Quantifying intracardiac organization of XXXX using temporospatial phase of the electrocardiogram.

@entity1 @entity591 @entity956 @entity955 @entity4710 @entity943
INTRODUCTION: Separating nonisthmus-dependent @entity956 ( @entity956 ) from "organized" @entity955 ( @entity955 ), or isthmus-dependent @entity956 , may be difficult using ECG characteristics alone. We hypothesized that temporal and spatial phase analysis of ECG atrial waveforms could effectively separate these rhythms by quantifying subtle variations in ECG atrial activation during @entity4710 ( @entity4710 ). METHODS AND RESULTS: We studied 52 @entity1 at electrophysiologic study (EPS) who demonstrated isthmus-dependent (n = 15) and nonisthmus-dependent (n = 9) @entity956 , @entity591 (n = 6), AV nodal reentry (n = 9), orthodromic reciprocating @entity591 (n = 6), and @entity955 (n = 7). Atrial activity was represented as a series of correlations of an atrial template to successive time samples of the @entity943 ECG. Spatial phase was analyzed as a reproducible relationship of this atrial activity between leads over time; temporal regularity was measured from power spectra. Spatial phase was maintained (coherent) in lead planes V5/aVF (XY), V5/V1 (XZ), and aVF/V1 (YZ) in 15 of 15 cases of isthmus-dependent @entity956 , but in only 1 of 9 cases of nonisthmus-dependent @entity956 (P < 0.01; chi2). Temporally, all cases of @entity956 showed one dominant peak on correlation spectra (magnitude >6 dB), suggesting one activation wavefront, although this was smeared in nonisthmus-dependent cases. In contrast, @entity955 showed inconsistent spatial phase in all planes and broad band spectra, consistent with multiple and/or variable activation paths. All other SVTs showed spatial coherence and one dominant spectral peak. CONCLUSION: Coherence of temporal and spatial phase is a powerful approach to measure the spatial organization of intracardiac activation from the ECG that reveals a spectrum from @entity4710 to isthmus-dependent and nonisthmus-dependent @entity956 , to @entity955 .
