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Pulmonary veins (PVs) are the predominant sources of paroxysmal atrial fibrillation (AF), and electrical PV isolation has become an established interventional treatment for patients suffering from AF. There are a few cases describing PV tachycardias; however, mechanisms of PV arrhythmogenicity resulting in PV tachycardias remain incompletely understood. We report on a patient who underwent PV isolation for paroxysmal AF, in whom a persistent PV tachycardia was observed within an isolated vein. This tachycardia was stable in nature and different pacing manoeuvres revealed electrophysiological features consistent with reentry (Lasso displaying the entire tachycardia cycle length, concealed entrainment, overdrive termination, and induction by programmed stimulation) as the underlying mechanism.

Aims: In the setting of right ventricular outflow tract-tachycardia (RVOT-T), data about long-term follow-up (FU) with respect to the therapeutic strategies are missing. All patients (pts) referred to our institution during the last 20 years for the treatment of RVOT-T were studied in a retrospective analysis to assess mortality and efficacy of treatment., Methods and Results: One hundred and thirty-three patients (77 female; 39+/-13 years) with sustained RVOT-T were included in this study. At the time of first presentation, diagnosis of RVOT-T was made by complete invasive and non-invasive diagnostic assessment, including electrophysiology study and two-dimensional echocardiography. After 135+/-68 months (median 136, range 29-248), patients were invited to undergo clinical assessment. Of the 133 pts, 127 (95%) survived and six (5%) died from non-cardiac disease. Anti-arrhythmic (AA) drugs were given to 62 of the 133 pts (47%); of them 32 (52%) had recurrences during follow-up. The mean time to recurrence was 10.02 years (95% CI 7.46-12.59). The other 71 study patients (53%) underwent catheter ablation. The procedure was successful in 58 pts (82%). During follow-up, 30 (52%) of the 58 successfully treated patients had recurrences of RVOT-T. The mean time to recurrence was 6.28 years (95% CI 4.96-7.6). RVOT-T recurrences were similar in morphology to those treated previously in 33% and different in 67% of cases., Conclusions: Long-term follow-up in patients with RVOT-T is favourable. Catheter ablation is effective in this setting. However, late recurrences with similar or different morphology may arise in half of the patients after initially successful treatment. AA drug therapy is a valid initial therapeutic option, since it is effective in about half of the patients.

Introduction: Pulmonary veins (PVs) are the predominant location of triggers for atrial fibrillation (AF), but little is known about the electrophysiologic properties of PVs. In addition, the influence of amiodarone on the electrophysiologic properties of PVs has not been elucidated., Methods and Results: Fifty-five patients with symptomatic and drug-resistant AF were divided into two groups: group 1 patients (n=29) without antiarrhythmic drug therapy at the time of electrophysiologic study (EPS), and group 2 patients (n=26) undergoing continuous long-term treatment with amiodarone. EPS including programmed stimulation of both atria and within the PVs was performed in both groups. In group 1, the effective refractory period (ERP) of all PVs (174 +/- 62 msec) was significantly shorter than the ERP of the left atrium ([LA] 254 +/- 30 msec, P=0.0001) and right atrium ([RA] 221 +/- 29 msec, P=0.0001). The same pattern was observed in group 2 (PV: 210 +/- 58 msec; LA: 259 +/- 35 msec, P=0.0001; RA: 246 +/- 37 msec, P=0.0255). The ERP of all stimulated PVs was significantly lower in group 1 (174 +/- 62 msec) than in group 2 (210 +/- 58 msec; P=0.0001). The ERP of the left superior and right superior PVs and RA but not the left inferior PV and LA were significantly increased in patients treated with amiodarone. Decremental conduction properties were observed in all stimulated PVs, and there were no significantly differences between the maximal decrement of both groups., Conclusion: The distinctive electrophysiologic properties of PVs are emphasized by amiodarone therapy. Long-term amiodarone treatment is responsible for heterogeneous alteration of the PV electrophysiology, which may account for the individual antiarrhythmic responses in a subset of patients with paroxysmal AF.