Insights from a cardiac resynchronization optimization clinic as part of a heart failure disease management program. J Am Coll Cardiol. 2009;53:765-773. [PMID: 19245967 DOI: 10.1016/j.jacc.2008.11.024]

Selection of candidates for cardiac resynchronization therapy and implantation management: an Italian survey promoted by the Italian Association of Arrhythmology and Cardiac Pacing

BACKGROUND

Cardiac resynchronization therapy (CRT) represents an effective heart failure treatment, associated with reduction in mortality and heart failure hospitalizations. This Italian survey aimed to address relevant CRT issues.

METHODS

An online survey was administered to AIAC members.

RESULTS

One hundred and five electrophysiologists participated, with a median of 40 (23-70) CRT implantations/year (33% in high-volume centres). Forty-five percent of respondents (especially working in high-volume centres) reported an increase in CRT implantations in the last 2 years, in 16% a decrease, and in 38% CRT remained stable. Seventy-five percent of respondents implanted CRT only in patients with European Heart Rhythm Association (EHRA) class I indications. All operators collected ECG and echocardiography before implantation. Eighty-five percent of respondents selected coronary sinus target vein empirically, whereas 10% used mechanical and/or electrical delay techniques. Physicians working in high-volume centres reported a lower failure rate compared with others (16 vs. 34%; P = 0.03). If the coronary sinus lead could not be positioned in the target branch, 80% placed it in another vein, whereas 16% opted for a surgical approach or for conduction system pacing (CSP). Eighty percent accomplished CRT optimization in all patients, 17% only in nonresponders. Regarding anticoagulation, high agreement with EHRA guidelines emerged.

CONCLUSION

CRT represents a valid therapeutic option in heart failure treatment. Nowadays, CRT implantations remain stable and are mainly performed in patients with class I indications. ECG remains the preferred tool for patient selection, whereas imaging is increasingly used to determine the left pacing target area. In most patients, the left ventricular lead can be successfully positioned in the target vein, but in some cases, the result can be unsatisfactory; however, the decision to explore alternative resynchronization approaches is rarely pursued.

Association Between use of an Adaptive Cardiac Resynchronization Therapy Algorithm and Healthcare Utilization and Cost

OBJECTIVES

To assess the association between use of adaptive pacing on clinical and economic outcomes of CRT recipients in a real-world analysis.

BACKGROUND

The AdaptivCRTTM algorithm was shown in prior subgroup analyses of prospective trials to achieve clinical benefits, but a large prospective trial showed nonsignificant changes in the endpoint of mortality or heart failure hospitalizations.

METHODS

CRT-implanted patients from the Optum Clinformatics® database with ≥90 days of follow-up were included. Remote monitoring data was used to classify patients based on CRT setting - adaptive biventricular and left ventricular pacing (aCRT) vs. standard biventricular pacing (Standard CRT). Inverse probability of treatment weighting was used to adjust for baseline differences between groups. Mortality, 30-day readmissions, healthcare utilization, and payer and patient costs were evaluated post-implantation.

RESULTS

This study included 2,412 aCRT and 1,638 Standard CRT patients (mean follow-up: 2.4 ± 1.4 years), with balanced baseline characteristics after adjustment. The aCRT group was associated with lower all-cause mortality (adjusted hazard ratio = 0.88 [95% confidence interval (CI):0.80, 0.96]), fewer all-cause 30-day readmissions (adjusted incidence rate ratio = 0.87 [CI:0.81, 0.94]), and fewer all-cause and HF-related inpatient, outpatient, and emergency department (ED) visits. The aCRT cohort was also associated with lower all-cause outpatient payer-paid amounts and lower all-cause and HF-related inpatient and ED patient-paid amounts.

CONCLUSIONS

In this retrospective analysis of a large real-world cohort, use of an adaptive CRT algorithm was associated with lower mortality, reduced healthcare resource utilization, and lower payer and patient costs.

LAY SUMMARY

While cardiac resynchronization therapy (CRT) improves quality of life and clinical outcomes for certain heart failure patients, some patients do not respond to this therapy. Adaptive CRT algorithms (aCRT), such as AdaptivCRTTM, have been developed with the goal of improving effectiveness of CRT, and consequently, clinical and economic outcomes. This research study used a large database of administrative claims data - which contains information on patient demographics, diagnoses, healthcare services received, mortality, and cost data - to compare clinical and economic outcomes between CRT patients with the aCRT algorithm turned on (aCRT group) and CRT patients with the aCRT algorithm turned off (standard CRT group). Statistical methods were used to adjust for baseline differences between the aCRT group and standard CRT groups. Ultimately, the aCRT group was found to have a lower risk of all-cause mortality, fewer all-cause 30-day readmissions, fewer hospital visits (including inpatient, outpatient, and emergency department visits), and lower costs to payers and patients for specific types of costs.

Pilot study to evaluate left-to-right ventricular offset in biventricular pacing-comparison of electrocardiographic imaging and ECG

INTRODUCTION

Biventricular pacing (BiVp) improves outcomes in systolic heart failure patients with electrical dyssynchrony. BiVp is delivered from epicardial left ventricular (LV) and endocardial right ventricular (RV) electrodes. Acute electrical activation changes with different LV-RV stimulation offsets can help guide individually optimized BiVp programming. We sought to study the BiVp ventricular activation with different LV-RV offsets and compare with 12-lead ECG.

METHODS

In five patients with BiVp (63 ± 17-year-old, 80% male, LV ejection fraction 27 ± 6%), we evaluated acute ventricular epicardial activation, varying LV-RV offsets in 20 ms increments from -40 to 80 ms, using electrocardiographic imaging (ECGI) to obtain absolute ventricular electrical uncoupling (VEUabs, absolute difference in average LV and average RV activation time) and total activation time (TAT). For each patient, we calculated the correlation between ECGI and corresponding ECG (3D-QRS-area and QRS duration) with different LV-RV offsets.

RESULTS

The LV-RV offset to attain minimum VEUabs in individual patients ranged 20-60 ms. In all patients, a larger LV-RV offset was required to achieve minimum VEUabs (36 ± 17 ms) or 3D-QRS-area (40 ± 14 ms) than that for minimum TAT (-4 ± 9 ms) or QRS duration (-8 ± 11 ms). In individual patients, 3D-QRS-area correlated with VEUabs (r 0.65 ± 0.24) and QRS duration correlated with TAT (r 0.95 ± 0.02). Minimum VEUabs and minimum 3D-QRS-area were obtained by LV-RV offset within 20 ms of each other in all five patients.

CONCLUSIONS

LV-RV electrical uncoupling, as assessed by ECGI, can be minimized by optimizing LV-RV stimulation offset. 3D-QRS-area is a surrogate to identify LV-RV offset that minimizes LV-RV uncoupling.

Implications of ventricular arrhythmia after cardiac resynchronization therapy

BACKGROUND

Conflicting data are available on whether ventricular arrhythmia (VA) or shock therapy increases mortality. Although cardiac resynchronization therapy (CRT) reduces the risk of VA, little is known about the prognostic value of VA among patients with CRT devices.

OBJECTIVES

The purpose of this study was to evaluate the implications of VA as a prognostic marker for CRT.

METHODS

We investigated 330 CRT patients within 1 year after CRT device implantation. The primary endpoint was the composite endpoint of all-cause death or hospitalization for heart failure.

RESULTS

Forty-three patients had VA events. These patients had a significantly higher risk of the primary endpoint, even among CRT responders (P = .009). Fast VA compared to slow VA was associated with an increased risk of the primary endpoint (hazard ratio [HR] 2.14; 95% confidence interval [CI] 1.06-4.34; P = .035). Shock therapy was not associated with a primary endpoint (shock therapy vs antitachycardia pacing: HR 1.49; 95% CI 0.73-3.03; P = .269). The patients with VA had a lower prevalence of response to CRT (23 [53%] vs 202 [70%]; P = .031) and longer left ventricular paced conduction time (174 ± 23 ms vs 143 ± 36 ms; P = .003) than the patients without VA.

