Closed surgical mitral valvotomy is the procedure of choice in most patients with symptomatic pliable mitral stenosis in developing countries. The procedure is efficacious and safe. Mitral valvotomy performed with a balloon has shown similar good results, with infrequent complications in selected subjects. Because there is a paucity of studies comparing the two techniques, this study was undertaken to compare the results of percutaneous balloon mitral valvuloplasty with those of closed commissurotomy as determined by catheterization studies. Forty-five patients with tight pliable mitral stenosis were randomly assigned to one of two groups: 23 patients had balloon valvuloplasty by the single catheter technique (group I) and 22 underwent closed surgical valvotomy (group II). The two groups were similar with regard to clinical and hemodynamic findings before intervention. Mitral valve area increased from 0.8 +/- 0.3 to 2.1 +/- 0.7 cm2 in group I (p less than 0.001) and from 0.7 +/- 0.2 to 1.3 +/- 0.3 cm2 in group II (p less than 0.001). Pulmonary artery pressure and pulmonary vascular resistance decreased in both groups, but these changes did not reach statistical significance in group II. Treadmill exercise time increased from 3.8 +/- 2.3 to 7.3 +/- 2.6 min in group I (p less than 0.001) and from 4 +/- 2.6 to 5.6 +/- 2.6 min in group II (p less than 0.001). There were no deaths. One patient in each group developed moderate (3+) mitral regurgitation. A small interatrial shunt (less than 1.5:1) was detected in three patients in group I immediately after the procedure.(ABSTRACT TRUNCATED AT 250 WORDS)

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The objective of the study was to evaluate the susceptibility of genetically predisposed to salt sensitivity Dahl rats to psychological stress and the effect of sodium ion on stress development. After weaning, Dahl salt‐resistant (DR) and two groups of salt‐sensitive (DS) rats were fed low‐Na (0.5 per cent NaCI) and high‐Na (8 per cent NaCI) diets for 2 months. A constellation of sensorimotor and behavioural tests were employed. The psychological stress was produced using a new model of acoustic startle device. DS weanling rats showed significantly increased sensorimotor reactivity, increased emotionality and increased sensitivity to acoustic stress, as compared to DR weanling rats. All the above parameters were exaggerated after 2‐month Na loading: there was a significant decrease in the latency of the stressful response and increased magnitude of the hypertensive response to auditory stress. Blood pressure of Na‐loaded DS rats increased by 43 per cent after auditory stress, as compared to 18 per cent increase in the Na‐restricted rats. The effect of Na ion was mediated by an increased activity of the sympathetic nervous system (SNS). The chronic effect of Na restriction showed reduced SNS responsiveness and diminished neurohumoral reserve to maintain cardiovascular homeostasis. Risks of both Na loading and Na depletion in sodium sensitivity were discussed. © 1998 John Wiley & Sons, Ltd.

death.3 Although not proven, patients with serious