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Maximal exercise testing can be safely used to assess pregnant cardiac patients

      Objective

      Pregnancy is traditionally considered a contraindication to exercise testing, especially in women with heart disease, despite the fact that pregnancy and labor constitute a natural stress to the heart. Exercise testing is often required to provide objective assessments of cardiac function. Relying on assessments performed at rest to estimate whether the cardiovascular system has enough reserve to cope with the stresses of pregnancy and labor may be suboptimal. We evaluated the safety of maximal exercise testing during pregnancy.

      Study design

      We have performed maximal cardiopulmonary exercise testing more than 230 times in 63 pregnant women at varying stages of pregnancy, ranging from 12 to 38 weeks gestation. The exercise was performed on a treadmill according to standard Bruce protocol, with measurement of respiratory gases and hemodynamic variables including cardiac output and cardiac power output. Thirty-nine of the subjects were normal healthy controls and twenty-four were referred for investigation of known cardiac abnormalities. Women with absolute contraindications to exercise testing such as aortic aneurysm, Marfan's syndrome, outflow tract obstruction or serious arrhythmias were excluded.

      Results

      Pregnant women were happy to take part in maximal exercise tests during pregnancy. All tests were completed without significant complications. The minor complications were a vasovagal reaction and an asymptomatic salvo of ventricular tachycardia, neither requiring intervention. The results of the exercise test can grade the cardiovascular reserve of individual subjects, enabling assessment of functional impairment in patients with structurally abnormal hearts.

      Conclusion

      Maximal symptom-limited exercise testing can be safely carried out in pregnancy, under adequate supervision in a specialised centre, even up to 38 weeks gestation.