CONCLUSION

VA occurrence within 1 year was related to paced electrical delay and poor response to CRT. VA could be associated with poor prognosis among CRT patients.

Exploring QRS Area beyond Patient Selection in CRT-Can It Guide Left Ventricular Lead Placement?

Vectorcardiographic QRS area is a promising tool for patient selection and implantation guidance in cardiac resynchronization therapy (CRT). Research has mainly focused on the role of QRS area in patient selection for CRT. Recently, QRS area has been proposed as a tool to guide left ventricular lead placement in CRT. Theoretically, vector-based electrical information of ventricular fusion pacing, calculated from the basic 12-lead ECG, can give real-time insight into the extent of resynchronization at any LV lead position, as well as any selected electrode on the LV lead. The objective of this review is to provide an overview of the background of vectorcardiographic QRS area and its potential in optimizing LV lead location in order to optimize the benefits of CRT.

Clinical outcomes and predictors of delayed echocardiographic response to cardiac resynchronization therapy

INTRODUCTION

The clinical outcomes and mechanisms of delayed responses to cardiac resynchronization therapy (CRT) remain unclear. We aimed to investigate the differences in outcomes and gain insight into the mechanisms of early and delayed responses to CRT.

METHODS

This retrospective study included 110 patients who underwent CRT implantation. Positive response to CRT was defined as ≥15% reduction of left ventricular (LV) end-systolic volume on echocardiography at 1 year (early phase) and 3 years (delayed phase) after implantation. The latest mechanical activation site (LMAS) of the LV was identified using two-dimensional speckle-tracking radial strain analysis.

RESULTS

Seventy-eight (71%) patients exhibited an early response 1 year after CRT implantation. Of 32 non-responders in the early phase, 12 (38%) demonstrated a delayed response, and 20 (62%) were classified as non-responders after 3 years. During the follow-up time of 10.3 ± 0.5 years, the delayed and early responders had a similar prognosis of mortality and heart failure (HF) hospitalization. In contrast, non-responders had a worse prognosis. Multivariate analysis revealed that a longer duration (months) between initial HF hospitalization and CRT (odds ratio [OR]: 1.126; 95% confidence interval [CI]: 1.036-1.222; p = .005), non-exact concordance of LV lead location with LMAS (OR: 32.744; 95% CI: 1.101-973.518; p = .044), and pre-QRS duration (OR: 0.901; 95% CI: 0.827-0.981; p = .016) were independent predictors of delayed response to CRT compared with early response.

CONCLUSION

The prognoses were similar regardless of the response time after CRT. A longer history of HF, suboptimal LV lead position, and shorter pre-QRS duration were related to delayed response than early response.

Multimodality Imaging for Selecting Candidates for CRT: Do We Have a Single Alley to Increase Responders?

Cardiac resynchronization therapy has evolved in recent years to provide a reduction of morbidity and mortality for many patients with heart failure. Its application and optimization is an evolving field and its use requires a multidisciplinary approach for patient and device selection, technical preprocedural planning, and optimization. While echocardiography has always been considered the first line for the evaluation of patients, additional imaging techniques have gained increasing evidence in recent years. Today different details about heart anatomy, function, dissynchrony can be investigated by magnetic resonance, cardiac computed tomography, nuclear imaging, and more, with the aim of obtaining clues to reach a maximal response from the electrical therapy. The purpose of this review is to provide a practical analysis of the single and combined use of different imaging techniques in the preoperative and perioperative phases of cardiac resynchronization therapy, underlining their main advantages, limitations, and information provided.

Imaging in patients with cardiovascular implantable electronic devices: part 2-imaging after device implantation. A clinical consensus statement of the European Association of Cardiovascular Imaging (EACVI) and the European Heart Rhythm Association (EHRA) of the ESC

Cardiac implantable electronic devices (CIEDs) improve quality of life and prolong survival, but there are additional considerations for cardiovascular imaging after implantation-both for standard indications and for diagnosing and guiding management of device-related complications. This clinical consensus statement (part 2) from the European Association of Cardiovascular Imaging, in collaboration with the European Heart Rhythm Association, provides comprehensive, up-to-date, and evidence-based guidance to cardiologists, cardiac imagers, and pacing specialists regarding the use of imaging in patients after implantation of conventional pacemakers, cardioverter defibrillators, and cardiac resynchronization therapy (CRT) devices. The document summarizes the existing evidence regarding the role and optimal use of various cardiac imaging modalities in patients with suspected CIED-related complications and also discusses CRT optimization, the safety of magnetic resonance imaging in CIED carriers, and describes the role of chest radiography in assessing CIED type, position, and complications. The role of imaging before and during CIED implantation is discussed in a companion document (part 1).

The impact of chronotropic incompetence on atrioventricular conduction times in heart failure patients

BACKGROUND

Intrinsic atrioventricular (AV) conduction is used to optimize AV intervals with cardiac resynchronization therapy (CRT) in most device algorithms. Atrial pacing and heart rate affect conduction times, but little is known regarding differeces among chronotropic incompetent(CI) and competent(CC) patients to guide programming.

METHODS

RAVE was a multicenter prospective trial of CRT patients. Heart rate was increased with incremental atrial pacing and with submaximal exercise. According to the maximal heart rate achieved during exercise, patients were classified as either CI or CC. For CI patients, an additional symptom-limited exercise with rate-adaptive pacing activated was performed. Intracardiac intervals were measured from the implantable lead electrograms in multiple postures.

RESULTS

There were 12 subjects with CI and 24 with CC. With atrial pacing, AV interval immediately increased and gradually increased with incremental atrial pacing in all patients. However, the changes in the atrial to right ventricular (ARV) and atrial to left ventricular (ALV) intervals with increasing atrial pacing rates were about threefold greater in CI patients compared to CC patients (24.3 ± 28.9 vs. 7.2 ± 5.5 ms/10 bpm for ARV and 22.7 ± 25.6 vs. 7.1 ± 5.7 ms/10 bpm for ALV in the standing position, p < 0.05). In CI pacing with rate-adaptive pacing during exercise, AV interval changes with paced heart rate were variable.

CONCLUSIONS

The AV response to overdrive atrial pacing at rest may provide a simple means of identifying chronotropic competence in CRT patients. For patients with CI, who often require rate-adaptive atrial pacing, rate-adaptive AV algorithms should be adjusted individually.

Effectiveness of conduction system pacing for cardiac resynchronization therapy: A systematic review and network meta-analysis

INTRODUCTION

Cardiac resynchronization therapy (CRT) with biventricular pacing (BiV-CRT) is ineffective in approximately one-third of patients. CRT with Conduction system pacing (CSP-CRT) may achieve greater synchronization. We aimed to assess the effectiveness of CRT with His pacing (His-CRT) or left bundle branch pacing (LBB-CRT) in lieu of biventricular CRT.

