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Objective: To determine the predictive value of findings on continuous ambulatory electrocardiographic monitoring in elderly subjects. Design - Retrospective chohort study. Ten year follow up of randomly selected elderly subjects who participated in ambulatory electrocardiography study in 1982. Mortality data derived from offical registers. Setting: Turku, Finland. Subjects: 480 people aged 65 or older in 1982 who were living in the coummunity, of whom 72% agreed to participate. Main outcome measures: Mortality from cardiac and non-cardiac causes during 10 year follow up. Results: In the univariate analysis adjusted for age, risk of death from cardiac causes was increased among those with ventricular ectopy of more than 100 beats during the day (odds ratio 2.6; 99% confidence interval 1.4 to 6.1) or at night (3.3; 1.1 to 9.8) and in those with multifocal ventricular ectopic beats during the day (2.3; 1.0 to 5.0) or night (3.0; 1.3 to 7.1) compared with those with no ventricular ectopy. Sinoatrial paused exceeding 1.5 seconds during the day (4.5; 1.8 to 11.1) were also associated with excess mortality from cardiac causes. None of the findings on ambulatory electrocardiography predicted death from non- cardiac causes. A further study of explantory variables in the stepwise logistic regression analysis showed that sinoatrial pauses exceeding 1.5 seconds (4.0; 95% confidence interval 1.8 to 8.9) and night time multifoucal ventricualr ectopy (2.7; 1.2 to 5.9) predicted excess mortality from cardiac causes independently of age or clinically evident heart disease. Conclusion: Daytime sinoatrial pauses exceeding 1.5 secods and night time multifocal ventricular ectopy in the ambulatory electrocardiogram predict increased mortality form cardic causes independenlty of clinically evident cardiac diseases in unselected elderly subjects.

The effect of coronary artery bypass grafting (CABG) on standard cardiovascular reflex tests and pupillometry was studied in 15 patients with coronary artery disease without previous myocardial infarction. The heart rate responses to the deep breathing test and to the Valsalva manoeuvre were attenuated after CABG, whereas CABG had no effect on the beat-to-beat measured blood pressure responses (Finapres) or the pupillometric variables. Although the heart rate responses diminished in almost all of the patients after CABG, the values, however, remained in most cases within the age-related normal range. It is concluded that the attenuation of heart rate responses after CABG is due to perioperative local damage on the effector organ or autonomic nerves rather than due to dysfunction on the baroreceptor level or in cranial level of the autonomic nervous system. Because the blood pressure responses were not affected by CABG and the heart rate responses after CABG mainly remained within the normal range indicating sufficient parasynthetic activity, it is probable that the clinical significance of the effects of CABG on the autonomic nervous system is not very important.

To study the usefulness of standard cardiovascular autonomic reflex tests in the elderly, 224 healthy controls and 49 aged diabetic patients were examined. Based on the data obtained from healthy controls, age-related reference values for several autonomic indices were calculated and their usefulness was tested with aged diabetic patients. It was found (1) that in elderly subjects (aged > or = 50 years) the indices based on heart rate differences are more suitable for the assessment the autonomic parasympathetic control than indices based on R/R interval ratios, (2) that the tests (and indices) of choice in the elderly subjects are the Valsalva manoeuvre (Valsalva difference and tachycardia difference) and the active orthostatic test (Max-Rest difference, immediate and later change in systolic blood pressure), (3) that the usefulness of the deep breathing test is limited in the elderly, (4) that such commonly used indices as the Valsalva ratio and the Max/Min ratio in orthostatic test are not useful in the elderly, and (5) that the isometric handgrip test is of little use in the assessment of the autonomic function in the elderly. In conclusion, standard cardiovascular autonomic reflex tests can be used in the assessment of autonomic function to some extent also in the elderly subjects. However, one must bear in mind the limitations in their applicability in that age group.

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.

Possible effects of environmental stress-induced elevation of the heart rate on the magnitude of cardiovascular autonomic responses were studied in 123 healthy subjects. The nocturnal heart rate was evaluated using ambulatory 24-h ECG monitoring. Some of the cardiovascular responses were found to be significantly weaker in those subjects whose resting heart rate during testing was greater than 10 beats min-1 higher than the resting nocturnal heart rate. It is thus highly important to minimize the environmental disturbances during autonomic testing.

The effect of acute dose of caffeine (4 mg kg-1) on cardiovascular autonomic responses were studied in 10 healthy subjects. Standard cardiovascular reflex tests were used during which heart rate and blood pressure were continuously measured. Each subject was tested twice in a random order, with and without prior use of caffeine. It was found that immediate heart rate responses following standing up were lower under influence of caffeine. Blood pressures were systematically, although non-significantly, higher and blood pressure responses in isometric handgrip test stronger when caffeine was used before testing. It is suggested that caffeine should not be used before autonomic testing. This is especially important when the test(s) are performed for research purposes or in order to study the blood pressure responses. If the tests are made for diagnostic purposes the following rules should be adopted: (1) if the subject has used caffeine before testing but all heart rate responses are within normal ranges, it can be assumed that the subject does not have cardiac parasympathetic neuropathy and retesting is not necessary: (2) if the patient has used caffeine before testing and the results suggest presence of autonomic neuropathy, the patient must be retested without the prior use of caffeine.

Thirty-four patients with RA, 76 diabetic subjects (DM) and 67 healthy controls (CR) were studied in order to study cardiovascular autonomic function in RA. Valsalva manoeuvre, deep breathing test and active orthostatic test were used. Resting heart rate (resting HR) was markedly elevated in the RA and DM groups. Therefore, the groups were compared using analysis of variance with age and resting HR as covariates. The analyses showed no differences in cardiovascular responses between the RA group and CR group but cardiovascular responses were significantly diminished in the DM group compared with both the CR group and RA group. Our data indicate that the parasympathetic efferent pathway mediating cardiovascular reflexes via the nervus vagus is intact in RA. Thus elevated resting HR in RA does not seem to be due to peripheral parasympathetic damage. Physical deconditioning may explain the elevation of resting HR in patients with RA.

Summary. The effects of smoking habits on aotnomic cardiovascular heart rate reflexes were studied in 143 healthy subjects by using the Valsalva manoeuvre and deep breathing tests. Smoking seemed to cause attenuation of the Valsalva heart rate response. This attenuation was present also after adjustment for possible confounding factors including alcohol consumption. Our findings show that in subjects with smoking history there may occur dysfunction in some part of the autonomic reflex arch mediating the Valsalva heart rate response.