AF Inducibility Is Related to Conduction Abnormalities at Bachmann's Bundle

A single-center trial of electrographic flow mapping and concomitant voltage mapping in sinus rhythm and atrial fibrillation (FLOW EVAL-AF)

BACKGROUND

Electrographic flow (EGF) mapping reconstructs atrial electrical wavefront propagation, potentially revealing sources of atrial fibrillation (AF). Electrographic flow consistency (EGFC) measures the concurrence of wavefront patterns and may provide insights into atrial substrate health. This study aimed to compare EGF patterns during atrial fibrillation (AF) with sinus rhythm (SR) and explore the correlation between EGFC and regional bipolar voltage.

METHODS

In this single-center, prospective study, AF patients underwent mapping of the atria using bipolar voltage and EGF mapping. Mapping was performed during both AF and SR using a 16-electrode grid catheter (bipolar mapping) and a 64-pole basket catheter (EGF mapping). EGFC was computed as the average modulus of individual EGF vectors, reflecting flow pattern consistency.

RESULTS

Ten patients were enrolled. EGF identified 11 sources with a mean source activity of 32 ± 9% during AF. Eight out of eleven sources in AF converted to passive "sinks" when mapped in SR. EGFC was significantly lower during AF compared to SR (0.74 ± 0.14 vs 1.0 ± 0.11 AUs, P < 0.01), consistent with EGFC quantifying the more chaotic wavefront propagation during arrhythmia. No spatial correlation between areas of high EGFC during AF and SR was observed. EGFC correlated with bipolar voltage across rhythms and atria (r = 0.647, P < 0.0001).

CONCLUSION

EGF patterns varied by rhythm with AF showing lower EGFC values. EGFC correlated with bipolar voltage across rhythms and atria, suggesting its potential as an atrial myopathy marker akin to high-density voltage mapping and offering insights into atrial substrate health. Trial registration ClinicalTrials.gov Identifier: NCT06260670.

Tic-Tac: A Translational Approach in Mechanisms Associated with Irregular Heartbeat and Sinus Rhythm Restoration in Atrial Fibrillation Patients

Atrial fibrillation (AF) is a prevalent cardiac condition predominantly affecting older adults, characterized by irregular heartbeat rhythm. The condition often leads to significant disability and increased mortality rates. Traditionally, two therapeutic strategies have been employed for its treatment: heart rate control and rhythm control. Recent clinical studies have emphasized the critical role of early restoration of sinus rhythm in improving patient outcomes. The persistence of the irregular rhythm allows for the progression and structural remodeling of the atria, eventually leading to irreversible stages, as observed clinically when AF becomes permanent. Cardioversion to sinus rhythm alters this progression pattern through mechanisms that are still being studied. In this review, we provide an in-depth analysis of the pathophysiological mechanisms responsible for maintaining AF and how they are modified during sinus rhythm restoration using existing therapeutic strategies at different stages of clinical investigation. Moreover, we explore potential future therapeutic approaches, including the promising prospect of gene therapy.

Clinical Relevance of Sinus Rhythm Mapping to Quantify Electropathology Related to Atrial Fibrillation

Progression of AF is accompanied by structural and electrical remodelling, resulting in complex electrical conduction disorders. This is defined as electropathology and it increases with the progression of AF. The severity of electropathology, thus, defines the stage of AF and is a major determinant of effectiveness of AF therapy. As specific features of AF-related electropathology are still unknown, it is essential to first quantify the electrophysiological properties of atrial tissue and then to examine the inter- and intra-individual variation during normal sinus rhythm. Comparison of these parameters between patients with and without a history of AF unravels quantified electrophysiological features that are specific to AF patients. This can help to identify patients at risk for early onset or progression of AF. This review summarises current knowledge on quantified features of atrial electrophysiological properties during sinus rhythm and discusses its relevance in identifying AF-related electropathology.