METHODS AND RESULTS

The PubMed, Embase, Web of Science, Scopus, and the Cochrane Library were systematically searched until August 19, 2023, for original studies including patients with reduced left ventricular ejection fraction (LVEF) who received His- or LBB-CRT, that reported either CSP-CRT success, LVEF, QRS duration (QRSd), or New York Heart Association (NYHA) classification. Effect measures were compared with frequentist network meta-analysis. Thirty-seven publications, including 20 comparative studies, were included. Success rates were 73.5% (95% CI: 61.2-83.0) for His-CRT and 91.5% (95% CI: 88.0-94.1) for LBB-CRT. Compared to BiV-CRT, greater improvements were observed for LVEF (mean difference [MD] for His-CRT +3.4%; 95% CI [1.0; 5.7], and LBB-CRT: +4.4%; [2.5; 6.2]), LV end-systolic volume (His-CRT:17.2mL [29.7; 4.8]; LBB-CRT:15.3mL [28.3; 2.2]), QRSd (His-CRT: -17.1ms [-25.0; -9.2]; LBB-CRT: -17.4ms [-23.2; -11.6]), and NYHA (Standardized MD [SMD]: His-CRT:0.4 [0.8; 0.1]; LBB-CRT:0.4 [-0.7; -0.2]). Pacing thresholds at baseline and follow-up were significantly lower with LBB-CRT versus both His-CRT and BiV-CRT. CSP-CRT was associated with reduced mortality (R = 0.75 [0.61-0.91]) and hospitalizations risk (RR = 0.63 [0.42-0.96]).

CONCLUSION

This study found that CSP-CRT is associated with greater improvements in QRSd, echocardiographic, and clinical response. LBB-CRT was associated with lower pacing thresholds. Future randomized trials are needed to determine CSP-CRT efficacy.

Maximizing QRS duration reduction in contemporary cardiac resynchronization therapy is feasible and shorter QRS duration is associated with better clinical outcome

BACKGROUND

We aimed to evaluate if optimization by maximizing QRS duration (QRSd) reduction is feasible in an all-comer cardiac resynchronization therapy (CRT) population, and if reduced, QRSd is associated with a better clinical outcome.

METHODS

Patients with LBBB receiving CRT implants during the period 2015-2020 were retrospectively evaluated. Implants from 2015-2017 were designated as controls. Starting from 2018, an active 12-lead electrogram-based optimization of QRSd reduction was implemented (intervention group). QRSd reduction was evaluated in a structured way at various device AV and VV settings, aiming to maximize the reduction. The primary endpoint was a composite of heart failure hospitalization or death from any cause.

RESULTS

A total of 254 patients were followed for up to 6 years (median 2.9 [1.8-4.1]), during which 82 patients (32%) reached the primary endpoint; 53 deaths (21%) and 58 (23%) heart failure hospitalizations. Median QRS duration pre-implant was 162 ms [150-174] and post-implant 146ms [132-160]. Mean reduction in QRS duration was progressively larger for each year during the intervention period, ranging from - 9.5ms in the control group to - 24 in the year 2020 (p = 0.005). QRS reduction > 14 ms (median value) was associated with a lower risk of death or heart failure hospitalization (adjusted HR 0.54 [0.29-0.98] (p = 0.04).

CONCLUSIONS

Implementing a general strategy of CRT device optimization by aiming for shorter QRS duration is feasible in a structured clinical setting and results in larger reductions in QRS duration post-implant. In patients with a larger QRS reduction, compared to those with a smaller QRS reduction, there is an association with a better clinical outcome.

Progress in Cardiac Resynchronisation Therapy and Optimisation

Cardiac resynchronisation therapy (CRT) has become the cornerstone of heart failure (HF) treatment. Despite the obvious benefit from this therapy, an estimated 30% of CRT patients do not respond ("non-responders"). The cause of "non-response" is multi-factorial and includes suboptimal device settings. To optimise CRT settings, echocardiography has been considered the gold standard but has limitations: it is user dependent and consumes time and resources. CRT proprietary algorithms have been developed to perform device optimisation efficiently and with limited resources. In this review, we discuss CRT optimisation including the various adopted proprietary algorithms and conduction system pacing.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

Adaptive versus conventional cardiac resynchronisation therapy in patients with heart failure (AdaptResponse): a global, prospective, randomised controlled trial

BACKGROUND

Continuous automatic optimisation of cardiac resynchronisation therapy (CRT), stimulating only the left ventricle to fuse with intrinsic right bundle conduction (synchronised left ventricular stimulation), might offer better outcomes than conventional CRT in patients with heart failure, left bundle branch block, and normal atrioventricular conduction. This study aimed to compare clinical outcomes of adaptive CRT versus conventional CRT in patients with heart failure with intact atrioventricular conduction and left bundle branch block.

METHODS

This global, prospective, randomised controlled trial was done in 227 hospitals in 27 countries across Asia, Australia, Europe, and North America. Eligible patients were aged 18 years or older with class 2-4 heart failure, an ejection fraction of 35% or less, left bundle branch block with QRS duration of 140 ms or more (male patients) or 130 ms or more (female patients), and a baseline PR interval 200 ms or less. Patients were randomly assigned (1:1) via block permutation to adaptive CRT (an algorithm providing synchronised left ventricular stimulation) or conventional biventricular CRT using a device programmer. All patients received device programming but were masked until procedures were completed. Site staff were not masked to group assignment. The primary outcome was a composite of all-cause death or intervention for heart failure decompensation and was assessed in the intention-to-treat population. Safety events were collected and reported in the intention-to-treat population. This study is registered with ClinicalTrials.gov, NCT02205359, and is closed to accrual.

FINDINGS

Between Aug 5, 2014, and Jan 31, 2019, of 3797 patients enrolled, 3617 (95·3%) were randomly assigned (1810 to adaptive CRT and 1807 to conventional CRT). The futility boundary was crossed at the third interim analysis on June 23, 2022, when the decision was made to stop the trial early. 1568 (43·4%) of 3617 patients were female and 2049 (56·6%) were male. Median follow-up was 59·0 months (IQR 45-72). A primary outcome event occurred in 430 of 1810 patients (Kaplan-Meier occurrence rate 23·5% [95% CI 21·3-25·5] at 60 months) in the adaptive CRT group and in 470 of 1807 patients (25·7% [23·5-27·8] at 60 months) in the conventional CRT group (hazard ratio 0·89, 95% CI 0·78-1·01; p=0·077). System-related adverse events were reported in 452 (25·0%) of 1810 patients in the adaptive CRT group and 440 (24·3%) of 1807 patients in the conventional CRT group.

INTERPRETATION

Compared with conventional CRT, adaptive CRT did not significantly reduce the incidence of all-cause death or intervention for heart failure decompensation in the included population of patients with heart failure, left bundle branch block, and intact AV conduction. Death and heart failure decompensation rates were low with both CRT therapies, suggesting a greater response to CRT occurred in this population than in patients in previous trials.

FUNDING

Medtronic.

Electrical Synchrony Optimization for Left Bundle Branch Area Pacing in Patients With Bradycardia and Heart Failure

Left bundle branch area pacing (LBBAP) has emerged as a promising physiological pacing modality. This study was designed to investigate the acute impact of the atrioventricular delay (AVD) on cardiac electrical characteristics and identify an optimal range of AVDs for LBBAP to achieve electrical atrioventricular and interventricular synchrony. Patients indicated for ventricular or biventricular pacing were studied during routine follow-ups at least 3 months after LBBAP implantation. Patients were excluded if they had a complete AV block or persistent atrial fibrillation. AVD was programed from 40 to 240 ms or until intrinsic conduction occurred. Optimal AVD was determined by the electrocardiography criteria, including QRS duration, reduced R-wave in lead V1, reduced notching or slurring in lateral leads, and more desirable precordial QRS transition. A total of 38 patients (age 68.7 ± 10.3 years; 16 male (42%); 18 dual-chamber pacemakers and 20 cardiac resynchronization therapy devices; average follow-up period 15.1 ± 10.2 months) were included. The fusion of LBBAP and intrinsic right ventricular conduction occurred in 21 patients with corresponding optimal AVD determined. A great proportion (∼85%) of the optimal AVDs ranged from 50% to 80% of the observed atrium-to-left bundle branch-sensing (A-LBBS) intervals. The linear correlation between the optimal AVD and corresponding A-LBBS interval (optimal AVD = 0.84 × [A-LBSs interval] - 36 ms) produced R = 0.86 and p <0.0001. In conclusion, AVD selection during LBBAP greatly impacted the ventricular electrical characteristics and the optimal AVD was linearly correlated with the corresponding A-LBBS interval.

