Influence of atrial flutter ablation on right to left inter-atrial conduction.
OBJECTIVE
Ablation of the atrial isthmus between the tricuspid annulus and the inferior vena cava changes P-wave morphology during low lateral right atrial pacing. For better understanding of the mechanism of this alteration, the sequence of activation of the inter-atrial septum and the left atrium were compared before and after ablation of the isthmus between the inferior vena cava and the tricuspid annulus.


RESULTS
In 13 patients, left atrial mapping was performed using a duodecapolar electrode catheter advanced to the far distal coronary sinus. The inter-atrial septum was mapped using a right atrial duodecapolar electrode catheter. Conduction times were measured during low lateral right atrial pacing from the pacing artefact and during sinus rhythm from the earliest right atrial electrogram to every intra-cardiac electrogram before and after the ablation. During low lateral right atrial pacing, isthmus ablation resulted in a significant delay in every left atrial lead. Changes were maximal at the posterior aspect of the left atrium and minimal at its anterior aspect. No significant change was discernible on the inter-atrial septum. During sinus rhythm, atrial activations remained unchanged.


CONCLUSIONS
Electrocardiographic changes of P-wave morphology result from alteration in the sequence of left atrial activation rather than that of the inter-atrial septum.
Hôpital Cardiovasculaire et Pneumologique Louis Pradel BP Lyon-Montchat, 69394 Lyon Cedex 03, France.
M
M
Fatemi
G
G
Kirkorian
P
P
Chevalier
P
P
Lavaud
C
C
Bellon
A
A
Da Costa
E
E
Bonnefoy
P
P
Touboul
D001282:Atrial Flutter / Q000503:physiopathology / Q000601:surgery*; D018780:Body Surface Potential Mapping; D017115:Catheter Ablation; D005260:Female; D006325:Heart Atria / Q000503:physiopathology*; D006329:Heart Conduction System / Q000503:physiopathology* / Q000601:surgery; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged