Cardiac Resynchronization Therapy Pacing Research Articles

Comparisons of long-term clinical outcomes with left bundle branch pacing, left ventricular septal pacing, and biventricular pacing for cardiac resynchronization therapy

BackgroundLeft bundle branch pacing (LBBP) and left ventricular septal pacing (LVSP) are referred to as left bundle branch area pacing. ObjectiveThis study investigated whether long-term clinical outcomes differ in patients undergoing LBBP, LVSP, and biventricular pacing (BiVP) for cardiac resynchronization therapy (CRT). MethodsConsecutive patients with reduced left ventricular ejection fraction (LVEF <50%) undergoing CRT were prospectively enrolled if they underwent successful LBBP, LVSP, or BiVP. The primary composite end point was all-cause mortality or heart failure hospitalization. Secondary end points included all-cause mortality, heart failure hospitalization, and echocardiographic measures of reverse remodeling. ResultsA total of 259 patients (68 LBBP, 38 LVSP, and 153 BiVP) were observed for a mean duration of 28.8 ± 15.8 months. LBBP was associated with a significantly reduced risk of the primary end point by 78% compared with both BiVP (7.4% vs 41.2%; adjusted hazard ratio [aHR], 0.22 [0.08–0.57]; P = .002) and LVSP (7.4% vs 47.4%; aHR, 0.22 [0.08–0.63]; P = .004]. The adjusted risk of all-cause mortality was significantly higher in LVSP than in BiVP (31.6% vs 7.2%; aHR, 3.19 [1.38–7.39]; P = .007) but comparable between LBBP and BiVP (2.9% vs 7.2%; aHR, 0.33 [0.07–1.52], P = .155). Propensity score adjustment also obtained similar results. LBBP showed a higher rate of echocardiographic response (ΔLVEF ≥10%: 60.0% vs 36.2% vs 16.1%; P < .001) than BiVP or LVSP. ConclusionLBBP yielded long-term clinical outcomes superior to those of BiVP and LVSP. The role of LVSP for CRT needs to be reevaluated because of its high mortality risk.

Left bundle branch pacing lead for sensing ventricular arrhythmias in implantable cardioverter-defibrillator: A pilot study (LBBP-ICD study)

BackgroundLeft bundle branch pacing (LBBP) has been suggested as an alternative modality for biventricular pacing in cardiac resynchronization therapy (CRT)–eligible patients. As it provides stable R-wave sensing, LBBP has been recently used to provide sensing of ventricular arrhythmia in patients receiving implantable cardioverter-defibrillator (ICD) with CRT. ObjectiveThe aim of this study was to analyze the long-term safety and efficacy of the LBBP lead for appropriate detection of ventricular arrhythmia and delivery of antitachycardia pacing (ATP) in patients requiring defibrillator therapy with CRT. MethodsCRT-eligible patients who underwent successful LBBP-optimized ICD and LBBP-optimized CRT with defibrillator were enrolled. The LBBP lead was connected to the right ventricular-P/S port after capping the IS-1 connector plug of the DF-1–ICD lead. LBBP-optimized ICD or LBBP-optimized CRT with defibrillator was decided on the basis of correction of conduction system disease. Documented arrhythmic episodes and therapy delivered were analyzed. ResultsThirty patients were enrolled. The mean age was 59.7 ± 10.5 years. LBBP resulted in an increase in left ventricular ejection fraction from 29.9% ± 4.6% to 43.9% ± 11.2% (P < .0001). During a mean follow-up of 22.9 ± 12.5 months, 254 ventricular arrhythmic events were documented. Appropriate events (n = 225 [89%]) included nonsustained ventricular tachycardia (VT) (n = 212 episodes [94%]), VT (n = 8 [3.5%]), and ventricular fibrillation (n = 5 [2.5%]). ATP efficacy in terminating VT was 75%. Eleven percent of episodes (n = 29) were inappropriately detected because of T-wave oversensing. Inappropriate therapy (ATP) was delivered for 14 episodes (5.5%). Three patients (10%) had worsening of tricuspid regurgitation. ConclusionSensing from the LBBP lead for arrhythmia detection is safe as ∼90% of the episodes were detected appropriately. Future studies with a dedicated LBBP-defibrillator lead along with algorithms to avoid oversensing can help in combining defibrillation with conduction system pacing.

