Victoria L. Vetter

Electrophysiologic residua and sequelae of surgery for congenital heart defects.

Postoperative arrhythmias may occur in any patient who undergoes intracardiac surgery for a congenital heart defect. The correction of certain intracardiac heart defects predisposes to a large incidence of cardiac arrhythmias. Ventricular arrhythmias and conduction disturbances are seen after correction of tetralogy of Fallot, ventricular septal defect and atrioventricular canal defect. Supraventricular arrhythmias and sinus nodal dysfunction may be seen after surgery for transposition of the great arteries or atrial septal defect. The identification, evaluation and treatment of these patients are discussed.

Associated Symptoms in the Ten Days Before Diagnosis of Kawasaki Disease

OBJECTIVE To describe common associated symptoms within the 10 days before diagnosis in subjects enrolled in the Pediatric Heart Networks trial of steroid therapy in Kawasaki disease (KD). STUDY DESIGN Patients with acute KD were enrolled between days 4 and 10 of illness at 8 centers between 2002 and 2004. We defined common associated symptoms as those occurring in >or=10% of patients. Principal clinical criteria for KD were not included in this analysis. RESULTS Among 198 patients, irritability was reported in 98 (50%), vomiting in 88 (44%), decreased food/fluid intake in 73 (37%), cough in 55 (28%), diarrhea in 52 (26%), rhinorrhea in 37 (19%), weakness in 37 (19%), abdominal pain in 35 (18%), and joint pain (arthralgia or arthritis) in 29 (15%). One or more gastrointestinal symptom (vomiting, diarrhea, or abdominal pain) was present in 120 patients (61%) and 69 patients (35%) had >or= 1 respiratory symptom (rhinorrhea or cough). CONCLUSIONS Nonspecific symptoms occur commonly in children with KD. To reduce delays in diagnosis, clinicians should be educated that such symptoms may comprise a significant component in the chief complaint.

Implications of anesthesia in children with long QT syndrome.

BACKGROUND: Patients with congenital long QT syndrome (LQTS) are susceptible to an episodic malignant ventricular tachyarrhythmia known as torsade de pointes, which can result in a cardiac arrest and death. Patients can suffer severe cardiac events resulting in syncope, seizures, and sudden cardiac death during times of physical and emotional stress and when exposed to certain drugs including anesthetics. We describe the occurrence of perioperative adverse events (AEs) related to arrhythmias in children with congenital LQTS exposed to volatile general anesthesia and describe associated risk factors. METHODS: We performed a retrospective cohort study of children with LQTS undergoing general anesthesia for noncardiac surgery or device implant, or revision for cardiac rhythm management. This study was a retrospective chart review with data collection from computerized and electronic patient medical records. RESULTS: Seventy-six patients with congenital LQTS were identified who had a total of 114 anesthetic encounters. Of the 114 anesthetic encounters, there were 3 AEs, 2 definite and 1 probable AE, for an incidence of 2.6%. The events occurred in boys (aged 11, 13, and 15 years) while undergoing noncardiac surgery under volatile general anesthesia. All were receiving &bgr;-blocker therapy preoperatively. The AEs occurred in close proximity to the administration of reversal drugs (anticholinesterase/anticholinergic combinations) and the antiemetic ondansetron. The events occurred during emergence from anesthesia, and exclusively in the group of patients who received both reversal drugs and ondansetron. All were treated successfully with short-term antiarrhythmic drug therapy and discharged the next morning. CONCLUSIONS: There is an increased risk of AEs during periods of enhanced sympathetic activity, especially emergence. This risk seems to be further enhanced if drugs are administered at this time that are known either to prolong the corrected QT interval or the transmural dispersion of repolarization or increase the incidence of tachycardia. Restriction of medications that adversely affect ion channels and intense vigilance and monitoring during this time and in the postoperative phase could help prevent occurrence or progression of AEs.

Cardiovascular Effects of Medications for the Treatment of Attention-Deficit Hyperactivity Disorder

