Active implantable medical device for atrial stimulation for the treatment of heart failure with preserved ejection fraction

A method for resynchronization of the contraction of the heart chambers, the method comprising:

• sensing right atrial depolarizations;
• sensing left atrial depolarizations;
• and
• delivering, selectively on the basis of adjustable controlling parameters, left atrial stimulation pulses according to a stimulation protocol, the stimulation protocol comprising:
• after a first cardiac cycle without left atrial stimulation, delivering a left atrial stimulation pulse during an immediately consecutive second cardiac cycle at an inter-atrial coupling interval,
• wherein the inter-atrial coupling interval applied during the second immediately consecutive cardiac cycle is a short coupling interval shorter than a sinus rhythm coupling interval, so that the left atrial stimulation pulse delivered during the second cardiac cycle is a premature pulse;
• delivering a not premature left-atrial stimulation pulse during a third cardiac cycle immediately subsequent to the second cardiac cycle, at an inter-atrial coupling interval corresponding to the sinus rhythm coupling interval;
• assessing a right atrial coupling interval between the right atrial depolarizations during the second and third cardiac cycles;
• comparing the right atrial coupling interval to the sinus rhythm coupling interval;
• and
• modifying at least one of the adjustable controlling parameters if necessary according to the result of the comparison.

A cardiac resynchronization system, comprising:

• a stimulation/detection electrode for positioning in the right atrium of a heart;
• a stimulation/detection electrode for positioning in the left atrium of the heart;
• wherein the electrodes are configured to be coupled to an implantable medical device, the implantable medical device comprising a generator and digital processor circuits configured to:
• sense right atrial depolarizations from the stimulation/detection electrode;
• sense left atrial depolarizations from the stimulation/detection electrode;
• and
• deliver a left atrial stimulation pulse during a cardiac cycle immediately following a preceding cardiac cycle with no left atrial stimulation, the left atrial stimulation pulse delivered at an inter-atrial coupling interval,
• wherein the inter-atrial coupling interval is a short coupling interval shorter than a sinus rhythm coupling interval;
• deliver a second left-atrial stimulation pulse during an immediately subsequent cardiac cycle at an inter-atrial coupling interval corresponding to the sinus rhythm coupling interval;
• assess a right atrial coupling interval between the right atrial depolarizations during the consecutive cardiac cycles;
• compare the right atrial coupling interval to the sinus rhythm coupling interval;
• and
• determine whether to modify the inter-atrial coupling interval based on the result of the comparison.