2023 HRS/APHRS/LAHRS guideline on cardiac physiologic pacing for the avoidance and mitigation of heart failure

Cardiac physiologic pacing (CPP), encompassing cardiac resynchronization therapy (CRT) and conduction system pacing (CSP), has emerged as a pacing therapy strategy that may mitigate or prevent the development of heart failure (HF) in patients with ventricular dyssynchrony or pacing-induced cardiomyopathy. This clinical practice guideline is intended to provide guidance on indications for CRT for HF therapy and CPP in patients with pacemaker indications or HF, patient selection, pre-procedure evaluation and preparation, implant procedure management, follow-up evaluation and optimization of CPP response, and use in pediatric populations. Gaps in knowledge, pointing to new directions for future research, are also identified.

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

BACKGROUND

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.

OBJECTIVE

We aimed to clarify the association between %e-CRT and clinical outcomes.

METHODS

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.

RESULTS

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% [93.7%-98.3%]). 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 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 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.

CONCLUSION

High %e-CRT is associated with high CRT responder prevalence and low HF hospitalization risk.

Conduction system pacing on track to replace CRT? Review of current evidence and prospects of conduction system pacing

Conduction system pacing (CSP) has been emerging over the last decade as a pacing option instead of conventional right ventricular (RV) pacing and biventricular (BiV) pacing. Numerous case reports, some observational studies and a few randomized control trials have looked at optimum pacing strategies for heart failure (HF) with left bundle branch block (LBBB) or cases where left ventricular (LV) dysfunction is anticipated due to chronic RV pacing (RVP). Evolution of pacing strategies from standard RVP to septal RVP, BiV pacing and now CSP have shown improving hemodynamic responses and possible ease of implantation of CSP systems. In this review article, we review the literature on the evolution of CSP and common scenarios where it might be beneficial.

Targeted left ventricular lead positioning to the site of latest activation in cardiac resynchronization therapy: a systematic review and meta-analysis

AIMS

Several studies have evaluated the use of electrically- or imaging-guided left ventricular (LV) lead placement in cardiac resynchronization therapy (CRT) recipients. We aimed to assess evidence for a guided strategy that targets LV lead position to the site of latest LV activation.

METHODS AND RESULTS

A systematic review and meta-analysis was performed for randomized controlled trials (RCTs) until March 2023 that evaluated electrically- or imaging-guided LV lead positioning on clinical and echocardiographic outcomes. The primary endpoint was a composite of all-cause mortality and heart failure hospitalization, and secondary endpoints were quality of life, 6-min walk test (6MWT), QRS duration, LV end-systolic volume, and LV ejection fraction. We included eight RCTs that comprised 1323 patients. Six RCTs compared guided strategy (n = 638) to routine (n = 468), and two RCTs compared different guiding strategies head-to-head: electrically- (n = 111) vs. imaging-guided (n = 106). Compared to routine, a guided strategy did not significantly reduce the risk of the primary endpoint after 12-24 (RR 0.83, 95% CI 0.52-1.33) months. A guided strategy was associated with slight improvement in 6MWT distance after 6 months of follow-up of absolute 18 (95% CI 6-30) m between groups, but not in remaining secondary endpoints. None of the secondary endpoints differed between the guided strategies.

CONCLUSION

In this study, a CRT implantation strategy that targets the latest LV activation did not improve survival or reduce heart failure hospitalizations.

Cardiac Resynchronization Therapy beyond Nominal Settings: An IEGM-Based Approach for Paced and Sensed Atrioventricular Delay Offset Optimization in Daily Clinical Practice

Optimization of the atrioventricular (AV) delay has been performed in several landmark trials in cardiac resynchronization therapy (CRT), although it is often not performed in daily practice. Our aim was to study optimal AV delays and investigate a simple intracardiac electrogram (IEGM)-based optimization approach. 328 CRT patients with paired IEGM and echocardiography optimization data were included in our single-center observational study. Sensed (sAV) and paced (pAV) AV delays were optimized using an iterative echocardiography method. The offset between sAV and pAV delays was calculated using the IEGM method. The mean age of the patients was 69 ± 12 years; 64% were men, 48% had ischemic etiology of heart failure. During echocardiographic optimization, an offset of 73 ± 18 ms was found, differing from nominal AV settings (p < 0.001). Based on the IEGM method, the optimal offset was 75 ± 25 ms. The echocardiographic and IEGM-generated AV offset delays showed good correlation (R2 = 0.62, p < 0.001) and good agreement according to Bland-Altman plot analysis. CRT responders had a near zero offset difference between IEGM and echo optimization (-0.2 ± 17 ms), while non-responders had an offset difference of 6 ± 17 ms, p = 0.006. In conclusion, optimal AV delays are patient-specific and differ from nominal settings. pAV delay can easily be calculated from IEGM after sAV delay optimization.

Special Issue: Latest Advances in Delivery and Outcomes of Cardiac Resynchronization Therapy and Conduction System Pacing

Cardiac Resynchronization Therapy (CRT) is an established technique to improve morbidity and mortality in selected heart failure patients [...].

Considering Diastolic Dyssynchrony as a Predictor of Favorable Response in LV-Only Fusion Pacing Cardiac Resynchronization Therapy

Background: CRT improves systolic and diastolic function, increasing cardiac output. Aim of the study: to assess the outcome of LV diastolic dyssynchrony in a population of fusion pacing CRT. Methods: Diastolic dyssynchrony was measured by offline speckle-tracking-derived TDI timing assessment of the simultaneity of E″ and A″ basal septal and lateral walls. New parameters introduced: E″ and, respectively, A″ time (E″T/A″T) as the time difference between E″ (respectively, A″) peak septal and lateral wall. Patients were divided into super-responders (SR), responders (R), and non-responders (NR). Results: Baseline characteristics: 62 pts (62 ± 11 y.o.) with idiopathic DCM, EF 27 ± 5.2%; 29% type III diastolic dysfunction (DD), 63% type II, 8% type I. Average follow-up 45 ± 19 months: LVEF 37 ± 7.9%, 34%SR, 61%R, 5%NR. The E″T decreased from 90 ± 20 ms to 25 ± 10 ms in SR with significant LV reverse remodeling (LV end-diastolic volume 193.7 ± 81 vs. 243.2 ± 82 mL at baseline, p < 0.0028) and lower LV filling pressures (E/E' 13.2 ± 4.6 vs. 11.4 ± 4.5, p = 0.0295). DD profile improved in 65% of R with a reduction in E/E' ratio (21 ± 9 vs. 14 ± 4 ms, p < 0.0001). Significant cut-off value calculated by ROC curve for LV diastolic dyssynchrony is E″T > 80 ms and A″T > 30 msec. Conclusions: The study identifies the cut-off values of diastolic dyssynchrony parameters as predictors of favorable outcomes in responders and super-responder patients with fusion CRT pacing. These findings may have important implications in patient selection and follow-up.

Long-term outcomes in nonprogressors to cardiac resynchronization therapy

BACKGROUND

Among patients with heart failure undergoing cardiac resynchronization therapy (CRT), patients with a minimal change in left ventricular ejection fraction (LVEF) have recently been defined as "nonprogressors" rather than as "nonresponders." Little is known regarding long-term outcomes of nonprogressors.

OBJECTIVE

We sought to evaluate outcomes in patients undergoing CRT on the basis of echocardiographically determined response status.

