3 research outputs found
Relationship between body surface potential maps and atrial electrograms in patients with atrial fibrillation
PhD ThesisAtrial fibrillation (AF) is the most common cardiac arrhythmia. It is
distinguished by fibrillating or trembling of the atrial muscle instead of normal
contraction. Patients in AF have a much higher risk of stroke. AF is often driven
by the left atrium (LA) and the diagnosis of AF is normally made from lead V1 in
a 12-lead electrocardiogram (ECG). However, lead V1 is dominated by right
atrial activity due to its proximal location to the right atrium (RA). Consequently
it is not well understood how electrical activity from the LA contributes to the
ECG. Studies of the AF mechanisms from the LA are typically based on
invasive recording techniques. From a clinical point of view it is highly desirable
to have an alternative, non-invasive characterisation of AF.
The aim of this study was to investigate how the LA electrical activity was
expressed on the body surface, and if it could be observed preferentially in
different sites on the body surface. For this purpose, electrical activity of the
heart from 20 patients in AF were recorded simultaneously using 64-lead body
surface potential mapping (BSPM) and bipolar 10-electrode catheters located in
the LA and coronary sinus (CS). Established AF characteristics such as
amplitude, dominant frequency (DF) and spectral concentration (SC) were
estimated and analysed. Furthermore, two novel AF characteristics (intracardiac
DF power distribution, and body surface spectral peak type) were proposed to
investigate the relationship between the BSPM and electrogram (EGM)
recordings.
The results showed that although in individual patients there were body
surface sites that preferentially represented the AF characteristics estimated
from the LA, those sites were not consistent across all patients. It was found
that the left atrial activity could be detected in all body surface sites such that all
sites had a dominant or non-dominant spectral peak corresponding to EGM DF.
However, overall the results suggested that body surface site 22 (close to lead
V1) was more closely representative of the CS activity, and site 49 (close to the
posterior lower central right) was more closely representative of the left atrial
activity. There was evidence of more accurate estimation of AF characteristics
using additional electrodes to lead V1
Non-invasive estimation of left atrial dominant frequency in atrial fibrillation from different electrode sites: Insight from body surface potential mapping
© 2014, CardioFront LLC. All rights reserved. The dominant driving sources of atrial fibrillation are often found in the left atrium, but the expression of left atrial activation on the body surface is poorly understood. Using body surface potential mapping and simultaneous invasive measurements of left atrial activation our aim was to describe the expression of the left atrial dominant fibrillation frequency across the body surface. 20 patients in atrial fibrillation were studied. The spatial distributions of the dominant atrial fibrillation frequency across anterior and posterior sites on the body surface were quantified. Their relationship with invasive left atrial dominant fibrillation frequency was assessed by linear regression analysis, and the coefficient of determination was calculated for each body surface site. The correlation between intracardiac and body surface dominant frequency was significantly higher with posterior compared with anterior sites (coefficient of determination 67±8% vs 48±2%,
Comparison of body surface and intracardiac ECG recordings in patients with atrial fibrillation during electrophysiological studies
Atrial fibrillation (AF) dominant frequency (DF) is thought to reflect the degree of organisation of underlying atrial activity (AA). Our aim was to evaluate the relationship between the DFs from the body surface electrocardiogram (ECG) and intracardiac electrogram (EGM). Surface recordings of the ECG with 64 electrodes were obtained from 12 patients during AF ablation procedures. After subtracting ventricular activity (QRST), DF was obtained from spectral analysis of the channel exhibiting the largest AF component. Intracardiac recordings from the coronary sinus (CS) were obtained simultaneously, the DF was extracted from the channel closest to the left atrium. 24 recordings of 2 minute duration were analysed. Mean (SD) DF of the body surface ECG recording was 6.09 (0.87) Hz, and for intracardiac recording was 5.78 (0.84). Although in individual subjects there were differences in DF between the surface and intracardiac recordings up to 1.6 Hz, overall the difference was only 0.31 (0.64) Hz and was not significant. © 2013 Springer-Verlag