Peri-mitral Atrial Flutters: Comparing ECG F Wave Morphology To Intracardiac Electrical Activity

BackgroundPeri-mitral atrial flutters(PMAFLs)frequently develop after atrial fibrillation(AF)ablation,post-cardiac surgery or spontaneous atrial scaring.They usually have distinctive flutter wave morphology on surface ECG.However,the determinants of the flutter wave morphology have been less studied.MethodsWe retrospectively reviewed 24 patients with PMAFLs who underwent bi-atrial high-resolution mapping with Rhythmia LUMIPOINT software.We analyzed the overlap between the right atrial(RA)activation time and flutter wave duration and compared the proportion of the endocardial area that was activated in both atria during the flutter wave duration.Bi-atrial activation patterns and interatrial conductions were also identified.ResultsThe mean tachycardia cycle length(TCL)was 264±60 ms,with RA activation time 155±45 ms(60.8±20.6% of the TCL),and the flutter wave duration 107±31 ms(41.6±11.7% of the TCL).The overlap between the RA activation time and the flutter wave duration was 102±29 ms,which takes 68.5±17.2% of the RA activation time and95.7±9.1% of the flutter wave duration respectively.Quantitative analysis also showed that during the flutter wave duration,more percentage of the endocardial area was activated in the RA than in the LA(73.0±12.7% vs.45.2±13.0%,p<0.001).We consistently observed that the RA anterior wall rightward activation corresponded to the positive component in V1 in both flutter patterns,and the RA downward activation corresponded to the positive component in the counterclockwise(CCW)group,or the upward activation corresponded to the negative component in the clockwise(CW)group in the inferior leads.The passive RA activation patterns were varied with spontaneous atrial scarring or previous linear ablation.ConclusionsECG flutter wave morphology of PMAFLs is mainly dependent on RA activation patterns.