Cardiac resynchronization therapy in patients with permanent atrial fibrillation. Is it mandatory to ablate the atrioventricular junction to obtain a good response?

[History of cardiac resynchronization therapy : 30 years of electrotherapeutic management for heart failure]

The first permanent biventricular pacing system was implanted more than 30 years ago. In this article, the historical development of cardiac resynchronization therapy (CRT), starting with the pathophysiological concept, followed by the initial "proof of concept" studies and finally the large prospective-randomized studies that led to the implementation of CRT in heart failure guidelines, is outlined. Since the establishment of CRT, both an expansion of indications, e.g., for patients with mild heart failure and atrial fibrillation, but also the return to patients with broad QRS complex and left bundle branch block who benefit most of CRT has evolved. New techniques such as conduction system pacing will have major influence on pacemaker therapy in heart failure, both as an alternative or adjunct to CRT.

The Benefit of Atrioventricular Junction Ablation for Permanent Atrial Fibrillation and Heart Failure Patients Receiving Cardiac Resynchronization Therapy: An Updated Systematic Review and Meta-analysis

BACKGROUND

Atrial fibrillation (AF) is correlated with a poor biventricular pacing and inadequate response to cardiac resynchronization therapy (CRT). Biventricular pacing improvement can be achieved by conducting the atrioventricular junction ablation (AVJA). We aimed to investigate the benefit of AVJA for permanent AF and heart failure with reduced ejection fraction (HFrEF) patients receiving CRT.

METHODS

In August 2020, a systematic review and meta-analysis study comparing CRT plus AVJA versus CRT for permanent AF and HFrEF patients was conducted. Relevant articles were identified through the electronic scientific database such as ClinicalTrials.gov, ProQuest, ScienceDirect, PubMed, and Cochrane. The pooled risk ratio (RR) and pooled mean difference (MD) were estimated.

RESULTS

A total of 3199 patients from 14 cohort studies were involved in this study. Additional AVJA reduced cardiovascular mortality (RR = 0.75, 95% confidence interval [CI] = 0.61 to 0.93, P < 0.01) in permanent AF and HFrEF patients receiving CRT. Biventricular pacing rate was higher in CRT plus AVJA group (MD = 8.65%, 95% CI = 5.62 to 11.67, P < 0.01) than in CRT alone group. The reverse remodeling characterized by the reduction of left ventricular end-diastolic diameter (LVEDD) was greater in the CRT plus AVJA group (MD = -2.11 mm, 95% CI = -3.79 to -0.42, P = 0.01).

CONCLUSION

In permanent AF and HFrEF patients receiving CRT, AVJA effectively increased the biventricular pacing rate. Adequate biventricular pacing rate provided a better response to the CRT marked by the greater ventricular reverse remodeling and survival from cardiovascular mortality.

A prognostic nomogram for event-free survival in patients with atrial fibrillation before cardiac resynchronization therapy

Background

Atrial fibrillation (AF), one of the most common comorbidities of heart failure (HF), is associated with worse long-term prognosis in HF patients receiving cardiac resynchronization therapy (CRT). However, there is still no convenient tool to identify CRT candidates with AF who are at high risk of mortality and hospitalization due to HF.

Methods

We included 152 consecutive patients with AF for CRT in our hospital from January 2009 to July 2019. Multiple imputation was used for missing values. With imputed datasets, a multivariate Cox regression model was performed for variable selection using the backward stepwise method to predict all-cause mortality and HF readmissions. A nomogram and nomogram-based scoring system were constructed from the selected predictors. Then, internal validation and calibration were achieved by the bootstrap method, deriving the corrected concordance index and calibration curves. Sensitivity analysis was also performed to validate our selected predictors.

Results

Five predictors were incorporated in the nomogram, including N-terminal pro brain natriuretic protein (NT-proBNP) > 1745 pg/mL, history of syncope, previous pulmonary hypertension, moderate or severe tricuspid regurgitation, thyroid-stimulating hormone (TSH) > 4 mIU/L. The concordance index (0.70, 95% CI 0.62–0.77), corrected concordance index (0.67, 95% CI 0.59–0.74) and calibration curve showed optimal discrimination and calibration of the established nomogram. A significant difference in overall event-free survival was recognized by the nomogram-derived scores for patients with high risk (> 50 points), intermediate risk (21–50 points) and low risk (0–20 points) before CRT.

Conclusion

Our internally validated nomogram may be an applicable tool for the early risk stratification of CRT candidates with AF.

