Sally-Ann B Clur1, Arja S Vink2, Susan P Etheridge2, Pascale G Robles de Medina2, Annika Rydberg2, Michael J Ackerman2, Arthur A Wilde2, Nico A Blom2, D Woodrow Benson2, Ulrike Herberg2, Mary T Donofrio2, Bettina F Cuneo2. 1. Departments of Pediatric Cardiology, Obstetrics and Gynecology, and Cardiology, Academic Medical Center, Amsterdam, The Netherlands (S.-A.B.C., A.S.V., P.G.R.d.M., A.A.W., N.A.B.). Department of Pediatric Cardiology, University of Utah & Primary Children's Hospital, Salt Lake City (S.P.E.). Department of Clinical Sciences, Pediatrics, Umeå University, Sweden (A.R.). Department of Cardiology, Mayo Clinic, Rochester, MN (M.J.A.). Department of Pediatrics, Medical College of Wisconsin, Milwaukee (D.W.B.). Department of Pediatric Cardiology, University of Bonn, Germany (U.H.). Pediatric Cardiology, Children's National Medical Center, Washington, DC (M.T.D.). The Heart Institute, Department of Pediatrics, Children's Hospital Colorado, Denver (B.F.C.). s.a.clur@amc.nl. 2. Departments of Pediatric Cardiology, Obstetrics and Gynecology, and Cardiology, Academic Medical Center, Amsterdam, The Netherlands (S.-A.B.C., A.S.V., P.G.R.d.M., A.A.W., N.A.B.). Department of Pediatric Cardiology, University of Utah & Primary Children's Hospital, Salt Lake City (S.P.E.). Department of Clinical Sciences, Pediatrics, Umeå University, Sweden (A.R.). Department of Cardiology, Mayo Clinic, Rochester, MN (M.J.A.). Department of Pediatrics, Medical College of Wisconsin, Milwaukee (D.W.B.). Department of Pediatric Cardiology, University of Bonn, Germany (U.H.). Pediatric Cardiology, Children's National Medical Center, Washington, DC (M.T.D.). The Heart Institute, Department of Pediatrics, Children's Hospital Colorado, Denver (B.F.C.).
Abstract
BACKGROUND: Long-QT syndrome (LQTS), an inherited cardiac repolarization disorder, is an important cause of fetal and neonatal mortality. Detecting LQTS prenatally is challenging. A fetal heart rate (FHR) less than third percentile for gestational age is specific for LQTS, but the sensitivity is only ≈50%. Left ventricular isovolumetric relaxation time (LVIRT) was evaluated as a potential diagnostic marker for fetal LQTS. METHODS AND RESULTS: LV isovolumetric contraction time, LV ejection time, LVIRT, cycle length, and FHR were measured using pulsed Doppler waveforms in fetuses. Time intervals were expressed as percentages of cycle length, and the LV myocardial performance index was calculated. Single measurements were stratified by gestational age and compared between LQTS fetuses and controls. Receiver-operator curves were performed for FHR and normalized LVIRT (N-LVIRT). A linear mixed-effect model including multiple measurements was used to analyze trends in FHR, N-LVIRT, and LV myocardial performance index. There were 33 LQTS fetuses and 469 controls included. In LQTS fetuses, the LVIRT was prolonged in all gestational age groups (P<0.001), as was the N-LVIRT. The best cutoff to diagnose LQTS was N-LVIRT ≥11.3 at ≤20 weeks (92% sensitivity, 70% specificity). Simultaneous analysis of N-LVIRT and FHR improved the sensitivity and specificity for LQTS (area under the curve=0.96; 95% confidence interval, 0.82-1.00 at 21-30 weeks). N-LVIRT, LV myocardial performance index, and FHR trends differed significantly between LQTS fetuses and controls through gestation. CONCLUSIONS: The LVIRT is prolonged in LQTS fetuses. Findings of a prolonged N-LVIRT and sinus bradycardia can improve the prenatal detection of fetal LQTS.
BACKGROUND:Long-QT syndrome (LQTS), an inherited cardiac repolarization disorder, is an important cause of fetal and neonatal mortality. Detecting LQTS prenatally is challenging. A fetal heart rate (FHR) less than third percentile for gestational age is specific for LQTS, but the sensitivity is only ≈50%. Left ventricular isovolumetric relaxation time (LVIRT) was evaluated as a potential diagnostic marker for fetal LQTS. METHODS AND RESULTS: LV isovolumetric contraction time, LV ejection time, LVIRT, cycle length, and FHR were measured using pulsed Doppler waveforms in fetuses. Time intervals were expressed as percentages of cycle length, and the LV myocardial performance index was calculated. Single measurements were stratified by gestational age and compared between LQTS fetuses and controls. Receiver-operator curves were performed for FHR and normalized LVIRT (N-LVIRT). A linear mixed-effect model including multiple measurements was used to analyze trends in FHR, N-LVIRT, and LV myocardial performance index. There were 33 LQTS fetuses and 469 controls included. In LQTS fetuses, the LVIRT was prolonged in all gestational age groups (P<0.001), as was the N-LVIRT. The best cutoff to diagnose LQTS was N-LVIRT ≥11.3 at ≤20 weeks (92% sensitivity, 70% specificity). Simultaneous analysis of N-LVIRT and FHR improved the sensitivity and specificity for LQTS (area under the curve=0.96; 95% confidence interval, 0.82-1.00 at 21-30 weeks). N-LVIRT, LV myocardial performance index, and FHR trends differed significantly between LQTS fetuses and controls through gestation. CONCLUSIONS: The LVIRT is prolonged in LQTS fetuses. Findings of a prolonged N-LVIRT and sinus bradycardia can improve the prenatal detection of fetal LQTS.
Authors: Arja Suzanne Vink; Irene M Kuipers; Rianne H A C M De Bruin-Bon; Arthur A M Wilde; Nico A Blom; Sally-Ann B Clur Journal: Pediatr Cardiol Date: 2018-05-22 Impact factor: 1.655