Gerald A. Serwer

Prospective assessment after pediatric cardiac ablation: demographics, medical profiles, and initial outcomes.

Introduction: A multicenter prospective study was designed and implemented to assess the short‐ and longer‐term results and risks associated with radiofrequency (RF) ablation in children.

Clinical Benefits of Remote Versus Transtelephonic Monitoring of Implanted Pacemakers

OBJECTIVES The purpose of this study was to evaluate remote pacemaker interrogation for the earlier diagnosis of clinically actionable events compared with traditional transtelephonic monitoring and routine in-person evaluation. BACKGROUND Pacemaker patient follow-up procedures have evolved from evaluating devices with little programmability and diagnostic information solely in person to transtelephonic rhythm strip recordings that allow monitoring of basic device function. More recently developed remote monitoring technology leverages expanded device capabilities, augmenting traditional transtelephonic monitoring to evaluate patients via full device interrogation. METHODS The time to first diagnosis of a clinically actionable event was compared in patients who were followed by remote interrogation (Remote) and those who were followed per standard of care with office visits augmented by transtelephonic monitoring (Control). Patients were randomized 2:1. Remote arm patients transmitted pacemaker information at 3-month intervals. Control arm patients with a single-chamber pacemaker transmitted at 2-month intervals. Control arm patients with dual-chamber devices transmitted at 2-month intervals with an office visit at 6 months. All patients were seen in office at 12 months. RESULTS The mean time to first diagnosis of clinically actionable events was earlier in the Remote arm (5.7 months) than in the Control arm (7.7 months). Three (2%) of the 190 events in the Control arm and 446 (66%) of 676 events in the Remote arm were identified remotely. CONCLUSIONS The strategic use of remote pacemaker interrogation follow-up detects actionable events that are potentially important more quickly and more frequently than transtelephonic rhythm strip recordings. The use of transtelephonic rhythm strips for pacemaker follow-up is of little value except for battery status determinations. (PREFER [Pacemaker Remote Follow-up Evaluation and Review]; NCT00294645).

Extracellular Potentials Related to Intracellular Action Potentials in the Dog Purkinje System

Simultaneous extracellular and intracellular recordings of normal action potentials, action potentials initiated at a time when the membrane was partially depolarized (by premature beats or elevated extracellular potassium), and action potentials at reduced temperature were made for Purkinje strands from the left ventricle of the dog with a 50μ tungsten extracellur electrode and a special guarded intracellular microelectrode. The peak-to-peak amplitude of the extracellular wave form was proportional to the maximum rate of rise of the intracellular action potential, and the duration of the extracellular wave form was proportional of the duration of the upstroke of the intracellular potential. Wave forms of extracellular potentials were computed from the recorded intracellular potentials with an equation which included the effects of membrane currents away from the point of observation. The computed wave forms accurately reproduced the recorded extracellular wave forms in all cases, and the wave forms were not directly porportional to the second spatial derivative or the second temporal derivative of the intracellular potential. Extracellular potentials are shown to be directly related to the spatial distribution of the intracellular potential and as such are a sensitive index of propagation and a source of information of the kind previously thought to be obtainable only with an intracllular electrode.

Usefulness of the bidirectional Glenn procedure as staged reconstruction for the functional single ventricle

The bidirectional Glenn operation may be particularly useful as an intermediate procedure before Fontan correction in high-risk patients. From October 1989 through February 1992, 50 patients 1 to 60 months old (median 12) have undergone a bidirectional Glenn operation. Diagnoses included hypoplastic left heart syndrome in 21 patients, pulmonary atresia with intact ventricular septum in 10, tricuspid valve atresia in 9, other complex univentricular heart defects in 9, and Ebsteins anomaly in 1. Mean pulmonary vascular resistance was 2.2 +/- 0.2 Wood U (range 0.5 to 7.3) and mean pulmonary artery area Nakata index was 318 +/- mm2/m2 (range 80 to 821). Additional procedures were performed in 17 patients, including pulmonary artery reconstruction in 15 (29%) and bilateral caval anastomoses in 5 (10%). There were 4 hospital deaths (8%). Two deaths resulted from myocardial infarction in patients with pulmonary atresia with intact ventricular septum and sinusoids and 1 from severe pulmonary vascular disease in a patient with hypoplastic left heart syndrome. There was 1 late death from pneumonia. Actuarial survival is 92 +/- 4% at 1 month and beyond, with a mean follow-up of 13.4 +/- 1 months. Risk factor analysis showed that pulmonary vascular resistance > 3 Wood U and pulmonary artery distortion were associated with increased mortality. Twelve patients have undergone a Fontan procedure at a mean duration after bidirectional Glenn of 18 months with 1 death (8%). The bidirectional Glenn procedure provides excellent palliation in high-risk patients and appears useful as a staging procedure before Fontan correction.

Use of radiofrequency current to ablate accessory connections in children.