Feasibility study on cardiac resynchronization in the treatment of heart failure by single left bundle branch pacing

To examine the feasibility of single left bundle branch pacing for cardiac resynchronization therapy (CRT) by carrying out a frequency adaptive atrioventricular delay (RAAVD) algorithm and automatic optimization of the single left bundle branch pacing atrioventricular interval (AVI) based on the right atrioventricular interval (RAS–RVS). Thirty-six patients with CRT class Ia indications according to the European Society of Cardiology 2016 guidelines and implanted with RAAVD functional three-chamber pacemakers were prospectively enrolled in this study. Patients were divided into a single left bundle branch pacing group (n = 21) and a standard biventricular pacing group (n = 15). The optimization of the two groups was performed under standard cardiac colour Doppler ultrasound, followed by the comparison of the QRS width, cardiac function improvement, and echocardiography indicators. The ratio of AVI to the right atrial-right ventricular interval (RAS–RVS) after single LV pacing optimization was defined as the single left bundle branch pacing coefficient (LUBBPε). In comparison to the BVP, the QRS was significantly narrowed (P = 0.017), accompanied by a significantly increased proportion of patients with NYHA class I and II, as well as the 6MWT. Compared with standard biventricular pacing, LVEDD was significantly shortened (P = 0.045), accompanied by significantly improved LAD, AVVTI, EA distance/RR, IVMD, and TS-SD after the operation. RAS–RVS was 156 ± 33 ms, the optimized AVI was 102 ± 10 ms, and LUBBPε was calculated to be 0.66 ± 0.06. Depending on the LUBBPε, a three-chamber pacemaker with a single left bundle branch pacing system was developed based on RAS–RVS-optimized AVI automatically. A three-chamber pacemaker with single left bundle branch pacing can achieve CRT based on RAS–RVS, reaching the optimal AVI of 66% of RAS–RVS.

Right sided approach for left bundle branch pacing using lumen-less lead: Technical considerations and follow-up outcome.

Left bundle branch pacing has gained significant momentum in the last few years. The procedure involves deploying the lead deep inside the interventricular septum through left subclavian vein. We aimed at analyzing the feasibility, efficacy and long-term outcome of left bundle branch pacing (LBBP) using lumen-less lead through the right subclavian vein. This was a retrospective-institutional, single center observational study done in consecutive patients who underwent LBBP using 3830 selectsecuretm lead. Left subclavian venous access was the primary strategy for lead implantation. Patients requiring right sided approach due to venous obstruction or persistent left superior-vena-cava (PLSVC) for LBBP were included in the study. Right sided approach was successful in 16 out of 19 (84%) attempted patients. C315-His catheter was used in all patients without modifying its curvature. PLSVC(n = 7), left venous obstruction (n = 7), right sided device upgradation (n = 1) and left pocket infection (n = 1) were the reasons for right sided approach. Mean follow-up duration was 17 ± 12 months. LBBP resulted in reduction in QRS duration from 137.3 ± 37.8 ms to 122.3 ± 9.5 ms (p-.13) and increase in LV ejection fraction from 46.2 ± 16.3% to 54.4 ± 11.6% (p-.11). The mean fluoroscopy duration and radiation dose were significantly high in right sided approach (n = 16) as compared to left sided approach (n = 293). In patients requiring cardiac-resynchronization therapy (CRT), right sided LBBP resulted in reduction in QRS duration from 171.8 ± 18.5 to 125.5 ± 11.9 ms (p-.0001) and increase in LVEF from 29.1 ± 3.8 to 45.1 ± 11.9% (p-.005). Right sided LBBP is feasible, safe and effective in patients requiring pacing for symptomatic bradyarrhythmia and CRT. Further development in dedicated tools for right-sided approach would help in reducing the fluoroscopy-duration and radiation-dose.

Conduction system pacing: overview, definitions, and nomenclature.

Pacing from the right ventricle is associated with an increased risk of development of congestive heart failure, increases in total and cardiac mortality, and a worsened quality of life. Conduction system pacing has become increasingly realized as an alternative to right ventricular apical pacing. Conduction system pacing from the His bundle and left bundle branch area has been shown to provide physiologic activation of the ventricle and may be an alternative to coronary sinus pacing. Conduction system pacing has been studied as an alternative for both bradycardia pacing and for heart failure pacing. In this review, we summarize the clinical results of conduction system pacing under a variety of different clinical settings. The anatomic targets of conduction system pacing are illustrated, and electrocardiographic correlates of pacing from different sites in the conduction system are defined. Ultimately, clinical trials comparing conduction system pacing with standard right ventricular apical pacing and cardiac resynchronization therapy pacing will help define its benefit and risks compared with existing techniques.

