Article Text

Download PDFPDF
Characterisation of heart rate response to exercise in the sick sinus syndrome.
  1. W Holden,
  2. J H McAnulty,
  3. S H Rahimtoola

    Abstract

    Patients with sick sinus syndrome have abnormalities of the sinoatrial node. We have measured the heart rate response to exercise in 7 patients with sick sinus syndrome without significant associated heart disease (group A) mean age 53.4 years, and compared this with 7 'normal' patients who were age-matched to within 5 years (group B), and 7 younger, well-trained subjects (group C). All underwent maximal treadmill exercise. Although maximum oxygen consumption (VO2max), 1/min per kg, in group A was not significantly different from group B (23.8 +/- 4.7 vs 19.9 +/- 0.8, mean +/- SE) maximum heart rate, beats/min, in group A was significantly lower than in group B (124 +/- 8.9 vs 163 +/- 3.7, P less than 0.001). At the end of 3 minutes of Bruce Stage I exercise, group A patients had a heart rate less than 130/minute (95% confidence level), whereas group B patients had heart rates greater than 134/minute. VO2 was plotted against heart rate (HR). Patients in group A had a significantly lower slope (deltaHR 5.20 +/- 0.33/delta1 ml VO2/kg per min, P less than 0.001). There was no significant difference in the slopes between groups A and C. On exercise patients with sick sinus syndrome have a normal VO2, but a reduced heart rate response as compared with age-matched normal patients. This abnormal heart rate response to the physiological stimulus of exercise may be of help in the evaluation of patients with sick sinus syndrome who do not have significant underlying heart disease.

    Statistics from Altmetric.com

    Request Permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.