Biomedical subjects

Christine C Chiu

Publications and source records attributed to Christine C Chiu.

4 recordsLinked to original sources

PubMed2006

Evaluation of computerized interpretation of the pediatric electrocardiogram.

The purpose of this research was to determine the frequency and factors affecting disagreement between pediatric cardiologist (MD1 or MD2) and the computer-assisted interpretation (CAI) of pediatric electrocardiograms from patients with heart disease (HD, n = 586) or normal heart (n = 561). Significant disagreement was found in HD (146/586, 25%) compared with normal heart (64/561, 11%) (P < .001). The CAI overinterpreted prolonged QT, sinus rhythm with ectopy, and right ventricular hypertrophy; CAI underinterpreted sinus rhythm, sinus arrhythmia, and right bundle branch block (P < .05). Increased disagreement was independently associated with HD (odds ration [OR], 2.2), younger patient age at the time of the electrocardiogram, if the computer interpretation had more than 3 separate diagnostic statements (OR, 3.2) and if the overreading cardiologist was MD1 (OR, 2.9). Although CAI is helpful, pediatric cardiologists were more likely to disagree with the computer in rhythm diagnosis, recognition of bundle branch block, hypertrophy, and QT interval analysis.

Adolescent↗

PubMed2006

Chronotropic incompetence in young patients with late postoperative atrial flutter: a case-control study.

AIMS: Atrial flutter causes late postoperative morbidity in congenital heart disease (CHD). Sinoatrial node dysfunction is associated with late postoperative atrial flutter, but pacing interventions driven by minimum heart rates (HR) have yielded mixed results. METHODS AND RESULTS: A retrospective case-control study was used to test the hypothesis that late postoperative atrial flutter is associated with chronotropic incompetence in active young CHD patients. Control CHD patients aged < or =18 years without documented supraventricular ectopy (n = 42) were matched with 42 patients (cases) having atrial flutter onset > or =6 months postoperatively. Minimum, average, and maximum non-flutter HRs were obtained from outpatient ambulatory 24 h ECG (Holter) recordings and graded exercise tests. Chronotropic competence was assessed using percentage of age-specific predicted maximum HR achieved, and calculated chronotropic index. Effects of rate-adaptive programming and maximum atrial pacing rates were analysed in 19 permanently paced cases. Least square estimates of minimum HRs were similar in cases and controls (54+/-2 vs. 52+/-2 bpm). Average HRs were lower in cases (75+/-2 vs. 81+/-2 bpm, P=0.02). Cases and controls differed most significantly with respect to percentage of predicted maximum HR achieved (67+/-2 vs. 80+/-2%, P < 0.001). This difference remained highly significant when the data were adjusted for age, sex, permanent pacing, and negatively chronotropic medication usage at the time of testing. Among paced patients, atrial flutter was significantly less likely to be observed in the setting of rate-adaptive pacing [odds ratio (OR) = 0.36; P < 0.05], and the likelihood of detecting atrial flutter decreased relative to the maximum programmed atrial pacing rate (OR 0.87 for every 5% increment in maximum pacing rate relative to maximum predicted HR for age; P < 0.05). CONCLUSION: Late postoperative atrial flutter is associated with chronotropic incompetence in paediatric CHD patients.

Adolescent↗

PubMed2006

Natural history of postoperative heart block in congenital heart disease: implications for pacing intervention.

After half a century of major progress in congenital heart disease management, atrioventricular conduction block continues to complicate 1-3% of surgical procedures. Unless treated with an implanted pacemaker, permanent postoperative heart block is associated with 28-100% mortality. Postoperative heart block often proves to be transient, typically resolving within 10 days of onset. The duration of postoperative heart block is widely used as a key determinant for permanent pacemaker implantation. Current professional pacemaker implantation guidelines are largely based on this criterion. However, available natural history data suggest that other factors, such as residual conduction system injury, likely play a role in increasingly recognized cases of very late postoperative mortality and morbidity in patients who have experienced transient postoperative heart block. As growing numbers of congenital heart disease patients survive into adulthood, and artificial pacemaking capabilities continue to improve, it might be necessary to reconsider and refine currently accepted pacing indications for postoperative heart block.

Cardiac Pacing, Artificial↗

PubMed2004

Usability assessment of pacemaker programmers.

There is a perception among clinicians of usability differences in the user interface of pacemaker programmers, but there is an absence of literature in this area. The purpose of this study was to describe usability differences in pacemaker programmers. Forty-two programmer users completed self-administered questionnaires and two usability experts independently performed heuristic evaluation to identify features that violated general usability principles. Programmers from seven manufacturers (coded A-G) were evaluated. There was a balanced representation of users: nurses (58%) versus technologists (40%) who are employed in community (50%) versus academic (45%) hospitals, novice versus expert users based on the median users' programming experience of 60 months (range 1-300 months). Significant differences between programmers were found in overall user satisfaction and ease of programmer use (P < 0.0001) in the display, controls, operation, and physical dimension of the programmers (P < 0.05). Heuristic evaluations showed frequent violations of usability principles in all programmers. Problematic areas include reliance on user recall, inconsistency in operation of critical controls, poor readability, and not anticipating user wants or action. Programmer interface designs do not consistently meet user needs or general usability principles. This impacts on the safe and effective use of programmers. Guidelines in programmer design should be established, particularly with respect to labeling, location, and operation of critical controls.

Cardiac Pacing, Artificial↗