Comparative study of the effects of left ventricular and biventricular pacing on indices of cardiac function and clinical status of heart failure patients: preliminary results of READAPT study

Abstract Nonresponse to cardiac resynchronization therapy (CRT) has been related with right ventricular dysfunction. Preferential left ventricular pacing (pLVP) can overcome iatrogenic right ventricular dysfunction by achieving left ventricle resynchronization and by allowing for intrinsic activation of the right side, with ramifications extending beyond cardiac output and atrial fibrillation occurrence. Moreover, the AdaptivCRT® algorithm also automatically adjusts interventricular (V-V) delay every minute, optimizing it by means of comparing relative activation delay between right and left ventricles (electrically – driven optimization). In the present study we evaluated the effects of a pLVP algorithm on 50 heart failure patients (all Caucasians, 49% male; 66 +/- 8 years old; 46% ischemic cardiomyopathy; 41% diabetics; NYHA II-III) following randomization to standard biventricular pacing and pLVP, on echocardiographic and cardiopulmonary exercise test indices of functional status, as well as a self-reported quality of life questionnaire. Device programming was based on echocardiography-evaluated maximization of stroke volume and subsequent interventricular and atrioventricular delay adjustments delegated to the device. The follow-up consisted of 6 and 12-months visits; after the 1rst month of optimizing maximum CRT response. Results Significant comparative effects of LVP over optimized CRT were noted regarding RV systolic velocity in TDI even from 6-months from baseline (6% increase, p=0.01); while end-systolic diameter of left ventricle was increased by 4% in 6-months in CRT group (p=0.01), while no significant difference was observed in LVP group. At 12 months endsystolic volume was significantly decreased (16%, p=0.01) and left ventricular systolic longitudinal strain was improved in 12 months in LVP group compared to CRT group (p- for interaction =0.001). Additionally, in cardiorespiratory exercise test LVP group showed improved inotropic reserve compared to CRT group according to maximum SBP achieved (20% increase, p&amp;lt;0.01 for interaction); while all other cardiorespiratory indices shoed borderline significant changes at 12 -months. Minnesota score was significantly reduced in LV-P group by 70% at 6-months; whereas no significant change was observed in CRT group (p for interaction &amp;lt;0.01). Conclusions In the preliminary findings of READAPT study, it seems that LV pacing optimized by a standardized echocardiographic protocol in patients with preserved AV conduction, LBBB, can achieve a higher percentage of synchronized LV pacing associated with improved patient quality of life; right ventricular function and endsystolic volume at 6 and 12-months of follow-up, over echo-optimized CRT pacing.

Cardiac magnetic resonance-derived myocardial scar is associated with echocardiographic response and clinical prognosis of left bundle branch area pacing for cardiac resynchronization therapy.

Left bundle branch area pacing (LBBAP) is a novel approach for cardiac resynchronization therapy (CRT), but the impact of myocardial substrate on its effect is poorly understood. This study aims to assess the association of cardiac magnetic resonance (CMR)-derived scar burden and the response of CRT via LBBAP. Consecutive patients with CRT indications who underwent CMR examination and successful LBBAP-CRT were retrospectively analysed. Cardiac magnetic resonance late gadolinium enhancement was used for scar assessment. Echocardiographic reverse remodelling and composite outcomes (defined as all-cause death or heart failure hospitalization) were evaluated. The echocardiographic response was defined as a ≥15% reduction of left ventricular end-systolic volume. Among the 54 patients included, LBBAP-CRT resulted in a 74.1% response rate. The non-responders had higher global, septal, and lateral scar burden (all P < 0.001). Global, septal, and lateral scar percentage all predicted echocardiographic response [area under the curve (AUC): 0.857, 0.864, and 0.822; positive likelihood ratio (+LR): 9.859, 5.594, and 3.059; and negative likelihood ratio (-LR): 0.323, 0.233, and 0.175 respectively], which was superior to QRS morphology criteria (Strauss left bundle branch abnormality: AUC: 0.696, +LR 2.101, and -LR 0.389). After a median follow-up time of 20.3 (11.5-38.7) months, higher global, lateral and septal scar burdens were all predictive of the composite outcome (hazard ratios: 4.996, 7.019, and 4.741, respectively; P's < 0.05). Lower scar burden was associated with higher response rate of LBBAP-CRT. The pre-procedure CMR scar evaluation provides further useful information to identify potential responders and clinical outcomes.

Incidence of Radiotherapy Induced Cardiac Implantable Electronic Devices Malfunction: Australian-Based Observation Study.

