| Part One:Characteristics and radiofrequency ablation outcomes of atrial tachycardia originating from the distal portion of the left atrial appendageObjectives Although very few studies have described focal atrial tachycardia (AT) originating from the left atrial appendage (LAA), there are no detailed descriptions of the characteristics and response to ablative therapy of AT originating from the distal portion of the LAA (LAAd). The goal of this study was to characterize electrocardiographic and electrophysiologic features and radiofrequency catheter ablation (RFCA) outcomes in patients with focal AT originating from the LAAd.Methods Fourteen patients (2.1%) with focal AT originating from the LAAd out of668undergoing RFCA for focal AT are reported. Activation mapping was performed during tachycardia to identify the earliest activation site in left atrium (LA) and LAA. P waves were classified as negative, positive, isoelectric, or biphasic. LAA angiography was performed to identify the atrial origin site before and after RFCA.Results All fourteen patients studied (mean age,25±10years;9women; mean symptom duration,5±5years) had AT foci originating from the LAAd. Tachycardia, which was incessant in all, demonstrated a characteristic P-wave morphology and endocardial activation pattern:P wave was negative in leads I and aVL, highly positive in the inferior leads and broad and positive in lead VI, and leads V2-V6showed an flat or upright component. Catheter manipulation in LAAd caused mechanical interruption of AT in12of14patients, and RFCA was acutely successful in13of14patients; mean tachycardia cycle length was433±70ms; and the earliest endocardial activation at the successful RFCA sites occurred47.1±4.3ms before the onset of P wave. There were no complications in any of the14patients, and long-term success was achieved in13of13successful RFCA patients over a median follow-up of5±2years.Conclusions The LAAd is an uncommon site of origin for focal AT (2.1%incidence). In this case series, focal ATs originating from the LAAd had typical electrophysiologic and electrocardiographic characteristics, and focal ablation yielded long-term success in the majority of patients. Part Two:Characteristics and radiofrequency ablation outcomes of atrial tachycardia originating from the apex of the right atrial appendageObjectives The goal of this study was to characterize electrocardiographic and electrophysiologic features and radiofrequency catheter ablation (RFCA) outcomes in patients with focal atrial tachycardia (AT) originating from the apex of the right atrial appendage (RAA).Methods Eight patients (1.2%) with focal AT originating from the apex of the RAA out of668undergoing RFCA for focal AT are reported. Activation mapping was performed during tachycardia to identify the earliest activation site in right atrium and RAA.Results All eight patients (mean age,22.8±5.5years;4women; mean symptom duration,4.9±2.7years) had AT foci originating from the apex of the RAA. Tachycardia, which was incessant in all, demonstrated a characteristic P-wave morphology and endocardial activation pattern:P-wave was deep negative in leads V1and V2, high positive in inferior leads and positive in lead I in all8patients. Catheter manipulation in RAA apex caused mechanical interruption of AT in5of8patients, and RFCA was acutely successful in all8patients; mean tachycardia cycle length was390±41ms; and the earliest endocardial activation at the successful RFCA sites occurred45±5.1ms before the onset of P wave. There were no complications in any of the8patients, and long-term success was achieved in all8patients over a median follow-up of4.1±1.4years.Conclusions The apex of the RAA is an uncommon site of origin for focal AT (1.2%). ATs at this location showed typical electrophysiologic and electrocardiographic characteristics and focal ablation was associated with long-term success. Part Three:The relationship between anatomy of the pulmonary veins analyzed by MDCT and atrial fibrillationObjectives To describe anatomy of the pulmonary veins and left atrium in patients with atrial fibrillation analyzed by MDCT, to compare the prevalence of pulmonary vein variants and diameters of pulmonary vein ostia in atrial fibrillation patients and controls, and to investigate the effect of pulmonary vein anatomy, pulmonary vein dimensions, and left atrium dimensions on the outcome of radiofrequency catheter ablation for atrial fibrillation.Methods In our department from January2004to October2011,950consecutive patients (739males,211females) with drug-refractory atrial fibrillation and800controls (607males,193females) without atrial fibrillation were eligible for inclusion. The patients underwent MDCT prior to radiofrequency catheter ablation to evaluate pulmonary vein anatomy and left atrium diameters, and the controls underwent MDCT because of suspected coronary heart disease or aortic disease. Circumferential pulmonary vein isolation was performed guided by Cartomerge electroanatomical mapping. The pulmonary vein anatomy, pulmonary vein dimensions and left atrium dimensions were evaluated three dimensionally using MDCT. The patients were followed up for47.8±26.2months.Results The mean number of pulmonary veins per patient were2-6. The mean number of left pulmonary veins per patient were1-3, the mean number of right pulmonary veins per patient were1-4. The variations of patients included common trunk(14.7%), middle pulmonary vein(directly into the left atrium19.4%) and accessory pulmonary vein(2.3%), the total proportion of variation was34.9%. All superior veins had a statistically significant greater mean ostial diameter than all inferior veins (P<0.001), this was also true when the left superior and left inferior pulmonary veins were compared (P<0.001). The right superior pulmonary vein ostial diameter was significantly larger than the left superior pulmonary vein ostial diameter (P=0.007), and the right inferior pulmonary vein diameter was significantly larger than the left inferior pulmonary vein diameter (P<0.001). The right superior, right inferior, right middle and accessory right inferior pulmonary veins had a statistically significant smaller mean distance to first bifurcation than the left superior and left inferior pulmonary veins. The right inferior pulmonary veins had a statistically significant smaller mean distance to first bifurcation than the other pulmonary veins. A normal pulmonary vein pattern was observed in618(65.1%) of atrial fibrillation patients vs.643(80.4%) in controls (P=0.003). Atrial fibrillation patients had significantly more left common trunk (14.6%vs.5.3%, P=0.029) and more right middle pulmonary vein (directly into the left atrium)(19.1%vs.12.2%, P=0.037) than controls. The size of all pulmonary vein ostia was significantly larger in atrial fibrillation patients than in controls for all veins(P<0.001). In the recurrence group, a greater prevalence of persistent atrial fibrillation was found than in the nonrecurrence group (35.4%vs.11.9%, P=0.035). The left atrium diameter was significantly larger in the recurrence group than in the nonrecurrence group (43.24±2.35mm vs.39.18±4.51mm, P=0.019). Persistent atrial fibrillation (OR:1.932,95%CI:1.258-2.839, P=0.042), the duration of atrial fibrillation prior to catheter ablation(OR:2.165,95%CI:0.957-3.639, P=0.017) and left atrium diameter (OR:5.098,95%CI:1.024-7.178, P=0.009) were independent predictors of atrial fibrillation recurrence.Conclusions Variations in number and insertion of pulmonary veins were observed in a considerable number of atrial fibrillation patients, the characteristics of pulmonary vein dimensions and the distance to the first bifurcation do existed. The prevalence of pulmonary vein variants and diameters of pulmonary vein and left atrium were related to the occurrence of atrial fibrillation. Persistent atrial fibrillation, the duration of atrial fibrillation prior to catheter ablation and left atrium diameter were independent predictors of atrial fibrillation recurrence, which should be investigated further. |
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