Objective To study the physiological responses to noninvasive cardiovascular autonomic function tests in normal pregnancy. Design Cardiovascular autonomic responses in 60 women at 22 to 29 weeks gestation and 62 nonpregnant women were investigated using the Valsalva manoeuvre as well as orthostatic, quiet breathing, deep breathing, and isometric handgrip tests. Results Compared with nonpregnant women, those who were pregnant showed significantly lower heart rate variability during normal breathing and a blunted tachycardic reaction to blowing during the Valsalva manoeuvre. The vagally controlled biphasic heart rate response to standing was also attenuated in the pregnant group. Conclusions The cardiovascular responses were blunted in mid‐pregnancy indicating a decrease in parasympathetic cardiovascular control.

Spectral analysis of heart rate variability was used to study autonomic nervous control in mid-pregnancy. Fifty women (age 22-36 years) with singleton pregnancies (mean duration of gestation 27.7 weeks) and 39 non-pregnant female controls (age 21-39 years) were studied using controlled breathing and orthostatic tests. During spontaneous breathing the overall heart rate variability was lower in pregnant subjects indicating a decreased parasympathetic tone at rest. The decreased parasympathetic tone probably counts for the increased heart rate in pregnancy. The parasympathetic efferent capacity of autonomic cardiac control was found to be similar in pregnant and non-pregnant subjects, as no difference was seen during controlled breathing in periodic heart rate variability between the groups. Standing up caused a similar change in low frequency and mid-frequency bands in both groups, but high frequency heart rate variability increased in pregnant subjects and decreased in the controls indicating an increased sympathetic tone at rest in mid-pregnancy.

The aim was to evaluate clinical and subclinical cardiac toxicity of epirubicin-docetaxel (ET) combination. Breast cancer patients were given epirubicin (75 mg/m2 for 15 min), followed 1 h later by a 1-h infusion of docetaxel (75 mg/m2) q3w as first-line treatment. Cardiac function was monitored using a 24-h ambulatory electrocardiogram (ECG), left ventricular ejection fraction (LVEF), physical examination and chest radiography. The median LVEF did not decrease during the course of the treatment: median LVEF was 64% prior to treatment and 68% after cycle 8. The 24-h ECG did not reveal any significant changes in heart rate variability. The number of extrasystoles or cardiac arrhythmia did not increase with the ET treatment. No patient experienced congestive heart failure during treatment or the mean follow-up of 34 months. We conclude that first-line ET caused no major cardiac changes during 6 months of treatment (8 cycles) or during follow-up. Twenty-four-hour ECG, combined with echocardiography to measure LVEF, was a feasible method for the close monitoring of the cardiac effects during chemotherapy.

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Luutonen S, Neuvonen P, Ruskoaho H, . Finland). The role of potassium in postural hypotension : electrolytes and neurohumoral factors in elderly hypertensive patients using diuretics. J lntern Med 1995: 2 3 7 : 375-80.Objective. To study the association between postural hypotension and (i) electrolyte levels and (ii) neurohumoral factors in elderly hypertensive patients using diuretics. Design. Cross-sectional study of patients and controls. Setting. The subjects were gathered from senior citizen clubs or they were referred to the study by general practitioners. The subjects were examined on a geriatric ward in Turku City Hospital. Subjects. Seven subjects with postural hypotension and 13 controls.Measurements. Plasma electrolyte levels and neurohumoral response to head-up tilt.Results. There were significantly more hypokalaemic subjects in the postural hypotension group (5/ 7) than in the control group (1/.13) (P < 0.01). The plasma potassium level was negatively correlated to plasma aldosterone ( r = -0.57: P < 0.01) and renin activity ( r = -0.69: P < 0.001). Subjects with postural hypotension had higher levels of noradrenaline, both supine (P < 0.05) and during tilt (P < 0.05).There were no significant differences in supine or tilt levels of plasma adrenaline, vasopressin, atrial natriuretic peptide, aldosterone and renin activity between the groups. Conclusion. The results suggest that potassium depletion is associated with postural hypotension in elderly hypertensive patients using diuretics. However, it is unclear whether there is a causative link between potassium depletion and postural hypotension or whether they are both caused by some other factor, e.g. volume contraction.