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.

Erythropoietin (Epo) and EpoR expression and 2 waves of erythropoiesis.

Erythropoiesis occurs in 2 distinct waves during embryogenesis: the primitive wave in the extra-embryonic yolk sac (YS) followed by the definitive wave in the fetal liver and spleen. Even though progenitors for both cell types are present in the YS blood islands, only primitive cells are formed in the YS during early embryogenesis. In this study, it is proposed that erythropoietin (Epo) expression and the resultant EpoR activation regulate the timing of the definitive wave. First, it was demonstrated that Epo and EpoR gene expressions are temporally and spatially segregated: though EpoR is expressed early (embryonic days 8.0-9.5) in the yolk sac blood islands, no Epo expression can be detected in this extra-embryonic tissue. Only at a later stage can Epo expression be detected intra-embryonically, and the onset of Epo expression correlates with the initiation of definitive erythropoiesis. It was further demonstrated that the activation of the EpoR signaling pathway by knocking-in a constitutively active form of EpoR (R129C EpoR) can lead to earlier onset of definitive erythropoiesis in the YS. Thus, these results provide the first in vivo mechanism as to how 2 erythroid progenitor populations can coexist concurrently in the YS yet always differentiate successively during embryogenesis.

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.

Usefulness of routine surveillance biopsies in children more than one year after orthotopic heart transplantation.

This retrospective study examines the usefulness of routine biopsies following the first year after transplant. This study found that routine biopsies detect few episodes of rejection in the first year after transplant and were less useful than nonroutine biopsies.

Long-term results of triple-drug-based immunosuppression in nonneonatal pediatric heart transplant recipients.

BACKGROUND: Few reports document long-term results of pediatric cardiac transplantation in which triple therapy (cyclosporine, azathioprine, and corticosteroids) was the mainstay of immunosuppression. This report details a single center's pediatric transplant experience and analyzes the relative contributions of selected pre/posttransplant risk factors on long-term morbidity and mortality. METHODS: Retrospective data were collected for all non-neonatal pediatric transplant recipients including: presenting diagnosis, cardiac hemodynamics (particularly pulmonary vascular resistance index), donor ischemic time, occurrence of postoperative infections, episodes of allograft rejection, incidence of posttransplant lymphoproliferative disease or coronary artery disease (CAD), and overall survival. Analysis of single variables and a Cox-proportional hazards model were utilized to determine the impact of pre/posttransplant risk factors on long-term survival. RESULTS: From 1984 to 1995, 64 patients (mean age, 8.3 years), 46 of whom had cardiomyopathy and 18 who had inoperable complex congenital heart disease, underwent cardiac transplantation and received triple-drug immunosuppression. Orthotopic transplantation was performed unless the pulmonary vascular resistance index remained >6 um2 (despite use of pulmonary vasodilator). One patient required heterotopic transplantation. Average donor ischemic time was 217 min. An average of 1.2 rejection episodes/patient occurred (average follow-up period: 50 months). No patient developed posttransplant lymphoproliferative disease, but 22 patients (34%) developed CAD. Overall survival was 80%, 60%, and 57% at 1, 5, and 10 years, respectively. Of outcome variables analyzed, rejection frequency was significantly increased in patients who subsequently developed CAD, but the presence of CAD was not significantly correlated with mortality. CONCLUSION: Triple-drug-based immunosuppressive maintenance therapy in pediatric heart transplant recipients results in good long-term graft survival.

Left ventricular mechanics and geometry in patients with congenital complete atrioventricular block.

BACKGROUND: Radiographic evidence of cardiomegaly is common in patients with congenital complete atrioventricular block (CCAVB). It has been speculated that left ventricular (LV) remodeling and increased stroke volume counteract the bradycardia, but the effects of slow heart rate and atrioventricular asynchrony on LV dimensions, geometry, wall stress, and function have not been examined in detail. METHODS AND RESULTS: Thirty patients with CCAVB without associated congenital heart disease (mean age, 8.5+/-5.3 years; range, 0.2 to 20 years) were included in a cross-sectional two-institution study. Thirty-five echocardiograms were performed using standard techniques. ECG and 24-hour ECG recordings were reviewed. Seven patients did not receive a pacemaker, whereas 23 patients underwent pacemaker implantation after the echocardiogram. Compared with normal control subjects, LV volume (Z score=1.5+/-1.3) and LV mass (Z=1.2+/-1.5) were significantly increased, whereas LV mass-to-volume ratio (1.1+/-0.3) and geometry (short-axis diameter/length ratio=0.65+/-0.09) were normal. LV end-systolic stress (ESS) (a measure of afterload) was normal (Z score=0.2+/-2.3), whereas shortening fraction (Z=3+/-2.9) and velocity of circumferential fiber shortening (VCF) (Z=3+/-3.1) were increased. The relationship between VCF and ESS (a preload-insensitive and afterload-adjusted index of contractility) was increased (Z=2.2+/-2) with only small increase in preload (Z=1.02+/-1.1). Regression analyses showed no significant change over age in LV mass, volume, geometry, loading conditions, or systolic function. Patients who ultimately met criteria for pacemaker implantation did not differ from those who did not in terms of heart rate or LV function but did have increased LV volume (Z score=1.8+/-1.4 versus 0.4+/-0.9, P=.03) and LV mass (Z score=1.7+/-1.2 versus 0.2+/-1.7, P=.001) compared to the unpaced group. CONCLUSIONS: In most patients with CCAVB, the LV was enlarged with normal geometry and enhanced systolic function during the first two decades of life. The degree of LV dilation and enhanced function did not significantly change with age. In patients who ultimately underwent pacemaker implantation LV function did not differ from those who remained unpaced, but evidence of a slightly increased load manifested as increased end-diastolic volume and mass.

