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

Animal Models of Dyssynchrony

Cardiac resynchronization therapy (CRT) is an important therapy for patients with heart failure and conduction pathology, but the benefits are heterogeneous between patients and approximately a third of patients do not show signs of clinical or echocardiographic response. This calls for a better understanding of the underlying conduction disease and resynchronization. In this review, we discuss to what extent established and novel animal models can help to better understand the pathophysiology of dyssynchrony and the benefits of CRT

Endocardial left ventricular pacing across the interventricular septum for cardiac resynchronization therapy: clinical results of a pilot study

Background Cardiac resynchronization therapy (CRT) is an effective treatment for selected patients with heart failure, but it can be limited by the inability to place the left ventricular (LV) lead via the coronary sinus. Objective The purpose of this study was to develop an alternative approach, placing the LV lead endocardially via an interventricular septal puncture, and to assess the feasibility and safety of this technique. Methods All patients were anticoagulated with warfarin (international normalized ratio 2.5–3.5). A superior approach ventricular transseptal puncture using radiofrequency energy was performed. An active fixation pacing lead was delivered to the mapped site of latest electrical activation on the endocardial LV. Results Twenty patients were recruited, 15 with failed transvenous LV lead placement and 5 nonresponders to CRT. Mean (± SD) age was 67 ± 12, with 80% male, QRS duration 157 ± 14 ms, ischemic etiology 45%, New York Heart Association functional class 2.9 ± 0.4, and LV ejection fraction 28% ± 7%. The procedure was successful in all, with no serious complications. Clinical composite score improved at 6 months in 65% and worsened in 35%. LV ejection fraction improved >5% in 88%, from 28% ± 7% to 41% ± 9%. Six-minute walking distance improved >10% in 64%, from 248 ± 125 m to 316 ± 109 m. One patient suffered a lacunar ischemic stroke after 5 months with partial neurological recovery, associated with labile international normalized ratios. After 2.0 ± 1.0 years of follow-up, 3 patients died (2 pneumonia, 1 heart failure), and 2 patients suffered transient ischemic attacks. Conclusion LV endocardial pacing via interventricular septal puncture in patients for whom standard CRT is not possible is similarly effective and durable, with significant but potentially acceptable risks

Endocardial left ventricular pacing across the interventricular septum for cardiac resynchronization therapy: clinical results of a pilot study

Background Cardiac resynchronization therapy (CRT) is an effective treatment for selected patients with heart failure, but it can be limited by the inability to place the left ventricular (LV) lead via the coronary sinus. Objective The purpose of this study was to develop an alternative approach, placing the LV lead endocardially via an interventricular septal puncture, and to assess the feasibility and safety of this technique. Methods All patients were anticoagulated with warfarin (international normalized ratio 2.5–3.5). A superior approach ventricular transseptal puncture using radiofrequency energy was performed. An active fixation pacing lead was delivered to the mapped site of latest electrical activation on the endocardial LV. Results Twenty patients were recruited, 15 with failed transvenous LV lead placement and 5 nonresponders to CRT. Mean (± SD) age was 67 ± 12, with 80% male, QRS duration 157 ± 14 ms, ischemic etiology 45%, New York Heart Association functional class 2.9 ± 0.4, and LV ejection fraction 28% ± 7%. The procedure was successful in all, with no serious complications. Clinical composite score improved at 6 months in 65% and worsened in 35%. LV ejection fraction improved &gt;5% in 88%, from 28% ± 7% to 41% ± 9%. Six-minute walking distance improved &gt;10% in 64%, from 248 ± 125 m to 316 ± 109 m. One patient suffered a lacunar ischemic stroke after 5 months with partial neurological recovery, associated with labile international normalized ratios. After 2.0 ± 1.0 years of follow-up, 3 patients died (2 pneumonia, 1 heart failure), and 2 patients suffered transient ischemic attacks. Conclusion LV endocardial pacing via interventricular septal puncture in patients for whom standard CRT is not possible is similarly effective and durable, with significant but potentially acceptable risks.</p