Can pediatric residents interpret electrocardiograms?

The purpose of this study was to assess the electrocardiogram (ECG) interpretation skills of pediatric residents in a controlled environment and determine if the level of residency training (intern vs senior) improves accuracy. A list of ECG diagnoses was provided to four pediatric residency educators with instructions to categorize each diagnosis as follows: I, all residents; II, the majority of residents, including all senior residents; III, less than the majority of residents; and IV, few residents should be able to interpret correctly. Only those categories that the entire panel believed all residents (category I) or all senior residents (category II) should be able to interpret correctly were included. The test included 17 ECGs: 14 category I and 3 category II. A total of 132 residents participated: 78 interns and 54 seniors. Both groups scored below expected levels. Mean correct score among seniors was 10.9 out of the expected 17 (p < 0.001). Mean correct score for interns was 7.7 out of the expected 14 (p < 0.00l). No difference in ECG interpretation accuracy was found between residency programs. In general, pediatric residents' ECG interpretation skills are less accurate than expected. Although there is a trend toward improvement during training, senior residents fell short of the expectations of the panel. We speculate that focused education in this area will improve resident ECG interpretation and benefit patient care by (1) facilitating referral and treatment of patients with cardiovascular disease and (2) decreasing referrals for erroneous interpretations.

Long-term follow-up of arrhythmias in pediatric orthotopic heart transplant recipients: incidence and correlation with rejection

BACKGROUND

Arrhythmias in adult orthotopic heart transplant (OHT) recipients are common and have been used as predictors of rejection. Because of the paucity of information in pediatric OHT recipients, the purpose of this study was to determine the incidence and correlation of arrhythmias with rejection or with coronary artery disease (CAD) in children.

METHODS

We retrospectively reviewed the records, electrocardiograms (ECGs), and 24-hour ambulatory ECGs of patients who underwent OHT from January 1984 to December 1999. We excluded arrhythmias occurring in the first 2 weeks after OHT.

RESULTS

Sixty-nine patients underwent OHT, received triple-immunosuppression therapy, were discharged home, and have been followed for a mean of 4.7 years (0.3-13 years). Each patient had an average of 10 ECGs and three 24-hour ECGs. Twenty-six patients had 33 arrhythmias: sinus bradycardia (n = 9), atrial tachycardia (n = 9), ventricular tachycardia (n = 3), and Wenckebach periodicity (n = 6). Sinus bradycardia was treated with theophylline in 8 patients, and 2 required pacemakers. Atrial tachycardias (atrial flutter in 4 patients and atrial ectopic tachycardia in 5) were treated with digoxin, propranolol, or procainamide. Ventricular tachycardia was treated with mexiletine, lidocaine, and amiodarone. There were 65 episodes of rejection, 20 of which were moderate/severe (> or =3B). Only Wenckebach was associated with the presence of either rejection or CAD (p < 0.05).

CONCLUSIONS

We noted clinically significant arrhythmias in 38% of the pediatric OHT recipients. Sinus bradycardia, atrial tachyarrhythmias, and ventricular tachycardia occurred with the same frequency. Only new-onset Wenckebach periodicity was noted in the presence of either CAD or rejection. No arrhythmia was of negative predictive value for rejection or CAD. From this data, we suggest that new-onset Wenckebach prompt evaluation for rejection or CAD.

The emergency department versus the computer: which is the better electrocardiographer?

Electrocardiograms (ECGs) are frequently ordered in the pediatric emergency department (ED). Pediatric cardiologists are generally not asked to interpret every ECG; thus, ED patient management is often guided by the ED physicians' ECG interpretation. The objective of this study was to analyze the accuracy of ECG interpretation by ED physicians and a computer-generated interpretation and compare the two. A 12-month prospective study was performed in a pediatric ED. All patients (<22 years) who had an ECG in the ED were included. The ED physicians and the computer interpretation were compared to a reference standard. Each electrocardiographic diagnosis, as well as the ECG as a whole, was assigned to one of the following predetermined classes: I, normal sinus rhythm; II, minimal clinical significance; III, indeterminate clinical significance; IV, those of definite clinical significance. Both groups correctly interpreted all normal (class I) ECGs. The computer correctly interpreted approximately 75% of the class II and class III ECGs, whereas the ED physicians correctly interpreted 36% of both groups. For the class IV ECGs, both the computer and the ED physicians performed poorly, correctly interpreting just 14% and 28%, respectively. The computer proved to be more accurate than the ED physicians in interpreting ECGs of less than critical significance (classes II and III), but neither group was able to correctly interpret even a simple majority of the most significant abnormalities (class IV). We speculate that distributing the computer-generated interpretation to the ED physicians and formal review of all ED ECGs by a skilled interpreter may decrease the number of missed diagnoses.