To assess the incidence rate of cardiac implantable electronic devices (CIED) malfunction with radiotherapy (RT) and identify factors resulting in CIED malfunction. The working hypothesis is that CIED malfunction is associated with higher photon beam energy, treatment anatomical location, device type and dose to device. This retrospective review involved 441 patients with CIED treated with RT. Clinical information, RT (prescription, dose to device, beam energy, anatomical regions treated etc.) and CIED details (type, manufacturer, and device malfunction) were collected from electronic medical records. A total of 344 patients (78%) had a permanent pacemaker (PPM), 44 patients (10%) had implantable cardioverter defibrillator (ICD), 44 patients (10%) had CRT-defibrillator (CRT-D) and 9 (2%) had cardiac resynchronization therapy-pacing (CRT-P). The median prescribed dose was 36 Gy (IQR 1.8-80 Gy). 17 out of 441 patients (3.9%) experienced an CIED malfunction event. This group had a higher prescribed median dose of 42.5 Gy (IQR 20-77 Gy) and beam energy of 14 MV (12-18 MV). None of the malfunctions resulted in clinical symptoms. Median dose to CIED was 0.28 Gy (IQR 0-3.3). No patents received dose to device ≥2 Gy. Using logistic regression, the predictors of CIED malfunction were photon beam energy use ≥10 MV (OR 5.73; 95% CI, 1.58-10.76), anatomical location of RT above the diaphragm (OR 5.2, 95% CI, 1.82-15.2), and having an ICD (OR 4.6, 95% CI, 0.75-10.2). We have demonstrated that photon beam energies ≥10 MV, RT to above the diaphragm and ICD devices are significantly associated with CIED malfunction. The recorded CIED malfunctions in this study were minor malfunctions which did not result in any clinical symptoms. Stringent adherence to the local institution's CIED treatment guidelines, utilization of safety measures and careful choice of beam energy are recommended to minimize risk of symptomatic CIED malfunctions.

Conduction system pacing vs. biventricular pacing for cardiac resynchronization therapy in heart failure with reduced ejection fraction: An updated systematic review and meta-analysis

Conduction system pacing (CSP) is considered an effective and physiological form of pacing in patients requiring cardiac resynchronization therapy (CRT). To compare electrocardiographic (ECG), echocardiographic (ECHO) characteristics and clinical outcomes among patients with heart failure with reduced ejection fraction (HFrEF) undergoing CRT with CSP or biventricular pacing (BVP). This study protocol was registered in the PROSPERO registry (CRD42022375155) and the review was conducted per the PRISMA protocol. Four major databases were searched from inception till October 20, 2022, for relevant studies comparing CSP to BVP for CRT in patients with HFrEF. From a total of 10,072 references identified, 35 full-text were assessed and 18 studies (6 RCTs, 12 observational studies) were included in the review. Following left bundle branch area pacing (LBBAP), on average, paced QRS duration was 28 ms narrower in comparison to BVP (MD -27.69, CI -36.59 to -18.80), and a similar result was obtained with HBP vs. BVP as well. Left ventricular ejection fraction (LVEF) improvement was greater with CSP in comparison to BVP [LBBAP (MD 6.03, CI 4.16-7.91); HBP (MD 3.79, CI 0.46-7.11); HPSP (MD 6.60, CI 4.42-8.78). There were higher odds of being responders (OR 3.82, CI 1.88-7.75)/super responders (OR 2.08, CI 1.53-2.82) (per ECHO findings) in the CSP group, and overall mortality (OR 0.61, CI 0.40-0.93) and hospitalization for HF (HHF) (OR 0.37, CI 0.25-0.55) was lower in CSP group. Our analysis showed better ECG, ECHO, and clinical outcomes in terms of mortality and HHF with CSP compared to BVP.

Significance of effective cardiac resynchronization therapy pacing for clinical responses: An analysis based on the effective cardiac resynchronization therapy algorithm

