This study shows that it is possible to achieve complete isolation of the posterior LA including all PVs without posterior vertical lesions. Box isolation is associated with a high clinical success rate.

Heterogeneous conduction was observed at the roof and inferior region of the posterior LA in most of these AF patients. The conduction properties of the posterior LA are affected by the direction of the wavefronts, and this may play an important role in the initiation and maintenance of AF. The complete isolation of the posterior LA may prevent AF.

Introduction: Radiofrequency catheter ablation (RFCA) that targets pulmonary veins (PV) is an established treatment for paroxysmal atrial fibrillation (PAF). Recent studies have demonstrated that RFCA can eliminate PAF in over 90% of patients. However, the effectiveness for persistent or permanent AF has not been clarified.Methods and Results: 27 patients (29%) had persistent or permanent AF. RFCA including PV antrum isolation (PVAI) was performed using a circular mapping catheter in the patients with persistent or permanent AF. Four patients (15%) underwent only PVAI. Thirteen patients (48%) underwent PVAI and left atrium roof and/or mitral isthmus linear ablation. Ten patients (37%) underwent PVAI and RFCA to an area with complex fractionated atrial electrograms. All patients were observed for over a year. After repeat ablation at mean followup of 16 AE 5 months, 23 patients (85%) had normal sinus rhythm and were free of symptomatic AF or atrial flutter. Three patients required antiarrhythmic drugs to maintain sinus rhythm during follow-up period. One patient had a transient phrenic nerve injury. Two patients were documented with sustained atrial tachycardia (AT). Mapping in 2 patients showed a macro reentry AT due to gaps in the ablation lines and further ablation was needed. No other complications including PV stenosis occurred.Conclusions: The present study demonstrated that RFCA is an effective and feasible treatment for persistent or permanent AF. (J Arrhythmia 2007; 23: 229-235)

Introduction: Coronary sinus (CS) and biatrial pacing have been reported to be more effective than right atrial appendage (RAA) pacing for preventing atrial fibrillation (AF). However, the effects of atrial pacing on hemodynamics are still unknown. Methods and Results: Eleven patients with AF who underwent PV isolation were studied. Two quadripolar electrode catheters were placed in RAA and CS. After a transseptal approach, a thermodilution catheter was introduced into the left superior pulmonary vein (LSPV). The mean LSPV pressure was directly measured during pacing from the distal site of the CS (CS‐d) and RAA, and simultaneous pacing from CS‐d and RAA. The P wave duration during pacing from the RAA+CS‐d was significantly shorter than that during pacing from the RAA (83 ± 16 vs. 121 ± 18 ms, P < 0.05). No significant difference in LSPV pressure was found among the three pacing configurations (RAA, CS‐d, RAA+CS‐d pacing; 16 ± 7, 16 ± 4, 17 ± 3 mmHg, respectively). Conclusions: LSPV pressure was not affected by CS‐d, or biatrial pacing. Shortening of the P wave duration by biatrial pacing may contribute to the prevention of AF. The electrophysiological effects of pacing may play a more important role in preventing AF rather than the hemodynamic effects.

Introduction: We examined whether the additional use of amiodarone (AMD) under implantable cardioverter-defibrillator (ICD) therapy may have beneficial effects in patients at risk for lethal ventricular arrhythmias with structural heart diseases.Methods: Sixty patients (47 males, mean age, 62 AE 13 years) with structural heart disease who underwent ICD implantation were retrospectively analyzed. There were 2 groups: one group (AMD group) was treated with AMD (n ¼ 33) and the other group (non-AMD group) was treated without AMD (n ¼ 27). We compared the incidence and appropriateness of ICD shock therapy between two groups.Results: During a mean follow-up of 28 AE 17 months, we identified a total of 62 episodes in 18 patients (30%) who received ICD shock therapy. ICD shock episodes were significantly less frequent in AMD group than in non-AMD group (15% versus 48%, P < 0:01), while inappropriate shock episodes were greater in non-AMD group than in AMD group (49% versus 4%, P ¼ 0:03). In cumulative probability of shock events, the risk of events was significantly lower in AMD group (P ¼ 0:007). Of 4 patients who died in AMD group, we observed one fatal pulmonary fibrosis.Conclusions: Additional AMD therapy in patients with an ICD may be effective in reducing the risk of shock discharge. (J Arrhythmia 2010; 26: 103-110)