Use of intravenous amiodarone for postoperative junctional ectopic tachycardia in children

To assess the efficacy and safety of intravenous (IV) amiodarone for the treatment of postoperative junctional ectopic tachycardia (JET) in children, we retrospectively reviewed 11 patients treated with IV amiodarone for JET between 1/92 and 2/00. Data included heart rate and hemodynamics pre- and post-amiodarone, drug dosage, duration of therapy, and effect. Success was defined as reversion to sinus rhythm or slowing to a hemodynamically stable rate. The mean heart rate prior to amiodarone was 203 bpm, and the mean systolic blood pressure was 64 mmHg. Mean IV amiodarone loading dose was 8.2 +/- 4.0 mg/kg, followed by an infusion in 7 patients at a dose of 12.9 +/- 3.9 mg/kg/day for a duration of 74.3 +/- 46.9 hours. At 1 hour post-load, mean heart rate was 147 bpm and mean systolic blood pressure was 88 mmHg for the group. Three patients were in sinus rhythm, 4 in intermittent sinus rhythm with accelerated junctional rhythm, and 4 patients solely accelerated junctional rhythm. Control of JET persisted in 9 patients. Of the two patients requiring additional treatment, both had received a 5 mg/kg load and neither was on an infusion. Five patients were paced at some point following amiodarone: four to improve hemodynamics and one for late sinus bradycardia. Side effects included hypotension with loading (1) and late sinus bradycardia (1). One patient was discharged on oral amiodarone. Intravenous amiodarone given in doses of 10 mg/kg in two 5 mg/kg increments, followed by an infusion of 10-15 mg/kg/day for 48-72 hours, appears to be safe and effective for postoperative JET in patients who fail conventional therapy or who are hemodynamically unstable. Long-term oral therapy is usually not necessary.

Transient dilated cardiomyopathy in a newborn exposed to idarubicin and all-trans-retinoic acid (ATRA) early in the second trimester of pregnancy

Acute promyelocytic leukemia was diagnosed in a 28-year-old pregnant woman at 13 gestational weeks. She was immediately started on idarubicin and all-trans-retinoic acid (ATRA) and achieved remission after her fourth cycle of treatment. Serial fetal ultrasonograms throughout pregnancy did not reveal any intrauterine growth retardation or other obvious malformations. The mother delivered a term (36.7 gestational weeks), 2720-gram female neonate. The infant was admitted to the intermediate care nursery for observation due to transient mild respiratory distress during the peripartum period. Because of right ventricular hypertrophy on an electrocardiogram, an echocardiogram was performed on the first day of life which showed moderate dilation of the right atrium and right ventricle with mildly depressed function, two small secundum atrial septal defects, and a small patent ductus arteriosus. The neonate remained hemodynamically stable and no arrhythmias were detected. The remainder of the hospital course was uneventful. When reassessed 1-1/2 months later, she was doing well and did not show any signs of congestive heart failure. A repeat echocardiogram at that time demonstrated complete resolution of the right heart enlargement and closure of the ductus arteriosus with persistence of the small and hemodynamically insignificant secundum atrial septal defects.

Aneurysmal dilatation of the ductus arteriosus in a neonate

Fetal ultrasound provides the capacity for early detection of a variety of congenital heart diseases. We report a case of aneurysmal dilatation of a patent ductus arteriosus detected in utero and subsequently confirmed by transthoracic echocardiography in the neonatal period. Prompt recognition of the ductus aneurysm with resultant surgical ligation may have averted potentially serious complications from this condition.

