Association between dissociated firing in isolated pulmonary veins and the initiation and maintenance of atrial fibrillation.

BACKGROUND

Whether dissociated firing (DiFi) in isolated pulmonary veins (PVs) implies arrhythmogenicity of the particular PVand, therefore, a better outcome of PV isolation (PVI) for paroxysmal atrial fibrillation (PAF) is debated.

METHODS

Thirty-one patients undergoing their first PVI for PAF were studied. Isoproterenol was infused for induction, and the triggering PV was identified. During sustained PAF, sequential recordings were made with a decapolar circular mapping catheter from each PV. The dominant frequency (DF) was determined using fast Fourier transformation. Spontaneous DiFi was monitored for 30 min after PVI.

RESULTS

PAF was triggered by the PVs in all patients. Fourteen (45 %) patients had DiFi after PVI in at least one PV. It was recorded most commonly from the left upper (84 %) and lower (67 %), less commonly from the right upper (31 %) PV. Out of the 23 PVs with DiFi, 13 (57 %) showed sporadic ectopic beats while 10 (44 %) had sustained ectopic rhythm or isolated tachycardia. There was no difference in size between PVs with or without DiFi (5.9±1.2 vs. 5.6±1.0 cm ostial perimeter, p=0.40). Triggering PVs more commonly showed any DiFi, compared to nontriggering PVs (68 vs. 27 %, p=0.003) and more commonly had sustained DiFi (53 vs. 0 %, p<0.001). During PAF PVs with any DiFi showed faster maximal DF compared to PVs without DiFi (7.1±1.3 vs. 5.9±1.1 Hz, p=0.001). Higher maximal DF was recorded in PVs with sustained versus sporadic DiFi versus PVs without DiFi (7.5 ±0.9 vs. 6.8±1.6 vs. 5.9±1.1 Hz, respectively, p=0.002). Patients with DiFi after PVI had a longer mean time to recurrent PAF compared to those without DiFi (52 vs. 32 months, p=0.048).

CONCLUSIONS

Dissociated firing in isolated PVs is associated with their role in the initiation and maintenance of PAF.