Cardiovascular Implantable Electronic Devices -> Bradycardia Devices: -> Device Technology D-PO02 - Poster Session II (ID 47) Poster

D-PO02-093 - Pulse Optimization Can Reduce The Energy Cost Of His Bundle Pacing (ID 1011)


Background: His bundle pacing (HBP) entails physiological ventricular activation, with acknowledged hemodynamic and clinical benefits. However, it may require an increased energy expense.
Objective: HBP pulse optimization to reduce the battery consumption.
Methods: HBP safety margin (SM) was curtailed by including an additional ventricular lead in the pacing system, aimed at capture checking and myocardial stimulation only in the event of HBP failure (back-up on demand). A suitable CRT-P device was implanted to allow this approach in patients with preserved atrial function. In 14 cases with AVB, the HBP strength-duration curve was derived for both the mean and nominal threshold voltage, taking into account the waveform exponential decay which occurs during pulse emission. The charge drain per pulse was worked out as a function of pulse duration, considering a 20% SM with respect to the nominal threshold: it corresponds to the product of the pulse charge times the applied tension multiplier.
Results: Mean and nominal threshold pulse @1 ms averaged 1.65 ± 0.81 and 2.16 ± 1.01 V, respectively, with rheobase of 0.86 ± 0.41 V and chronaxie of 0.91 ± 0.47 ms. Although the chronaxie exceeded 1 ms in 30% of the cases, the nominal threshold generally featured just a mild decrease beyond 0.8 ms duration. The figure compares the nominal (Vimp_th) and mean threshold (Vm_th) in a representative case. The pulse duration ensuring 20% SM with minimum consumption averaged 0.59 ± 0.29 ms: 1 ms setting instead of the individual optimal duration implied a mean consumption increase of 41% to achieve the same SM.
Conclusion: Pulse optimization is advisable and can substantially reduce the energy cost of HBP.