Jeanny K. Park

Concept mapping assessment in medical education: a comparison of two scoring systems

Background  Concept mapping has the potential to measure important aspects of a students evolving knowledge framework in a way that conventional examinations cannot. This is important because development of an elaborate and well‐structured knowledge framework is a critical step toward becoming an expert in a particular field. Little is known about the best way to score concept maps in the setting of medical education. Therefore, as a preliminary step in addressing this question, we compared two different scoring systems for validity: a structural method based on the organization of a maps hierarchical structure and a relational method based, not on structure, but on the quality of each individual map component.

Use of an implantable cardioverter defibrillator in an eight-month-old infant with ventricular fibrillation arising from a myocardial fibroma.

We report our experience with use of a ICD in a 7‐month‐old infant who presented with VF. We utilized an epicardial patch and active generator in the abdomen. Development of mediastinitis required explantation and eventual replacement with a subcutaneous patch and active generator in the abdomen.

Absent Pulmonary Valve with Tricuspid Atresia or Severe Tricuspid Stenosis: Report of Three Cases and Review of the Literature

Absence of the pulmonary valve occurs usually in association with tetralogy of Fallot and occasionally with an atrial septal defect or as an isolated lesion. Very rarely it occurs with tricuspid atresia, intact ventricular septum, and dysplasia of the right ventricular free wall and of the ventricular septum. We present the clinical, anatomic, and histologic findings of a new case, and for the first time, the data from two patients with absent pulmonary valve and severe tricuspid stenosis, who exhibited similar histologic findings. We also reviewed the clinical and anatomic data of 24 previously published cases and compared them with the new cases. In all three new cases, the myocardium of the right ventricle was very abnormal. In the two cases with tricuspid stenosis, large segments of myocardium were replaced with sinusoids and fibrous tissue. In the case with tricuspid atresia, the right ventricular free wall contained only fibroelastic tissue. The ventricular septum in all three patients showed asymmetric hypertrophy and in two of the three patients, multiple sinusoids had replaced large segments of myocardial cells. The left ventricular free wall myocardium and the walls of the great arteries were unremarkable. Our data indicate that myocardial depletion involving the right ventricular free wall and the ventricular septum and its replacement by sinusoids and fibroelastic tissue occur not only in cases of absent pulmonary valve with tricuspid atresia but also in cases of absent pulmonary valve with tricuspid stenosis. The degree of myocardial depletion varies and is more severe when the tricuspid valve is atretic.

Pregnancy in Postural Orthostatic Tachycardia Syndrome

Introduction: Postural orthostatic tachycardia syndrome (POTS) is a rare disease characterized by syncope, sinus tachycardia, and orthostasis due to autonomic dysfunction.

Prolonged QT Interval Corrected for Heart Rate During Diabetic Ketoacidosis in Children

OBJECTIVE To evaluate the effect of diabetic ketoacidosis (DKA) on the QT interval corrected for heart rate (QTc) in children. Ketosis occurs in several conditions, including DKA and alcoholic ketoacidosis, and during use of very low-carbohydrate diets. Prolongation of the QTc has been described in a few children receiving ketogenic diets, but cardiac effects of ketosis have not otherwise been investigated. DESIGN For this observational study, we performed electrocardiography during DKA and after recovery. We measured QTc as the QT interval divided by the square root of the R-R interval and correlated QTc with clinical variables. SETTING The pediatric emergency department and intensive care unit of an academic medical center. PATIENTS Thirty children with type 1 diabetes mellitus and DKA. MAIN OUTCOME MEASURE The QTc during DKA. RESULTS The mean (SD) QTc during DKA was 450 (38) milliseconds (range, 378-539 milliseconds). After recovery from DKA, the mean (SD) QTc decreased to 407 (36) milliseconds (range, 302-485 milliseconds; difference, 43 milliseconds; 95% confidence interval, 23-63 milliseconds) (P < .001). Fourteen of the 30 children (47%) had prolonged QTc during DKA (range, 450-539 milliseconds). After recovery from DKA, only 4 children (13%) had persistent QTc prolongation (range, 451-485 milliseconds). The anion gap was significantly associated with QTc prolongation (correlation coefficient, 0.49; P = .006). Most patients had no electrolyte abnormalities or hypoglycemia to account for QTc prolongation. CONCLUSIONS Prolonged QTc occurs frequently during DKA and is correlated with ketosis. Current guidelines regarding cardiac monitoring of children during DKA should be strictly followed, and electrocardiographic screening of patients with other ketotic conditions should be considered.

Test Characteristics of a Level I or II Fetal Ultrasound in Detecting Structural Heart Disease

At the University of California Davis Medical Center, a screening fetal ultrasound examination (level I or II) incorporates a comprehensive segmental evaluation of the fetal heart. This study evaluated the reliability of the fetal ultrasound exam in the detection of abnormal heart anatomy. Our retrospective study reviewed results of 614 antenatal patients that had a screening fetal ultrasound exam. All patients subsequently underwent a detailed targeted fetal cardiac ultrasound exam performed by a pediatric cardiac sonographer and reviewed by a board-certified pediatric cardiologist. Of these 614 patients, 60 fetuses had structural heart disease by the targeted fetal exam. The screening fetal ultrasound exam correctly identified 55 of the 60, with 5 false negatives (8.3% false-negative rate) and 1 false positive (1.7% false-positive rate). Our study suggests that if a screening fetal ultrasound exam incorporates a segmental evaluation of the fetal heart it can reliably detect abnormal heart anatomy. At our institution a targeted fetal cardiac exam is now used to confirm and provide detailed assessment of the heart anatomy when a screening fetal exam is positive for heart disease.

Analysis of body surface area as a determinant of impedance during radiofrequency catheter ablation in adults and children

Since most radiofrequency (RF) generators used for catheter ablation approximate a constant voltage output, applied power is inversely proportional to the impedance load of the system. Knowledge of the expected impedance load for a patient may facilitate selection of safer and more effective voltage output. Preliminary observations suggest that in adults, impedance is directly proportional to body surface area (BSA), thus prompting this study to determine whether this relation was maintained in smaller patients undergoing RF catheter ablation. Prospective analysis of impedance from 949 RF deliveries in 76 patients (BSA, 0.69-2.3 m2) revealed the mean impedance for all deliveries to be 103 +/- 8 ohms. Two-phase linear regression analysis revealed a significant, direct correlation between impedance and BSA in patients with a BSA > or = 1.5 m2 (P = .001); however, for patients with a BSA < 1.5 m2 there was no correlation. These results indicate that as patient size decreases below 1.5 m2, impedance is constant. Radiofrequency catheter ablation procedures in children may require selection of a voltage output similar to that used in adults in order to produce effective RF lesions.

Use of Transvenous DDD Pacing in a One-Year-Old with Symptomatic Hypertrophic Cardiomyopathy

Abstract. Symptomatic hypertrophic cardiomyopathy (HCM) is rare in infants. Therapeutic options are limited and include β-blocker or calcium-channel blocker therapy or surgical myotomy/myectomy. Atrioventricular sequential pacing has been utilized as an alternative to surgery in symptomatic adults with HCM. We report our results with transvenous dual chamber pacing in an infant with symptomatic HCM.