In Heart Failure Patients with Left Bundle Branch Block Single Lead MultiSpot Left Ventricular Pacing Does Not Improve Acute Hemodynamic Response To Conventional Biventricular Pacing. A Multicenter Prospective, Interventional, Non-Randomized Study.

Introduction Recent efforts to increase CRT response by multiSPOT pacing (MSP) from multiple bipols on the same left ventricular lead are still inconclusive. Aim The Left Ventricular (LV) MultiSPOTpacing for CRT (iSPOT) study compared the acute hemodynamic response of MSP pacing by using 3 electrodes on a quadripolar lead compared with conventional biventricular pacing (BiV). Methods Patients with left bundle branch block (LBBB) underwent an acute hemodynamic study to determine the %change in LV+dP/dtmax from baseline atrial pacing compared to the following configurations: BiV pacing with the LV lead in a one of lateral veins, while pacing from the distal, mid, or proximal electrode and all 3 electrodes together (i.e. MSP). All measurements were repeated 4 times at 5 different atrioventricular delays. We also measured QRS-width and individual Q-LV durations. Results Protocol was completed in 24 patients, all with LBBB (QRS width 171±20 ms) and 58% ischemic aetiology. The percentage change in LV+dP/dtmax for MSP pacing was 31.0±3.3% (Mean±SE), which was not significantly superior to any BiV pacing configuration: 28.9±3.2% (LV-distal), 28.3±2.7% (LV-mid), and 29.5±3.0% (LV-prox), respectively. Correlation between LV+dP/dtmax and either QRS-width or Q-LV ratio was poor. Conclusions In patients with LBBB MultiSPOT LV pacing demonstrated comparable improvement in contractility to best conventional BiV pacing. Optimization of atrioventricular delay is important for the best performance for both BiV and MultiSPOT pacing configurations. Trial Registration ClinicalTrials.gov NTC0188314

QRS width values at different pacing modes.

<p>QRS-width reduction by BiV pacing approximates 15% and is only slightly more reduced by MultiSPOT pacing. It has weak correlation with % LV+dP/dtmax increase (R = -0.136). (B)</p

Regression curve constructed through percentage LV+dP/dtmax changes during each configuration depending on AV delay in one patient.

<p>Red dot indicates calculated maximal average response at AV-best. AV = 0 indicates AV-delay calculated by CardioSyncTM formula. AV-delay delta stands for change from AV-delay calculated by CardioSyncTM formula in ms.</p

QLV/QRS values upon different pacing modes.

<p>Normalized QLV/QRS values for the different electrodes on the Multi-electrode LV lead.Data and correlations are presented as mean±SD. * indicates significant different from MultiSPOT.</p

Numbers of local and central ethics committees approvals for all participating sites.

<p>Numbers of local and central ethics committees approvals for all participating sites.</p

Boxplot of LV+dP/dtmax % increase for the different configurations.

<p>Distal, mid and prox denote LV-electrode position on the LV-lead. MultiSPOT denote pacing on all three LV-electrode positions simultaneously. Solid line depicts mean value and boxes are 75 and 25 percentiles. Whiskers represent 2.5 and 97.5% percentiles.</p

Flowchart of the enrolled patients.

<p>Flowchart of the enrolled patients.</p

Study inclusion and exclusion criteria.

<p>Study inclusion and exclusion criteria.</p