The conduction system and the myocardium of five patients with Romano-Ward syndrome and one patient with the Jervell and Lange-Nielsen syndrome were studied to determine the cause of the prolonged QT interval. The patients were 9 and 15 months and 2, 5 and 19 years of age, respectively. All had a prolonged QTc interval. A sixth patient was a 16 year old girl who died suddenly; several members of her family had a prolonged QT interval. The only common finding in the conduction system in all cases was marked fatty infiltration in the approaches to the atrioventricular (AV) node. In four, the AV bundle was lobulated, with loop formation in one. In four, the AV bundle and bundle branches showed fibrosis. The ventricular myocardium in all cases was chronically inflamed. In two cases, the AV node was partially embedded in the central fibrous body. It is not clear how these changes are related to the disturbance in the repolarization process and the prolongation of the QT interval. However, it is interesting that all patients had an abnormality in the conduction system.

To evaluate the detectability of cardiac septal defects by electrocardiographically synchronized (ECG-gated) magnetic resonance imaging (MRI), 48 subjects were imaged, including 18 normal and 30 abnormal subjects in whom 22 ventricular septal defects (VSDs) and nine atrial septal defects (ASDs) had been diagnosed angiographically. Two ELECTROCARDIOGRAPHICALLY synchronized (ECG-gated) magnetic resonance imaging (MRI) is a noninvasive technique that has been successfully applied to the heart by various investigators.1`7 MRI of congenital cardiac malformations has been reported in preliminary studies demonstrating the practicality of the technique.8-10 However, images in these studies were read under unblinded conditions, and only one included normal controls. We have employed controlled, blinded readings to explore the detectability of atrial and ventricular septal defects (ASDs and VSDs) by ECG-gated MRI. MethodsInstrumentation. Patients were imaged with a commercial MRI system (Technicare, Inc., Solon, OH) that incorporates a superconducting magnet operating at 0.5 T. Small subjects were examined with a radiofrequency coil that has an aperture 28 cm in diameter and was designed primarily to image the head (head coil). Larger patients were examined with an RF coil that has an aperture of 55 cm and was designed to image the adult human torso (body coil).Images were acquired and reconstructed with software supplied by the manufacturer, by means of a two-dimensional Fourier transform method. A spin-echo pulse sequence was used in all cases with an echo time of 30 msec. All scans were ECG gated with Hewlett-Packard telemetry equipment and a Technicare cardiac gating interface.8 The repetition time was equal to the RR interval. Four sets of signals were averaged for each image. The plane selecting excitation pulse (and thus the images) had a nominal thickness of 0.75 cm (full-width-at-halfmaximum). Nine to 12 parallel, cross-sectional images were acquired simultaneously, separated by 0.5 cm gaps. A second, similar set of nine to 12 images was then acquired, offset 0.62 cm from the previous collection, to examine the regions between the images of the first collection. When possible, images were obtained in transaxial, coronal, and sagittal orientations. Images were rarely collected in fewer than two orientations. A modified left anterior oblique image set, in which the ventricular and atrial septa were perpendicular to the imaging plane, was obtained in the majority of cases.Patient selection. Forty-eight subjects were studied over a 6 month period, including 18 normal volunteers and 30 patients with congenital heart disease. Of these, nine patients had angiographically proven ASDs (mean age + SD 12.5 + 11 years, range 0.7 to 38), and 22 patients had angiographically proven VSDs (age 7.3 + 5.4 years, range 0.3 to 21) (

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