Background Persistent atrial fibrillation (PeAF) can change to paroxysmal AF (PAF) after antiarrhythmic drug medication and cardioversion. Purpose We investigated whether electrical posterior box isolation (POBI) may improve rhythm outcome of catheter ablation in those patient group. Methods We prospectively randomized 114 patients with PeAF to PAF (male 75%, 59.8±9.9 years old) to circumferential pulmonary vein isolation (CPVI) alone group (n=57) and additional POBI group (n=57). The primary end-point was AF recurrence after a single procedure, and the secondary end-point was a recurrence pattern, cardioversion rate, and the response to antiarrhythmic drugs (AADs). Results After a mean follow-up of 22.5±9.4 months, the clinical recurrence rate did not significantly differ between the two groups (29.8% vs. 28.1%, p=0.836; log rank p=0.815) The recurrence rate for atrial tachycardias (17.6% vs. 43.8%, p=0.141) was higher in POBI group, but the cardioversion rates (13.5% vs. 8.5%, p=0.434) were not significantly different between two groups. At the final follow-up, sinus rhythm was maintained without antiarrhythmic drug in 52.6% in CPVI group and 59.7% of POBI group (p=0.452). No significant difference was found in the major complication rates between the two groups (5.3% vs. 1.8%, p=0.618), but the total ablation time was significantly longer in the POBI group (4397±842 sec vs. 5337±1517 sec, p<0.001). Conclusion In patients with persistent AF converted to paroxysmal AF by AAD, the addition of POBI to CPVI did not improve the rhythm outcome of catheter ablation nor influence overall safety. Funding Acknowledgement Type of funding source: None

Background Endothelin receptor antagonist (ERA) is well-established for targeted therapy of pulmonary arterial hypertension (PAH). According to the guidelines, comprehensive evaluation of responses to PAH-targeted therapy is recommended 3 to 6 months after treatment onset. Early detection of response to ERA after starting new treatment may be of clinical value to establish next therapeutic plan. Purpose We sought to investigate whether NT-proBNP plays a reliable role for early maker of responses to ERA in PAH patients. Methods Sixty four patients (age >19 years old) with a confirmatory diagnosis of PAH were enrolled who were treated with ERA (bosentan or macitentan) in two tertially PAH experts centers. NT-proBNP measurements were performed at baseline, 1 month and 6 months after ERA treatment. Clinical characteristics including WHO functional class, laboratory test, and echocardiographic results were systematically collected. Result Sixty four patients were finally analyzed who completed the 6 months of follow-up. Etiology of PAH was as follows: idiopathic PAH (n=25), connective tissue disease associated PAH (n=16) and congenital heart disease assocciated PAH (n=24). Mean age was 50±15 years-old and female were predominant (75%). NTproBNP level was changed from 703pg/ml [207–2748] at baseline, 301 pg/ml [126–1314] at 1 month and 297pg/ml [106–901] at 6 months after ERA treatment. Although, NT proBNP level in overall population was significantly decreased after ERA treatment, NT proBNP level before treatment showed poor correlation with those at 6 months (R2=0.32). However, change of NT proBNP at 1 month from baseline showed strongly correlated with change of NT proBNP at 6 months from baseline with linear regression model analysis (R2 =0.90, p<0.001). Conclusions Assessment of early change in nt-proBNP with only a month of treatment is associated with midterm response to ERA treatment in PAH. It can help to early decision making for early intensive therapy and rapid escalation of PAH medication in non-responsive PAH patients for initial therapy. The relationship of BNP Funding Acknowledgement Type of funding source: Private company. Main funding source(s): Handok