Ventricular Repolarization Sequence During Right Ventricular Endocardial and Left Ventricular Epicardial Pacing : Monophasic Action Potential Mapping in Swine

Content Provider	Semantic Scholar
Author	Xia, Yunlong Kongstad, Ole Platonov, Pyotr Holm, Magnus Olsson, Bertil Yang, Yanzong Yuan, Shiwen
Copyright Year	2010
Abstract	Previous studies have suggested that the sequence of ventricular repolarization follows that of activation during sinus rhythm and atrial pacing. However, the repolarization sequence during ventricular pacing is unknown. Using the CARTO mapping system on 10 healthy pigs, global monophasic action potentials (MAPs) were recorded from the left ventricular (LV) and right ventricular (RV) endocardium at 121 ¡ 35 sites during right atrial (RA) pacing, RV apex endocardial (RVEndo) pacing and LV laterobasal epicardial (LVEpi) pacing. The MAP mapping procedure of each pacing protocol was performed within 3 h. Local activation time (AT), MAP duration (MAPd) and end-of-repolarization (EOR) time were measured, and three-dimensional global maps of the AT and EOR were constructed. The results showed that 1) MAPd in both ventricles during RVEndo pacing was similar to that during RA pacing (p . 0.05), whereas MAPd during LVEpi pacing was significantly greater than that during RVEndo pacing (p , 0.05); 2) in all maps, there was a negative correlation between MAPd and AT and a positive correlation between EOR time and AT (p , 0.05–0.001); and 3) during RA pacing, the EOR sequence followed the AT sequence in both ventricles. Strikingly, the EOR sequence was also consistent with the AT sequence in both ventricles either during RVEndo pacing or during LVEpi pacing, even though the mapping was performed under abrupt changing of the pacing site. The ventricular repolarization sequence followed the activation sequence not only during RA pacing, but also during RVEndo pacing and LVEpi pacing, suggesting the importance of the activation sequence in governing repolarization patterns. Significant changes in repolarization from an altered activation sequence could happen within a few hours in vivo, implying that electrical remodeling of the ventricles may be rapidly induced by altered activation sequence.
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