METHODS

We reviewed the medical charts of patients with an LVEF of ≤35% and a QRS duration of ≥120 ms undergoing CRT at the Cleveland Clinic, Johns Hopkins Hospital, and Johns Hopkins Bayview Medical Center between 2003 and 2014. Response to CRT was defined on the basis of LVEF change as follows: super-responders ≥20%, responders 6%-19%, nonprogressors 0%-5%, and progressors <0%. Survival free of left ventricular assist device (LVAD) implantation and heart transplantation was compared on the basis of response classification.

RESULTS

A total of 1058 patients were included and had a mean follow-up 8.7 ± 5.4 years, over which time there were 606 end points (37 LVAD implants, 32 heart transplants, and 537 deaths). Survival free of LVAD and heart transplant differed significantly between response groups after CRT both in the mid-term (4 years) and in the long-term (8.7 ± 5.4 years), with super-responders achieving the best outcomes and progressors the worst (P < .001). In multivariate analysis, nonprogressors had superior outcomes to progressors (P = .02) at 4 years of follow-up. Over the duration of follow-up (8.7 ± 5.4 years), there was no significant difference in survival between those 2 groups (P = .18).

CONCLUSION

Nonprogressors to CRT have superior medium-term outcomes but similar long-term outcomes to progressors and inferior outcomes to responders and super-responders.

Impact of long-term optimizing atrioventricular delay using device-based algorithms on cardiac resynchronization therapy

Sub-optimal atrioventricular delay (AVD) is one of the main causes of non-responder for cardiac resynchronization therapy (CRT). Recently, device-based algorithms (DBAs) that provide optimal AVD based on intracardiac electrograms, have been developed. However, their long-term effectiveness is still unknown. This study aims to investigate the effect of optimizing AVD using DBAs over a long period, on the prognosis of patients undergoing CRT. A total of 118 patients who underwent CRT at our hospital between April 2008 and March 2018, were retrospectively reviewed; 61 of them with optimizing AVD using DBAs were classified into the treated group (group 1), and the remaining 57 were classified into the control group (group 2). The median follow-up period was 46.0 months. The responder and survival rate in group 1 were significantly better than those in group 2 (group 1 vs. group 2: responder rate = 64% vs. 46%, p = 0.046; survival rate: 85.2% vs. 64.9%, p = 0.02). Moreover, investigating only the non-responder population showed that group 1 had an improved survival rate compared to group 2 (group 1 vs. group 2 = 72.7% vs. 45.1%, p = 0.02). Optimizing AVD using DBAs was a significant contributor to the improved survival rate in CRT non-responders in multivariate analysis (HR 3.6, p = 0.01). In conclusion, the long-term optimizing AVD using DBAs improved the survival rate in CRT and the prognosis of CRT non-responders, as well.

Electrocardiogram Belt guidance for left ventricular lead placement and biventricular pacing optimization

BACKGROUND

Patients with ischemic cardiomyopathy, non-left bundle branch block, or QRS duration <150 ms have a lower response rate to cardiac resynchronization therapy (CRT) than did other indicated patients. The ECG Belt system (EBS) is a novel surface mapping system designed to measure electrical dyssynchrony via the standard deviation of the activation times of the left ventricle.

OBJECTIVES

The objectives of this study were to evaluate the efficacy of the EBS in patients less likely to respond to CRT and to determine whether EBS use in lead placement guidance and device programming was superior to standard CRT care.

METHODS

This was a prospective randomized trial of patients with heart failure and EBS-guided CRT implantation and programming vs standard CRT care. The primary end point was relative change in left ventricular end-systolic volume from baseline to 6 months postimplantation.

RESULTS

A total of 408 patients from centers in Europe and North America were randomized. Although both patients with EBS and control patients had a mean improvement in left ventricular end-systolic volume, there was no significant difference in relative change from baseline (P = .26). While patients with a higher baseline standard deviation of the activation times derived greater left ventricular reverse remodeling, improvement in electrical dyssynchrony did not correlate with the extent of reverse remodeling.

CONCLUSION

The findings of the present study do not support EBS-guided therapy for CRT management of heart failure with reduced ejection fraction.

Finding New Insights in Cardiac Resynchronization Therapy and the Pathophysiology behind Left Ventricular Dyssynchrony

Over the past two decades, cardiac resynchronization therapy (CRT) became an established treatment option for patients with symptomatic heart failure [...].

Hemodynamic Doppler echocardiographic evaluation of permanent His bundle and biventricular pacing after AV nodal ablation

placing after atrioventricular (AV) nodal ablation for permanent atrial fibrillation (AF) may include cardiac resynchronization therapy (CRT) with either His bundle pacing (HBP) or biventricular pacing (BVP), or conventional single site right ventricular apical pacing (RVAP). To determine the relationship between pacing method and hemodynamic outcome, we used Doppler echocardiographic methods to evaluate left ventricular (LV) hemodynamics after AV nodal ablation and either HBP, BVP, or RVAP.

Method

20 patients were evaluated > 6 months after AV nodal ablation, 10 each with chronic HBP or BVP, and all with RVAP lead. Doppler echocardiography was used to measure 3 parameters indicative of CRT: 1) LV dP/dt, 2) the LV pre-ejection interval, and 3) myocardial performance index, relative to intra-patient RVAP.

Results

Primary endpoint of LV dP/dt on average improved by > 17% with both HBP and BVP, compared to RVAP. HBP but not BVP, had improvement across all three parameters.

Conclusion

HBP provides LV electromechanical synchrony across multiple echo Doppler parameters. Both HBP and BVP were hemodynamically superior to RVAP following AV nodal ablation.

Multidisciplinary heart failure care program: an experience from Colombia

The prevalence of Heart Failure is growing alarmingly; its treatment consumes health resources and affects the quality of life of patients.

OBJECTIVE

to describe the changes in NYHA functional Class, ejection fraction, hospitalizations and mortality after 8 years of follow up in a multidisciplinary heart failure program in Colombia as a model for lower and middle income countries.

METHODS

An observational study was performed with the retrospective analysis of the information RESULTS: 1757 patients were included, The NYHA functional class at the beginning of the program was: NYHA I 23.5%, NYHA II 50.3%, NYHA class Improvement was observed at the end of the follow-up with an increase in the percentage of patients in Functional Class NYHA I and II. The reduction in hospitalizations were 35% less (mean: 0.68 ± 0.95, p < 0.0001), a reduction in the length of stay in the hospital was 13.2% (before: 4.46 ± 7.16, after 3.87 ± 8.1 days, p < 0.001). The total mortality after eight years of follow-up was 6.6 % (n = 116).

CONCLUSION

Multidisciplinary follow-up in HF programs improves Functional Class and EF, decreases hospital admissions as well as hospitalization and the length of stay. This is a very simple and successful model of care for this disease that can be implemented for countries of lower- and middle-income countries.

Cardiac resynchronization considerations in left bundle branch block

Cardiac resynchronization therapy (CRT) via biventricular pacing (BiVP) is an established treatment for patients with left ventricular systolic heart failure and intraventricular conduction delay resulting in wide QRS. Seminal trials demonstrating mortality benefit from CRT were conducted in patients with wide left bundle branch block (LBBB) pattern on electrocardiogram (ECG) and evidence of clinical heart failure. The presence of conduction block was assumed to correlate with commonly applied criteria for LBBB. More recent data has challenged this assertion, revealing that LBBB pattern may include distinct underlying pathophysiology, including patients with complete conduction block, either at the left-sided His fibers or the proximal left bundle, intact Purkinje activation with wide LBBB-like QRS, and patients demonstrating both proximal block and distal delay. Currently, BiVP-CRT is indicated for all QRS duration ≥150 ms and may be considered for BBB patterns from 130 to 149 ms with robust clinical data to support its use. Despite this, however, there remains a significant number of non-responders to BVP. Conduction system pacing (CSP) has emerged as an alternative approach to deliver CRT and correct QRS in patients with conduction block. Newer hybrid approaches which combine CSP and traditional BiVP-CRT and may hold promise for patients with IP or mixed-level block. As various approaches to CRT continue to be studied, physiologic phenotyping of the LBBB pattern remains an important consideration.