Use of tissue plasminogen activator in a stroke after radiofrequency ablation of a left-sided accessory pathway

We describe the case of a 12-year-old girl who had a thromboembolic stroke after radiofrequency ablation of a left posterior accessory pathway involving a transseptal procedure. Symptoms of a stroke occurred 7 hours 15 minutes after completion of the procedure. Tissue plasminogen activator (tPA) was given 2 hours 30 minutes after the onset of symptoms, with complete resolution of her neurologic symptoms. No adverse effects from the tPA were seen. Because of the late onset of symptoms in this case, overnight in-hospital observation is warranted for patients who undergo radiofrequency ablation of a left-sided accessory pathway or an accessory pathway in a patient with the ability to shunt right to left. In this case, tPA was an effective and safe drug to use following a cerebral thromboembolic event occurring after a cardiac catheterization procedure.

Stent dilation of superior vena cava and innominate vein obstructions permits transvenous pacing lead implantation

The purpose of this study was to assess the feasibility of stent dilation of venous obstructions/occlusions to permit transvenous pacing lead implantation. Innominate vein or superior vena cava (SVG) obstruction may preclude the implantation of transvenous pacing leads. Patients with d-transposition of the great arteries, after a Mustard or Senning procedure, and children with previously placed transvenous pacing leads are at higher risk for this vascular complication. From May 1993 to January 1996, eight pediatric patients who underwent transvenous pacing lead implantation or replacement were found to have significant innominate vein or SVC obstruction or occlusion. Utilizing intravascular stents, a combined interventional and electrophysiological approach was used to relieve the venous obstruction and to permit implantation of a new transvenous pacing lead. Two patients had complete SVC occlusion requiring puncture through the obstruction with a transseptal needle. Vessel recanalization was achieved with balloon dilation and stent implantation. The remaining six patients had severe venous obstruction with a mean minimum diameter of 3.1 +/- 3.3 mm. The mean pressure gradient across the obstructed veins was 8.6 +/- 7.3 mmHg. Following implantation of 15 Palmaz P308 stents in eight vessels, the mean diameter increased to 14.2 +/- 1.9 mm and the mean pressure gradient across the stented vessels decreased to 1.0 +/- 2.0 mmHg. A transvenous pacing lead was implanted successfully through the stent(s) immediately or 6-8 weeks later. Innominate vein and SVC obstruction can be safely and effectively relieved with intravascular stents and permit immediate or subsequent transvenous pacing lead implantation.

Left-sided atrioventricular nodal ablation using the transseptal approach: clinico-histopathologic correlation

To our knowledge, prograde access to the left ventricle to perform a left-sided AV node (AVN) ablation has not been reported. We present the case of a patient with Noonan's syndrome and supravalve aortic stenosis who required aortic valve replacement with a mechanical valve. Due to chronic atrial fibrillation, a transvenous pacing system was implanted and transcatheter radiofrequency ablation of the AVN was performed. Attempts at right-sided AVN ablation were unsuccessful. Due to the presence of the mechanical aortic valve, a left-sided AVN ablation was performed successfully using the transseptal approach. The patient died suddenly 6 months after the procedure, and the histologic study of the heart is reported.

Ventricular tachycardia during repair of gastroschisis

Ventricular tachycardia has been reported after blunt cardiac trauma in both children and adults. However, to the best of our knowledge, there are no reports of sudden onset of ventricular tachycardia at the time of surgical closure of gastroschisis. This case describes a patient with gastroschisis who developed a medically resistant ventricular tachycardia upon reduction of the gastroschisis.

Congenital complete atrioventricular block

Congenital complete atrioventricular block is found in 1 of 22,000 live births. Over time, it has become apparent that these patients represent not a single distinct disease process, but several processes with the common manifestation of atrioventricular block. The evaluation of these patients to determine their risk of sudden death and need for pacing is not well defined.

Pediatric use of intravenous amiodarone: efficacy and safety in critically ill patients from a multicenter protocol

OBJECTIVE

The purpose of this study was to analyze the efficacy and safety of intravenous amiodarone in young patients with critical, drug-resistant arrhythmias.

BACKGROUND

Intravenous amiodarone has been investigated in adults since the early 1980s. Experience with the drug in young patients is limited. A larger pediatric study group was necessary to provide responsible guidelines for the drug's use before its market release.

