QT/QS2 index in patients with arterial hypertension, mitral valve prolapse and hyperthyroidism]

QT/QS2 ratio has been assessed in 26 patients with both borderline and mild hypertension and mitral valve prolapse syndrome (19 patients), and hyperthyroidism (16 patients) in comparison with method control groups. The following polycardiographic parameters have been analyzed: QT, QTp, QS2, QT/QS2, and QTp/QS2. Higher values of QT/QS2 ratio have been noted in patients with mitral valve prolapse syndrome and hyperthyroidism than that in the control group. There has been no difference in patients with mild hypertension while the values of the analyzed parameter have been significantly lower in patients with borderline hypertension. QT has been longer than QS2 (QT)QS2 1/in 9 (56%) patients with hyperthyroidism. A positive correlation between QT/QS2 ratio and ++thyroxine levels have been noted in these patients. QT values have been higher than QS2 values only in 1 patient with mild hypertension. It seems that QT/QS2 value has limited value as an indirect index of the adrenergic activity in the dysfunction of the autonomic nervous system.     

Mechanism of the post-haemorrhagic vasopressin release from the posterior pituitary lobe

The mechanism of post-haemorrhagic vasopressin release from the neurohypophysis was studied in rats anaesthetized with urethane. Neurohypophysial vasopressin content was determined according to Dekański and plasma renin activity by radioimmunoassay. In animals bled (1.5% body weight) 60 min after induction of anaesthesia and 30 min after bilateral nephrectomy vasopressin content of the posterior pituitary was significantly higher than in sham-nephrectomized rats. However, when haemorrhage was produced 240 min after induction of anaesthesia and 210 min after nephrectomy, the neurohypophysial vasopressin content was low and similar as that in non-nephrectomized animals. It is concluded that in the phase directly following haemorrhage vasopressin release depends on acute activation of the renin-angiotensin system. Other mechanisms, possibly circulatory reflexes, are involved in the late phase, during prolonged anaesthesia.