Outcomes of cardiac resynchronisation therapy in patients with heart failure with atrial fibrillation: a systematic review and meta-analysis of observational studies

Background

Cardiac resynchronisation therapy (CRT) is beneficial in selected patients with heart failure (HF) in normal sinus rhythm (NSR). We sought to evaluate the impact of CRT with or without atrioventricular junction (AVJ) ablation in patients with HF with concomitant atrial fibrillation (AF).

Methods and results

Literature was searched (inception through 30 August 2017) for observational studies that reported outcomes in patients with HF with CRT and AF that reported all-cause and cardiovascular mortality. Thirty-one studies with 83, 571 patients were included. CRT did not decrease mortality compared with internal cardioverter defibrillator or medical therapy alone in patients with HF and AF with indications for CRT (OR: 0.851, 95% CI 0.616 to 1.176, p=0.328, I2=86.954). CRT-AF patients had significantly higher all-cause and cardiovascular mortality than CRT-NSR patients ([OR: 1.472, 95% CI 1.301 to 1.664, p=0.000] and [OR: 1.857, 95% CI 1.350 to 2.554, p=0.000] respectively). Change in left ventricular ejection fraction was not different between CRT patients with and without AF (p=0.705). AVJ ablation, however, improved all-cause mortality in CRT-AF patients when compared with CRT-AF patients without AVJ ablation (OR: 0.485, 95% CI 0.247 to 0.952, p=0.035). With AVJ ablation, there was no difference in all-cause mortality in CRT-AF patients compared with CRT-NSR patients (OR: 1.245, 95% CI 0.914 to 1.696, p=0.165).

Conclusion

The results of our meta-analysis suggest that AF was associated with decreased CRT benefits in patients with HF. CRT, however, benefits patients with AF with AVJ ablation.

Cardiac Resynchronization Therapy: How to Decrease Nonresponders

Nonresponse to cardiac resynchronization therapy (CRT) is still a major issue in therapy expansion. The description of fast, simple, cost-effective methods to optimize CRT could help in adapting pacing intervals to individual patients. A better understanding of the importance of appropriate patient selection, left ventricular lead placement, and device programming, together with a multidisciplinary approach and an optimal follow-up of the patients, may reduce the percentage of nonresponders.

Device pacing diagnostics overestimate effective cardiac resynchronization therapy pacing results of the hOLter for Efficacy analysis of CRT (OLÉ CRT) study

BACKGROUND

A high percentage of biventricular (BiV) or left ventricular (LV) pacing in cardiac resynchronization therapy (CRT) devices has been associated with superior clinical outcomes. However, the percent ventricular (%V) pacing reported by CRT devices simply indicates the number of paces the device has delivered and not the proportion of pacing that has captured the LV effectively.

OBJECTIVE

The purpose of this study was to determine whether a beat-by-beat evaluation of effective pacing would provide a more accurate evaluation of CRT delivery.

METHODS

An automatic electrogram (EGM)-based algorithm that classifies each LV pace as effective or ineffective based on detection of QS/QS-r morphology on the unipolar LV EGM during pacing was developed and validated. LV EGMs that were recorded by 24-hour Holter from 57 CRT patients were postprocessed. The percent effective CRT (%e-CRT) pacing was calculated by dividing the time spent in e-CRT pacing by the total time of the recording.

RESULTS

In this CRT cohort, the average %V pacing (94.8% ± 8%) significantly overestimated the %e-CRT pacing (87.5% ± 23%; P <.001). A significant minority of subjects (18%) had a discrepancy of at least 3 percentage points between %V pacing and %e-CRT pacing (mean 39% ± 41%).

CONCLUSION

Current device pacing diagnostics overestimate the amount of CRT pacing actually delivered. The new algorithm quantifies ineffective CRT pacing, which enables clinicians to identify patients with this issue and to address the reasons behind suboptimal CRT delivery.

Cardiac resynchronization therapy in patients with atrial fibrillation: a meta-analysis

BACKGROUND AND OBJECTIVE

To combine the results of the best scientific evidence in order to compare the effects of cardiac resynchronization therapy (CRT) in heart failure patients with atrial fibrillation (AF) and in sinus rhythm (SR) and to determine the effect of atrioventricular nodal ablation in AF patients.

METHODS

The electronic databases PubMed, B-On and Cochrane CENTRAL were searched, and manual searches were performed, for randomized controlled trials and cohort studies up to November 2012. The endpoints analyzed were all-cause and cardiovascular mortality and response to CRT.

