Systems and methods for controlling ventricular pacing in patients with long inter-atrial conduction delays
Techniques are provided for use by implantable medical devices for controlling ventricular pacing. In one example, optimal atrio-ventricular and interventricular pacing delay values are determined for pacing the heart of the patient based, in part, on a measured inter-atrial conduction delay. Atrio-ventricular conduction delays are then measured within the patient. The atrio-ventricular pacing delays are compared with the measured atrio-ventricular conduction delays. If the atrio-ventricular pacing delays are less than the measured atrio-ventricular conduction delays, biventricular pacing is delivered using the atrio-ventricular pacing delay and the interventricular pacing delay. However, if the atrio-ventricular pacing delays are not less than the corresponding atrio-ventricular conduction delays, as can occur if the inter-atrial conduction delay is large, then alternative pacing regimes are selectively enabled, such as monoventricular pacing in the chamber having the longer conduction delay value, biventricular pacing with negative hysteresis, or biventricular pacing with pacing delays reduced using predetermined offset values.
1. A method for controlling the delivery of cardiac pacing therapy using an implantable cardiac stimulation device, the method comprising:
measuring an inter-atrial conduction time delay (IACT) and an atrio-ventricular conduction delay (AR/PR);
determining an atrio-ventricular pacing delay (AV/PV) and an interventricular pacing delay (W) for use in pacing the heart of the patient based, in part, on the measured inter-atrial conduction time delay (IACT);
comparing the atrio-ventricular pacing delay (AV/PV) with the measured atrio-ventricular conduction delay (AR/PR);
if the atrio-ventricular pacing delay (AV/PV) is less than the measured atrio-ventricular conduction delay (AR/PR), delivering biventricular pacing using the atrio-ventricular pacing delay (AV/PV) and the interventricular pacing delay (VV); and
if the atrio-ventricular pacing delay (AV/PV) is not less than the corresponding atrio-ventricular conduction delay (AR/PR), selectively enabling an alternative pacing regime;
wherein selectively enabling an alternative pacing regime includes selectively enabling one of monoventricular pacing, biventricular pacing with negative hysteresis, and biventricular pacing with AV/PV delays reduced using predetermined offset values;
wherein selectively enabling monoventricular pacing includes:
determining a minimum value (PR MIN /AR MIN ) for the atrio-ventricular conduction delay (PR/AR) based on a comparison of AR/PR values measured for the left ventricle (LV) and the right ventricle (RV);
comparing the minimum value (PR MIN /AR MIN ) for the atrio-ventricular conduction delay against a predetermined minimum delay threshold (PR MIN-TH /AR MIN-TH ) while also comparing the inter-atrial conduction delay (IACT) against a predetermined inter-atrial conduction delay threshold (IACT TH ); and
selectively enabling monoventricular pacing if either the inter-atrial conduction delay (IACT) is greater than the inter-atrial delay threshold (IACT TH ) or if the minimum value (PR MIN /AR MIN ) for the intrinsic atrio-ventricular pacing delay (IACT) is less than the predetermined minimum delay threshold (PR MIN-TH /AR MIN-TH ).
2. The method of claim 1 wherein comparing the atrio-ventricular pacing delay (AV/PV) with the measured atrio-ventricular conduction delay (AR/PR) is performed to compare the atrio-ventricular pacing delay (AV/PV) with a minimum value (PR MIN /AR MIN ) of the measured atrio-ventricular conduction delay (AR/PR) derived based on a comparison of atrio-ventricular conduction delay (AR/PR) values measured for the left ventricle (LV) and the right ventricle (RV).
3. The method of claim 1 wherein selectively enabling monoventricular pacing therapy further includes:
comparing the inter-atrial conduction delay (IACT) to the minimum intrinsic atrio-ventricular conduction delay (PR MIN ); and
enabling monoventricular pacing only if the inter-atrial conduction delay (IACT) does not exceed the minimum intrinsic atrio-ventricular conduction delay (PR MIN ).
4. The method of claim 3 wherein enabling monoventricular pacing therapy further includes:
delivering monoventricular pacing to the left ventricle if VV>0; and
delivering monoventricular pacing to the right ventricle if VV≦0.
5. The method of claim 1 wherein the implantable device is equipped to perform biventricular pacing with negative hysteresis and biventricular pacing with AV/PV delays reduced using predetermined offset values and wherein the device selects between the two based on a user selection.
6. A method for controlling the delivery of cardiac pacing therapy using an implantable cardiac stimulation device, the method comprising:
measuring an inter-atrial conduction time delay (IACT) and an atrio-ventricular conduction delay (AR/PR);
determining an atrio-ventricular pacing delay (AV/PV) and an interventricular pacing delay (VV) for use in pacing the heart of the patient based, in part, on the measured inter-atrial conduction time delay (IACT);
comparing the atrio-ventricular pacing delay (AV/PV) with the measured atrio-ventricular conduction delay (AR/PR);
if the atrio-ventricular pacing delay (AV/PV) is less than the measured atrio-ventricular conduction delay (AR/PR), delivering biventricular pacing using the atrio-ventricular pacing delay (AV/PV) and the interventricular pacing delay (VV); and
if the atrio-ventricular pacing delay (AV/PV) is not less than the corresponding atrio-ventricular conduction delay (AR/PR), selectively enabling an alternative pacing regime;
wherein selectively enabling an alternative pacing regime includes selectively enabling one of monoventricular pacing, biventricular pacing with negative hysteresis, and biventricular pacing with AV/PV delays reduced using predetermined offset values;
wherein selectively enabling biventricular pacing with negative hysteresis includes:
determining a minimum value (PR MIN /AR MIN ) for the atrio-ventricular conduction delay (PR/AR) based on a comparison of AR/PR values measured for the left ventricle (LV) and the right ventricle (RV);
comparing the minimum value (PR MIN /AR MIN ) for the atrio-ventricular conduction delay against a predetermined minimum delay threshold (PR MIN-TH /AR MIN-TH ) while also comparing the inter-atrial conduction delay (IACT) against a predetermined inter-atrial conduction delay threshold (IACT TH ); and
selectively enabling biventricular pacing with negative hysteresis if the inter-atrial conduction delay (IACT) is less than the inter-atrial delay threshold (IACT TH ) and if the minimum value (PR MIN /AR MIN ) for the intrinsic atrio-ventricular pacing delay (IACT) is greater than the predetermined minimum delay threshold (PR MIN-TH /AR MIN-TH ).
