Electrophysiological measurements that can explain and guide temporary accelerated pacing to avert (re)occurrence of torsade de pointes arrhythmias in the canine chronic atrioventricular block model

Sofieke C Wijers; Alexandre Bossu; Albert Dunnink; Jet D M Beekman; Rosanne Varkevisser; Alfonso Aranda Hernández; Mathias Meine; Marc A Vos

doi:10.1016/j.hrthm.2017.02.007

Electrophysiological measurements that can explain and guide temporary accelerated pacing to avert (re)occurrence of torsade de pointes arrhythmias in the canine chronic atrioventricular block model

Heart Rhythm. 2017 May;14(5):749-756. doi: 10.1016/j.hrthm.2017.02.007. Epub 2017 Feb 14.

Authors

Sofieke C Wijers¹, Alexandre Bossu¹, Albert Dunnink¹, Jet D M Beekman¹, Rosanne Varkevisser¹, Alfonso Aranda Hernández², Mathias Meine³, Marc A Vos⁴

Affiliations

¹ Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands.
² Medtronic Bakken Research Center, Maastricht, The Netherlands.
³ Department of Cardiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands.
⁴ Department of Medical Physiology, Division of Heart and Lungs, University Medical Center Utrecht, Utrecht, The Netherlands. Electronic address: m.a.vos@umcutrecht.nl.

PMID: 28213055
DOI: 10.1016/j.hrthm.2017.02.007

Abstract

Background: Pacing at higher rates is known to suppress torsade de pointes (TdP) arrhythmias. Nevertheless, exact application and mechanism need further clarification. In the anesthetized canine chronic atrioventricular block model, ventricular remodeling is responsible for a high and reproducible incidence of TdP upon a challenge with dofetilide.

Objective: We used this model to investigate by what mechanism accelerated pacing averts TdP and what repolarization parameter could be used to guide temporary accelerated pacing (TAP).

Methods: Ten dogs with repetitive TdP after administration of dofetilide when paced at 60 beats/min were selected. In a serial experiment, TAP was initiated at 100 beats/min after the first ectopic beat. Electrocardiogram and right and left ventricular (LV) monophasic action potential durations (MAPDs) were recorded. In a subset, vertical dispersion was determined with a duodecapolar catheter. Temporal dispersion was quantified as short-term variability (STV). Arrhythmias were quantified with the arrhythmia score.

Results: The increase in repolarization parameters observed after administration of dofetilide was counteracted by TAP (eg, LV MAPD from 381 ± 94 ms back to 310 ± 17 ms; P < .05). Temporal dispersion (STV_LVMAPD) increased from 0.69 ± 0.37 to 2.59 ± 0.96 ms (P < .05) after administration of dofetilide and back to 1.15 ± 0.54 ms (P < .05) with TAP. This was accompanied by suppression of recurrent TdP in 7 of 10 dogs (P < .05) and a trend toward reduction in vertical (spatial) dispersion from 56 ± 25 to 31 ± 4 ms (P = .06). In those dogs, seconds after capture of TAP, almost all ectopy disappeared, causing a decrease in arrhythmia score from 21 ± 12 to 4 ± 3 (P < .05).

Conclusion: TAP is effective in averting TdP by decreasing spatial and temporal measures of repolarization. Increase in temporal dispersion (STV) can guide TAP.

Keywords: Dispersion; Pacing; Prevention; Short-term variability; Torsade de pointes.

MeSH terms

Animals
Atrioventricular Block / complications
Atrioventricular Block / physiopathology*
Atrioventricular Block / therapy*
Cardiac Pacing, Artificial / methods*
Chronic Disease
Disease Models, Animal
Dogs
Electrophysiologic Techniques, Cardiac
Electrophysiological Phenomena
Heart Rate / physiology
Recurrence
Torsades de Pointes / etiology
Torsades de Pointes / physiopathology*
Torsades de Pointes / prevention & control*
Ventricular Remodeling / physiology