APAF: Assessment of Cardiac Resynchronization Therapy in Patients With Permanent Atrial Fibrillation

A suboptimal level of resynchronization (cardiac resynchronization therapy \[CRT\]) achieved in many patients with actual standards and techniques based on tissue-Doppler echocardiography could be more effective to obtain better CRT results. Eligible patients who successfully received atrioventricular (AV) junction ablation and biventricular (BiV) pacing are randomised to a comparison between a strategy of right ventricular (RV) apical pacing with delayed CRT based on clinical indications with a strategy of early optimal CRT based on an echocardiographic stratification. End-points: * Acute echo comparison (acute echo study) * Quality of life and exercise tolerance (Short-term clinical study) * Composite end-point of CRT clinical failure (Long-term clinical study)