Real-world clinical burden among patients with and without heart failure worsening after cardiac resynchronization therapy

OBJECTIVE

Cardiac resynchronization therapy (CRT) can improve cardiac function in patients with heart failure (HF); however, in some patients, HF worsens despite CRT. This study characterized the long-term clinical burden of patients with and without HF worsening (HFW) within 6 months post CRT implantation.

METHODS

A claims database (2007-2018) was used to identify two cohorts of adults: those with HFW within 180 days post-CRT and those with no HFW (NHFW). The evaluated clinical outcomes were cardiovascular events/complications, HF-related interventions, hospice enrollment, and all-cause mortality. Inverse probability of treatment weighting (IPTW) was used to adjust for confounders; adjusted comparisons were assessed using weighted Cox proportional hazard ratios (HRs).

RESULTS

Among the 12,753 adults analyzed (HFW: N = 4,785; NHFW: N = 7,968), the mean age was 72 years and the mean duration of follow-up was approximately 2 years. The clinical burden was greater for HFW than for NHFW in terms of all-cause mortality (19.7% vs. 12.1%) and occurrence of atrial fibrillation (57.4% vs. 51.2%). In the IPTW-adjusted Cox proportional hazard analyses, patients with HFW had a 54% higher average hazard of experiencing all-cause mortality compared to NHFW (adjusted average HR = 1.54, 95% confidence interval [CI]: 1.41-1.70; p < .001). Of the clinical events experienced by ≥5% of patients, the greatest differences in average hazard were for HF decompensation (adjusted average HR = 1.83, 95% CI: 1.60-2.09) and HF decompensation or death (HR = 1.63, 95%CI: 1.50-1.77).

CONCLUSION

Patients with early HFW post-CRT experienced a significantly higher clinical burden than those without HFW. Vigilance for signs of worsening HF in the first 6 months post-CRT is warranted.

Treatment of cardiac resynchronization therapy non-responders: current approaches and new frontiers

INTRODUCTION

Cardiac resynchronization therapy (CRT) has developed into a very effective technology for patients with decreased systolic function and has substantially improved patients' clinical course. However, non-responsiveness to CRT, described as lack of reverse cardiac chamber remodeling, leading to lack to improve symptoms, heart failure hospitalizations or mortality, is common, rather unpredictable, and not fully understood.

AREAS COVERED

This article aims to discuss key factors that are impacting CRT response; from patient selection to LV lead position, to structured follow-up in CRT clinics. Secondly, common causes and interventions for CRT non-responsiveness are discussed. Next, insight is given into technologies representing new and feasible interventions as well as pacing strategies in this group of patients that remain challenging to treat. Finally, an outlook is given into future scientific development.

EXPERT OPINION

Despite the progress that has been made, CRT non-response remains a significant and complex problem. Patient management in interdisciplinary teams including heart failure, imaging, and cardiac arrhythmia experts appears critical as complexity is increasing and CRT non-response often is a multifactorial problem. This will allow optimization of medical therapy, the use of new integrated sensor technologies and telemedicine to ultimately optimize outcomes for all patients in need of CRT.

Nonischemic Super-Responders in Fusion CRT Pacing with Normal Atrioventricular Conduction

Background: Fusion CRT pacing (FCRT) is noninferior to biventricular pacing, according to the current data. The aim of this study is to assess the response to FCRT and to identify predictors of super-responders (SRs) in a nonischemic population with normal AV conduction. Methods: LV-only CRT patients (pts) with a right atrium/left ventricle pacing system implanted in two CRT centers in Romania were included. Device interrogation, exercise tests, echocardiography, and individualized drug optimization were performed every 6 months during close follow-up. SRs pts were defined as those with left ventricular end-systolic volume (LVESV) improvement ≥30% and stable ejection fraction (LVEF) ≥45%. Results: A total of 25 out of 83 pts (31%) were SRs, with nonischemic LBBB low EF cardiomyopathy (50 male, 62 ± 9 y.o.) initially included. Mean follow-up was 5 years ± 27 months. Patients were divided in two groups: SRs and non-SRs (52 responders/6 hypo-responders). Two predictors were found in the SRs group: a higher baseline LVEF (SRs 29 ± 5% vs. non-SRs 26 ± 5%, p = 0.02) and a lower pulmonary arterial systolic pressure (SRs 38 ± 11 mm Hg vs. non-SRs 50 ± 15 mmHg, p = 0.003). Baseline severe mitral regurgitation was found in 11% of SRs vs. 64% in the non-SRs group. Conclusions: SRs in the selected NICM-FCRT group are significative high. Higher baseline LVEF and mild pulmonary arterial hypertension were independently associated with super-response.

A multimodal deep learning model for cardiac resynchronisation therapy response prediction

We present a novel multimodal deep learning framework for cardiac resynchronisation therapy (CRT) response prediction from 2D echocardiography and cardiac magnetic resonance (CMR) data. The proposed method first uses the 'nnU-Net' segmentation model to extract segmentations of the heart over the full cardiac cycle from the two modalities. Next, a multimodal deep learning classifier is used for CRT response prediction, which combines the latent spaces of the segmentation models of the two modalities. At test time, this framework can be used with 2D echocardiography data only, whilst taking advantage of the implicit relationship between CMR and echocardiography features learnt from the model. We evaluate our pipeline on a cohort of 50 CRT patients for whom paired echocardiography/CMR data were available, and results show that the proposed multimodal classifier results in a statistically significant improvement in accuracy compared to the baseline approach that uses only 2D echocardiography data. The combination of multimodal data enables CRT response to be predicted with 77.38% accuracy (83.33% sensitivity and 71.43% specificity), which is comparable with the current state-of-the-art in machine learning-based CRT response prediction. Our work represents the first multimodal deep learning approach for CRT response prediction.

Impact of cardiac resynchronization therapy optimization inside a heart failure programme: a real-world experience

AIMS

This study sought to describe and evaluate the impact of a routine in-hospital cardiac resynchronization therapy (CRT) programme, including comprehensive heart failure (HF) evaluation and systematic echo-guided CRT optimization.

METHODS AND RESULTS

CRT implanted patients were referred for optimization programme at 3 to 12 months from implantation. The program included clinical and biological status, standardized screening for potential cause of CRT non-response and systematic echo-guided atrioventricular and interventricular delays (AVd and VVd) optimization. Initial CRT-response and improvement at 6 months post-optimization were assessed with a clinical composite score (CCS). Major HF events were tracked during 1 year after optimization. A total of 227 patients were referred for CRT optimization and enrolled (71 ± 11 years old, 77% male, LVEF 30.6 ± 7.9%), of whom 111 (48.9%) were classified as initial non-responders. Left ventricular lead dislodgement was noted in 4 patients (1.8%), and loss or ≤90% biventricular capture in 22 (9.7%), mostly due to arrhythmias. Of the 196 patients (86%) who could undergo echo-guided CRT optimization, 71 (36.2%) required VVd modification and 50/144 (34.7%) AVd modification. At 6 months post-optimization, 34.3% of the initial non-responders were improved according to the CCS, but neither AVd nor VVd echo-guided modification was significantly associated with CCS-improvement. After one-year follow-up, initial non-responders maintained a higher rate of major HF events than initial responders, with no significant difference between AVd/VVd modified or not.

CONCLUSIONS

Our study supports the necessity of a close, comprehensive and multidisciplinary follow-up of CRT patients, without arguing for routine use of echo-guided CRT optimization.

What Have We Learned in the Last 20 Years About CRT Non-Responders?

