Unusual sinus arrhythmia

Gratadour, P; Cividjian, Andrei; Sagnard, Pierre; Parlow, Joel L.; Viale, J. P.; Quintin, Luc

doi:10.1016/j.ijcard.2007.04.138

Cited by 6 publications

(1 citation statement)

References 22 publications

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“…In this study, we used a cyclic pacing pattern, specifically oscillation in CL, to elicit alternans. Clinically, oscillation in heart rate has been observed in heart failure, post-myocardial infarction, or hypertensive patients [7]–[9], and has been found to immediately precede the onset of arrhythmia [9]. However, the linkage of this oscillation to arrhythmia initiation has not been previously investigated.…”

Section: Introductionmentioning

confidence: 99%

Oscillation in Cycle Length Induces Transient Discordant and Steady-State Concordant Alternans in the Heart

Weinberg

Tung

2012

PLoS ONE

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Alternans is a beat-to-beat alternation of the cardiac action potential duration (APD) or intracellular calcium (Cai) transient. In cardiac tissue, alternans can be spatially concordant or discordant, of which the latter has been shown to increase dispersion of repolarization and promote a substrate for initiation of ventricular fibrillation. Alternans has been studied almost exclusively under constant cycle length pacing conditions. However, heart rate varies greatly on a beat-by-beat basis in normal and pathological conditions. The purpose of this study was to determine if applying a repetitive but non-constant pacing pattern, specifically cycle length oscillation (CLO), promotes or suppresses a proarrhythmic substrate. We performed computational simulations and optical mapping experiments to investigate the potential consequences of CLO. In a single cell computational model, CLO induced APD and Cai alternans, which became “phase-matched” with the applied oscillation. As a consequence of the phase-matching, in one-dimensional cable simulations, neonatal rat ventricular myocyte monolayers, and isolated adult guinea pig hearts CLO could transiently induce spatial and electromechanical discordant alternans followed by a steady-state of concordance. Our results demonstrated that under certain conditions, CLO can initiate ventricular fibrillation in the isolated hearts. On the other hand, CLO can also exert an antiarrhythmic effect by converting an existing state of discordant alternans to concordant alternans.

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Section: Introductionmentioning

confidence: 99%