Multisite pacing via a quadripolar lead for cardiac resynchronization therapy

Anodal Capture for Multisite Pacing with a Quadripolar Left Ventricular Lead: A Feasibility Study

Background: Up to 40% of patients are CRT non-responders. Multisite pacing, using a unique quadripolar lead, also called multipoint/multipole pacing (MPP), is a potential alternative. We sought to determine the feasibility of intentional anodal capture using a single LV quadripolar lead, to reproduce MPP without the need of a specific algorithm (so-called “pseudo MPP”). Methods: Consecutive patients implanted with a commercially available CRT device and a quadripolar LV lead in our department were prospectively included. The electric charge (Q, in Coulomb) of RV and LV pacing spikes were calculated for all available LV pacing configurations at the threshold. The best MPP was defined as the configuration with the lowest consumption (Q_RV + Q_{best LV1} + Q_{best LV2}). The best “pseudo MPP” (Q_RV + Q_{LV1–LV2 with anodal capture}) and best BVp (Q_RV + Q_{best LV}) were also calculated. A theoretical longevity was estimated for each configuration at the threshold without a safety margin. Results: A total of 235 configurations were tested in 15 consecutive patients. “Pseudo-MPP” was feasible in 80% of patients with 3.1 ± 2.6 vectors available per-patient and LV_proximal-LV_distal (most distant electrodes) vectors were available in 47% of patients. Each MPP pacing spike electrical charge was comparable to “pseudo-MPP” (18,428 ± 6863 µC and 20,528 ± 5509 µC, respectively, p = 0.15). Theoretical longevity was 6.2 years for MPP, 5.6 years for “pseudo-MPP” and 13.7 years for BVp. Conclusions: “Pseudo MPP” using intentional anodal capture with a quadripolar left ventricular lead, mimicking conventional multisite pacing, is feasible in most of CRT patients, with comparable energy consumption. Further studies on their potential clinical impact are needed.

Cardiac resynchronization therapy with multipoint pacing via quadripolar lead versus traditional biventricular pacing: A systematic review and meta-analysis of clinical studies on hemodynamic, clinical, and prognostic parameters

Background

Cardiac resynchronization therapy (CRT) is one of the cornerstones of heart failure (HF) therapy, as it has reduced mortality and morbidity and has shown improvement in functional capacity. Multipoint pacing (MPP) is a way of configuring CRT with the aim to improve the percentage of patients who respond to CRT.

Objective

To demonstrate the effectiveness of the MPP compared to traditional biventricular pacing (BiV).

Methods

We performed a systematic review and meta-analysis according to PRISMA guidelines of studies in which MPP vs BiV strategy were compared.

Results

MPP use is associated with a higher rate of patients experiencing functional improvement (odds ratio: 2.51, 95% confidence interval [CI], 1.56–4.06; P = .0002) and with higher delta LV dP/dt_max (mean difference, 1.82; 95% CI, 0.24–3.39; P = .0240) with respect to BiV. MPP and BiV have no significantly different effect on left ventricular end-systolic volume (LVESV) (mean difference, 0.39; 95% CI, -11.12 to 11.89; P = .9475); moreover, there is no significant difference between the 2 treatments regarding hospitalization for HF (odds ratio, 0.70; 95% CI, 0.32 to 1.54; P = .3816) and all-cause death (odds ratio, 0.81; 95% CI, 0.40 to 1.62; P = .5460). MPP is associated with a significantly lower projected battery longevity (mean difference -8.66 months; 95% CI, -13.67 to -3.66; P = .00007) with respect to BiV.

Conclusion

MPP significantly improves functional class and acute hemodynamic parameters with respect to BiV. Prognostic indices and LVESV are not significantly influenced by MPP. MPP is associated with a significant reduction in projected battery longevity.

Cardiac resynchronization therapy with intraoperative epicardial mapping via minithoracotomy: 10 years' experience

Background

Cardiac resynchronization therapy (CRT) is considered an efficient method to improve the left ventricular (LV) dysfunction with left bundle branch block. However, coronary venous anatomy is not appropriate in about 10% of the cases; thus other alternatives, such as epicardial lead implantation via minithoracotomy are needed.

Methods

During the period 2007‐2017, a total of 57 patients were operated at our institute via left anterior minithoracotomy after an unsuccessful transvenous CRT. The best position of the LV epicardial electrode was determined by intraoperative epicardial mapping, that is locating the latest activation spot relative to the right ventricular (RV) electrode. The authors analyzed the survival by Kaplan‐Meier estimator with Tarone‐Ware equality test and multiple Cox regression analysis, the changes of the LV ejection fraction (LVEF) and dimensions, the development of the impedance and threshold of the LV epicardial electrode, the possible associations between the survival and intraoperative sensed RV‐LV activation delay.

Results

The intraoperative RV‐LV activation delay was 92.250 ± 26.538 milliseconds. There were no intraoperative complications except ventricular fibrillation in three patients. Within 30 days there were neither wound healing complications nor pocket hematoma. There was no significant difference in survival with regard to gender or etiology, but significantly better survival was found in the cohort with intraoperative sensed RV‐LV activation delay >86 milliseconds. The LVEF and dimensions improved following the operation and continued to be improved in the survivors.

Conclusion

CRT via minithoracotomy with epicardial mapping is a safe, efficient, simple, and reproducible second‐line alternative to the transvenous method.