supernormal left ventricular diastolic function in the triathletes. Left ventricular relaxation and filling properties were measured along the longitudinal and transverse axes by pulsed Doppler tissue imaging, which was useful for evaluating left ventricular diastolic function. We determined that triathletes may develop supernormal left ventricular diastolic function with increased diastolic reserves.

Chronic haemodialysis with bicarbonate dialysate. Technical and clinical aspects.

Bicarbonate as a physiological buffer should be preferred in haemodialysis treatments. The use of bicarbonate dialysis, however, varies from 30 to 100% in the different industrialised countries. Except for the many advantages using bicarbonate dialysate, there are also clinical pitfalls in the use of the bicarbonate buffer substrate. Furthermore, technical problems can be expected in the use of varying dialysate bicarbonate concentrations, as in the concomitant use of acetate and bicarbonate dialysate in the same dialysis unit. This paper deals with the clinical and technical aspects of bicarbonate dialysis.