Burt I. Bromberg

Randomized comparison of atenolol and fludrocortisone acetate in the treatment of pediatric neurally mediated syncope

Overall, these results indicate that oral treatment of neurally mediated syncope is safe and efficacious. Further randomized trials in children will be required to determine the significance of a placebo effect, as well as potential differences in results related to the mechanism of syncope.

Aortic aneurysm after patch aortoplasty repair of coarctation: A prospective analysis of prevalence, screening tests and risks

Twenty-nine children were evaluated prospectively for the presence of an aortic aneurysm at the repair site 1 to 19 years after patch aortoplasty repair of coarctation of the aorta. In each child, noninvasive evaluation included a chest X-ray film, computed tomography of the chest and two-dimensional echocardiography. The presence and size of an aortic aneurysm were determined quantitatively by measuring the ratio of the diameter of the thoracic aorta at the repair site to the diameter of the aorta at the diaphragm (aortic ratio). An aortic ratio of greater than or equal to 1.5 was judged abnormal and was shown to be significantly greater than the aortic ratio of a normal control group. An aortogram was obtained in each child if any noninvasive screening test was found to be abnormal. As assessed by the aortogram, the prevalence of aortic aneurysm was 24% in this patient group. The sensitivity of echocardiography and chest computed tomography for detecting an aneurysm was 71% and 66%, and the specificity 76% and 85%, respectively. The chest X-ray film was 100% sensitive and 68% specific in determining the presence of an aneurysm. Although the data are not statistically significant, they suggest that children undergoing patch aortoplasty as the primary procedure (rather than a reoperation after earlier resection), and children in whom a Dacron patch is utilized may be at increased risk for aneurysm formation.(ABSTRACT TRUNCATED AT 250 WORDS)

Transcatheter occlusion of ruptured sinus of Valsalva aneurysm: Innovative use of available technology

A 9‐year‐old boy was found to have ruptured sinus of Valsalva aneurysm (RSVA) and aortic coarctation. Following relief of aortic coarctation by balloon angioplasty, transcatheter coil occlusion of the RSVA was performed successfully under transesophageal echocardiographic and fluoroscopic monitoring; bioptome‐assisted delivery of 0.052″ Gianturco coil was undertaken via a 7 Fr sheath stabilized by an 0.035″ guidewire passing through the RSVA and the sheath. This report details the technique of occlusion. Cathet Cardiovasc Intervent 2003;58:130–134.

Acute termination of supraventricular tachyarrhythmias in children by transesophageal atrial pacing

S upraventricular tachyarrhythmia, in contrast to arrhythmias in adults, is the most common abnormal tachycardia in infants and chi1dren.l When the tachyarrhythmia is reentrant, conversion by physiologic, pharmacologic or electrical interruption of conduction within a limb of the circuit is highly probable. Manipulation of physiologic vagal tone, the obviously preferred mode, is not successful or feasible in a number of patients. Pharmacologic manipulation has been the most commonly used; however, digoxin and propranolol may require several hours for conversion. Intravenous administration of verapamil offers prompt termination2v3; however, in newborns it may be unsuccessful and carries the risk of hypotension, bradycardia, apnea and negative inotropy, especially in patients with coexisting congestive heart failure.4 Electrical conversion by transvenous atria1 pacing or by direct current cardioversion requires invasive entry for 1 technique and frequently general anesthesia for the other. Recent reports from our institution5-7 as well as from otherssvg have demonstrated the usefulness, simplicity and safety of transesophageal atria1 burst pacing for conversion of reentrant tachyarrhythmias in infants and children. The technique, however, has not been included among the recent recommendations of several authorities.10-12 Our purpose, therefore, is to report our experience with transesophageal pacing in infants and children so that the technique may be more widely known. 43 14f4 8-20 43 5f2 3-10

Transcatheter electrical ablation of accessory pathways in children.

BROMBERG, B.I., et al.: Transcatheter Electrical Ablation of Accessory Pathways in Children. Supraventricular tachycardia (SVT), the most common sustained symptomatic arrhythmia of childhood, is often supported hy a manifest or concealed accessory pathway. Permanent interruption of the accessory pathway usually requires surgical division. Recent experience with electrical ablation of posterior septal pathways in adults prompted us to apply the technique to children. Six children, ages 8 to 15 years, underwent a complete electrophysiological study followed by transcatheter electrical ablation. Five of the 6 children, 3 with a right posterior septal and 2 with a left posterior septal pathway, were approached with the ablation catheter at the os of the coronary sinus. In the remaining patient, a left lateral pathway was mapped with an electrode catheter in the coronary sinus and then approached with the ablation catheter through the patent foramen into the left atrium. Two patients are asymptomatic 18–24 months postabla‐tion; one patient had return of anomalous conduction between 7 and 21 days after ablation. Two patients had transient interruption of anomalous conduction, whereas one patient experienced no effect. We conclude that in carefully selected patients, transcatheter electrical ablation ofers an alternative to surgery for permanent interruption of an accessory pathway. (PACE, Vol. 12, November 3989)

Implantable loop recorder monitoring for refining management of children with inherited arrhythmia syndromes

