International journal of cardiology
-
Previous reports that subjects with anxiety symptoms are at higher risk of sudden death may imply that anxiety induces stable sympathetic hyperactivity. To address this subject, in persons with and without anxiety symptoms, we evaluated autonomic nervous system activity by power spectral analysis of heart-rate and arterial-pressure variability at baseline (rest) and after sympathetic stress (tilt). The 117 subjects selected (56 men and 61 women, age range 23-87 years) were subdivided by questionnaire into three groups: 49 subjects (mean age 55.8+/-2.8 years) had no anxiety symptoms; 36 (mean age 56.8+/-3.6 years) had one anxiety symptom; and 32 (mean age 55.0+/-2.9 years) had two or more anxiety symptoms. ⋯ Recordings of resting systolic arterial pressure variability showed that the group with two or more anxiety symptoms had significantly higher LF power (P<0.05) than symptomless controls. Our findings suggest that persons with high anxiety scores have baseline cardiac sympathetic hyperactivity. They also have low heart-rate variability, possibly explaining their susceptibility to sudden cardiac death.
-
Randomized Controlled Trial Comparative Study Clinical Trial
Heart rate variability after acute myocardial infarction in patients treated with atenolol and metoprolol.
Heart rate variability (HRV) reflects autonomous activity that influences the heart. It has been shown that HRV is depressed during acute myocardial infarction (AMI) and that it recovers with time. Beta-blockers reduce mortality after AMI and changes in sympathico-vagal activity have been suggested to be of importance. Under certain animal experimental conditions, metoprolol has been reported to increase vagal tone more than atenolol, which could have clinical implications. The purpose of the present study was to compare the effects of atenolol and metoprolol treatments on HRV during 6 weeks after AMI and to follow the post MI changes in HRV in patients on betablockers. ⋯ There was no evidence of more increased vagal tone with metoprolol compared to atenolol as has been suggested from animal models. In patients also on chronic treatment with beta blockers, an increase of HRV was seen during the first weeks post MI.