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Updated: Jul 16, 2025

Electrophysiological Assessment of Murine Atria with High-Resolution Optical Mapping
Published on: February 22, 2018
Electrophysiologic Determinants of Isoelectric Intervals on Surface Electrocardiograms During Atrial Tachycardia:
Yosuke Nakatani1, Masateru Takigawa1, F Daniel Ramirez2
1Department of Cardiac Pacing and Electrophysiology, Hôpital Cardiologique du Haut-Lévêque, Centre Hospitalier Universitaire de Bordeaux, Pessac, France; IHU LIRYC-Centre Hospitalier Universitaire Bordeaux, Universitaire Bordeaux, Institut National de la Santé et de la Recherche Médicale U1045, Pessac, France.
Background:
Substrate abnormalities can alter atrial activation during atrial tachycardias (ATs) thereby influencing AT-wave morphology on the surface electrocardiogram.
Objectives:
This study sought to identify determinants of isoelectric intervals during ATs with complex atrial activation patterns.
Methods:
High-density activation maps of 126 ATs were studied. To assess the impact of the activated atrial surface on the presence of isoelectric intervals, this study measured the minimum activated area throughout the AT cycle, defined as the smallest activated area within a 50-millisecond period, by using signal processing algorithms (LUMIPOINT).
Results:
ATs with isoelectric intervals (P-wave ATs) included 23 macro-re-entrant ATs (40%), 26 localized-re-entrant ATs (46%), and 8 focal ATs (14%), whereas those without included 46 macro-re-entrant ATs (67%), 21 localized-re-entrant ATs (30%), and 2 focal ATs (3%). Multivariable regression identified smaller minimum activated area and larger very low voltage area as independent predictors of P-wave ATs (OR: 0.732; 95% CI: 0.644-0.831; P < 0.001; and OR: 1.042; 95% CI: 1.006-1.080; P = 0.023, respectively). The minimum activated area with the cutoff value of 10 cm2 provided the highest predictive accuracy for P-wave ATs with sensitivity, specificity, and positive and negative predictive values of 96%, 97%, 97%, and 95%, respectively. In re-entrant ATs, smaller minimum activated area was associated with lower minimum conduction velocity within the circuit and fewer areas of delayed conduction outside of the circuit (standardized β: 0.524; 95% CI: 0.373-0.675; P < 0.001; and standardized β: 0.353; 95% CI: 0.198-0.508; P < 0.001, respectively).
Conclusions:
Reduced atrial activation area and voltage were associated with isoelectric intervals during ATs.
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