METHODS

Eight centers obtained institutional approval of a standardized protocol. Other centers were approved on a compassionate use basis after contacting the primary investigator (J.C.P).

RESULTS

Forty patients were enrolled. Standard management in all failed. Many patients had early postoperative tachyarrhythmias (25 of 40), with early successful treatment in 21 (84%) of 25. Twelve patients had ventricular tachyarrhythmias: seven had successful therapy, and six died, none related to the drug. Eleven patients had atrial tachyarrhythmias: 10 of 11 had immediate success, but 3 later died. Fourteen patients had junctional ectopic tachycardia, which was treated with success (sinus rhythm or slowing, allowing pacing) in 13 of 14, with no deaths. Three other patients had supraventricular tachycardias, with success in two and no deaths. The average loading dose was 6.3 mg/kg body weight, and 50% of patients required a continuous infusion. Four patients had mild hypotension during the amiodarone bolus. One postoperative patient experienced bradycardia requiring temporary pacing. There were no proarrhythmic effects. Deaths (9 [23%] of 40) were not attributed to amiodarone.

CONCLUSIONS

Intravenous amiodarone is safe and effective in most young patients with critical tachyarrhythmia. Intravenous amiodarone can be lifesaving, particularly for postoperative junctional ectopic tachycardia, when standard therapy is ineffective.

Cisapride-induced long QT interval

A 2-month-old infant with gastroesophageal reflux was treated with cisapride. Bradycardia developed and an electrocardiogram revealed 2:1 atrioventricular conduction and a prolonged QT interval. After cessation of cisapride therapy, both the rhythm and the QT interval returned to normal. Prolonged QT interval during treatment with cisapride may occur in children as in adults.

Flecainide and amiodarone: combined therapy for refractory tachyarrhythmias in infancy

OBJECTIVES

This study assessed the safety and efficacy of combined flecainide and amiodarone therapy in controlling refractory tachyarrhythmias in infants.

BACKGROUND

Single-drug as well as standard combination medical therapy for tachyarrhythmias in infants sometimes fails. In those cases, one may consider interventional therapy. However, this option may carry a high risk of morbidity and mortality in infants. The natural history of tachyarrhythmias in infants often favors eventual resolution and reinforces the importance of selecting an effective medical regimen.

METHODS

We performed a retrospective analysis of nine infants (median age 2 months) who received combined flecainide and amiodarone therapy for attempted control of refractory tachyarrhythmias. Trough serum drug levels of flecainide were monitored, and 24-h ambulatory electrocardiographic monitoring was used to determine efficacy of therapy.

RESULTS

Single-drug treatment with flecainide or amiodarone failed in all of the infants studied. An average of four drugs failed (range one to six) before administration of combined flecainide and amiodarone therapy. During combined therapy, the flecainide dose was 70 to 110 mg/m2 per day, and that for amiodarone was 7.5 to 13.5 mg/kg per day for a mean (+/- SD) of 9 +/- 2 days to load and 5 to 12 mg/kg per day as maintenance. Successful control of tachyarrhythmias was demonstrated in seven (78%) of nine infants (95% confidence interval 46% to 99%) (three of three with congenital junctional ectopic tachycardia, three of three with supraventricular tachycardia and one of three with ventricular tachycardia). During combined therapy, flecainide trough levels ranged from 350 to 731 ng/ml. Corrected QT intervals varied from 0.440 to 0.488 ms. No proarrhythmia occurred. None of the infants required a pacemaker, and all had normal left ventricular dimensions and fractional shortening by echocardiography. Eight of nine infants had a structurally normal heart. One infant had surgical correction of an atrioventricular septal defect.

CONCLUSIONS

Combination therapy with flecainide and amiodarone appears to be safe and effective in controlling refractory tachyarrhythmias in infants. The combination of flecainide and amiodarone may obviate the need for early interventional therapy or may allow delay until the child is older.

Persistence of ventricular arrhythmia after resolution of occult myocarditis in children and young adults

OBJECTIVES

We sought to examine whether resolution of occult myocarditis in children with associated ventricular arrhythmia correlated with the presence of arrhythmia at late follow-up.