High percent ventricular pacing maximizes cardiac resynchronization therapy (CRT) response. An effective CRT algorithm classifies each left ventricular (LV) pace as effective or ineffective on the basis of the detection of QS or QS-r morphology on the electrogram; however, the relationship between percent effective CRT pacing (%e-CRT) and responses is unclear. We aimed to clarify the association between %e-CRT and clinical outcomes. Of the 136 consecutive CRT patients, 49 using the adaptive and effective CRT algorithm with percent ventricular pacing > 90% were evaluated. The primary and secondary outcomes were heart failure (HF) hospitalization and prevalence of CRT responders, defined as patients with an improvement in LV ejection fraction of ≥10% or a reduction in LV end-systolic volume of ≥15% after CRT device implantation, respectively. We divided the patients into the effective group (n = 25) and the less effective group (n = 24) by the median value of %e-CRT (97.4%). During the median follow-up period of 507 days (interquartile range 335-730 days), the effective group had a significantly lower risk of HF hospitalization than did the less effective group as revealed by Kaplan-Meier analysis (log-rank, P = .016). Univariate analysis revealed %e-CRT ≥ 97.4% (hazard ratio 0.12; 95% confidence interval 0.01-0.95; P = .045) as a predictor of HF hospitalization. The effective group had a higher prevalence of CRT responders than did the less effective group (23 [92%] vs 9 [38%]; P < .001). Univariate analysis revealed that %e-CRT ≥ 97.4% (odds ratio 19.20; 95% confidence interval 3.63-101.00; P < .001) was a predictor of CRT response. High %e-CRT is associated with high CRT responder prevalence and low HF hospitalization risk.

Electrophysiologic effects of left bundle branch area pacing: comparing left ventricular septal pacing and left bundle branch pacing

Abstract Funding Acknowledgements Type of funding sources: Private company. Main funding source(s): Medtronic Background Left bundle branch area pacing(LBBAP) has been introduced as a more physiological pacing alternative to anti-bradycardia pacing and as an alternative to biventricular pacing in cardiac resynchronization therapy (CRT). LBBAP is the common denominator of left ventricular septal pacing(LVSP) and left bundle branch pacing(LBBP). In LVSP, there is only capture of the myocardium on the left side of the interventricular septum, whereas in LBBP there is additional capture of the left bundle branch(LBB) and subsequent Purkinje fibers. Purpose To investigate the electrophysiological differences between LBBP and LVSP. Methods Patients with a permanent pacemaker indication due to bradycardia or heart failure according to current guidelines were included and underwent LBBAP implantation. At baseline and during implantation, electrical activation parameters were recorded pacing at different sites (Right ventricle, LVSP and LBBP), using the standard 12-lead ECG and the ECG BELT. Electrophysiologic measures included: QRS duration, QRSarea calculated from the vectorcardiogram after conversion from the ECG using the Kors matrix, and standard deviation of activation time(SDAT) measured through the ECG BELT. Both QRS area and SDAT are known markers of ventricular dyssynchrony. Results 28 patients (17 male), with an age of 67±7 yrs underwent LBBAP. 21(75%) had a pacing indication for bradycardia with a baseline narrow QRS and 7(25%) for heart failure with a baseline LBBB. In 17 patients (61%) LBB capture was achieved. The remaining patients were treated with LVSP. In patients with baseline narrow QRS, both LVSP and LBBP showed a significant increase in QRS duration(p&amp;lt;0.001, p&amp;lt;0.001 resp.), without a significant difference in QRS duration between LVSP and LBBP(fig. 1 A). There was no significant difference in SDAT between LVSP and LBBP compared to baseline narrow QRS, and a significant SDAT reduction in patients with underlying LBBB (p=0.005, p&amp;lt;0.001 resp.) Furthermore, there was no significant SDAT difference between LVSP and LBBP(fig. 1 B). LVSP showed a small but significant increase in QRSarea compared to baseline narrow QRS (p=0.011) where LBBP showed no difference compared to baseline narrow QRS. Compared to baseline LBBB both LVSP and LBBP showed a significant QRSarea reduction (p=0.003, p&amp;lt;0.001 resp.). Moreover, there was a small but significant reduction in QRSarea when LBBP was achieved over LVSP(p=0.044) (fig. 1 C). Conclusion LVSP and LBBP showed a similar effect on ventricular synchrony in terms of SDAT, with levels of synchrony comparable to normal physiologic activation. Left bundle branch capture resulted in a small, but significant improvement in QRSarea over LVSP. Fig. 1 Relative changes in QRS duration(A), SDAT (B) and QRS area (C) compared to baseline narrow QRS (bradypacing) and baseline heart failure with LBBB. *p&amp;lt;0.05 compared to baseline, **p&amp;lt;0.05 for bradypacing and heart failure with LBBB combined.