RESULTS

We included 19 studies involving 5324 patients: 1399 in AF and 3925 in SR. All-cause mortality was more likely in patients with AF compared to patients in SR (OR = 1.69; 95% CI: 1.20–2.37; p = 0.002). There were no statistically significant differences in cardiovascular mortality (OR = 1.36; 95% CI: 0.92–2.01; p = 0.12). AF was associated with an increased likelihood of lack of response to CRT (OR = 1.41; 95% CI: 1.15–1.73; p = 0.001). Among subjects with AF, ablation of the atrioventricular node was associated with a reduction in all-cause mortality (OR = 0.42; 95% CI: 0.22–0.80; p = 0.008), cardiovascular death (OR = 0.39; 95% CI: 0.20–0.75; p = 0.005) and the number of non-responders to CRT (OR = 0.30; 95% CI: 0.10–0.90; p = 0.03).

CONCLUSIONS

The presence of AF is associated with increased likelihood of all-cause death and non-response to CRT, compared to patients in SR. However, many patients with AF benefit from CRT. Atrioventricular nodal ablation appears to increase the benefits of CRT in patients with AF.

How to Improve Cardiac Resynchronization Therapy Benefit in Atrial Fibrillation Patients: Pulmonary Vein Isolation (and Beyond)

Although cardiac resynchronization therapy (CRT) is an important treatment of symptomatic heart failure patients in sinus rhythm with low left ventricular ejection fraction and ventricular dyssynchrony, its role is not well defined in patients with atrial fibrillation (AF). CRT is not as effective in patients with AF because of inadequate biventricular capture and loss of atrioventricular synchrony. Both can be addressed with catheter ablation of AF. It is still unclear if these therapies offer additive benefits in patients with ventricular dyssynchrony. This article discusses the role and techniques of catheter ablation of AF in patients with heart failure, and its application in CRT recipients.

How to Improve Cardiac Resynchronization Therapy Benefit in Atrial Fibrillation Patients: Pulmonary Vein Isolation (and Beyond)

Although cardiac resynchronization therapy (CRT) is an important treatment of symptomatic heart failure patients in sinus rhythm with low left ventricular ejection fraction and ventricular dyssynchrony, its role is not well defined in patients with atrial fibrillation (AF). CRT is not as effective in patients with AF because of inadequate biventricular capture and loss of atrioventricular synchrony. Both can be addressed with catheter ablation of AF. It is still unclear if these therapies offer additive benefits in patients with ventricular dyssynchrony. This article discusses the role and techniques of catheter ablation of AF in patients with heart failure, and its application in CRT recipients.

Cardiac Resynchronization Therapy: How to Decrease Nonresponders

Nonresponse to cardiac resynchronization therapy (CRT) is still a major issue in therapy expansion. The description of fast, simple, cost-effective methods to optimize CRT could help in adapting pacing intervals to individual patients. A better understanding of the importance of appropriate patient selection, left ventricular lead placement, and device programming, together with a multidisciplinary approach and an optimal follow-up of the patients, may reduce the percentage of nonresponders.

Effects of atrioventricular nodal ablation on permanent atrial fibrillation patients with cardiac resynchronization therapy: a systematic review and meta-analysis

Cardiac resynchronization therapy (CRT) is a well-established therapy for patients with heart failure (HF) and wide QRS configuration, especially for those in sinus rhythm. However, for those with permanent AF, atrioventricular nodal (AVN) ablation use remains under debate. Our objective was to evaluate clinical outcomes and mortality of AVN ablation in HF patients with permanent AF receiving CRT. Electronic publication database and reference lists through October 1, 2013 were searched. Observational cohort studies comparing CRT patients with AF who received either AVN ablation or medical therapy were selected. Outcomes included mortality, CRT nonresponse, changes in left ventricular remodeling, and functional outcomes, such as New York Heart Association (NYHA) functional class, quality of life, and 6-minute hall walk distance. Of 1641 reports identified, 13 studies with 1256 patients were included. Among patients with permanent AF and insufficient biventricular pacing (< 90%), those who had undergone AVN ablation compared to those who did not had numerically lower all-cause mortality (risk ratio [RR]: 0.63, 95% confidence interval [CI]: 0.42 to 0.96, P = 0.03) and significantly lower nonresponse to CRT (RR: 0.41, 95% CI: 0.31 to 0.54, P < 0.00001). Furthermore, AVN ablation was not associated with additional improvements on left ventricular ejection fraction, NYHA functional class, 6-minute hall walking distance, and quality of life. In patients with permanent AF undergoing CRT, AVN ablation tended to reduce mortality potentially and improved clinical response when it was applied to patients with inadequate biventricular pacing (< 90%). Randomized controlled trials are needed to further address the efficacy of AVN ablation among this population.

