(P121) IMPACT OF SUPRAVENTRICULAR TACHYCARDIA ON PREGNANCY OUTCOMES

Background: Paroxysmal supraventricular tachycardia (PSVT) is the most common arrhythmia in pregnant women, in part due to the maternal physiological changes that occur during pregnancy. However, studies investigating the risk of new-onset and pre-existing PSVT in pregnancy, and the associated adverse maternal and fetal/neonatal outcomes are lacking. This study aimed to determine: 1) the proportion of women presenting with new-onset PSVT in pregnancy; 2) the impact of prior PSVT history on episode severity and management during pregnancy; and 3) the rate of adverse maternal and fetal/neonatal events among women with PSVT in pregnancy.

METHODS AND RESULTS: Prospective case-control study: 77 consecutive pregnancies in 75 women referred to the St. Paul’s Hospital Cardiac Obstetric Clinic between January 2010 and January 2022 secondary to findings consistent with or a history of atrioventricular nodal re-entrant tachycardia (AVNRT) and atrioventricular re-entrant tachycardia (AVRT) PSVT without documented structural heart disease. Maternal cardiac, obstetric, and fetal/neonatal adverse events were compared to a control group consisting of 57 women with low risk, normal pregnancies and no cardiac diagnosis. Among the PSVT cohort (n=77), 63 (82%) cases had a prior diagnosis of PSVT with the remaining 18% presenting with new-onset PSVT in pregnancy. Sixty-eight percent of those with a prior PSVT diagnosis had recurrence in pregnancy. Those with a more recent history within 5 years of pregnancy were more likely to experience PSVT during pregnancy compared to those with a more a more remote history (81% vs. 31%, p< 0.001). Similarly, they also experienced a higher frequency of PSVT during pregnancy and increased rates of chemical cardioversion (38% vs. 12%, p=0.05). There was a higher rate of adverse obstetrical events in the PSVT group vs. controls (8% vs. 0%, p=0.03), however this is likely due to higher prevalence of obstetric risk factors among the PSVT cohort. Rates of adverse fetal and neonatal events were similar between the PSVT group vs. controls (17% vs. 19%, p=0.72).

Conclusion: PSVT events were safely managed in pregnancy with no major adverse cardiac events and similar fetal/neonatal outcomes as healthy controls. The notable occurrence of new-onset PSVT in our cohort suggests a need for heightened awareness and proactive management strategies. Recurrence and burden of PSVT during pregnancy is frequent and leads to management complexities among those with a history of PSVT, reinforcing the need for pre-pregnancy counselling and the role of catheter ablation for definitive management of PSVT prior to pregnancy.