PO-03-080 OPTIMIZING POST-IMPLANT CRT MANAGEMENT

Implementing a post-implant cardiac resynchronization therapy (CRT) clinic using a combined electrophysiology (EP) & heart failure (HF) advanced practice provider (APP) model may improve subspecialty collaboration & prevent delays in device & medical optimization. Some previously described models evaluate patients 6 months post-procedure. Early follow-up post-implant may further improve response. To determine if a 1 month post-implant device interrogation provides actionable data to improve CRT response at 6 months using a dual-APP multidisciplinary model. We designed a multidisciplinary clinic to formally evaluate patients after CRT device implant. The team involves an advanced HF APP, an EP APP & a HF nurse. Standard device clinic follow up is maintained with the addition of a device interrogation at 1 month to evaluate device function & CRT pacing. Interventions are made at 1 month as necessary. Patients are then seen in the multidisciplinary clinic 6 months following implant & undergo device interrogation, ECG, echocardiogram, & 6-minute walk test. Patients are simultaneously seen by the APPs & a unified plan of care is developed. The electronic medical records were reviewed prospectively for clinical characteristics pre-implant & at 1 & 6 months post-implant, which were summarized with descriptive statistics, including correlation between 1 month data & 6 month CRT response. CRT responders at 6 months were defined as having an LVEF improvement of ≥5% & a reduction in LVESVi ≥10%. Ninety-six patients seen in the clinic from September 2020 to April 2022 were evaluated. The mean age was 70 years; 66 (69%) were male; 40 (42%) had ischemic cardiomyopathy; 53 (56%) had no documented arrhythmia history prior to device implant; 13 (13.5%) were considered to have permanent atrial fibrillation (AF). Of these patients, 52 (54%) were considered CRT responders at 6 months. One month CRT pacing >95% correlated with 6 month CRT response (coefficient of 0.11, std error 0.04, p= 0.01). PVC burden >5% negatively correlated with CRT response (coefficient of 0.15, std error 0.15, p=.02). AF burden did not correlate with CRT response (coefficient of 0.01, std error 0.01, p=0.14). Multivariate analysis did not show these variables to be independently predictive of CRT response. An APP-led, early post-implant evaluation of CRT patients may provide an opportunity to improve six-month CRT response.

Conduction system versus biventricular pacing in heart failure with non-left bundle branch block.

The benefits of cardiac resynchronization therapy (CRT) with biventricular pacing (BiV) is significantly lower when applied to heart failure (HF) patients with non-left bundle branch block (LBBB) conduction delay. We investigated clinical outcomes of conduction system pacing (CSP) for CRT in non-LBBB HF. Consecutive HF patients with non-LBBB conduction delay undergoing CSP were propensity matched for age, sex, HF-etiology, and atrial fibrillation (AF) in a 1:1 ratio to BiV from a prospective registry of CRT recipients. Echocardiographic response was defined as an increase in left ventricular ejection fraction (LVEF) by ≥10%. The primary outcome was the composite of HF-hospitalizations or all-cause mortality. A total of 96 patients were recruited (mean age 70 ± 11years, 22% female, 68% ischemic HF and 49% AF). Significant reductions in QRS duration and LV dimensions were seen only after CSP, while LVEF improved significantly in both groups (p < 0.05). Echocardiographic response occurred more frequently in CSP than BiV (51% vs. 21%, p < 0.01), with CSP independently associated with four-fold increased odds (adjusted odds ratio 4.08, 95% confidence interval [CI] 1.34-12.41). The primary outcome occurred more frequently in BiV than CSP (69% vs. 27%, p < 0.001), with CSP independently associated with 58% risk reduction (adjusted hazard ratio [AHR] 0.42, 95% CI 0.21-0.84, p = 0.01), driven by reduced all-cause mortality (AHR 0.22, 95% CI 0.07-0.68, p < 0.01), and a trend toward reduced HF-hospitalization (AHR 0.51, 95% CI 0.21-1.21, p = 0.12). CSP provided greater electrical synchrony, reverse remodeling, improved cardiac function and survival compared to BiV in non-LBBB, and may be the preferred CRT strategy for non-LBBB HF.

A New Electromechanical Wave Imaging Dispersion Metric for the Characterization of Ventricular Activation in Different Cardiac Resynchronization Therapy Pacing Schemes.

Conventional biventricular (BiV) pacing cardiac resynchronization therapy (CRT) is an established treatment for heart failure patients. Recently, multiple novel CRT delivering technologies such as His-Bundle pacing have been investigated as alternative pacing strategies for optimal treatment benefit. Electromechanical Wave Imaging (EWI), a high frame-rate echocardiography-based modality, is capable of visualizing the change from dyssynchronous activation to resynchronized BiV-paced ventricles in 3D. This proof-of-concept study introduces a new EWI-based dispersion metric to further characterize ventricular activation. Patients with His-Bundle device implantation (n = 4), left-bundle branch block (n = 10), right-ventricular (RV) pacing (n = 10), or BiV pacing (n = 15) were imaged, as well as four volunteers in normal sinus rhythm (NSR). EWI successfully mapped the ventricular activation resulting from His-Bundle pacing. Additionally, very similar activation patterns were obtained in the NSR subjects, confirming recovery of physiological activation with His pacing. The dispersion metric was the most sensitive EWI-based metric that identified His pacing as the most efficient treatment (lowest activation time spread), followed by BiV and RV pacing. More specifically, the dispersion metric significantly (p < 0.005) distinguished His pacing from the other two pacing schemes as well as LBBB. The initial findings presented herein indicate that EWI and its new dispersion metric may provide a useful resynchronization evaluation clinical tool in CRT patients under both novel His-Bundle pacing and more conventional BiV pacing strategies.