Background Implantable loop recorders (ILRs) are conventionally utilized to elucidate the mechanism of atypical syncope. The objective of this study was to assess the impact of these devices on management of pediatric patients with known or suspected inherited arrhythmia syndromes. Methods and Results A retrospective chart review was undertaken of all pediatric patients with known or suspected inherited arrhythmia syndromes in whom an ILR was implanted from 2008 to 2015. Captured data included categorization of diagnosis, treatment, transmitted tracings, and the impact of ILR tracings on management. Transmissions were categorized as symptomatic, autotriggered, or routine. Actionable transmissions were abnormal tracings that directly resulted in a change of medical or device therapy. A total of 20 patients met the stated inclusion criteria (long QT syndrome, n=8, catecholaminergic polymorphic ventricular tachycardia,n=9, Brugada syndrome, n=1, arrhythmogenic right ventricular cardiomyopathy, n=2), with 60% of patients being genotype positive. Primary indication for implantation of ILR included ongoing monitoring +/− symptoms (n=15, 75%), suspicion of noncompliance (n=1, 5%), and liberalization of recommended activity restrictions (n=4, 25%). A total of 172 transmissions were received in patients with inherited arrhythmia syndromes, with 7% yielding actionable data. The majority (52%) of symptom events were documented in the long QT syndrome population, with only 1 tracing (5%) yielding actionable data. Automatic transmissions were mostly seen in the catecholaminergic polymorphic ventricular tachycardia cohort (81%), with 21% yielding actionable data. There was no actionable data in routine transmissions. Conclusions ILRs in patients with suspected or confirmed inherited arrhythmia syndromes may be useful for guiding management. Findings escalated therapies in 30% of subjects. As importantly, in this high‐risk population, the majority of symptom events represented normal or benign rhythms, reassuring patients and physicians that no further intervention was required.

Surgical management of children and young adults with the Wolff-Parkinson-White syndrome

SummaryThe Wolff-Parkinson-White syndrome, as originally described, includes palpitations, tachycardia, and an abnormal electrocardiogram (short PR interval and wide QRS complex). The clinical manifestations are dependent upon a reentrant tachycardia supported by an accessory connection bridging the atrioventricular junction and frequently appear during the first two decades of life. Palpitations are the usual symptoms; less frequently, severe symptoms, such as syncope and sudden death, may result from very rapid atrioventricular conduction across the accessory connection during atrial fibrillation. We report the surgical management of 30 young patients with this syndrome, including 6 with life-threatening tachycardia. Surgical interruption of the accessory connection(s) was curative in 90% (27/30) of the patients; life-threatening symptoms were eliminated in the other three. Based on the limited knowledge of the natural history of the Wolff-Parkinson-White syndrome, the individual patient symptoms, and the electrophysiologic properties of each patients accessory pathway(s), an algorithm is presented outlining the treatment options. This experience strongly suggests that surgical treatment of the Wolff-Parkinson-White syndrome is safe, effective, and possibly the preferred treatment for this disorder in selected young symptomatic patients.

MECHANISM OF 2:1 ATRIOVENTRICULAR BLOCK IN INFANTS WITH CONGENITAL LONG QT SYNDROME

The mechanism of 2:1 atrioventricular block in infants with the congenital long QT syndrome has been postulated to result from a long ventricular effective refractory period interrupting conduction of successive sinus impulses. Three infants age 1-2 days exhibited bradycardia demonstrated to be 2:1 atrioventricular block by the surface electrocardiogram. Mean sinus cycle length (SCL) was 0.56 sec where as mean QT interval was 0.65 sec (QTc 0.63); this .07 sec difference between the SCL and mean QTc was sufficient to block successful capture of the ventricles by successive sinus impulses. Programmed ventricular extrastimulation in one patient demonstrated a markedly prolonged ventricular effective period (480 sec) at ventricular basic cycle length (BCL) 1000 msec shortening to 280 msec with a ventricular BCL of 400 msec. Permanent ventricular pacing shortened the ventricular effective refractory period in each infant and effectively suppressed polymorphic ventricular arrhythmias in the affected two. We conclude that the mechanism of 2:1 atrioventricular block in infants with the congenital long QT syndrome is a function of the age related SCL relative to the QT interval as well as the markedly prolonged but rate dependent ventricular effective refractory period. Ventricular pacemaker implant is effective in increasing ventricular rate, shortening ventricular effective refractory period, and suppressing complex ventricular arrhythmias.

ATRIAL FLUTTER IN INFANCY: NO NEED FOR CHRONIC PROPHYLAXIS

Many authorities recommend digoxin for one year for atrial flutter (AT.FL) in infants with normal structural hearts. To re-examine this recommendation the electrocardiogram, response to programmed extrastimulation, (PES) (n=3), and clinical course in six infants with AT.FL. alone were reviewed. AT.FL exhibited a regular sawtooth pattern with a cycle length of 148 msec (range: 130-160 msec). Age at diagnosis was 34 days (range: birth (n=4) to 180 days). There were two males and four females; all were initiallly treated with digoxin but only two converted to sinus rhythm. AT.FL resolved spontaneously in two, two were converted with atrial overdrive pacing. Post-conversion electrocardiogram demonstrated normal P wave axis, PR interval .14 sec (range: .12-.16 sec), P wave duration .08 sec, and P wave amplitude .23 mV (3 > .25 mV) at heart rate 142 bpm. Post-conversion atrial PES with burst pacing in three failed to initiate AT.FL and demonstrated normal atrial effective refractory periods (158 msec; range: 150-173 msec) and normal atrioventricular conduction system effective refractory periods (199 msec; range: 180-216 msec). Only two patients were maintained on digoxin, six months and one year after conversion. Follow-up was 5.5 years (1.5 - 18 years) without recurrence. These data suggest that AT.FL in infants without structural heart disease, following conversion, is self-limited and not easily inducible by extrastimulation. We conclude that infants with atrial flutter alone, following cardioversion, do not require chronic prophylaxis.