Rochester, NY—Concerns have been raised over the use of oral contraceptives (OC) in women with congenital long-QT syndrome (LQTS).

Part of the issue, according to the new study, is that the safety of OC use based on the sex hormone content is not well understood in women with that heart condition.

In light of that, University of Rochester Medical Center–led researchers sought to evaluate the association of OC with the risk of cardiac events (CE) in that cohort. Results were published in the Heart Rhythm Journal.

The study began in 2010, when information on menarche onset, OC use, pregnancy, and menopause were obtained from women enrolled in the Rochester LQTS Registry. Investigators categorized the type of OC as:
• Progestin-only
• Estrogen-only or
• Combined (estrogen/progestin)

The study team looked at time-dependent OC use in relation to total number of syncope, aborted cardiac arrest, and LQTS-related sudden cardiac death events from menarche onset through age 40 years. The authors adjusted results based on genotype, QTc duration, and time-dependent beta-blocker therapy.

Participants were 1,659 female LQTS patients followed through March 2021; 22% of them were treated with an OC. Researchers report that, during a cumulative follow-up of 35,797 years, 2,027 cardiac events occurred.

Multivariate analysis indicated that progestin-only OC was associated with a significant 2.8-fold (P = .01) increased risk of CE among women who did not receive beta-blocker therapy and that beta-blockers were highly protective during progestin-only OC treatment (HR = 0.22; P = .01); P-value for beta-blocker-by-OC interaction = .006). Still, the risk associated with OC use without concomitant beta-blocker treatment was substantial in women with LQT2, the authors emphasized.

“Our findings suggest that progestin-only OC should not be administered in LQTS women without concomitant beta-blocker therapy. OC should be used with caution in LQT2 women,” researchers conclude.

A 2014 study from researchers from the same institution published in the same journal found that OC therapy use did not affect LQTS-related CEs in the study population.

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