Key result
Availability of 6 left ventricular pacing configurations increased the probability of reaching LV thresholds <1.5 V at 0.4 ms from 51% (with 2 configurations) to 67%.
Why the study?
Do different left ventricular pacing configurations in cardiac resynchronization therapy affect pacing impedance, voltage thresholds, and energy requirements?
Observational (n=49)
Do different left ventricular pacing configurations in cardiac resynchronization therapy affect pacing impedance, voltage thresholds, and energy requirements?
Different LV pacing configurations in CRT have significantly different energy requirements, and having 6 configurations increases the probability of optimizing LV pacing output.
Answers are grounded in this paper and cite their sources.
Multiple LV configurations may enable lower-output CRT programming; leaves open whether this extends device longevity in prospective use.
BACKGROUND: Cardiac resynchronization therapy (CRT) demands high energy utilization due to continuous biventricular pacing. Current technology allows 6 pacing configurations for a bipolar left ventricular (LV) lead. Understanding the energy requirements for each configuration will allow optimization of pacing output. METHODS AND RESULTS: Pacing impedance, LV voltage threshold at 1.5 ms (rheobase) and 0.4 ms and chronaxie were obtained in 6 LV configurations in 49 consecutive patients undergoing CRT implantation or replacement. Strength-duration curves were derived using the Lapicque formula. Pacing impedances and voltage thresholds at 1.5 and 0.4 ms, calculated minimum threshold energy at chronaxie, current drain, energy thresholds at 0.4 ms, and strength-duration curves were statistically different between LV configurations (P<0.05). The lowest threshold energy requirements were found in Tip→right ventricular (RV) coil and Tip→Can configuration. Energy strength-duration curves involving the ring as the cathode (Ring→RV, Ring→Can, and Ring→Tip) had the highest LV thresholds. The pacing configuration with the lowest energy threshold correlated 89% of the time with the lowest voltage threshold at 0.4 ms. The probability to reach LV thresholds <1.5 V at 0.4 ms was increased from 51% with 2 LV configurations to 67% with 6 LV configurations. CONCLUSIONS: Pacing impedance, LV thresholds, minimum threshold energy at chronaxie, current drain, voltage, and energy strength-duration curves were statistically different between LV pacing configurations. LV pacing configuration with the lowest voltage threshold does not always reflects the lowest energy threshold, particularly in the presence of a low impedance configuration. The availability of 6 LV configurations increases the probability of optimizing LV pacing output.
No takes yet. Share an insight, caveat, or question.
Huizar et al. (2011) conducted an observational in Cardiac resynchronization therapy (n=49). 6 left ventricular pacing configurations vs. Different configurations was evaluated on Pacing impedance, LV voltage threshold, chronaxie, minimum threshold energy, current drain, and strength-duration curves (p=<0.05). Availability of 6 left ventricular pacing configurations increased the probability of reaching LV thresholds <1.5 V at 0.4 ms from 51% (with 2 configurations) to 67%.
Synapse has enriched 10 related papers. Consider them for comparative context: