Long QT Syndrome and Pregnancy
Objectives: This study was designed to investigate the clinical course of women with long QT syndrome (LQTS) throughout their potential childbearing years
Background: Only limited data exist regarding the risks associated with pregnancy in women with LQTS
Methods: The risk of experiencing an adverse cardiac event, including syncope, aborted cardiac arrest, and sudden death, during and after pregnancy was analyzed for women who had their first birth from 1980 to 2003 (n = 391). Time-dependent Kaplan-Meier and Cox proportional hazard methods were used to evaluate the risk of cardiac events during different peripartum periods
Results: Compared with a time period before a woman's first conception, the pregnancy time was associated with a reduced risk of cardiac events (hazard ratio [HR] 0.28, 95% confidence interval [CI] 0.10 to 0.76, p = 0.01), whereas the 9-month postpartum time had an increased risk (HR 2.7, 95% CI 1.8 to 4.3, p < 0.001). After the 9-month postpartum period, the risk was similar to the period before the first conception (HR 0.91, 95% CI 0.55 to 1.5, p = 0.70). Genotype analysis (n = 153) showed that women with the LQT2 genotype were more likely to experience a cardiac event than women with the LQT1 or LQT3 genotype. The cardiac event risk during the high-risk postpartum period was reduced among women using beta-blocker therapy (HR 0.34, 95% CI 0.14 to 0.84, p = 0.02)
Conclusions: Women with LQTS have a reduced risk for cardiac events during pregnancy, but an increased risk during the 9-month postpartum period, especially among women with the LQT2 genotype. Beta-blockers were associated with a reduction in cardiac events during the high-risk postpartum time period. (J Am Coll Cardiol 2007;49: 1092–8) © 2007 by the American College of Cardiology Foundation.
The hereditary long QT syndrome (LQTS) is characterized by prolonged ventricular repolarization and a variable clinical course with arrhythmia-related recurrent syncope, aborted cardiac arrest (ACA), and sudden death. Mutations in several ion-channel genes are known to cause LQTS, the most common of which are found in potassium-channel KCNQ1 (LQT1) and hERG (LQT2) genes, and in the sodium-channel SCN5A (LQT3) gene. Genotype-phenotype studies have highlighted the clinical course in the 3 major LQTS subgroups. However, there have been only 3 studies evaluating the risks of pregnancy in patients with LQTS, with the report by Khositseth et al. identifying the LQT2 genotype as a risk factor for postpartum cardiac events in a small number of women. The present study was designed to investigate the clinical course of LQTS in women throughout the childbearing years with a comparison with those who did and did not experience pregnancy, with additional focus on the risk associated with different LQTS genotypes and the prophylactic effectiveness of beta-blocker therapy during and after pregnancy.
Abstract and Introduction
Abstract
Objectives: This study was designed to investigate the clinical course of women with long QT syndrome (LQTS) throughout their potential childbearing years
Background: Only limited data exist regarding the risks associated with pregnancy in women with LQTS
Methods: The risk of experiencing an adverse cardiac event, including syncope, aborted cardiac arrest, and sudden death, during and after pregnancy was analyzed for women who had their first birth from 1980 to 2003 (n = 391). Time-dependent Kaplan-Meier and Cox proportional hazard methods were used to evaluate the risk of cardiac events during different peripartum periods
Results: Compared with a time period before a woman's first conception, the pregnancy time was associated with a reduced risk of cardiac events (hazard ratio [HR] 0.28, 95% confidence interval [CI] 0.10 to 0.76, p = 0.01), whereas the 9-month postpartum time had an increased risk (HR 2.7, 95% CI 1.8 to 4.3, p < 0.001). After the 9-month postpartum period, the risk was similar to the period before the first conception (HR 0.91, 95% CI 0.55 to 1.5, p = 0.70). Genotype analysis (n = 153) showed that women with the LQT2 genotype were more likely to experience a cardiac event than women with the LQT1 or LQT3 genotype. The cardiac event risk during the high-risk postpartum period was reduced among women using beta-blocker therapy (HR 0.34, 95% CI 0.14 to 0.84, p = 0.02)
Conclusions: Women with LQTS have a reduced risk for cardiac events during pregnancy, but an increased risk during the 9-month postpartum period, especially among women with the LQT2 genotype. Beta-blockers were associated with a reduction in cardiac events during the high-risk postpartum time period. (J Am Coll Cardiol 2007;49: 1092–8) © 2007 by the American College of Cardiology Foundation.
Introduction
The hereditary long QT syndrome (LQTS) is characterized by prolonged ventricular repolarization and a variable clinical course with arrhythmia-related recurrent syncope, aborted cardiac arrest (ACA), and sudden death. Mutations in several ion-channel genes are known to cause LQTS, the most common of which are found in potassium-channel KCNQ1 (LQT1) and hERG (LQT2) genes, and in the sodium-channel SCN5A (LQT3) gene. Genotype-phenotype studies have highlighted the clinical course in the 3 major LQTS subgroups. However, there have been only 3 studies evaluating the risks of pregnancy in patients with LQTS, with the report by Khositseth et al. identifying the LQT2 genotype as a risk factor for postpartum cardiac events in a small number of women. The present study was designed to investigate the clinical course of LQTS in women throughout the childbearing years with a comparison with those who did and did not experience pregnancy, with additional focus on the risk associated with different LQTS genotypes and the prophylactic effectiveness of beta-blocker therapy during and after pregnancy.