1. Syncopal or near syncopal episodes have been observed in five subjects who stood or were tilted and in whom blood samples were being taken. 2. In all subjects bradycardia and hypotension developed before the onset of symptoms. Increases in plasma adrenaline concentrations occurred in all subjects, beginning before the faint. Changes in plasma noradrenaline concentrations were variable: in three subjects there was a marked fall and in the other two subjects an increase. Plasma vasopressin increased in all subjects. 3. Increases in plasma adrenaline may be contributing to the vasodilatation and arterial hypotension which occur during syncope.
1. Respiration during sleep was studied in 16 withdrawn alcoholic patients and in 12 control subjects. 2. The alcoholic patients had increased numbers of central ( P < 0.01) and of obstructive ( P < 0.05) apnoea and of hypopnoea episodes ( P < 0.01) as compared with controls. 3. Significant positive associations were found between the frequencies of central apnoea ( P < 0.05) or hypopnoea ( P < 0.01) and clinical evidence of central nervous system damage in the alcoholic patients. Hypopnoea also showed a significant association with vagal neuropathy ( P < 0.05), assessed by tests of cardioreflexes. 4. We conclude that abnormal respiratory events are common in abstinent alcoholic patients and that they are likely to be at least partly related to nervous damage.