First-in-human noninvasive left ventricular ultrasound pacing: A potential screening tool for cardiac resynchronization therapy.

A screening tool to predict response to cardiac resynchronization therapy (CRT) could improve patient selection and outcomes. The purpose of this study was to investigate the feasibility and safety of noninvasive CRT via transcutaneous ultrasonic left ventricular (LV) pacing applied as a screening test before CRT implants. P-wave-triggered ultrasound stimuli were delivered during bolus dosing of an echocardiographic contrast agent to simulate CRT noninvasively. Ultrasound pacing was delivered at a variety of LV locations with a range of atrioventricular delays to achieve fusion with intrinsic ventricular activation. Three-dimensional cardiac activation maps were acquired via the Medtronic CardioInsight 252-electrode mapping vest during baseline, ultrasound pacing, and after CRT implantation. A separate control group received only the CRT implants. Ultrasound pacing was achieved in 10 patients with a mean of 81.2 ± 50.8 ultrasound paced beats per patient and up to 20 consecutive beats of ultrasound pacing. QRS width at baseline (168.2 ± 17.8 ms) decreased significantly to 117.3 ± 21.5 ms (P<.001) in the best ultrasound paced beat and to 125.8 ± 13.3 ms (P <.001) in the best CRT beat. Electrical activation patterns were similar between CRT pacing and ultrasound pacing with stimulation from the same area of the LV. Troponin results were similar between the ultrasound pacing and the control groups (P = .96), confirming safety. Noninvasive ultrasound pacing before CRT is safe and feasible, and it estimates the degree of electrical resynchronization achievable with CRT. Further study of this promising technique to guide CRT patient selection is warranted.

Update in LV Only Fusion CRT Pacing: Annals and Future Perspectives.

Triple-chamber cardiac devices are utilized for cardiac resynchronization therapy (CRT) and is the standard-of-care therapy for heart failure (HF) patients in the current guidelines. In the setting of biventricular (BIV) pacing it involves a mandatory implantation of right ventricular (RV) lead that allows simultaneous BIV pacing with 0 ms VV (ventricular to ventricular) interval. Nevertheless, it seems that response to CRT is not related to RV lead position. RV pacing is known for deleterious effects on RV/Left Ventricle (LV) function and should not be used in persons with normal atrioventricular conduction (AV) and sinus rhythm. As it compensates for the additional asynchrony induced by unnecessary stimulation of RV pacing, only pacing the left ventricle (LV) may result in improved cardiac resynchronization therapy (CRT) outcomes and a decrease in the number of individuals who do not respond to the procedure. Furthermore, leadless LV fusion CRT pacing without RV lead could be a potential CRT therapy alternative to BIV pacing in nonischemic heart failure patients with preserved AV conduction. The aim of our study is to made an update in cardiac resynchronization therapy with LV only fusion pacing.

Wireless left ventricular endocardial left ventricular pacing (WiSE-CRT system)

We use CRT (Cardiac Resynchronization Therapy) to treat dyssynchrony and heart failure. However, 30-40% of patients do not respond to the current method. For these patients may solution be a new wireless endocardial CRT pacing. Power is supplied wirelessly via a subcutaneous ultrasound pulse generator. WiSE-CRT therapy offers many advantages, including the ability to provide local stimulation and targeted stimulation without regard to the implantation site in the left ventricle. Other benefits that were noted during treatment include QRS shorter duration, an increase in ejection fraction, and no need for treatment with anticoagulants. In addition, patients do not suffer from endocarditis associated with conventionally CRT. The efficacy of WiSE-CRT is tested, as it has already been positively evaluated in Europe.

