Little is known about potential relationships between sleep apnea, plasma aldosterone and diastolic dysfunction which is a very frequent finding among patients requiring permanent cardiac pacing. Sleep apnea is often under diagnosed by clinical examination. Confirmation tests are expensive and access is limited. A specific algorithm available in a recent pacemaker allows assessing breathing variations using minute ventilation sensor, with a good agreement between the respiratory disturbance index and polysomnography results for the diagnosis of severe sleep apnea.

The purpose of the study is to examine the diagnostic accuracy of a new pacemaker algorithm for the diagnosis of obstructive sleep apnea in patients presenting with diastolic dysfunction. The investigators also aim to highlight a correlation between plasma aldosterone levels and the severity of sleep apnea, with a reversal effect of ventilation therapy in this specific population.

Inclusion Criteria:

• indication for permanent cardiac pacing (third degree atrioventricular block, second degree atrioventricular block mobitz 2 type, symptomatic sinus node dysfunction including brady-tachy form of sick sinus syndrome or bradyarrhythmia)
• Diastolic dysfunction diagnosed at the transthoracic echocardiography

Exclusion Criteria:

• younger than 18 years old
• lack of informed consent form
• impossibility to fit in the scheduled study plan
• indication for cardiac resynchronization or left ventricular ejection fraction lower than 45%
• indication for epicardial pacemaker, known severe sleep apnea treated by continuous positive airway pressure