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.

Cerberus-like is a secreted factor with neutralizing activity expressed in the anterior primitive endoderm of the mouse gastrula.

We report the isolation of mouse cerberus-like (cer-l), a gene encoding a novel secreted protein that is specifically expressed in the anterior visceral endoderm during early gastrulation. Expression in the primitive endoderm starts before the appearance of the primitive streak and lasts until the head-fold stage. In later stages, a second region of expression is found in newly formed somites. Mouse cer-l shares some sequence similarity with Xenopus cerberus (Xcer). In Xenopus assays cer-l, like Xcer, mRNA acts as a potent neuralizing factor that induces forebrain markers and endoderm, but is unable to induce ectopic head-like structures as Xcer does. In addition to cer-l, anterior visceral endoderm was found to express the transcription factors Lim1, goosecoid and HNF-3beta that are also present in trunk organizer cells. A model of how head and trunk development might be regulated is discussed. Given its neuralizing activity, the secreted protein Cer-l is a candidate for mediating inductive activities of anterior visceral endoderm.

Effect of donor-recipient size mismatch on left ventricular remodeling after pediatric orthotopic heart transplantation.

Left ventricular (LV) hypertrophy has been reported after orthotopic heart transplantation. This study was designed to determine the pattern of LV remodeling in the first year after pediatric orthotopic heart transplantation and to elucidate the mechanism responsible for changes in LV dimensions. Serial echocardiograms of 20 children who underwent cardiac transplantation were analyzed off-line, and the following LV parameters were measured and indexed to body surface area (BSA): short-axis diameters, posterior wall thickness, length, mass, and volume in systole and diastole. Mass/volume and short-axis diameter/length ratios and ejection fraction were calculated. In 5 patients, the donor's echocardiogram was also available for analysis. The patient's systemic blood pressure at the time of the echocardiogram, ischemic time of the donor heart, number of rejection episodes, biopsy scores, and body size of the donor and patient were recorded. Patients were assigned to 2 groups based on their donor-recipient weight ratio:group 1, < or = 1.2 (n = 9); and group 2, > 1.2 (n = 11). In group 1, LV mass index remained within normal limits throughout the study period. In group 2, mass index was significantly increased 2 weeks after transplantation (72 +/- 24 vs 133 +/- 37 g/BSA1.5, p = 0.0008). LV volume, geometry, ejection fraction, systemic blood pressure, and number of rejection episodes did not differ significantly between groups. The excess LV mass index in group 2 regressed significantly during the first year after transplantation from 133 +/- 37 to 93 +/- 17 g/BSA1.5 (p < 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of a leukotriene receptor antagonist in prevention of hyperoxic lung injury in newborn rabbits.

Prolonged exposure to hyperoxia can result in significant lung injury and has been associated with the development of bronchopulmonary dysplasia. Leukotrienes (LT) recruit polymorphonuclear leukocytes (PMN) to the lung, increase vascular permeability, and have therefore been postulated to play a role in the pathogenesis of hyperoxic lung injury. This study investigates ICI 198,615 (ICI), an LTD4 and LTE4 receptor antagonist in preventing hyperoxic lung injury in newborn rabbits. Matched littermates of 7-day-old rabbits received ICI (0.1 or 1.0 microM/kg/h) or vehicle alone, were exposed to greater than 95% O2, and sacrificed after 48, 72, 84 and 96 h of exposure. Bronchoalveolar alveolar lavage fluid (BAL) of the left lung was analyzed for white cell count, differential, absolute number of PMNs, total protein, and cyclooxygenase products 6-keto-PGF1 alpha, and thromboxane B2. Lung water was quantified utilizing the right lung. Results demonstrated no significant differences between the ICI groups or between the ICI groups and controls. In conclusion, the administration of the LTD4 and LTE4 receptor antagonist ICI 198,615 was insufficient to reduce the formation of pulmonary edema, reduce mortality or attenuate hyperoxic lung injury. These experiments suggest that a number of other mediators may be involved in the hyperoxic lung injury process and that the functional inhibition of a portion of the arachidonic acid cascade was not sufficient to either prevent or attenuate hyperoxic lung injury in newborn rabbits.