Influence of underlying substrate on atrial tachyarrhythmias after pulmonary vein isolation.

BACKGROUND

Recurrent atrial tachyarrhythmias occur as a result of residual atrial arrhythmogenic substrates after atrial fibrillation (AF) ablation. In patients with AF, electrograms with reduced amplitudes indicate diseased myocardium.

OBJECTIVE

The purpose of this study was to investigate the association between the distribution of low-voltage areas and the type of induced atrial tachyarrhythmias.

METHODS

Our prospective observational study enrolled 152 consecutive AF patients scheduled for an initial ablation (46% persistent AF). After pulmonary vein isolation, voltage mapping was performed during sinus rhythm, and regions with reduced electrogram amplitudes (<0.5 mV) were defined as low-voltage areas. Burst pacing was performed to investigate the inducibility of atrial tachyarrhythmias.

RESULTS

Low-voltage areas were more frequently observed in patients with persistent AF than paroxysmal AF (50% vs. 34%, P = .048). A higher proportion of patients with low-voltage areas presented with inducibility of atrial tachyarrhythmias than those without, as follows: AF 70% vs. 16% (P = .0001); perimitral macroreentrant atrial tachycardia (AT) 18% vs. 0% (P = .0001); and roof-dependent macroreentrant AT 13% vs. 0% (P = .01). Investigation into the regional distribution of low-voltage areas revealed that patients with perimitral macroreentrant AT more frequently coincided with low-voltage areas than those without in the septal (100% vs. 18%, P <.0001) and anterior regions (55% vs. 11%, P = .001), and those with roof-dependent AT in the roof (75% vs. 15%, P <.0001) and posterior regions (75% vs. 15%, P = .0001).

CONCLUSION

Low-voltage areas are associated with high inducibility of atrial tachyarrhythmias after pulmonary vein isolation. In addition, the distribution of low-voltage areas is specific for each type of macroreentrant AT.