Impact of irrigated energy application on the right coronary artery hemodynamics: FFR measurement in patients who underwent ablation of common type atrial flutter.

Objective: The purpose of this first in vivo study was to assess the incidence of thermal influence to the right coronary artery (RCA) during ablation of common type atrial flutter (Aflu) by measuring the fractional flow reserve (FFR) in the vessel before, under and after ablation.

Methods: In thirty three patients ablated we performed coronary angiography (CA) before and at the end of the procedure. The FFR wire was positioned in the distal, the isthmus underlying, part of the RCA. Before and after the procedure FFR measurement was done at baseline and during adenosine administration. During the whole ablation procedure FFR measurement was continuously carried on, to monitor a transient thermal impact to the RCA.

Results: Of the 33 patients observed, 25 males, 8 females, mean age 58 +/- 9.5 years, none with CAD, all patients, except one with unidirectional block, were successfully ablated. The FFR at rest and under medication with adenosine before and after ablation was 0.985/0.949 and 0.981/0.942, respectively (p = ns). The CA of the RCA did not reveal any morphological change. The mean FFR while ablation declined from 0.94 to 0.904 (p = ns). Twenty-six patients (78.8%) had no or moderate decrease in FFR, seven patients (21.2%) demonstrated a substantial decrease [five patients (15.2%), FFR < 0.9 and >0.75] or significant change [two patients (6.1%)], FFR < 0.75 consistent with a remarkable or significant reduction of coronary flow.

Conclusion: Ablation of AFlu did not alter RCA morphology; simultaneous FFR measurement showed severe depression of the FFR in a few patients, consistent with impairment in myocardial perfusion.