The effect of activation rate on left atrial bipolar voltage in patients with paroxysmal atrial fibrillation

Abstract

IntroductionBipolar voltage is used during electroanatomic mapping to define abnormal myocardium, but the effect of activation rate on bipolar voltage is not known. We hypothesized that bipolar voltage may change in response to activation rate. By examining corresponding unipolar signals we sought to determine the mechanisms of such changes.Methods and resultsLA extrastimulus mapping was performed during CS pacing in 10 patients undergoing first time paroxysmal atrial fibrillation ablation. Bipolar and unipolar electrograms were recorded using a PentaRay catheter (4‐4‐4 spacing) and indifferent IVC electrode, respectively. An S1S2 pacing protocol was delivered with extrastimulus coupling interval reducing from 350 to 200 milliseconds. At each recording site (119 ± 37 per LA), bipolar peak‐to‐peak voltage, unipolar peak to peak voltage and activation delay between unipole pairs was measured. Four patterns of bipolar voltage/extrastimulus coupling interval curves were seen: voltage attenuation with plateau voltage >1 mV (48 ± 15%) or <1 mV (22 ± 15%), and voltage unaffected by coupling interval with plateau voltage >1 mV (17 ± 10%) or <1 mV (13 ± 8%). Electrograms showing bipolar voltage attenuation were associated with significantly greater unipolar voltage attenuation at low (25 ± 28 mV/s vs. 9 ± 11 mV/s) and high (23 ± 29 mV/s vs. 6 ± 12 mV/s) plateau voltage sites (P < 0.001). There was a small but significant increase in conduction delay between unipole pairs at sites showing bipolar voltage attenuation (P = 0.026).ConclusionsBipolar electrogram voltage is dependent on activation rate at a significant proportion of sites. Changes in unipolar voltage and timing underlie these effects. These observations have important implications for use of voltage mapping to delineate abnormal atrial substrate.

Probabilistic Interpolation of Uncertain Local Activation Times on Human Atrial Manifolds

“…The recordings analyzed in this paper were part of a study involving patients with paroxysmal atrial fibrillation and undergoing first-time atrial fibrillation ablation, which is detailed elsewhere [4]. We analyzed recordings from three patients.…”

“…Electrograms are recorded using a multipolar catheter which records electrical activity on the endocardial surface at one or more locations, sometimes for multiple pacing protocols and catheter positions. LAT maps can be used to calculate conduction velocity maps [3], and different pacing protocols allow the dynamic response of the electro-anatomical substrate to be inferred [4]. Although advances in catheter design have increased the number of recordings that can be made simultaneously, longer procedure times pose a risk to the patient and a cost for the health care system, which places limits on the spatial density of the mapping observations, as well as how many pacing protocols and pacing locations can be used.…”

Impact of atrial programmed electrical stimulation techniques on unipolar electrogram morphology

“…The results of this study add more insight to how APES affects the unipolar morphology. This is important, because bipolar recording has its limitations for morphological characterization of tissue conduction properties 28,29 . To the best of our knowledge, no studies on the influence of electrical stimulation on the unipolar EGM morphology have been published.…”

“…We examined only one stimulation and one recording catheter position. Multisite high‐resolution recording and stimulation is needed to address regional and directional influences of APES on U‐AEGM morphology 29 . The degree of contact of the recording electrodes with the atrial wall during APES remains uncertain which could have influenced U‐AEGM morphology, in particular the amplitude.…”

“…This is important, because bipolar recording has its limitations for morphological characterization of tissue conduction properties. 28,29 To the best of our knowledge, no studies on the influence of electrical stimulation on the unipolar EGM morphology have been published. Our results showed similar findings for unipolar EGM amplitude and fractionation.…”