7. A method for controlling the delivery of cardiac pacing therapy using an implantable cardiac stimulation device, the method comprising:
measuring an inter-atrial conduction time delay (IACT) and an atrio-ventricular conduction delay (AR/PR);
determining an atrio-ventricular pacing delay (AV/PV) and an interventricular pacing delay (VV) for use in pacing the heart of the patient based, in part, on the measured inter-atrial conduction time delay (IACT);
comparing the atrio-ventricular pacing delay (AV/PV) with the measured atrio-ventricular conduction delay (AR/PR);
if the atrio-ventricular pacing delay (AV/PV) is less than the measured atrio-ventricular conduction delay (AR/PR), delivering biventricular pacing using the atrio-ventricular pacing delay (AV/PV) and the interventricular pacing delay (VV); and
if the atrio-ventricular pacing delay (AV/PV) is not less than the corresponding atrio-ventricular conduction delay (AR/PR), selectively enabling an alternative pacing regime;
wherein selectively enabling an alternative pacing regime includes selectively enabling one of monoventricular pacing, biventricular pacing with negative hysteresis, and biventricular pacing with AV/PV delays reduced using predetermined offset values;
wherein selectively enabling biventricular pacing with AV/PV delays reduced using predetermined offset values includes:
determining a minimum value (PR MIN /AR MIN ) for the atrio-ventricular conduction delay (PR/AR) based on a comparison of AR/PR values measured for the left ventricle (LV) and the right ventricle (RV);
comparing the minimum value (PR MIN /AR MIN ) for the atrio-ventricular conduction delay against a predetermined minimum delay threshold (PR MIN-TH /AR MIN-TH ) while also comparing the inter-atrial conduction delay (IACT) against a predetermined inter-atrial conduction delay threshold (IACT TH ); and
selectively enabling biventricular pacing with AV/PV delays reduced using predetermined offset values if the inter-atrial conduction delay (IACT) is less than the inter-atrial delay threshold (IACT TH ) and if the minimum value (PR MIN /AR MIN ) for the intrinsic atrio-ventricular pacing delay (IACT) is greater than the predetermined minimum delay threshold (PR MIN-TH /AR MIN-TH ).
8. The method of claim 7 wherein the offset values are in the range of 10-40 milliseconds (ms).
9. A method for controlling the delivering cardiac pacing therapy using an implantable cardiac stimulation device, the method comprising:
measuring an inter-atrial conduction time delay (IACT) and an atrio-ventricular conduction delay (AR/PR);
determining an atrio-ventricular pacing delay (AV/PV) and an interventricular pacing delay (VV) for use in pacing the heart of the patient based, in part, on the measured inter-atrial conduction time delay (IACT);
comparing the atrio-ventricular pacing delay (AV/PV) with the measured atrio-ventricular conduction delay (AR/PR);
if the atrio-ventricular pacing delay (AV/PV) is less than the measured atrio-ventricular conduction delay (AR/PR), delivering biventricular pacing using the atrio-ventricular pacing delay (AV/PV) and the interventricular pacing delay (VV); and
if the atrio-ventricular pacing delay (AV/PV) is not less than the corresponding atrio-ventricular conduction delay (AR/PR), selectively enabling an alternative pacing regime;
wherein determining the atrio-ventricular pacing delay (AV/PV) and the interventricular pacing delay (VV) includes:
measuring inter-atrial conduction time (IACT) delays with the patient;
determining atrio-ventricular (AV/PV) pacing delays based on the measured inter-atrial conduction time (IACT) delays;
determining an intrinsic interventricular conduction delay (A) and an interventricular correction term (ε) for the patient; and
determining an interventricular pacing delay (W) based on the intrinsic interventricular conduction delay (Δ) and the interventricular correction term (ε).
10. The method of claim 9 wherein determining the interventricular pacing delay (VV) based on the intrinsic interventricular conduction delay (Δ) and the interventricular correction term (ε) includes setting:
VV=α 1 (Δ+ε), where α 1 is a coefficient that is one of programmable or hard-coded within a range of values including 0.5.
11. The method of claim 9 wherein determining atrio-ventricular (AV/PV) pacing delays includes exploiting a correction factor θ.
12. The method of claim 11 further including the step of measuring 9 within the patient based on interventricular delays.
13. The method of claim 12 wherein measuring θ within the patient includes:
if the interventricular pacing delay (VV) is greater than zero, measuring a time delay (PL LV ) from a paced event in the ventricles until the resulting left ventricular (LV) evoked response, then subtracting a baseline value to yield θ; and
if the interventricular pacing delay (VV) is not greater than zero, measuring a time delay (PL RV ) from a paced event in the ventricles until the resulting right ventricular (RV) evoked response, then subtracting the baseline value to yield θ.