Focal cerebral ischemia and mitral valve prolapse in monozygotic twins.

Mitral valve prolapse (MVP) is a common frequently inherited cardiac valvular disorder. Ischemic cerebrovascular disease (ICVD) is an apparent complication of MVP. We report the concordance of MVP and ICVD in a pair of monozygotic twins. This occurrence reinforces the concepts that MVP is highly concordant in monozygotic twins and that it can be the cause of familial ICVD.

Variability of steady-state digoxin kinetics during administration of tablets or capsules.

An encapsulated solution of digoxin has been repeatedly shown to have greater bioavailability than tablet forms of the drug. It is predicted that such a preparation would show reduced within- and between-patient variability in absorption, as most studies in normal subjects have shown reduced intersubject variation with the capsule. We tested inter- and intrapatient variability during 4-week periods of dosing with digoxin capsules and tablets in 28 subjects with cardiac disease. In the overall group there were no significant differences between the formulations at steady state in between-patient variability in trough serum digoxin concentrations or 24-hour urinary digoxin excretion. Within-patient variability in urinary digoxin excretion was somewhat lower for the capsules. In a subgroup of six patients who excreted significant amounts of cardioinactive bacterial metabolites (digoxin reduction products [DRP]), the mean (+/- SD) percent urinary DRP excretion was less (p less than 0.05) during capsule (20.5% +/- 15.1%) than tablet (34.4% +/- 10.9%) dosing. Within-patient variability in urinary DRP excretion was much greater after tablets than capsules. Certain subgroups of patients should benefit from the enhanced bioavailability of digoxin capsule preparations.