Calmodulin mutation in long QT syndrome 15 associated with congenital heart defects further complicated by a functional 2:1 atrioventricular block: Management from foetal life to postpartum

Figures

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  Fig. 1. A. Foetal echocardiogram in four-chamber view showing diastolic ventricular septal thickness (6 mm, z score + 17) and right ventricular hypertrophy. B. Foetal echocardiogram: PW Doppler at the mitral valve reveals foetal sinus bradycardia (regular E and A waves) at a heart rate of 100 bpm. The myocardial performance index was 0.86 and was calculated during the systolic phase from the isovolumetric contraction time (28 ms), ejection time (196 ms), and isovolumetric relaxation time (164 ms). C. Echocardiogram at birth in the four-chamber view shows dilated right atrium and ventricle, moderate tricuspid valve regurgitation (two jets), apical right ventricular hypertrophy (red asterisk), and normal-sized left ventricles. D. Echocardiogram at birth in four-chamber view shows aneurysmatic left appendage with a width of 8 mm and a length of 12 mm. E. Echocardiogram at birth in the four-chamber view shows a small muscular ventricular septal defect (green arrow). F. Echocardiogram at birth in four-chamber view shows a wide 9 mm ostium secundum atrial septal defect (red arrow) shunting left to right and severe apical right ventricular hypertrophy (red asterisk). LA left atrium, LV left…

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  Fig. 2. A. Electrocardiogram at birth shows sinus rhythm at a heart rate of 110 bpm, normal AV and intraventricular conduction, long QTc of 640 ms (Bazet formula), T-wave alteration. B. One hour after birth, sinus bradycardia worsened and functional 2:1 atrioventricular block occurred with a ventricular rate of 50 bpm and a QT interval of 800 ms.

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  Fig. 3. A. After the 2:1 atrioventricular block, two boluses of lidocaine at 0.5 mg/kg were administered, which did not work, then two boluses of esmolol at 1 mg/kg, which were effective and restored sinus rhythm, as shown in the electrocardiogram: heart rate (HR) of 78 bpm and QT interval shortened to 680 ms due to the iv infusion of esmolol, refractory period of the ventricular tissue shortened, allowing the impulse to be conducted normally. B. ECG shows sinus rhythm at HR of 100 bpm and rate-dependent shortening of QT interval, with T waves completely engulfing P waves.