Associazione Nazionale Medici Cardiologi Ospedalieri



Double rhythm mapping for coherent electrophysiological substrate characterization in atrial fibrillation patients

Grossi Benedetta Milano (Milano) – Istituto Clinico Humanitas | Pagani Stefano Milano (Milano) – Politecnico Di Milano | Taormina Antonio Milano (Milano) – Istituto Clinico Humanitas | Ceriotti Carlo Milano (Milano) – Istituto Clinico Humanitas | Poggio Luca Milano (Milano) – Istituto Clinico Humanitas | Battaglia Vincenzo Milano (Milano) – Istituto Clinico Humanitas | Galimberti Paola Milano (Milano) – Istituto Clinico Humanitas | Del Monaco Guido Milano (Milano) – Istituto Clinico Humanitas | Gregusova Natalia Milano (Milano) – Istituto Clinico Humanitas | Latini Alessia Chiara Milano (Milano) – Istituto Clinico Humanitas | Valcher Stefano Milano (Milano) – Istituto Clinico Humanitas | Stankowski Kamil Milano (Milano) – Istituto Clinico Humanitas | Mincione Luca Milano (Milano) – Istituto Clinico Humanitas | Condorelli Gianluigi Milano (Milano) – Istituto Clinico Humanitas | Frontera Antonio Milano (Milano) – Istituto Clinico Humanitas

Background. Atrial fibrillation (AF) progresses with a cascade of combined structural, functional, and systemic dysfunctions. Electro-anatomical maps are employed to investigate pro-arrhythmic areas. However, single rhythm maps provide only a partial reconstruction: rhythm and wavefront directionality might mask some of these areas.

Purpose. To demonstrate that the combined quantitative analysis of different rhythm maps (i.e., parallel sinus rhythm and paced maps) could allow consistent identification of structural and functional defects sustaining AF.

Methods. Thirty AF clinical procedures have been performed with mapping system support. In particular, a sinus rhythm activation map and a paced map have been created with a multipolar catheter by setting an extra beat every three sinus beats. Areas of abnormal conduction have been identified and a comparison of electrophysiological biomarkers (EGMs voltage and fractionation) among the two rhythms has been performed.

Results. This comparative analysis allowed us to identify both structural and functional electrophysiological phenomena. Specifically, we distinguished: (i) abnormal conduction zones confirmed in both maps, both characterized by signal fractionation and a lower voltage (0,56 ± 0,18 mV) with respect to healthy atrial tissue (2,40 ± 0,41 mV), and (ii) abnormal conduction zones visible in only one of the two maps. In the latter, we distinguished whether the absence of the phenomena was due to wavefront orthogonality to the diseased area (revealed thanks to a change in wavefront direction) or due to the presence of a functional phenomenon induced by the pacing. In the first group signal fractionation has been detected in both rhythms and a lower voltage has been found (1,79 ± 1,1 mV) with respect to normal conduction zones (3,26 ± 0,98 mV), while in functional cases EGMs fractionation has been identified only in paced maps and no significant difference has been observed in terms of voltage.

Conclusion. Double rhythm mapping provides a more robust characterization of atrial abnormal conduction phenomena which better represent AF electrical substrate. It allows the distinction of true structural dysfunctions from dynamic ones thanks to the different wavefront directionality and paced rhythm. Moreover, the structural defects have been confirmed by EGMs analysis, which revealed both low voltage amplitude and high fractionation, characteristics that have not been reported in functional cases.