Visualizing intracardiac atrial fibrillation electrograms using spectral analysis

Abstract

Abstract-Atrial fibrillation is the most common cardiac arrhythmia, and it is associated with increased risk of stroke, heart failure and mortality. In this work we describe spectral analysis techniques that are being used in conjunction with visualization algorithms to help guide catheter ablation procedures that aim at treating patients with the arrhythmia. !Atrial Fibrillation (AF) is a serious problem as it can lead to stroke and heart failure, with increased mortality. To further complicate the problem, the precise electrical mechanisms underlying AF are not well understood. One effective treatment for AF is catheter ablation, whereby areas in the atria and/or nearby locations are targeted and ablated (or "burned"). However, results are variable, with a large number of patients requiring repeated procedures if AF recurs in the short term. Long term results are even less encouraging. One of the main issues with ablation is the decision on where to ablate that gives the maximum efficacy and safety. Improving understanding of the precise electrical mechanisms underlying AF is key to minimising the amount of "burning" with ablation and maximizing the gain. It is important that information is available to aid ablation decision and strategy either before or during the ablation procedure. Hence, techniques and technologies to characterize and map candidate locations for ablation need to be implemented in real-time. In this paper we describe a technique for mapping the dominant frequency (DF) of atrial electrograms and explore, implement and measure the processing time for several approaches for its implementation. Our solution leverages the parallel processing computation offered by multiple CPU cores, but more importantly, the massive parallel computational power available in current Graphic Processing Units (GPUs). We also describe techniques for visualizing the behavior of dominant frequency of intracardiac atrial electrograms. The visualization allows the mapping of the DFs using a color scale and isolating the main DF areas. We conclude that, with current technology and using an off-the-shelf, modern personal computer with a graphics card and costing about US$ 1,000 it is possible to implement real time DF mapping with a loading as low as 6.75% (up to 50% depending of the implementation strategy and the level of detail required). This changes the perspective of the problem from pure, basic research to translational, applied research and we propose an exciting new step forward in this important area. Atrial FibrillationMeasuring and modeling the genesis and propagation of the electrical activity in the heart in quantitative terms is a very important area of research that will help understand and treat heart arrhythmias. Atrial fibrillation (AF) is a heart rhythm disturbance characterized by uncoordinated and rapid electrical atrial activation which takes over from normal sinus rhythm, with consequent deterioration of the mechanical ability of the atria to pump blood effectively. The ventricles will beat irregu...

Distinctive Patterns of Dominant Frequency Trajectory Behavior in Drug‐Refractory Persistent Atrial Fibrillation: Preliminary Characterization of Spatiotemporal Instability

“…Previously, as in this study, analysis of DF behavior required a rather laborious process of exporting the continuous 2,048 VEGMs from the geometry that could only be done offline. With the purchase of more powerful computer, including the employment of parallel processing, we are now in a position to perform the analysis in real‐time, which makes it possible to provide clinically useable data to guide strategy during the ablation procedure.…”

“…After carrying out ventricular cancellation of the VEGMs, spectral analysis was performed on each of the 2,048 points, using Fast Fourier Transform (FFT) with a Hamming window to produce high density 3D DF maps . Segments of 4 seconds were used with sequential windows producing a 50% overlap (by shifting forward by 2 seconds) during FFT analysis.…”

An interactive platform to guide catheter ablation in human persistent atrial fibrillation using dominant frequency, organization and phase mapping

“…DF was defined as the frequency peak in the power spectrum within the physiological range of 4-10 Hz [16,22].…”

Three-dimensional dominant frequency mapping using autoregressive spectral analysis of atrial electrograms of patients in persistent atrial fibrillation

“…Therefore, the objectives of this paper were (1) to generate 3D DF maps using different autoregressive (AR) spectral estimation methods [with emphasis on selection of appropriate sampling rate and AR model order to estimate the DF for each of those 2048 simultaneous unipolar noncontact intracardiac atrium electrograms (AEGs)], (2) to compare the DF between those AR spectral estimation techniques and (3) to compare them with the maps produced using Fourier-based approach [ 15 ].…”