Although cardiac resynchronization therapy (CRT) has become well established in the treatment of heart failure, the management of patients who do not respond after CRT remains a key challenge. This review will summarize what we have learned about non-responders over the last 20 years and discuss methods for optimizing response, including the introduction of novel therapies.

Case Studies of Cardiac Resynchronization Therapy "Nonresponders"

Outcomes following cardiac resynchronization therapy (CRT) vary widely, with some patients experiencing normalization of left ventricular function to some who seem to be harmed by biventricular pacing. The care of CRT patients postoperatively is complex and requires input from physicians specializing in electrophysiology, heart failure, and often cardiac imaging. In this section, cases of apparent CRT suboptimal response from a dedicated CRT optimization clinic are presented.

Better outcome at lower costs after implementing a CRT-care pathway: comprehensive evaluation of real-world data

AIMS

Cardiac resynchronization therapy (CRT) requires intensive, complex, and multidisciplinary care for heart failure (HF) patients. Due to limitations in time, resources, and coordination of care, in current practice, this is often incomplete. We evaluated the effect of the introduction of a CRT-care pathway (CRT-CPW) on clinical outcome and costs.

METHODS AND RESULTS

The CRT-CPW focused on structuring CRT patient selection, implantation, and follow-up management. To facilitate and guarantee quality, checklists were introduced. The CRT-CPW was implemented in the Maastricht University Medical Centre in 2014. Physician-led usual care was restructured to a nurse-led care pathway. A retrospective comparison of data from CRT patients receiving usual care (2012-2014, 222 patients) and patients receiving care according to CRT-CPW (2015-2018, 241 patients) was performed. The primary outcome was the composite of all-cause mortality and HF hospitalization. Hospital-related costs of cardiovascular care after CRT implantation were analysed to address cost-effectiveness of the CRT-CPW. Demographics were comparable in the usual care and CRT-CPW groups. Kaplan-Meier estimates of the occurrence of the primary endpoint showed a significant improvement in the CRT-CPW group (25.7% vs. 34.7%, hazard ratio 0.56; confidence interval 0.40-0.78; P < 0.005), at 36 months of follow-up. The total costs for cardiology-related hospitalizations were significantly reduced in the CRT-CPW group [€17 698 (14 192-21 195) vs. 19 933 (16 980-22 991), P < 0.001]. Bootstrap cost-effectiveness analyses showed that implementation of CRT-CPW would be an economically dominant strategy in 90.7% of bootstrap samples.

CONCLUSIONS

The introduction of a novel multidisciplinary, nurse-led care pathway for CRT patients resulted in significant reduction of the combination of all-cause mortality and HF hospitalizations, at reduced cardiovascular-related hospital costs.

Design of Mid‐Q Response: A prospective, randomized trial of adaptive cardiac resynchronization therapy in Asian patients

Aims

The aim of the Mid‐Q Response study is to test the hypothesis that adaptive preferential left ventricular‐only pacing with the AdaptivCRT algorithm has superior clinical outcomes compared to conventional cardiac resynchronization therapy (CRT) in heart failure (HF) patients with moderately wide QRS duration (≥120 ms and <150 ms), left bundle branch block (LBBB), and normal atrioventricular (AV) conduction (PR interval ≤200 ms).

Methods

This prospective, multi‐center, randomized, controlled, clinical study is being conducted at approximately 60 centers in Asia. Following enrollment and baseline assessment, eligible patients are implanted with a CRT system equipped with the AdaptivCRT algorithm and are randomly assigned in a 1:1 ratio to have AdaptivCRT ON (Adaptive Bi‐V and LV pacing) or AdaptivCRT OFF (Nonadaptive CRT). A minimum of 220 randomized patients are required for analysis of the primary endpoint, clinical composite score (CCS) at 6 months post‐implant. The secondary and ancillary endpoints are all‐cause and cardiovascular death, hospitalizations for worsening HF, New York Heart Association (NYHA) class, Kansas City Cardiomyopathy Questionnaire (KCCQ), atrial fibrillation (AF), and cardiovascular adverse events at 6 or 12 months.

Conclusion

The Mid‐Q Response study is expected to provide additional evidence on the incremental benefit of the AdaptivCRT algorithm among Asian HF patients with normal AV conduction, moderately wide QRS, and LBBB undergoing CRT implant.

Standard care vs. TRIVEntricular pacing in Heart Failure (STRIVE HF): a prospective multicentre randomized controlled trial of triventricular pacing vs. conventional biventricular pacing in patients with heart failure and intermediate QRS left bundle branch block

AIMS

To determine whether triventricular (TriV) pacing is feasible and improves CRT response compared to conventional biventricular (BiV) pacing in patients with left bundle branch block (LBBB) and intermediate QRS prolongation (120-150 ms).

METHODS AND RESULTS

Between October 2015 and November 2019, 99 patients were recruited from 11 UK centres. Ninety-five patients were randomized 1:1 to receive TriV or BiV pacing systems. The primary endpoint was feasibility of TriV pacing. Secondary endpoints assessed symptomatic and remodelling response to CRT. Baseline characteristics were balanced between groups. In the TriV group, 43/46 (93.5%) patients underwent successful implantation vs. 47/49 (95.9%) in the BiV group. Feasibility of maintaining CRT at 6 months was similar in the TriV vs. BiV group (90.0% vs. 97.7%, P = 0.191). All-cause mortality was similar between TriV vs. BiV groups (4.3% vs. 8.2%, P = 0.678). There were no significant differences in echocardiographic LV volumes or clinical composite scores from baseline to 6-month follow-up between groups.

CONCLUSION

Implantation of two LV leads to deliver and maintain TriV pacing at 6 months is feasible without significant complications in the majority of patients. There was no evidence that TriV pacing improves CRT response or provides additional clinical benefit to patients with LBBB and intermediate QRS prolongation and cannot be recommended in this patient group.

CLINICAL TRIAL REGISTRATION NUMBER

Clinicaltrials.gov: NCT02529410.

Usefulness of Optimization of Interventricular Delay Using an Electrical Cardiometry Method in Patients with Cardiac Resynchronization Therapy Implantation

There are no studies examining interventricular (VV) delay optimization by an electrical cardiometry method in relation to subsequent cardiac function in cardiac resynchronization therapy (CRT) -implanted patients. This study aimed to compare the VV delay in CRT-implanted patients by the dp/dt and electrical cardiometry and to examine the optimization of VV delay and improvement of cardiac function. We examined 19 consecutive CRT-implanted patients. The protocol included biventricular stimulation with either simultaneous or sequential pacing, and we evaluated systolic volume (SV) using an electrical cardiometry and the dp/dt of the left ventricle. The optimal VV delay was determined by the maximum SV using the electrical cardiometry. Two groups were defined, those whose increase in SV was at or above the median and those whose SV increase was below the median; changes in left ventricular ejection fraction (LVEF). The correlation between the VV delay optimized by the electrical cardiometry and dp/dt methods was high (R = 0.61, P = 0.006). Compared to the baseline SV (43.4 mL), the SV increased to 47.8 mL with simultaneous biventricular pacing (versus baseline P = 0.008) and further increased to 49.8 mL with optimized VV delay (versus simultaneous biventricular pacing P = 0.020). LVEF after 6 months significantly improved in the above-median SV increase group (37.6 versus 28.2%, P = 0.041), but not in the below-median SV increase group (26.5 versus 26.5%, P = 0.985). In conclusion, the optimal VV delay by electrical cardiometry method was almost concordant with that by the dp/dt method. Cardiac function significantly improved in the group with the above-median SV increase.

