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.

Intraoperative radiofrequency ablation of the atrium: effectiveness for treatment of supraventricular tachycardia in congenital heart surgery

BACKGROUND

Supraventricular tachycardia (SVT) is common in surgical patients with congenital heart disease. Ablation and maze operations have been shown to be effective in treating SVT, but these procedures can be complex and time-consuming because of variable anatomy and a thickened right atrium. To simplify and shorten these procedures, we used a long, flexible radiofrequency probe capable of producing long ablation lines quickly and effectively. We report the initial results with this procedure.

METHODS

Six patients aged 6 weeks to 40 years with refractory SVT were referred for reoperation for repair of complex congenital heart disease (transposition of the great vessels, Ebstein's anomaly, single ventricle, tetralogy of fallot). Intraoperative radiofrequency ablation was performed in the right atrium for refractory SVT as an adjunct to surgical reconstruction (redo Fontan, right atrial reduction plasty, right ventricular outflow tract reconstruction, tricuspid repair). Lesions were made with a radiofrequency probe using temperatures of 70 degrees C for 60 seconds. Lesions were placed between the coronary sinus and the tricuspid valve, between the tricuspid valve and the inferior vena cava, between the atrial septal defect and the superior and inferior vena cava in patients with intraatrial reentry tachycardia/atrial flutter, and at the location of the accessory pathway in a patient with Wolff-Parkinson-White syndrome. The long, flexible probe has multiple independently controlled segments allowing ablation lesions that conform to the atrial morphology.

RESULTS

An average of five intraoperative radiofrequency ablation lesions per patient were made. Average time for ablation was 14 minutes. With up to 25 months' follow-up, 5 patients are in sinus rhythm, and 1 is in a paced atrial rhythm. The patient with Wolff-Parkinson-White syndrome showed no preexcitation after operation. No complications resulting from intraoperative radiofrequency ablation were encountered.

CONCLUSIONS

Intraoperative radiofrequency ablation in the atrium is a safe, effective, and expeditious procedure for control of SVT in patients undergoing reoperation for congenital heart disease with refractory SVT.

Flecainide and sotalol: a new combination therapy for refractory supraventricular tachycardia in children <1 year of age

OBJECTIVES

The goal of this study was to assess the efficacy and safety of the combination therapy of flecainide and sotalol for the treatment of refractory supraventricular tachycardia (SVT) in children <1 year of age.

BACKGROUND

Supraventricular tachycardia in infants can be refractory to single-drug as well as standard combination medical therapy. Radiofrequency ablation (RFA) is the definitive treatment of refractory SVT; however, interventional therapy poses a high risk of morbidity and mortality in this age group.

METHODS

A retrospective review was performed identifying infants who required flecainide and sotalol to control refractory SVT. Patient age, previous drug therapy, duration of treatment, flecainide levels and corrected QT intervals were recorded; 24 h Holter monitoring was utilized to gauge efficacy of treatment. Efficacy was defined as suppression of SVT to no more than rare nonsustained episodes or slowing of SVT to a clinically tolerable rate.

RESULTS

Ten patients (median age: 29 days, range: 1 to 241 days) failed at least two antiarrhythmic agents including either flecainide or sotalol as single agents before initiating combination therapy. Efficacy was achieved in all patients. The failure rate for therapy was reduced from 100% to 0% (95% confidence interval: 0% to 26%). The median doses used were: flecainide 100 mg/m(2)/day (range: 40 to 150 mg/m(2)/day) and sotalol 175 mg/m(2)/day (range: 100 to 250 mg/m(2)/day). Median duration of therapy was 16 months (range: 5 to 35 months). No proarrhythmia occurred.

CONCLUSIONS

The combination of flecainide and sotalol can safely and effectively control refractory SVT and may obviate the need for RFA in children <1 year.

Sinus node dysfunction associated with lithium therapy in a child

Lithium salts have been used extensively in both adults and children during the last 30 years, for the treatment of a variety of psychiatric conditions, including bipolar disorder The cardiac side effects of lithium in adult patients have been well described. However, to the best of our knowledge, there are no reports of lithium-induced cardiac side effects in pediatric patients. We describe the case of a 9-year-old boy who developed cardiac toxicity while receiving long-term lithium therapy.

Substitution of Asp114 or Arg116 in the fingers domain of moloney murine leukemia virus reverse transcriptase affects interactions with the template-primer resulting in decreased processivity

Reverse transcriptase, an essential retroviral DNA polymerase, replicates the single-stranded RNA genome of the retrovirus, producing a double-stranded DNA copy, which is subsequently integrated into the host's genome. Substitution of Ala for either Asp114 or Arg116, two highly conserved residues in the fingers domain of Moloney murine leukemia virus reverse transcriptase, results in enzymes (D114A or R116A) with significant defects in their abilities to processively synthesize DNA using RNA or DNA as a template. D114A and R116A enzymes also bind more weakly to template-primer in the presence of added deoxyribonucleotides, as seen by gel-shift analysis, but retain the ability to strand transfer and accumulate smaller RNase H cleavage products when compared to the wild-type enzyme. In addition, mutant proviruses, including D114A and R116A substitutions in Moloney murine leukemia virus reverse transcriptase, are not viable despite the presence of processed reverse transcriptase in the viral particles. A potential mechanistic role in processive synthesis for D114 and R116 is discussed in the context of our results, related studies on HIV-1 reverse transcriptase, and previous structural studies.

