Abstract 1816: Heart Rate Response as a Predictor of Pregnancy Outcome in Women With Congenital Heart Disease
Background: Cardiopulmonary exercise testing (CPET) is often used to evaluate exercise capacity and chronotropic response in women with congenital heart disease (CHD) who are considering pregnancy. There is no data on the predictive value of CPET for pregnancy outcome. The primary objective of this study was to determine the association between CPET parameters and maternal and neonatal outcomes in women with CHD.
Methods: This was a multicenter retrospective observational study of women with CHD who had undergone CPET testing at least 2 years prior to pregnancy; including the first trimester. CPET variables included peak oxygen consumption (pVO2) and measures of chronotropic response: chronotropic index [CI = (peak heart rate - resting heart rate)/(220-age-resting heart rate)], heart rate reserve (HRR = peak heart rate - resting heart rate), percentage of maximum age predicted heart rate (%MPHR) and peak heart rate (pHR). Patients with a pacemaker were excluded from the analysis of chronotropic response.
Results: We identified 80 pregnancies in 78 women from 8 adult CHD centers in North America. There were 4 spontaneous abortions and 1 termination. An adverse cardiac event occurred in 18% (14/80) of the pregnancies; congestive heart failure in 14% (11/80) and sustained symptomatic arrhythmia in 8% (6/80). There was one maternal death. Univariate predictors of an adverse cardiac event included CI (OR, 0.64; p = 0.01), HRR (OR, 0.74; p = 0.046), pHR (OR, 0.69; p = 0.02), and %MPHR (OR, 0.96; p = 0.04). Neonatal events excluding aborted pregnancies occurred in 20% (15/75); primarily preterm delivery (19%, 14/75). Predictors of an adverse neonatal event included CI (OR, 0.71; p = 0.04), HRR (OR, 0.74; p = 0.03), and pHR (OR, 0.72; p = 0.03). Peak VO2 was not a significant predictor of an adverse cardiac or neonatal outcome.
Conclusion: An abnormal heart rate response to exercise identifies women with CHD with a higher risk for maternal cardiac and neonatal adverse events. Stress testing with measures of chronotropic response may be an important tool in the risk stratification of women with CHD who are considering pregnancy.