BACKGROUND

Complex ventricular arrhythmias have been documented in children with myocarditis. Therapy is aimed at controlling the arrhythmia and any associated ventricular dysfunction. However, no reported studies have documented whether resolution of myocarditis in children is associated with resolution of the associated arrhythmias.

METHODS

We performed a retrospective analysis of 12 patients (mean age 12 years) with myocarditis. Ambulatory electrocardiographic (Holter) monitors were reviewed for ventricular arrhythmias at presentation and follow-up. Patients were assigned to Group I if they received corticosteroids in addition to any antiarrhythmic agents and to Group II if they did not receive steroids. Follow-up endomyocardial biopsy was performed in some patients, and results were analyzed in relation to the presence of arrhythmias at follow-up.

RESULTS

Eleven patients had ventricular tachycardia, and one had multiform couplets. Corticosteroids were given to seven patients (Group I). Follow-up biopsy was performed in seven patients (six received steroids), with resolution of inflammation in all; four of the seven still had ventricular arrhythmias but with improved control. Of the five patients without follow-up biopsy, three had persistent arrhythmia. Absence of inflammation at follow-up biopsy did not correlate with loss of ventricular arrhythmias, and there was no difference between Group I and II patients with respect to resolution of arrhythmia (Fisher exact test, p = 0.70, power 11%).

CONCLUSIONS

Complex ventricular arrhythmias persist after apparent resolution of occult myocarditis in children. Although these arrhythmias are easier to control after such resolution, the patients may require long-term antiarrhythmic therapy.

Acceleration of atrial ectopic tachycardia as a guide to successful radiofrequency ablation

Three children with atrial ectopic tachycardia (AET), ages 7-10 years, underwent radiofrequency ablation (RFA). Two had AET localized to the inferolateral orifice of the right atrial appendage, one had AET at the posteroinferior orifice of the left atrial appendage. Each patient received RFA at 15-16 watts for 30 seconds per application. Acceleration of AET rate was observed only during successful RFA application in each patient, occurring within 5 seconds and lasting 2-4 seconds. All unsuccessful applications failed to show this phenomenon. Observation of acceleration of AET rate during RFA was a useful predictor of successful procedure, possibly indicating destruction of abnormally automatic substrates.

Intravenous amiodarone for life-threatening tachyarrhythmias in children and young adults

OBJECTIVES

The purpose of this study was to evaluate the efficacy of intravenous amiodarone in young patients.

BACKGROUND

Oral amiodarone therapy has proved useful for problematic arrhythmias in children, but its pharmacokinetics with the oral route preclude its use in several acute settings.

METHODS

Intravenous amiodarone was administered in 1-mg/kg body weight aliquots followed by continuous infusion to patients with potentially life-threatening tachyarrhythmias that had not been abolished by standard therapies.

RESULTS

Ten patients (mean age 6.8 years) received intravenous amiodarone: for ventricular tachycardia in seven patients and for atrial tachycardia, junctional tachycardia and multiple arrhythmias in one patient each. Surgery for congenital heart defects had been performed previously in six patients. Two patients had a hamartoma causing ventricular tachycardia. Six of 10 patients had complete resolution of arrhythmia with intravenous amiodarone: 4 of 7 with ventricular tachycardia, 1 of 1 with atrial tachycardia and 1 of 1 with postoperative junctional ectopic tachycardia. Intravenous amiodarone was not successful in the two patients with a hamartoma but slowed ventricular tachycardia in one, allowing successful surgical cure. Average drug load at the time of effect was 4.8 mg/kg body weight. Four patients had transient hypotension during loading, corrected with volume or low dose calcium. Intravenous infusion of amiodarone, 10 mg/kg per day, continued an average of 3 days. Four of 10 patients died, all of nonarrhythmic causes not attributable to intravenous amiodarone.

CONCLUSIONS

Intravenous amiodarone was well tolerated in this small series of patients. Postoperative ventricular tachycardia was responsive to intravenous amiodarone in 80% (8 of 10) of the patients (95% confidence interval 40% to 99%). Use of this drug in acute, postoperative tachyarrhythmias may be lifesaving in some patients when standard intravenous therapies fail.