EAARN score, a predictive score for mortality in patients receiving cardiac resynchronization therapy based on pre-implantation risk factors

AIMS

The beneficial effects of CRT in patients with advanced heart failure, wide QRS, and low LVEF have been clearly established. Nevertheless, mortality remains high in some patients. The aims of our study were to identify the predictors of mortality in patients treated with CRT and to design a risk score for mortality.

METHODS AND RESULTS

A cohort of 608 consecutive patients treated with CRT from 2000 to 2011 in our centre was prospectively analysed. Baseline clinical and echocardiography variables were analysed and mortality data were collected. During a mean follow-up of 36.2 ± 29.2 months, 174 patients died: 123/174 (71%) due to cardiovascular causes, 25/174 (14%) non-cardiac causes, and 26/174 (15%) unknown aetiology. In a multivariate analysis the predictors of mortality were NYHA class IV [hazard ratio (HR) 2.54, 95% confidence interval (CI) 1.7-3.7, P < 0.001], glomerular filtration rate (GFR) <60 mL/min/1.73 m2 (HR 1.61, 95% CI 1.14-2.30, P = 0.008), AF (HR 1.67, 95% CI 1.19-2.3, P = 0.01), age ≥70 years (HR 1.44, (95% CI 1.04-2.00, P = 0.02), and LVEF <22% (HR 1.83, 95% CI 1.33-2.52, P ≤ 0.001). The EAARN score (EF, Age, AF, Renal dysfunction, NYHA class IV) summarizes the predictors. Each additional predictor increased the mortality: one predictor, HR 3.28 (95% CI 1.37-7.8, P = 0.008); two, HR 5.23 (95% CI 2.24-12.10, P < 0.001); three, HR 9.63 (95% CI 4.1-22.60, P < 0.001); and four or more, HR 14.38 (95% CI 5.8-35.65, P < 0.001).

CONCLUSION

The predictors of mortality have a significant add-on predictive effect on mortality. The EAARN score could be useful to stratify the prognosis of CRT patients.

Complete atrioventricular block does not reduce long-term mortality in patients with permanent atrial fibrillation treated with cardiac resynchronization therapy

AIMS

A maximum percentage of ventricular pacing is mandatory to obtain a good response to CRT. Atrioventricular junction (AVJ) ablation has been recommended to attain this objective in patients with AF.

THE AIMS OF OUR STUDY WERE

(i) to determine whether the presence of complete AVJ block (induced or spontaneous) improves survival in patients with permanent AF treated with CRT and (ii) to analyse the predictors of mortality in AF patients treated with CRT.

METHODS AND RESULTS

From a series of 608 patients treated with CRT in our centre from 2000 to 2011, a cohort of 155 patients with permanent AF was analysed. Patients in AF were divided into two groups, AF + AVJ block [76 (49%)] and AF non-AVJ block [79 (51%)]. Mean follow-up was 30 months (interquartile range 13-51 months). During the follow-up, 62 patients died. Overall and cardiovascular mortality were similar between both groups: hazard ratio (HR) 0.85, 95% confidence interval (CI) 0.51-1.39, P = 0.51 and HR 0.94, 95% CI 0.52-1.68, P = 0.82. Multivariate analysis identified three independent predictors of mortality: basal NYHA functional class IV (HR 2.25, 95% CI 1.12-4.22, P = 0.03), glomerular filtration rate (HR 0.98, 95% CI 0.96-0.99, P = 0.03), and LVEF (HR 0.94, 95% CI 0.89-0.99, P = 0.02).

CONCLUSIONS

AVJ block did not improve survival for patients in AF treated with CRT. Basal NYHA functional class IV, poor renal function, and LVEF were the independent predictors of mortality.

Atrial fibrillation in cardiac resynchronization therapy patients: should we ablate the atrioventricular node?

Prevalence of persistent atrial fibrillation in patients undergoing cardiac resynchronization therapy remains high. Several factors, including suboptimal biventricular capture rates, compound the significant mortality and response rates in patients with atrial fibrillation and severe heart failure. Atrioventricular nodal ablation provides the best mean of rate control in this population. In this article, the authors evaluate a recently published trial addressing this issue in a prospective fashion and discuss the results and clinical applications.