Few drugs have received as much media attention in recent years as hydroxychloroquine. Though used clinically for years and for several different conditions, there has been heated debate amongst physicians and other healthcare providers about the safety and efficacy of hydroxychloroquine in COVID-19. One major concern amongst skeptics has been the potential impact of hydroxychloroquine on those with heart conditions.

Results from a new study, known as the PATCH trial, have shown that hydroxychloroquine has reduced the risk for recurrent fetal blocks by more than 50% when used in women who had suffered congenital heart blocks. The data have been published in the Journal of the American College of Cardiology.

For this analysis, researchers initially studied 19 women who were given 400 milligrams (mg) of hydroxychloroquine daily, beginning by the 10th week of gestation and continuing through the end of their pregnancies. The scientists planned to terminate the study if 6 or more fetuses developed a congenital heart block and to enroll 35 more pregnant women for another phase of research if fewer than 3 participants developed a congenital heart block.

Given that only 2 of the fetuses from the first phase of the trial developed a congenital heart block, the researchers continued their investigation in more pregnant women and observed only 2 more congenital heart blocks. According to the authors, hydroxychloroquine is already indicated as a prophylactic measure in patients who are at high risk for recurrent fetal congenital heart block. More research is needed, though, to determine if hydroxychloroquine is justified in those whose risk for recurrent fetal congenital heart block is low.

Reference

Strasburger, J.F. & Wacker-Gussman, A. (2020). Congenital heart block in subsequent pregnancies of SSA/Ro-positive mothers: Cutting recurrence in half. Journal of the American College of Cardiology, 76(3), DOI: 10.1016/j.jacc.2020.05.052