PO-690-03 ATRIAL ELECTROMECHANICAL DISSOCIATION AS A NOVEL NON-INVASIVE PARAMETER OF EARLY REMODELING PROGRESSION DURING ATRIAL FIBRILLATION

Abstract

Electromechanical assessment during atrial fibrillation (AF) remains a significant knowledge gap in patient-specific characterization of atrial remodeling. Study electromechanical remodeling progression in a long-term pig model of AF and establish the clinical prognostic value of the atrial electromechanical relationship. Experimental group of pigs with AF (N=15) and a prospective clinical cohort (N=95) of symptomatic AF patients (episode duration ≤6 months) undergoing atrial remodeling characterization. Atrial electromechanical remodeling was assessed using simultaneous surface ECG recordings and tissue Doppler imaging (TDI) signals during echocardiography studies in AF. Electromechanical dissociation (EMD) was defined as faster atrial electrical activation rates (EAR) than the simultaneous counterpart TDI-derived mechanical activation rates (MAR). In patients, the primary outcome was cardioversion within a 24-h window after flecainide. Secondary outcomes were cardioversion of persistent AF and recurrences at 1-year. Pigs developed progressive EMD during the first weeks of AF-related remodeling (5-to-21 weeks after protocol initiation). EMD reached 2.29±2.47 Hz (p=0.04) at 12 weeks after the first recorded AF episode lasting ≥6 seconds. In pigs with long-lasting AF (342.5±86.6 d of self-sustained AF), high-resolution electroanatomical mapping and transesophageal echocardiography imaging demonstrated overt EMD (EAR-MAR=3.49±0.67 Hz) between local EARs from unipolar electrograms and the corresponding spatially and temporally synchronized MARs. In patients (55.0±11.6 years old), regardless of AF classification (paroxysmal or persistent AF), EMD was associated with failure of pharmacological cardioversion within the 24-h window after flecainide. EMD provided the highest increase in certainty for the primary outcome when added to AF classification compared to the increase provided by clinical variables and EARs. EMD was also associated with long-term AF recurrences both in the overall AF population and in the patient subset with persistent AF. Figure 1 summarizes the main study results. Atrial EMD is an early indicator of AF remodeling progression with prognostic value in acute and long-term rhythm control.