Intra-thoracic pressure swings induced by breathing manoeuvres during standard catheter-ablation procedure. Catheter-based electrical mapping and pressure in the left atrium and pulmonary veins during standard catheter-ablation procedure. Only patients with an apnea-hypopnea index > 5/h and documented premature atrial beats during the Mueller manoeuvre will be eligible for the catheter-based electrical mapping. Follow-up after 1 year for atrial fibrillation recurrence.

Intra-thoracic pressure swings induced by breathing manoeuvres during ECG-monitoring. Only patients with an apnea-hypopnea index < 5/h and no premature atrial beats during the Mueller manoeuvre will be assigned to the no intervention arm.

The MM will be carried out during a elective standard pulmonary vein isolation procedure. The MM will be performed using an occluded mouthpiece with a small air leak to prevent complete closure of the glottis during inspiration and thus assure negative pressure throughout the entire airway. After expiration, inspiration with a target negative intrathoracic pressure of -40mmHg will be carried out against the mouthpiece.

(Loop-)Catheter-based origin detection in patients with apnea-hypopnea index > 5/h in home sleep study and documented premature atrial beats during three time points: baseline (normal breathing), inspiration through a threshold load device, and the Mueller Manoeuvre (MM). Origins will be quantitatively marked at a left atrial map.

Catheter-based left atrial pressure measurement in patients with apnea-hypopnea index > 5/h in home sleep study and documented premature atrial beats during three time points: baseline (normal breathing), inspiration through a threshold load device, and the Mueller Manoeuvre. Changes in left atrial pressure will be recorded in cmH2O.