BackgroundSeveral investigators have recently ablated electrophysiologically mapped accessory connections in the adult human myocardium by using radiofrequency current. To examine the effectiveness and safety of radiofrequency current for ablation of accessory connections in children, 20 consecutive patients (age, 3–18 years) with preexcitation and/or supraventricular tachycardia were evaluated by electrophysiological study. Methods and ResultsNineteen of the 20 patients were completely studied and demonstrated accessory connections. After identification of the earliest retrograde atrial activation site, a steerable 7F catheter (with a 4-mm-long electrode at the distal tip) was placed within the ventricular cavity ipsilateral to the accessory connection and positioned at the atrioventricular valve annulus directly opposite the earliest point of retrograde atrial activation. Radiofrequency current was delivered at 50–65 volts for 10–60 seconds at a frequency of 500 kHz. Radiofrequency pulses were delivered for two to 26 trials. Upon completion of radiofrequency trials, repeat electrophysiological testing was performed. Thirteen of 19 subjects (68%) experienced definite successful ablation of their accessory pathway; an additional patient had probable successful ablation, yielding an overall success rate of 74%. Eighty-seven percent of individuals with a left-sided pathway had permanent ablation and 100% with a manifest left-sided pathway experienced successful ablation. Only 29% of the first seven patients had a successful result; in contrast, 92% of the next 12 patients had successful interruption of their accessory pathways. After ablation, 4-day continuous electrocardiographic telemetry disclosed no significant arrhythmias. CPK enzyme rises peaked at 12–24 hours. The rise was excessive and associated with general anesthesia in five patients. The isoenzyme MB fraction rose mildly in five other patients and returned to normal within 72 hours. No clinical or electrocardiographic evidence of myocardial ischemia was detected. Follow-up for 4–12 months indicates no return of preexcitation or tachycardia in any patient whose accessory connection was successfully ablated. ConclusionsThis experience indicates that radiofrequency current is an effective and safe technique for ablation of accessory connectionsin children.

HRS Expert Consensus Statement on remote interrogation and monitoring for cardiovascular implantable electronic devices

DavidSlotwiner,MD, FHRS, FACC(Chair),Niraj Varma,MD,PhD, FRCP(Co-chair), JosephG.Akar,MD,PhD, George Annas, JD, MPH, Marianne Beardsall, MN/NP, CCDS, FHRS, Richard I. Fogel, MD, FHRS, Nestor O. Galizio, MD, Taya V. Glotzer, MD, FHRS, FACC, Robin A. Leahy, RN, BSN, CCDS, FHRS, Charles J. Love, MD, CCDS, FHRS, FACC, FAHA, Rhondalyn C. McLean, MD, Suneet Mittal, MD, FHRS, Loredana Morichelli, RN, MSN, Kristen K. Patton, MD, Merritt H. Raitt, MD, FHRS, Renato Pietro Ricci, MD, John Rickard, MD, MPH, Mark H. Schoenfeld, MD, CCDS, FHRS, FACC, FAHA, Gerald A. Serwer, MD, FHRS, FACC, Julie Shea, MS, RNCS, FHRS, CCDS, Paul Varosy, MD, FHRS, FACC, FAHA, Atul Verma, MD, FHRS, FRCPC, Cheuk-Man Yu, MD, FACC, FRCP, FRACP From the Hofstra School of Medicine, North Shore Long Island Jewish Health System, New Hyde Park, New York, Cleveland Clinic, Cleveland, Ohio, Yale University School of Medicine, New Haven, Connecticut, Boston University School of Public Health, Boston, Massachusetts, Southlake Regional Health Centre, Newmarket, Ontario, Canada, St. Vincent Medical Group, Indianapolis, Indiana, Favaloro Foundation University Hospital, Buenos Aires, Argentina, Hackensack University Medical Center, Hackensack, New Jersey, Sanger Heart & Vascular Institute, Carolinas HealthCare System, Charlotte, North Carolina, New York University Langone Medical Center, New York City, New York, University of Pennsylvania Health System, Philadelphia, Pennsylvania, The Arrhythmia Institute at Valley Hospital, New York, New York, Department of Cardiovascular Diseases, San Filippo Neri Hospital, Rome, Italy, University of Washington, Seattle, Washington, VA Portland Health Care System, Oregon Health & Science University, Knight Cardiovascular Institute, Portland, Oregon, Johns Hopkins University, Baltimore, Maryland, Yale University School of Medicine, Yale-New Haven Hospital Saint Raphael Campus, New Haven, Connecticut, University of Michigan Congenital Heart Center, University of Michigan Health Center, Ann Arbor, Michigan, Brigham and Women’s Hospital, Boston, Massachusetts, Veterans Affairs Eastern Colorado Health Care System, University of Colorado, Denver, Colorado, and Department of Medicine and Therapeutics, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong, China.

