Key result
Local epicardial cooling and warming altered activation-recovery intervals and conduction velocity (p<0.05) but did not favor the induction of ventricular arrhythmias in isolated rabbit hearts (n=8).
Why the study?
Does local epicardial cooling/warming facilitate ventricular arrhythmia induction in isolated rabbit hearts?
Does local epicardial cooling/warming facilitate ventricular arrhythmia induction in isolated rabbit hearts?
p-value: p=<0.05
Epicardial-limited electrophysiological heterogeneities induced by local temperature changes do not facilitate ventricular arrhythmia induction in isolated rabbit hearts.
Epicardial temperature changes do not promote ventricular arrhythmias in rabbit hearts; leaves open translation to intact or clinical settings.
The electrophysiological heterogeneities of the myocardium are associated with vulnerability to arrhythmias. This study presents an experimental heterogeneity model based on local epicardial cooling/warming. The ventricular activation-recovery interval (ARl), conduction velocity (CV) and arrhythmogenic response to electrical pacing were determined. Electrical mapping was carried out on isolated rabbit hearts (n=8), using a specific electrode device for epicardial temperature control. With respect to baseline, ARl in the modified zone was prolonged (137 ± 22 ms vs 111 ± 13 ms, p<;0.05) under maximum hypothermia (22.3 ± 0.6 °C vs 36.7 ± 0.8 DC), and was shortened (98 ± 13 ms vs 107 ± 16 ms, p<;0.05) under conditions of hyperthermia (41.8 ± 0.3 °C vs 37.3 ± 0.4 DC). CV decreased (70 ± 17 cm/s vs 76 ± 17 cm/s, p<;0.05) under hypothermia and increased (79 ± 20 cm/s vs 75 ± 21 cm/s, p<;0.05) under hyperthermia. There were no changes in the unmodified zone. Repetitive responses were observed in four hearts, with no dependency between the appearance of responses and the induced modifications. Thermally induced dispersion of ARl and CV did not favor the induction of ventricular arrhythmias, probably because only a limited zone of the ventricular epicardium was affected.
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Guill et al. (2015) studied Ventricular arrhythmia (n=8). Local epicardial cooling/warming vs. Baseline was evaluated on Ventricular activation-recovery interval (ARI), conduction velocity (CV) and arrhythmogenic response to electrical pacing (p=<0.05). Local epicardial cooling and warming altered activation-recovery intervals and conduction velocity (p<0.05) but did not favor the induction of ventricular arrhythmias in isolated rabbit hearts (n=8).
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