The MADIT-ICD benefit score helps to select implantable cardioverter-defibrillator candidates in cardiac resynchronization therapy

AIMS

The aim of this study is to evaluate whether the MADIT-ICD benefit score can predict who benefits most from the addition of implantable cardioverter-defibrillator (ICD) to cardiac resynchronization therapy (CRT) in real-world patients with heart failure with reduced ejection fraction (HFrEF) and to compare this with selection according to a multidisciplinary expert centre approach.

METHODS AND RESULTS

Consecutive HFrEF patients who received a CRT for a guideline indication at a tertiary care hospital (Ziekenhuis Oost-Limburg, Genk, Belgium) between October 2008 and September 2016, were retrospectively evaluated. The MADIT-ICD benefit groups (low, intermediate, and high) were compared with the current multidisciplinary expert centre approach. Endpoints were (i) sustained ventricular tachycardia (VT) or ventricular fibrillation (VF) and (ii) non-arrhythmic mortality. Of the 475 included patients, 165 (34.7%) were in the lowest, 220 (46.3%) in the intermediate, and 90 (19.0%) in the highest benefit group. After a median follow-up of 34 months, VT/VF occurred in 3 (1.8%) patients in the lowest, 9 (4.1%) in the intermediate, and 13 (14.4%) in the highest benefit group (P < 0.001). Vice versa, non-arrhythmic death occurred in 32 (19.4%) in the lowest, 32 (14.6%) in the intermediate, and 3 (3.3%) in the highest benefit group (P = 0.002). The predictive power for ICD benefit was comparable between expert multidisciplinary judgement and the MADIT-ICD benefit score: Uno's C-statistic 0.69 vs. 0.69 (P = 0.936) for VT/VF and 0.62 vs. 0.60 (P = 0.790) for non-arrhythmic mortality.

CONCLUSION

The MADIT-ICD benefit score can identify who benefits most from CRT-D and is comparable with multidisciplinary judgement in a CRT expert centre.

A case report of balloon-assisted tracking to overcome coronary sinus competent valve: a novel technique in left ventricular lead implantation

Background

Competent lateral and posterolateral valves showed proximal tortuosity that might hinder left ventricular (LV) lead implantation in cardiac resynchronization therapy (CRT).

Case summary

A 57-year-old woman was diagnosed as non-ischaemic cardiomyopathy, no other comorbidities, complaining of dyspnoea [New York Heart Association (NYHA) class III], and on optimal medical therapy. Electrocardiogram showed left bundle branch block with QRS duration 150 ms. The patient was candidate for CRT. However, during LV lead implantation, a competent posterolateral vein valve and proximal tortuosity hindered LV lead implantation that was overcome by balloon-assisted tracking technique. At 9 months of follow-up, the patient had NYHA class II, ejection fraction improved to 38%, and all implanted leads were still in place.

Discussion

Balloon-assisted tracking technique can be used to cross coronary sinus and smaller veins with competent valves and coronary veins tortuosity.

Long-term outcomes in a randomized controlled trial of multimodality imaging-guided left ventricular lead placement in cardiac resynchronization therapy

AIMS

This study aims to investigate the long-term occurrence of the composite endpoint of heart failure (HF) hospitalization or all-cause death (primary endpoint) in patients randomized to cardiac resynchronization therapy (CRT) using individualized multimodality imaging-guided left ventricular (LV) lead placement compared with a routine fluoroscopic approach. Furthermore, this study aims to evaluate whether inter-lead electrical delay (IED) is associated with improved response rate of this endpoint.

METHODS AND RESULTS

We reviewed follow-up data until November 2020 for all 182 patients included in the ImagingCRT trial for the occurrence of HF hospitalization and all-cause death. During median (inter-quartile range) time to primary endpoint/censuring of 6.7 (3.3-7.9) years, the rate of the primary endpoint was 60% (n = 53) in the imaging group compared with 52% (n = 48) in the control group [hazard ratio (HR) 1.22, 95% confidence interval (CI) 0.83-1.81, P = 0.31]. Neither the risk of HF hospitalization (HR 1.11, 95% CI 0.62-1.99, P = 0.72) nor of all-cause death differed between treatment groups (HR 1.23, 95% CI 0.82-1.85, P = 0.32). The risk of the primary endpoint was significantly reduced among those with IED ≥100 ms when compared with those with IED <100 ms (HR 0.62, 95% CI 0.39-0.98, P = 0.04).

CONCLUSIONS

In this study, an individualized multimodality imaging-guided strategy targeting LV lead placement towards the latest mechanically activated non-scarred myocardial segment during CRT implantation did not reduce HF hospitalization or all-cause death when compared with routine LV lead placement during long-term follow-up. Targeting the latest electrical activation should be studied as an alternative individualized strategy for optimizing LV lead placement in CRT recipients.

Cost-effective analysis of automated programming optimization in cardiac resynchronization therapy: Holistic Markov modelling

BACKGROUND

Automated optimization algorithm (AdaptivCRT; Medtronic, Mounds View, MN, USA) allowing automated optimization of cardiac resynchronization therapy (CRT), has been introduced. However, little is known concerning its cost-effectiveness. This study aims to evaluate the potential economic benefits of AdaptivCRT of CRT.

METHODS

Markov modelling was informed by empirical data sourced from the AdaptivCRT Clinical Trial. Published meta-analyses were used to derive the impact of increasing response to hospitalization and mortality risks. Response was assessed via the clinical composite score.

RESULTS

Deterministic results suggested a mean survival of 10.97 years with adaptive algorithms against 10.5 years without (+0.47 in favour of novel algorithms). Heart failure hospitalization costs were modelled to ¥1,382,753 (US $12,686) with novel devices against ¥1,524,747 (US $13,989) with previous technology models. Sensitivity analyses show CRT with Adaptive algorithm was projected to provide cost savings in all scenarios.

CONCLUSIONS

The use of AdaptivCRT was projected to improve average patient survival and avoid costs in a Japanese healthcare setting.

Machine Learning Prediction of Cardiac Resynchronisation Therapy Response From Combination of Clinical and Model-Driven Data

Background: Up to 30–50% of chronic heart failure patients who underwent cardiac resynchronization therapy (CRT) do not respond to the treatment. Therefore, patient stratification for CRT and optimization of CRT device settings remain a challenge.

Objective: The main goal of our study is to develop a predictive model of CRT outcome using a combination of clinical data recorded in patients before CRT and simulations of the response to biventricular (BiV) pacing in personalized computational models of the cardiac electrophysiology.

Materials and Methods: Retrospective data from 57 patients who underwent CRT device implantation was utilized. Positive response to CRT was defined by a 10% increase in the left ventricular ejection fraction in a year after implantation. For each patient, an anatomical model of the heart and torso was reconstructed from MRI and CT images and tailored to ECG recorded in the participant. The models were used to compute ventricular activation time, ECG duration and electrical dyssynchrony indices during intrinsic rhythm and BiV pacing from the sites of implanted leads. For building a predictive model of CRT response, we used clinical data recorded before CRT device implantation together with model-derived biomarkers of ventricular excitation in the left bundle branch block mode of activation and under BiV stimulation. Several Machine Learning (ML) classifiers and feature selection algorithms were tested on the hybrid dataset, and the quality of predictors was assessed using the area under receiver operating curve (ROC AUC). The classifiers on the hybrid data were compared with ML models built on clinical data only.

Results: The best ML classifier utilizing a hybrid set of clinical and model-driven data demonstrated ROC AUC of 0.82, an accuracy of 0.82, sensitivity of 0.85, and specificity of 0.78, improving quality over that of ML predictors built on clinical data from much larger datasets by more than 0.1. Distance from the LV pacing site to the post-infarction zone and ventricular activation characteristics under BiV pacing were shown as the most relevant model-driven features for CRT response classification.

Conclusion: Our results suggest that combination of clinical and model-driven data increases the accuracy of classification models for CRT outcomes.