LEft Atrial Pacing in Diastolic Heart Failure

Inclusion Criteria: * Age ≥ 65 * Sinus rhythm, PR \< 220ms, QRS \< 110ms * Heart failure (NYHA class III-IV or II with hospitalization for heart failure) * Ejection Fraction \> 50%, restrictive mitral inflow, Lateral E/e' \> 12 or septal E/e' \> 15, Left atrial index volume \> 34 ml/m² * Atrial dyssynchrony syndrome: (TTE) inter-atrial time delay ≥ 70ms (difference between tricuspid and mitral P-A intervals or between mitral and tricupsid P-A' intervals with DTI) * Left atrio-ventricular asynchrony: Time Difference between tricupsid and mitral A wave duration ≥ 35ms.