The effective medications currently marketed for attention-deficit hyperactivity disorder (ADHD) have central and peripheral catecholaminergic effects that have been shown to result in statistically significant increases in heart rate and blood pressure. The impact of these medications on serious cardiovascular events in healthy children is unknown, but serious cardiovascular events related to ADHD medications are considered rare. However, children with cardiac pathology may be at greater risk given that increased sympathetic tone has been reported as a causal factor in generating ventricular arrhythmias in adults with coronary artery disease, and physical exercise has been consistently reported as a trigger for increased risk of sudden cardiac death in athletes with underlying cardiovascular disease.ADHD has high co-morbidity with anxiety and depression. These conditions in adults have been reported to have their own cardiovascular risks that may be compounded by interactions resulting from combined pharmacotherapeutic treatments; this interaction has not been evaluated in children. High rates of ADHD reported in subjects with cardiac pathology, as well as in patients with genetic disorders associated with cardiovascular pathology, also suggest that the prevalence of cardiac pathology in ADHD subjects may be greater than that in the general population. Currently, the US FDA and Health Canada require warnings on prescription labeling information for ADHD medications, suggesting that these medications should not generally be used in children or adults with ‘known’ serious cardiac pathology. Family history, medical history, and physical examination have very low sensitivity for identifying serious cardiac pathology, but this can be markedly enhanced in many instances with the use of electrocardiography, which has high specificity and sensitivity.Identifying and managing underlying cardiovascular pathology may not eliminate the risk of serious cardiovascular events but may increase the safety of using medication frequently required for effective management of ADHD. When the very common and serious consequences from untreated ADHD are also considered in the assessment of risks and benefits, even in the presence of cardiac pathology, it seems that the prescribing of ADHD medications in children should remain unchanged.

Managed Ventricular Pacing in Pediatric Patients and Patients With Congenital Heart Disease

Ventricular dyssynchrony induced by ventricular pacing (VP) may predispose patients to congestive heart failure. The detrimental effects of VP are directly related to the cumulative percentage of VP (Cum%VP). Managed VP (MVP) is a novel pacing algorithm developed to minimize unnecessary VP by uncoupling atrial pacing from VP. This retrospective analysis assessed the feasibility of using MVP in pediatric patients and patients with congenital heart disease (CHD). A multicenter review evaluated all pediatric patients <22 years old and older patients with CHD that had an implanted device using a MVP algorithm. Primary outcome variables were Cum%VP and adverse events. A subgroup analysis evaluated patients that had a DDD(R) pacemaker before a MVP device and compared Cum%VP before and after initiation of MVP. From 6 centers 62 patients (mean age 21.5 +/- 9.6 years) were included; 64% had CHD. With a MVP device, mean Cum%VP was 4.3 +/- 14.6% (range 0 to 83.7): Eleven patients were eligible for subgroup analysis. Compared with DDD(R), Cum%VP significantly decreased with MVP (67.1 +/- 29.4% vs 9.2 +/- 24.8%, p = 0.002). One MVP-related adverse event occurred; a patient with intermittent atrioventricular block had symptoms with frequent nonconducted atrial depolarizations and was reprogrammed to DDD. In conclusion, MVP can be used safely and can significantly reduce unnecessary VP in pediatric patients and patients with CHD.

Subcutaneous Array with Active Can Implantable Cardioverter Defibrillator Configuration: A Follow‐up Study

BACKGROUND Novel nontransvenous implantable cardioverter defibrillator (ICD) configurations are sometimes required for small children and children with complex congenital heart disease at risk for sudden death. Mid- to long-term follow-up of these nontraditional implant techniques is not well known. We assessed the mid-term performance of a subcutaneous lead technique used in our practice. METHODS Between July 2002 and November 2003, 4 patients (age 2.1-8.5 years, weight 13-33.3 kg, height 90-126.7 cm) received an ICD with a single-finger (n = 3) or 2-finger (n = 1) subcutaneous array with an active abdominal can and epicardial pace/sense lead. The subcutaneous tunnel was created via a subxiphoid incision using a tunneling tool within a sheath along the seventh intercostal space and extended posterior to the spine. Diagnoses included long QT syndrome (n = 2), idiopathic ventricular fibrillation (n = 1), and idiopathic dilated cardiomyopathy (n = 1). Implantable cardioverter defibrillator indications included syncope (n = 2) and cardiac arrest (n = 2). RESULTS Mean follow-up was 22.3 +/- 13.9 months. During follow-up, 1 patient underwent heart transplantation and the other 3 patients underwent generator replacement secondary to a manufacturers advisory. There was 1 appropriate and successful shock for ventricular fibrillation. This patient experienced a second episode of ventricular fibrillation that the ICD discharge failed to terminate. The arrhythmia spontaneously resolved. There were no inappropriate shocks. There was 1 instance of false detection of ventricular fibrillation because of intermittent T wave oversensing but therapy was not administered. There were no infections, lead fractures, or other complications during follow-up. CONCLUSION This novel nontransvenous ICD configuration can be used safely in a select group of pediatric patients and allows for the applicability of this life-saving technology to small children at high risk for sudden cardiac death.

