Novel parameters to improve quantification of repolarization reserve and arrhythmogenesis using a dofetilide challenge
| Autor: | Avram Oros, Rosanne Varkevisser, R. van der Nagel, Peter Oosterhoff, T. R. G. Stams, Marlies de Vos, H D M Beekman, Stephan K.G. Winckels |
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| Rok vydání: | 2013 |
| Předmět: |
Bradycardia
medicine.medical_specialty business.industry Torsades de pointes Dofetilide DCN PAC - Perception action and control medicine.disease Primary outcome Idioventricular rhythm Physiology (medical) Internal medicine Anesthesia medicine Cardiology Action potential duration Repolarization reserve medicine.symptom Cardiology and Cardiovascular Medicine Cardioversions business medicine.drug |
| Zdroj: | Heart Rhythm, 10, 1745-6 Heart Rhythm, 10, 11, pp. 1745-6 |
| ISSN: | 1547-5271 |
| Popis: | Item does not contain fulltext BACKGROUND: In the canine complete AV block (AVB) model with bradycardia, inducibility of drug-induced torsades de pointes (TdP) is usually the primary outcome parameter, whereas short-term variability (STV) of the left ventricular monophasic action potential duration (LV MAPD) is used as primary surrogate parameter. The dichotomous parameter inducibility is cumbersome because it requires >/=3 TdP episodes and does not take into account (multiple) ectopic beats or severity of TdP episodes. In this study, we introduce arrhythmia score (AS) and T25, using dofetilide (D) to improve quantification of repolarization reserve. METHODS: Experiments performed under general anesthesia in unremodeled, acute AVB dogs (aAVB, n = 13) and 3 groups of AVB dogs with chronic bradycardia but differences in remodeling due to alterations in chronic activation pattern were analyzed: spontaneous idioventricular rhythm (IVR, n = 19), more physiologic high-septal pacing (HSP, n = 10), and right ventricular apex pacing (RVA, n = 8). AS was calculated as 1 + mean number of beats of the 3 most severe arrhythmias after D (0.025 mg/kg/5 min), with scores of 50, 75, and 100, for 1, 2, and >/=3 cardioversions, respectively. T25 was defined as the time required to obtain 25-ms increase of LV MAPD after D. RESULTS: For groups aAVB, IVR, HSP and RVA, TdP inducibility was 0%, 74% (P |
| Databáze: | OpenAIRE |
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