Percutaneous balloon angioplasty for native coarctation of the aorta

Twenty-six children, aged 5 weeks to 14.7 years, underwent percutaneous balloon angioplasty for a discrete native coarctation of the aorta. The procedure reduced the systolic coarctation gradient acutely in all children. The mean systolic gradient decreased by 75%, from 48.6 +/- 2.4 before to 12.3 +/- 1.9 mm Hg after angioplasty (p less than 0.001). Long-term results were evaluated in 14 children by follow-up catheterization 12 to 26 months (mean 15.3) after angioplasty. At follow-up, the residual gradient averaged 11.7 +/- 3.7 mm Hg (range -5 to 36) and had not changed from that measured immediately after angioplasty (p = 0.64). Compared with preangioplasty values, the systolic pressure in the ascending aorta had improved substantially at follow-up (116.0 +/- 3.2 versus 143.9 +/- 3.1 mm Hg, p less than 0.001). On the basis of follow-up data, two groups of children were identified: Group 1 consisted of nine children with a good result, defined as a residual gradient less than 20 mm Hg and no aneurysm; Group 2 consisted of five children with a poor result, four with a residual gradient greater than 20 mm Hg (range 25 to 36) and one with an aneurysm at the dilation site. There was no statistical difference between the two groups in age at angioplasty, balloon size, ratio of balloon to isthmus diameters, follow-up duration, heart rate or cardiac output. However, of the four children with a residual gradient greater than 20 mm Hg, two were the youngest in the study, and in two the aorta was inadvertently dilated with a balloon 4 to 5 mm smaller than the isthmus diameter.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of atrial antitachycardia pacing using the Medtronic AT500 pacemaker in patients with congenital heart disease.

Patients with congenital heart disease are vulnerable to atrial tachyarrhythmias, especially after atrial surgeries. We evaluated the efficacy of atrial arrhythmia detection and antitachycardia pacing (ATP) using the Medtronic AT500 pacemaker in 28 patients with congenital heart disease (age 30 +/- 18 years). Of 15 patients with atrial arrhythmias, 14 had atrial tachycardia events that were appropriately detected. ATP was enabled for 167 treatable episodes, successfully converting 90 (54%). Rhythms classified as ventricular tachycardia were detected 127 times, yet most were actually atrial or sinus tachycardia with 1:1 atrioventricular conduction. Atrial tachycardias in congenital heart disease are amenable to ATP algorithms in the AT500 pacemaker.

Implantable Cardioverter Defibrillator Therapy for Life-Threatening Arrhythmias in Young Patients

AbstractObjectives: This study examined the indications, efficacy and outcomes of implantable cardioverter defibrillator (ICD) use in the pediatric population. Background: ICDs are first-line therapy for adults resuscitated from sudden cardiac death (SCD) or at high risk for life-threatening ventricular arrhythmias. Use of ICDs in children and young adults is infrequent and there are few data regarding this group. Methods: We abstracted and analyzed data for all patients in whom ICDs were implanted. Results: A total of 38 devices were implanted in 27 patients. Age ranged from 6 to 26 years (mean, 14) and weight ranged from 16 to 124 kg (mean, 47). Diagnoses included long QT syndrome (9), hypertrophic cardiomyopathy [6], repaired congenital heart disease [5];, and idiopathic ventricular tachycardia/fibrillation [4]. Indications comprised resuscitated SCD [15], syncope [9], and life-threatening ventricular arrhythmia [3]. Initial device placement was infraclavicular in 13, abdominal in 13 and intrathoracic in 1. Epicardial leads were used with 5 systems. A single coil lead was used in 17. Seven patients, all previously resuscitated from SCD, experienced 88 appropriate successful discharges. There were 6 inappropriate discharges in 3 patients. Mean time to device replacement was 3.1 years (n = 11). Complications included 2 infected systems, 2 lead dislodgments, 2 lead fractures, 1 post-pericardiotomy syndrome, 1 adverse event with defibrillation threshold (DFT); testing, and 1 patient with psychiatric sequelae. No deaths occurred with implanted ICDs. Conclusions: These data demonstrate that ICDs provide safe and effective therapy in young patients. The indications for ICDs as primary preventive therapy remain uncertain.

Noninvasive detection of retrograde descending aortic flow in infants using continuous wave Doppler ultrasonography Implications for diagnosis of aortic run-off lesions

Continuous wave Doppler ultrasonography was utilized to detect and characterize descending aortic blood flow velocity patterns in 27 preterm and term infants with or without an aortic run-off lesion proximal to the descending aorta. The effects of coexistent intracardiac defects on the velocity time profiles were evaluated by comparing records from patients with no intracardiac defects or systemic run-off lesions to those with a variety of intracardiac defects but no systemic run-off lesion. No significant alterations were noted. In all patients, the velocity tracing in systole was triangular in shape. During diastole, however, there were qualitative and quantitative differences between patients with and without a proximal run-off lesion. In those without a run-off lesion, retrograde descending aortic flow was present only in early diastole, and aortic flow velocity oscillated around the zero baseline during mid and late diastole. In those with a run-off lesion, retrograde flow present in early diastole continued throughout diastole. Quantitatively, the ratio of the area under the retrograde flow portion of the tracing to the forward flow portion was significantly greater in those with a run-off lesion. The velocity time profiles obtained with CW Doppler were similar to those previously obtained invasively with electromagnetic flow probes of catheter-mounted velocitometers. CW Doppler ultrasonograpy provides a reliable, noninvasive method for describing descending aortic blood flow velocity in infants.