Electrocardiographic intervals: QRS width and beyond

The pro-arrhythmic risk inherent to a new drug must be assessed at an early preclinical stage. Telemetry system implantation is a method widely used in vivo in various species. The present study was designed to assess whether conscious freely moving guineapigs can be used to predict QT prolongation in vivo. The guineapig has three advantages over the dog and the primate. First, it has specific ion channels similar to man; second, a smaller amount of test article is required for the investigation and third, its housing is less expensive. Under sterile conditions and isoflurane anaesthesia, telemetry transmitters were implanted intraperitoneally in male Dunkin Hartley guineapigs. Blood pressure, heart rate and electrocardiographic intervals were measured from two days up to eight months. Chronic implantation of the telemetry device did not lead to anatomic or macroscopic alterations in the abdominal cavity and no inflammation of the peritoneum or infection was observed. Four reference compounds were used: three positive (sotalol, terfenadine and dofetilide) and one negative reference (enalapril). Single oral administration of all three positive references dose-dependently induced bradycardia and QT corrected (QTc) prolongation. In contrast, neither enalapril nor its vehicle prolonged the QTc. These results demonstrate that the guineapig is both a suitable model and a good alternative to dogs or primates to assess the potential of compounds for QT interval prolongation in the early stages of drug development.

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Retention of Baseline Electrocardiographic Knowledge After a Blended-Learning Course

American Journal of Critical Care ◽

10.4037/ajcc2016556 ◽

2016 ◽

Vol 25 (1) ◽

pp. 61-67 ◽

Cited By ~ 4

Author(s):

Carol Ann Brooks ◽

Nancy Kanyok ◽

Colin O’Rourke ◽

Nancy M. Albert

Keyword(s):

Blended Learning ◽

Test Scores ◽

Mean Difference ◽

Therapeutic Interventions ◽

Work Characteristics ◽

Self Assessment ◽

Skill Retention ◽

Work Retention ◽

Electrocardiographic Intervals

Background Among nurses, skill retention after an electrocardiography blended-learning course is unknown. Objectives To compare 3- and 8-week electrocardiography test scores, compare scores by nurse and work characteristics and self-assessed electrocardiographic competence, and compare 1-year work retention with 3- and 8-week scores and change in scores from week 3 to week 8. Methods Data were collected on demographics, comfort with electrocardiography expectations, electrocardiography competence levels, and 1-year work retention. Correlational and comparative statistics were used in analyses. Results Of 69 nurses, 58% were somewhat comfortable with interventions for abnormal rhythms. Test scores were higher at 3 weeks than at 8 weeks: mean difference, 26%; P < .001. Scores at 8 weeks reflected intermediate skill retention and were not associated with nurse characteristics, electrocardiography background, comfort with rhythms and measurements, or 1-year work retention. Nurses with greater comfort for intervening when rhythm abnormalities occurred had higher median 8-week scores (P = .01) than did nurses with less comfort, and perceptions of electrocardiographic competence were associated with 8-week scores (r = 0.28; P = .02). Reduction in scores at 8 weeks was less severe in nurses with greater comfort at 3 weeks in measuring electrocardiographic intervals (P = .008) and applying therapeutic interventions (P = .009). Conclusions Skill retention and competence in electrocardiographic interpretation were intermediate and correlated with baseline self-assessment. Electrocardiographic interpretation, measurement, and interventions should be reinforced at the bedside.

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