Assessing cardiac resynchronization therapy response in heart failure patients: a comparative analysis of efficacy and outcomes between transvenous and epicardial leads

Cardiac resynchronization therapy (CRT) is an effective treatment for selected heart failure (HF) patients. Although transvenous implantation is the standard method, it is not feasible in some patients, so the epicardial lead emerges as an alternative. We aim to compare CRT response, procedure-related complications, and the occurrence of clinical outcomes between patients with transvenous and epicardial leads. In a single-center retrospective study, we enrolled consecutive HF patients submitted to CRT implantation with a defibrillator between 2013 and 2022. Clinical response was defined as an improvement of at least one of the New York Heart Association classes with no occurrence of cardiovascular death or HF hospitalization in the first year of follow-up. Echocardiographic response was attained with an increase in left ventricular ejection fraction 10% or a reduction of left ventricular end-diastolic volume >15% at 6-12 months after CRT implantation. Major adverse cardiovascular events (MACE) (cardiovascular mortality and HF hospitalization) and all-cause mortality were evaluated. From a total of 149 patients, 38% (n=57) received an epicardial lead. Clinical (63% versus 60%, p=0.679) and echocardiographic (63% versus 60%, p=0.679) responses were similar between the transvenous and epicardial groups. Patients in the transvenous group had a shorter hospital stay (2 versus 7 days, p<0.001). Procedure-related complications were comparable between groups (24% versus 28%, p=0.572), but left ventricular lead-related complications were more frequent in the transvenous group (14% versus 2%). During a median follow-up of 4.7 years, the rate of MACE was 30% (n=44), with no differences in both groups (p=0.591), neither regarding HF hospitalization (p=0.917) nor cardiovascular mortality (p=0.060). Nevertheless, the epicardial group had a higher rate of all-cause mortality (35% versus 20%, p=0.005), the majority occurring during long-term follow-up (>12 months), with no deaths in the postoperative period. Considering the comparable rates of CRT response, procedure-related complications, and MACE between groups, we conclude that epicardial lead is a feasible alternative for CRT when transvenous lead implantation is not possible. The occurrence of a higher number of all-cause deaths in epicardial patients in the long-term follow-up was mainly due to infectious complications (unrelated to the lead) and the progression of oncological/chronic diseases.

Imaging in patients with cardiovascular implantable electronic devices: part 1-imaging before and during device implantation. A clinical consensus statement of the European Association of Cardiovascular Imaging (EACVI) and the European Heart Rhythm Association (EHRA) of the ESC

More than 500 000 cardiovascular implantable electronic devices (CIEDs) are implanted in the European Society of Cardiology countries each year. The role of cardiovascular imaging in patients being considered for CIED is distinctly different from imaging in CIED recipients. In the former group, imaging can help identify specific or potentially reversible causes of heart block, the underlying tissue characteristics associated with malignant arrhythmias, and the mechanical consequences of conduction delays and can also aid challenging lead placements. On the other hand, cardiovascular imaging is required in CIED recipients for standard indications and to assess the response to device implantation, to diagnose immediate and delayed complications after implantation, and to guide device optimization. The present clinical consensus statement (Part 1) 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 undergoing implantation of conventional pacemakers, cardioverter defibrillators, and resynchronization therapy devices. The document summarizes the existing evidence regarding the use of imaging in patient selection and during the implantation procedure and also underlines gaps in evidence in the field. The role of imaging after CIED implantation is discussed in the second document (Part 2).

