SUMMARY We report a case of mucopolysaccharidosis type IV causing severe mitral stenosis in a 48-year-old woman.

1. Plethysmographic blood flow records made after venous occlusion of the forearm showed a biphasic response which was first vasodilator and then vasoconstrictor. 2. The myogenic nature of the vascoconstrictor phase was confirmed in eight subjects after total autonomic blockade with atropine, propranolol, phentolamine and guanethidine. 3. Forearm venous blood demonstrated a rise in hydrogen ion concentration and a fall in oxygen tension during venous occlusion, which may contribute to the vasodilatation phase.

1. Continuous intra-arterial ambulatory monitoring of blood pressure was recorded in 46 patients with mild to moderate hypertension under standardized conditions. M-mode echocardiography was performed after recording and left ventricular mass index calculated by standard formulae. 2. Systolic blood pressure from continuous recording was significantly correlated with left ventricular mass index (mean 24 h: r = 0.543, n = 45, P less than 0.001). Diastolic blood pressure exhibited a weaker but still significant correlation with left ventricular mass index (mean 24 h: r = 0.318, n = 45, P less than 0.05). Casual systolic blood pressure was significantly correlated with left ventricular mass index (r = 0.476, n = 46, P less than 0.001) but casual diastolic blood pressure did not correlate with left ventricular mass index (r = 0.245, n = 46). Awake blood pressure variability, age, resting plasma renin activity and resting plasma noradrenaline levels did not have a significant correlation with left ventricular mass index. 3. Nine patients were treated for 16 weeks with once-daily timolol and repeat ambulatory monitoring and M-mode echocardiography was performed with the same protocol. 4. Once-daily timolol provided good 24 h control of blood pressure and repeat echocardiography showed a reduction in left ventricular mass index in that group of patients (t = 2.59, P less than 0.05).

1 Nine hypertensive patients received by mouth daily doses of 400 mg of acebutolol and then, after a 2 week washout period, 80 mg of propranolol for 2 week periods in an open study. 2 Both treatments caused equivalent cardiac blockade as assessed by reduction in exercise tachycardia. 3 Both treatments lowered blood pressure, although this effect on pressure was better maintained in the case of acebutolol. 4 Forearm blood flow, at rest, was significantly reduced at 2 h after dosing with propranolol, but not after acebutolol. 5 This difference between the two drugs is probably due to the cardioselectivity of orally administered acebutolol in man.

Carotid pulse tracings and M-mode echocardiography were recorded in 25 patients on maintenance haemodialysis pre- and post-dialysis. Myocardial function, as assessed by fractional shortening and velocity of circumferential fibre shortening, was depressed in 7 out of 25 patients pre-dialysis (28%). Acute haemodialysis resulted in significant changes in body weight, mean arterial pressure, urea, creatinine and packed cell volumes in all patients. Left ventricular function, however, improved significantly only in that group of patients in which it was depressed prior to dialysis. Echocardiography provides a simple means for evaluating left ventricular function in patients on chronic haemodialysis and shows that cardiac performance improves with acute dialysis when it is depressed pre-dialysis.