Comparison of second-strand transfer requirements and RNase H cleavages catalyzed by human immunodeficiency virus type 1 reverse transcriptase (RT) and E478Q RT

Truncated tRNA-DNA mimics were examined in an in vitro assay for second-strand transfer during human immunodeficiency virus type 1 (HIV-1) reverse transcription. Strand transfer in this system requires the progressive degradation of the RNA within the 18-mer tRNA-DNA (plus-strand strong stop DNA) intermediate to products approximately 8 nucleotides in length. The ability of the truncated substrates to substitute for directional processing by RNase H or reverse transcriptase (RT) was examined. Using wild-type HIV-1 RT, substrates which truncated the 5' end of the tRNA primer by 6, 9, and 12 nucleotides (Delta6, Delta9, and Delta12, respectively) were recognized by RNase H and resulted in strand transfer. An overlap of 5 nucleotides between the acceptor and newly synthesized DNA template was sufficient for strand transfer. The mutant RT, E478Q correctly catalyzed the initial cleavage of the 18-mer tRNA-DNA mimic in the presence of Mn(2+); however, no directional processing was observed. In contrast, no RNase H activity was observed with the Delta6, Delta9, and Delta12 substrates with E478Q RT in this strand transfer assay. However, when complemented with Escherichia coli RNase H, E478Q RT supported strand transfer with the truncated substrates. E478Q RT did cleave the truncated forms of the substrates, Delta6, Delta9, and Delta12, in a polymerase-independent assay. The size requirements of the substrates which were cleaved by the polymerase-independent RNase H activity of E478Q RT are defined.

Neonatal arterial switch operation for transposition of the great arteries in a patient with mirror image dextrocardia and situs inversus totalis

The neonatal arterial switch operation has become the standard therapy for D-transposition of the great arteries in the absence of left ventricular outflow tract obstruction. We describe our experience of successful arterial switch operation after balloon atrial septostomy in a 5-day-old infant girl who had atrial and visceral situs inversus totalis, mirror image dextrocardia, and D-transposition of the great arteries. To our knowledge, ours is the first report of this operation in a patient with this anatomy.

Clonal changes in inflammatory pseudotumor of the lung: a case report

BACKGROUND

Pulmonary inflammatory pseudotumor, also known as plasma cell granuloma among many other names, is widely believed to be an inflammatory or reactive lesion rather than a neoplasm, although its pathogenesis is still controversial.

METHODS

Cytogenetic analysis was performed on a lung mass that showed typical clinical and pathologic features of inflammatory pseudotumor. Ultrastructural and immunohistochemical studies were performed in addition to routine histologic examination.

RESULTS

Cytogenetic study of the lesion revealed clonal anomalies of t(1;2)(q21;p23) and del(4)(q27). The patient, a 30-year-old woman, presented with an asymptomatic but enlarging right lower lobe mass for which partial right lower lobectomy was performed. The lung mass was well circumscribed radiographically and grossly. Microscopically, it was characterized by a loosely arranged spindle cell proliferation with prominent plasma cell infiltration. Fibroblastic and myofibroblastic differentiation of the spindle cells was demonstrated by ultrastructural and immunohistochemical studies.

CONCLUSION

To the authors' knowledge, this is the first report of clonal cytogenetic changes in a clinically and pathologically typical case of inflammatory pseudotumor in the lung. This finding suggests that pulmonary inflammatory pseudotumor might be a true neoplasm rather than a purely inflammatory or reactive lesion.

Clonal changes in inflammatory pseudotumor of the lung: a case report

BACKGROUND

Pulmonary inflammatory pseudotumor, also known as plasma cell granuloma among many other names, is widely believed to be an inflammatory or reactive lesion rather than a neoplasm, although its pathogenesis is still controversial.

METHODS

Cytogenetic analysis was performed on a lung mass that showed typical clinical and pathologic features of inflammatory pseudotumor. Ultrastructural and immunohistochemical studies were performed in addition to routine histologic examination.

RESULTS

Cytogenetic study of the lesion revealed clonal anomalies of t(1;2)(q21;p23) and del(4)(q27). The patient, a 30-year-old woman, presented with an asymptomatic but enlarging right lower lobe mass for which partial right lower lobectomy was performed. The lung mass was well circumscribed radiographically and grossly. Microscopically, it was characterized by a loosely arranged spindle cell proliferation with prominent plasma cell infiltration. Fibroblastic and myofibroblastic differentiation of the spindle cells was demonstrated by ultrastructural and immunohistochemical studies.

CONCLUSION

To the authors' knowledge, this is the first report of clonal cytogenetic changes in a clinically and pathologically typical case of inflammatory pseudotumor in the lung. This finding suggests that pulmonary inflammatory pseudotumor might be a true neoplasm rather than a purely inflammatory or reactive lesion.