Temporal Characteristics of Device-Based Individual and Integrated Risk Metrics in Patients With Chronic Heart Failure

BackgroundTemporal characteristics of a multimetric risk score and its individual parameters before, during, and after a heart failure (HF) event have not been defined. ObjectivesA large real-world patient cohort with implantable cardioverter-defibrillators and cardiac resynchronization therapy (CRT) defibrillators was used to define these temporal characteristics. MethodsDeidentified health records were linked to manufacturer’s device database in 17,886 patients. Multimetric risk score combined daily measures of impedance, heart rate, activity, heart rate variability, and atrial fibrillation (AF) burden, AF ventricular rate, CRT pacing, and ventricular tachycardia episodes and shocks. HF event was defined as an inpatient, emergency department, or observation unit stay with primary diagnosis of HF and intravenous diuretic agents administration. Changes in risk parameters during 60 days before, during, and after an HF event were compared in patients with no HF readmissions vs patients with HF readmission. ResultsA total of 1,174 patients had HF events with no HF readmission, and 282 patients had HF events with HF readmission. Diagnostic risk score was higher on all 60 days before and after a HF event in patients with HF readmission compared with patients with no readmission (P < 0.001). Change in risk score from admission to discharge was similar in patients with and without HF readmission, but the risk score fell more significantly 7 after discharge and 30 days after admission in patients without HF readmission (P < 0.001). ConclusionsTemporal characteristics of risk metrics were significantly different in patients with no HF readmissions vs patients with HF readmission; patients without HF recurrence had larger recovery of risk metrics values toward normal.

Bilateral septal pacing in combination with coronary venous pacing for cardiac resynchronization therapy.

Conventional right ventricular pacing combined with coronary venous pacing (CVP) is a mainstay for cardiac resynchronization therapy (CRT). However, QRS duration of conventional CRT may be frequently more than 130ms. This study aimed to evaluate the effectiveness of QRS narrowing by bilateral septal pacing (BSP) in combination with CVP for CRT (BSP-CRT). Fourteen patients with QRS>130ms of conventional CRT after failure of physiological conduction system pacing were enrolled. Electrophysiologic characteristics were compared among different modes of CRT during procedure. BSP which was defined as capture of both sides of interventricular septum manifested as shortened R wave peak time without a right bundle branch block QRS pattern. BSP-CRT were successfully achieved in 85.7% (12/14) patients. QRS duration at baseline was 185±13ms and significantly narrowed to 156±9ms during conventional CRT (n=14, P<.001), to 143±7ms during left ventricular septal pacing (LVSP) in combination with CVP for CRT (LVSP-CRT) (n=9, P<.001), and further to 122±10ms during BSP-CRT (n=12, P<.001). Notably, among 7 patients in whom both LVSP and BSP were achieved, BSP-CRT outperformed LVSP-CRT at QRS narrowing by 16% (P<.001). At 3-month follow-up, left ventricular ejection fraction improved from 29±6% to 41±8% (P<.001). BSP-CRT resulted in superior acute electrical synchronization to conventional CRT and might be considered as an alternative to conventional CRT with QRS more than 130ms.

Left Bundle Branch Area Pacing versus Biventricular Pacing for Cardiac Resynchronization Therapy on Morbidity and Mortality.

Left bundle branch area pacing (LBBAP) has emerged as an alternative to biventricular pacing (BVP) for cardiac resynchronization therapy (CRT). We aimed to compare the morbidity and mortality associated with LBBAP versus BVP in patients undergoing CRT implantation. Consecutive patients who received CRT from two high-volume implantation centers were retrospectively recruited. The primary endpoint was a composite of all-cause death and heart failure hospitalization, and the secondary endpoint was all-cause death. A total of 491 patients receiving CRT (154 via LBBAP and 337 via BVP) were included, with a median follow-up of 31months. The primary endpoint was reached by 21 (13.6%) patients in the LBBAP group, as compared with 74 (22.0%) patients in the BVP group [hazard ratio (HR) 0.70, 95% confidence interval (CI) 0.43-1.14, P = 0.15]. There were 10 (6.5%) deaths in the LBBAP group, as compared with 31 (9.2%) in the BVP group (HR 0.91, 95% CI 0.44-1.86, P = 0.79). No significant difference was observed in the risk of either the primary or secondary endpoint between LBBAP and BVP after multivariate Cox regression (HR 0.74, 95% CI 0.45-1.23, P = 0.24, and HR 0.77, 95% CI 0.36-1.67, P = 0.51, respectively) or propensity score matching (HR 0.72, 95% CI 0.41-1.29, P = 0.28, and HR 0.69, 95% CI 0.29-1.65, P = 0.40, respectively). LBBAP was associated with a comparable effect on morbidity and mortality relative to BVP in patients with indications for CRT.