Effect of heart rate and isoproterenol on pulmonary vein flow velocity following radiofrequency ablation: a Doppler color flow imaging study.
BACKGROUND
Application of radiofrequency energy at pulmonary vein (PV) ostium during focal atrial fibrillation (AF) ablation procedures increases flow velocity due to PV narrowing. Factors unrelated to ablation that effect PV flow velocity have not been described.


OBJECTIVE
The purpose of this study was to evaluate, using intracardiac echocardiography (ICE) imaging, the effect of isoproterenol (ISO) and heart rate (HR) on PV flow velocity Pre- and Post-ablation.


RESULTS
In 31 patients with AF undergoing LA-PV ostial ablation involving at least one PV ostium, an ICE catheter was placed in the RA to image and detect PV flow. PV ostial peak velocity was assessed in sinus rhythm Pre-, Post-ablation, during and after ISO (up to 20 microg/min). To separate HR versus ISO effect, PV velocity was measured during atrial pacing (after HR returned to baseline) at pacing rate matching HR with ISO. PV ostial velocity was assessed with ISO and pacing in 30 non-ablated and 33 ablated PVs. Ostial velocities of non-ablated PVs during ISO infusion (117 +/- 42 cm/s) were greater ( p < 0.03) than those during atrial pacing (78 +/- 26 cm/s) at matched HR (116 +/- 20, range 92-150 bpm). Ostial PV flow velocities of ablated PVs increased from 59 +/- 17 (30-95) cm/s Pre- to 95 +/- 25 (58-136) cm/s Post-ablation. During ISO infusion PV flow velocities in ablated PVs (118 +/- 34 cm/s) were also greater ( p < 0.03) than those during atrial pacing (96 +/- 37 cm/s) at matched HR (116 +/- 14, range 92-130 bpm). Atrial pacing alone produced no significant difference in PV flow velocities measured Pre- or Postablation.


CONCLUSIONS
ISO appears to increase ostial flow velocity of ablated and non-ablated PVs independent of HR effect. These effects are important to recognize when PV velocity is used as an index for interpreting the impact of PV ostial lesions on functionally significant PV narrowing.
Ren
Jian-Fang
JF
Division of Cardiovascular Medicine, Department of Medicine, University of Pennsylvania, School of Medicine, Philadelphia, PA, USA. jian-fang.ren@uphs.upenn.edu
Marchlinski
Francis E
FE
Callans
David J
DJ
D000318:Adrenergic beta-Agonists / Q000627:therapeutic use*; D000328:Adult; D001281:Atrial Fibrillation / Q000000981:diagnostic imaging / Q000503:physiopathology / Q000628:therapy; D001783:Blood Flow Velocity / Q000187:drug effects*; D001993:Bronchodilator Agents / Q000627:therapeutic use*; D017115:Catheter Ablation; D018618:Echocardiography, Doppler, Color; D005260:Female; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D007545:Isoproterenol / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D011667:Pulmonary Veins / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000503:physiopathology*; D016896:Treatment Outcome
D000318:Adrenergic beta-Agonists; D001993:Bronchodilator Agents; D007545:Isoproterenol