Left Ventricular Isovolumetric Relaxation Time Is Prolonged in Fetal Long-QT Syndrome

Clur, S. A.; Vink, Arja S.; Etheridge, Susan P.; Medina, P. G. Robles de; Rydberg, Annika; Ackerman, Michael J.; Wilde, Arthur A.M.; Blom, Nico A.; Benson, D. Woodrow; Herberg, Ulrike; Donofrio, Mary T.; Cuneo, Bettina F.

doi:10.1161/circep.117.005797

Cited by 28 publications

(25 citation statements)

References 45 publications

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“…As an observational exercise, we retrospectively measured the normalized L‐IVRT (L‐IVRT/atrial cycle length × 100) via Doppler at the mitral inflow and aortic outflow during both 2:1 AV block and sinus bradycardia. As reported in Clur et al, the optimal normalized L‐IVRT cutoff value for diagnosis of LQTS at 21‐30 weeks gestational age is 14.2% (CI 11.9‐14.3%) 10 . At our patient's 22 week gestation scan in 2:1 AV block, the normalized L‐IVRT was 20% (100 msec/500 msec × 100)—well above the reported cutoff value 10 .…”

Section: Discussionsupporting

confidence: 70%

“…At our patient's 22 week gestation scan in 2:1 AV block, the normalized L‐IVRT was 20% (100 msec/500 msec × 100)—well above the reported cutoff value 10 . At the 23 week gestation scan in sinus bradycardia, the normalized L‐IVRT was 11% (50 msec/450 msec × 100)—within the reported normal range 10 . This suggests fetal L‐IVRT may correlate to fetal QT and could be monitored as maternal treatment is adjusted.…”

Section: Discussionmentioning

confidence: 43%

“…As reported in Clur et al, the optimal normalized L‐IVRT cutoff value for diagnosis of LQTS at 21‐30 weeks gestational age is 14.2% (CI 11.9‐14.3%) 10 . At our patient's 22 week gestation scan in 2:1 AV block, the normalized L‐IVRT was 20% (100 msec/500 msec × 100)—well above the reported cutoff value 10 . At the 23 week gestation scan in sinus bradycardia, the normalized L‐IVRT was 11% (50 msec/450 msec × 100)—within the reported normal range 10 .…”

Section: Discussionmentioning

confidence: 62%

“…Fetal echocardiographic parameters such as left ventricular isovolumetric relaxation time (L‐IVRT) may also be useful in the prenatal diagnosis of LQTS as a mechanical representation of repolarization. A prolonged L‐IVRT has been associated with LQTS in some patients 10 . As an observational exercise, we retrospectively measured the normalized L‐IVRT (L‐IVRT/atrial cycle length × 100) via Doppler at the mitral inflow and aortic outflow during both 2:1 AV block and sinus bradycardia.…”

Section: Discussionmentioning

confidence: 99%

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Fetal diagnosis of KCNQ1‐variant long QT syndrome using fetal echocardiography and magnetocardiography

Desai

Wakai

Tsao

et al. 2020

Pacing Clinical Electrophis

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A pregnant woman with KCNQ1 variant long QT syndrome (LQTS) underwent fetal magnetocardiography (fMCG) after atrioventricular (AV) block was noted during fetal echocardiogramatypical for LQTS type 1. Concern for fetal LQTS on fMCG prompted monitoring of maternal labs, change of maternal beta blocker therapy, and frequent fetal echocardiograms. Collaboration between obstetricians, neonatologists, and pediatric cardiologists ensured safe delivery. Beta blocker therapy was initiated after birth, and postnatal evaluation confirmed genotype and phenotype positive LQTS in the infant. Our experience suggests diagnosis and evaluation of fetal LQTS can alter antenatal management to reduce risk of poor fetal and postnatal outcomes. K E Y W O R D S fetal bradycardia, fetal echocardiography, fetal magnetocardiography, long QT syndrome 1

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Section: Discussionsupporting

confidence: 70%

Section: Discussionmentioning

confidence: 43%

Section: Discussionmentioning

confidence: 62%

Section: Discussionmentioning

confidence: 99%

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Fetal diagnosis of KCNQ1‐variant long QT syndrome using fetal echocardiography and magnetocardiography

Desai

Wakai

Tsao

et al. 2020

Pacing Clinical Electrophis

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“…The measurements performed in these cases, were never validated in LQTS or correlated to QT-intervals. In a recently published multinational study, it was shown that the left ventricular isovolumetric relaxation time (LVIRT) is prolonged in LQTS foetuses, even when corrected for cycle length [ 40 ]. In our study we used a validated measurement for myocardial contraction duration, as a surrogate for QT-interval, and an approximation to the combination of the left ventricular isovolumetric relaxation time, the left ventricular contraction time and the LVIRT.…”

Section: Discussionmentioning

confidence: 99%

A Potential Diagnostic Approach for Foetal Long-QT Syndrome, Developed and Validated in Children

et al. 2018

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In patients with Long-QT Syndrome (LQTS), mechanical abnormalities have been described. Recognition of these abnormalities could potentially be used in the diagnosis of LQTS, especially in the foetus where an ECG is not available and DNA-analysis is invasive. We aimed to develop and validate a marker for these mechanical abnormalities in children and to test its feasibility in foetuses as a proof of principle. We measured the myocardial contraction duration using colour Tissue Doppler Imaging (cTDI) in 41 LQTS children and age- and gender-matched controls. Children were chosen to develop and validate the measurement of the myocardial contraction duration, due to the availability of a simultaneously recorded ECG. Feasibility of this measurement in foetuses was tested in an additional pilot study among seven LQTS foetuses and eight controls. LQTS children had a longer myocardial contraction duration compared to controls, while there was no statistical difference in heart rate. Measuring the myocardial contraction duration in children had a high inter- and intra-observer validity and reliably correlated with the QT-interval. There was an area under the curve (AUC) of 0.71, and the optimal cut-off value showed an especially high specificity in diagnosing LQTS. Measuring the myocardial contraction duration was possible in all foetuses and had a high inter- and intra-observer validity (ICC = 0.71 and ICC = 0.88, respectively). LQTS foetuses seemed to have a longer myocardial contraction duration compared to controls. Therefore, a prolonged contraction duration may be a potential marker for the prenatal diagnosis of LQTS in the future. Further studies are required to support the measurement of the myocardial contraction duration as a diagnostic approach for foetal LQTS.Electronic supplementary materialThe online version of this article (10.1007/s00246-018-1911-y) contains supplementary material, which is available to authorized users.

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Diagnostik und Therapie fetaler Arrhythmien

Gembruch¹,

Geipel²

2022

Die Geburtshilfe

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Left Ventricular Isovolumetric Relaxation Time Is Prolonged in Fetal Long-QT Syndrome

Abstract: The LVIRT is prolonged in LQTS fetuses. Findings of a prolonged N-LVIRT and sinus bradycardia can improve the prenatal detection of fetal LQTS.

Cited by 28 publications

References 45 publications

Fetal diagnosis of KCNQ1‐variant long QT syndrome using fetal echocardiography and magnetocardiography

Fetal diagnosis of KCNQ1‐variant long QT syndrome using fetal echocardiography and magnetocardiography

A Potential Diagnostic Approach for Foetal Long-QT Syndrome, Developed and Validated in Children

Diagnostik und Therapie fetaler Arrhythmien

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