Comparison of transesophageal and intracardiac electrophysiologic studies in characterization of supraventricular tachycardia in pediatric patients

Objectives.This study sought to determine the accuracy of transesophageal electrophysiologic studies in diagnosing and characterizing various mechanisms of supraventricular tachycardia in pediatric patients.Background.Transesophageal electrophysiologic studies are a relatively noninvasive means of characterizing supraventricular tachycardia. Although widely used, to our knowledge no data exist that directly compare information obtained from transesophageal electrophysiologic studies with that from intracardiac electrophysiologic studies.Methods.We reviewed the records of 57 pediatric patients undergoing both transesophageal and intracardiac electrophysiologic studies at our institution. The results of these studies were compared with respect to mechanism of tachycardia, localization of accessory atrioventricular (AV) connections (if present) and characterization of anterograde accessory connection conduction properties.Results.Tachycardia mechanisms were concordant in 56 of 57 patients: orthodromic reciprocating tachycardia in 43, antidromic reciprocating tachycardia in 1, both orthodromic and antidromic tachycardia in 2, AV node reentrant tachycardia in 5, atrial reentrant tachycardia in 4 and ectopic atrial tachycardia in 2. Of 29 patients with orthodromic reciprocating tachycardia using a concealed accessory connection, transesophageal study predicted the accessory connection site through changes induced by transient bundle branch block in 12. By the Bland-Altman method in 14 patients with pre-excitation, the anterograde accessory connection effective refractory period determined by transesophageal study compared favorably with that determined by intracardiac study (mean difference 5.0 ms, limits of agreement −55 and 65 ms).Conclusions.Transesophageal electrophysiologic studies are a highly accurate means of diagnosing and characterizing various mechanisms of supraventricular tachycardia in pediatric patients

Contribution of Fetal Magnetocardiography to Diagnosis, Risk Assessment, and Treatment of Fetal Arrhythmia

Background Fetal echocardiography has been the mainstay of fetal arrhythmia diagnosis; however, fetal magnetocardiography (fMCG) has recently become clinically available. We sought to determine to what extent fMCG contributed to the precision and accuracy of fetal arrhythmia diagnosis and risk assessment, and in turn, how this altered pregnancy management. Methods and Results We reviewed fMCG tracings and medical records of 215 pregnancies referred to the Biomagnetism Laboratory, UW‐Madison, over the last 10 years, because of fetal arrhythmia or risk of arrhythmia. We compared referral diagnosis and treatment with fMCG diagnosis using a rating scale and restricted our review to the 144 subjects from the tachycardia, bradycardia/AV block, and familial long QT syndrome categories. Additional fMCG findings beyond those of the referring echocardiogram, or an alternative diagnosis were seen in 117/144 (81%), and 81 (56%) were critical changes. Eight (5.5%) had resolution of arrhythmia before fMCG. At least moderate changes in management were seen in 109/144 (76%) fetuses, of which 35/144 (24%) were major. The most diverse fMCG presentation was long QT syndrome, present in all 3 referral categories. Four of 5 stillbirths were seen with long QT syndrome. Nine fetuses showed torsades de pointes ventricular tachycardia, of which only 2 were recognized before fMCG. Conclusions FMCG has a significant impact on prenatal diagnosis and management of arrhythmias or familial arrhythmia risk, which cannot be fully met by existing technology. The combination of fMCG and fetal echocardiography in fetal care centers will be needed in the future to optimize care

Magnetocardiography-Guided Management of an Unusual Case of Isoimmune Complete Atrioventricular Block Complicated by Ventricular Tachycardia

A fetus who was diagnosed at 25 weeks of gestation with isoimmune AV block presented at 34 weeks with a precipitous fall in ventricular rate and periods of tachycardia. Magnetocardiography revealed the tachycardia to be ventricular. After delivery, nonsustained ventricular tachycardia continued. The baby then successfully paced, and at higher ventricular rates the tachycardia resolved. Five years later the child has normal ventricular function and is doing well