Inverse relationship between fractionated electrograms and atrial fibrosis in persistent atrial fibrillation: combined magnetic resonance imaging and high-density mapping.

OBJECTIVES This study sought to evaluate the relationship between fibrosis imaged by delayed-enhancement (DE) magnetic resonance imaging (MRI) and atrial electrograms (Egms) in persistent atrial fibrillation (AF). BACKGROUND Atrial fractionated Egms are strongly related to slow anisotropic conduction. Their relationship to atrial fibrosis has not yet been investigated. METHODS Atrial high-resolution MRI of 18 patients with persistent AF (11 long-lasting persistent AF) was registered with mapping geometry (NavX electro-anatomical system (version 8.0, St. Jude Medical, St. Paul, Minnesota)). DE areas were categorized as dense or patchy, depending on their DE content. Left atrial Egms during AF were acquired using a high-density, 20-pole catheter (514 ± 77 sites/map). Fractionation, organization/regularity, local mean cycle length (CL), and voltage were analyzed with regard to DE. RESULTS Patients with long-lasting persistent versus persistent AF had larger left atrial (LA) surface area (134 ± 38 cm(2) vs. 98 ± 9 cm(2), p = 0.02), a higher amount of atrial DE (70 ± 16 cm(2) vs. 49 ± 10 cm(2), p = 0.01), more complex fractionated atrial Egm (CFAE) extent (54 ± 16 cm(2) vs. 28 ± 15 cm(2), p = 0.02), and a shorter baseline AF CL (147 ± 10 ms vs. 182 ± 14 ms, p = 0.01). Continuous CFAE (CFEmean [NavX algorithm that quantifies Egm fractionation] <80 ms) occupied 38 ± 19% of total LA surface area. Dense DE was detected at the left posterior left atrium. In contrast, the right posterior left atrium contained predominantly patchy DE. Most CFAE (48 ± 14%) occurred at non-DE LA sites, followed by 41 ± 12% CFAE at patchy DE and 11 ± 6% at dense DE regions (p = 0.005 and p = 0.008, respectively); 19 ± 6% CFAE sites occurred at border zones of dense DE. Egms were less fractionated, with longer CL and lower voltage at dense DE versus non-DE regions: CFEmean: 97 ms versus 76 ms, p < 0.0001; local CL: 153 ms versus 143 ms, p < 0.0001; mean voltage: 0.63 mV versus 0.86 mV, p < 0.0001. CONCLUSIONS Atrial fibrosis as defined by DE MRI is associated with slower and more organized electrical activity but with lower voltage than healthy atrial areas. Ninety percent of continuous CFAE sites occur at non-DE and patchy DE LA sites. These findings are important when choosing the ablation strategy in persistent AF.

[1]  Nicolas Derval,et al.  Functional Nature of Electrogram Fractionation Demonstrated by Left Atrial High-Density Mapping , 2012, Circulation. Arrhythmia and electrophysiology.

[2]  S. Landas,et al.  Spatial Distribution of Fibrosis Governs Fibrillation Wave Dynamics in the Posterior Left Atrium During Heart Failure , 2007, Circulation research.

[3]  Omer Berenfeld,et al.  Rotor meandering contributes to irregularity in electrograms during atrial fibrillation. , 2008, Heart rhythm.

[4]  Ruben Coronel,et al.  Activation Delay After Premature Stimulation in Chronically Diseased Human Myocardium Relates to the Architecture of Interstitial Fibrosis , 2001, Circulation.

[5]  R. Kobza,et al.  Visualization of the oesophagus in relation to the left atrium: an alternative concept. , 2007, Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology.

[6]  K. Nademanee,et al.  A new approach for catheter ablation of atrial fibrillation: mapping of the electrophysiologic substrate. , 2004, Journal of the American College of Cardiology.

[7]  D. Shah,et al.  Regional Disparities of Endocardial Atrial Activation in Paroxysmal Atrial Fibrillation , 1996, Pacing and clinical electrophysiology : PACE.

[8]  Ashok J. Shah,et al.  Noninvasive Panoramic Mapping of Human Atrial Fibrillation Mechanisms: A Feasibility Report , 2013, Journal of cardiovascular electrophysiology.

[9]  Ralph Lazzara,et al.  Autonomic Mechanism to Explain Complex Fractionated Atrial Electrograms (CFAE) , 2007, Journal of cardiovascular electrophysiology.

[10]  Nathalie Virag,et al.  Atrial fibrillatory cycle length: computer simulation and potential clinical importance. , 2007, Europace : European pacing, arrhythmias, and cardiac electrophysiology : journal of the working groups on cardiac pacing, arrhythmias, and cardiac cellular electrophysiology of the European Society of Cardiology.

[11]  Wouter-Jan Rappel,et al.  Treatment of atrial fibrillation by the ablation of localized sources: CONFIRM (Conventional Ablation for Atrial Fibrillation With or Without Focal Impulse and Rotor Modulation) trial. , 2012, Journal of the American College of Cardiology.

[12]  E. Kholmovski,et al.  Association of left atrial fibrosis detected by delayed-enhancement magnetic resonance imaging and the risk of stroke in patients with atrial fibrillation. , 2011, Journal of the American College of Cardiology.

[13]  M. Allessie,et al.  High-density mapping of electrically induced atrial fibrillation in humans. , 1994, Circulation.

[14]  O. Alfieri,et al.  Myocyte changes and their left atrial distribution in patients with chronic atrial fibrillation related to mitral valve disease. , 2005, Human pathology.

[15]  Joshua J. E. Blauer,et al.  Detection and Quantification of Left Atrial Structural Remodeling With Delayed-Enhancement Magnetic Resonance Imaging in Patients With Atrial Fibrillation , 2009, Circulation.

[16]  Nicolas Derval,et al.  Classifying fractionated electrograms in human atrial fibrillation using monophasic action potentials and activation mapping: evidence for localized drivers, rate acceleration, and nonlocal signal etiologies. , 2011, Heart rhythm.

[17]  B. Lindsay,et al.  Noninvasive Characterization of Epicardial Activation in Humans With Diverse Atrial Fibrillation Patterns , 2010, Circulation.

[18]  Prashanthan Sanders,et al.  Characterization of electrograms associated with termination of chronic atrial fibrillation by catheter ablation. , 2008, Journal of the American College of Cardiology.

[19]  Roger C Barr,et al.  Mechanism of origin of conduction disturbances in aging human atrial bundles: experimental and model study. , 2007, Heart rhythm.

[20]  Jacques M T de Bakker,et al.  The Pathophysiologic Basis of Fractionated and Complex Electrograms and the Impact of Recording Techniques on Their Detection and Interpretation , 2010, Circulation. Arrhythmia and electrophysiology.

[21]  J Clémenty,et al.  Spontaneous initiation of atrial fibrillation by ectopic beats originating in the pulmonary veins. , 1998, The New England journal of medicine.

[22]  Katja Zeppenfeld,et al.  Head-to-head comparison of contrast-enhanced magnetic resonance imaging and electroanatomical voltage mapping to assess post-infarct scar characteristics in patients with ventricular tachycardias: real-time image integration and reversed registration. , 2011, European heart journal.

[23]  L. Lo,et al.  The Optimal Automatic Algorithm for the Mapping of Complex Fractionated Atrial Electrograms in Patients With Atrial Fibrillation , 2010, Journal of cardiovascular electrophysiology.

[24]  Ulrich Schotten,et al.  Electropathological Substrate of Long-Standing Persistent Atrial Fibrillation in Patients With Structural Heart Disease: Longitudinal Dissociation , 2010, Circulation. Arrhythmia and electrophysiology.