Congenital long QT syndrome and 2:1 atrioventricular block: An optimistic outcome in the current era

BACKGROUND Previous studies of patients with long QT syndrome (LQTS) and 2:1 atrioventricular block (AVB) have reported a mortality rate greater than 50% during infancy. OBJECTIVE The purpose of this study was to determine the outcome of this high-risk population in the current era. METHODS A retrospective study from four tertiary care pediatric centers assessed patients with congenital LQTS and 2:1 AVB from January 2000 to January 2009. All neonates who presented with 2:1 AVB and prolonged QTc unrelated to medication were included in the study. Statistical analysis was performed using a paired t-test. Medical records were reviewed for ECG findings, genotype, medications, and device therapy. RESULTS Twelve patients that met the inclusion criteria were identified. All patients underwent diagnostic ECG in the first 24 hours of life. The average QTc interval prior to therapy was 616 +/- 99 ms (range 531-840 ms). Over a follow-up period of 71 +/- 45 months (range 15-158 months), 11 of 12 patients received devices (8 permanent pacemaker, 3 implantable cardioverter-defibrillator). Average age of device placement was 48 months (median 2 months, range 3 days to 10.5 years). All patients were treated with beta-blockers; mexiletine was added in three patients, and mexiletine and flecainide were added in one patient. Three (25%) patients experienced torsades de pointes while receiving beta-blockers, one of which was refractory to medical therapy. This patient underwent left cardiac sympathetic denervation and implantable cardioverter-defibrillator placement. Genotyping was available for 6 (50%) patients (2 SCN5A mutation, 4 KCNH2 mutation). At last follow-up, no mortality was observed. Follow-up QTc intervals had decreased (mean 480 +/- 20 ms, range 450-507 ms, P <.002). CONCLUSION Management of patients with LQTS and 2:1 AVB presents unique challenges. Despite historical data indicating poor prognosis, our study represents a cohort of high-risk LQTS patients with a relatively optimistic outcome. This finding reflects early diagnosis and intervention, coupled with improved management strategies, in the current era.

Ventricular tachycardia in infants with structurally normal heart: a benign disorder

We evaluated the presentation, treatment, and outcome of infants who present with ventricular tachycardia in the first year of life. Seventy-six infants were admitted to our institution with a diagnosis of ventricular tachycardia between January, 1987 and May, 2006. Forty-five infants were excluded from the study because of additional confounding diagnoses including accelerated idioventricular rhythm, Wolff-Parkinson-White syndrome, supraventricular tachycardia with aberrancy, long QT syndrome, cardiac rhabdomyoma, myocarditis, congenital lesions, or incomplete data. The remaining 31 included infants who had a median age at presentation of 1 day, with a range from 1 to 255 days, and a mean ventricular tachycardia rate of 213 beats per minute, with a range from 171 to 280, at presentation. The infants were treated chronically with propranolol (38.7%), amiodarone (12.9%), mexiletine (3.2%), propranolol and mexiletine (9.7%), or propranolol and procainamide (6.5%). The median duration of treatment was 13 months, with a range from 3 to 105 months. Ventricular tachycardia resolved spontaneously in all infants. No patient died, or received catheter ablation or device therapy. Median age at last ventricular tachycardia was 59 days, with a range from 1 to 836 days. Mean follow-up was 45 months, with a range from 5 to 164 months, with a mean ventricular tachycardia-free period of 40 months. Infants with asymptomatic ventricular tachycardia, a structurally normal heart, and no additional electrophysiological diagnosis all had spontaneous resolution of tachycardia. Furthermore, log-rank analysis of the time to ventricular tachycardia resolution showed no difference between children who received chronic outpatient anti-arrhythmic treatment and those who had no such therapy. While indications for therapy cannot be determined from this study, lack of symptoms or myocardial dysfunction suggests that therapy may not be necessary.

Heart Rhythm Society/Pediatric and Congenital Electrophysiology Society Clinical Competency Statement: training pathways for implantation of cardioverter-defibrillators and cardiac resynchronization therapy devices in pediatric and congenital heart patients.

1 eart Rhythm Society/Pediatric and Congenital lectrophysiology Society Clinical Competency Statement: raining pathways for implantation of cardioverter-defibrillators nd cardiac resynchronization therapy devices in pediatric and ongenital heart patients eveloped in collaboration with the American College of Cardiology and the American Heart ssociation. ndorsed by the Heart Rhythm Society, the Pediatric and Congenital Electrophysiology Society, he American College of Cardiology and the American Heart Association.

Heart Rhythm Society/Pediatric and Congenital Electrophysiology Society Clinical Competency Statement

1 eart Rhythm Society/Pediatric and Congenital lectrophysiology Society Clinical Competency Statement: raining pathways for implantation of cardioverter-defibrillators nd cardiac resynchronization therapy devices in pediatric and ongenital heart patients eveloped in collaboration with the American College of Cardiology and the American Heart ssociation. ndorsed by the Heart Rhythm Society, the Pediatric and Congenital Electrophysiology Society, he American College of Cardiology and the American Heart Association.