Mechanocardiography detects improvement of systolic function caused by resynchronization pacing

Objective.Cardiac resynchronization therapy (CRT) is commonly used to manage heart failure with dyssynchronous ventricular contraction. CRT pacing resynchronizes the ventricular contraction, while AAI (single-chamber atrial) pacing does not affect the dyssynchronous function. This study compared waveform characteristics during CRT and AAI pacing at similar pacing rates using seismocardiogram (SCG) and gyrocardiogram (GCG), collectively known as mechanocardiogram (MCG).Approach.We included 10 patients with heart failure with reduced ejection fraction and previously implanted CRT pacemakers. ECG and MCG recordings were taken during AAI and CRT pacing at a heart rate of 80 bpm. Waveform characteristics, including energy, vertical range (amplitude) during systole and early diastole, electromechanical systole (QS2) and left ventricular ejection time (LVET), were derived by considering 6 MCG axes and 3 MCG vectors across frequency ranges of >1 Hz, 20-90 Hz, 6-90 Hz and 1-20 Hz.Main results.Significant differences were observed between CRT and AAI pacing. CRT pacing consistently exhibited higher energy and vertical range during systole compared to AAI pacing (p< 0.05). However, QS2, LVET and waveform characteristics around aortic valve closure did not differ between the pacing modes. Optimal differences were observed in SCG-Y, GCG-X, and GCG-Y axes within the frequency range of 6-90 Hz.Significance.The results demonstrate significant differences in MCG waveforms, reflecting improved mechanical cardiac function during CRT. This information has potential implications for predicting the clinical response to CRT. Further research is needed to explore the differences in signal characteristics between responders and non-responders to CRT.

Heart Failure with Improved Ejection Fraction: Insight into the Variable Nature of Left Ventricular Systolic Function

The progress of contemporary cardiovascular therapy has led to improved survival in patients with myocardial disease. However, the development of heart failure (HF) represents a common clinical challenge, regardless of the underlying myocardial pathology, due to the severely impaired quality of life and increased mortality comparable with malignant neoplasms. Left ventricular ejection fraction (LVEF) is the main index of systolic function and a key predictor of mortality among HF patients, hence its improvement represents the main indicator of response to instituted therapy. The introduction of complex pharmacotherapy for HF, increased availability of cardiac-implantable electronic devices and advances in the management of secondary causes of HF, including arrhythmia-induced cardiomyopathy, have led to significant increase in the proportion of patients with prominent improvement or even normalization of LVEF, paving the way for the identification of a new subgroup of HF with an improved ejection fraction (HFimpEF). Accumulating data has indicated that these patients share far better long-term prognoses than patients with stable or worsening LVEF. Due to diverse HF aetiology, the prevalence of HFimpEF ranges from roughly 10 to 40%, while the search for reliable predictors and genetic associations corresponding with this clinical presentation is under way. As contemporary guidelines focus mainly on the management of HF patients with clearly defined LVEF, the present review aimed to characterize the definition, epidemiology, predictors, clinical significance and principles of therapy of patients with HFimpEF.

Predictors of echocardiographic response to cardiac resynchronization therapy: A systematic review with Meta-Analysis

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NYHA class II seems to predict response to CRT.

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We should not delay CRT, trying medical management first, even in mildly symptomatic patients.

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Atrial fibrillation patients must have the same indication for CRT as those in sinus rhythm.

Background

At least 30% of the patients do not respond to cardiac resynchronization therapy (CRT). We performed a systematic review and meta-analysis of real-world studies trying to identify predictors of response to CRT.

Methods

PubMed, Embase and Cochrane Central Register of Controlled Trials (CENTRAL) were searched for observational prospective studies, referring the evaluation of response to CRT, defined as a decrease in left ventricle end-systolic volume (LVESV) ≥ 15% at 6-month follow-up, via two-dimensional echocardiography.

Results

A total of 24 studies were included. The meta-analysis showed that female gender (p = 0.018), non-ischemic cardiomyopathy (NICM) (p < 0.001), left bundle branch morphology (LBBB) (p = 0.001), longer QRS (p < 0.001) and New York Heart Association (NYHA) class II (p = 0.014) appear to favor response to CRT. After ROC analysis and logistic regression procedures, female gender (kappa = 0.450; p < 0.001), NICM (kappa = 0.636; p < 0.001), LBBB (kappa = 0.935; p < 0.001), and NYHA class II (kappa = 0.647; p < 0.001) were identified as independent predictors of response to CRT, being LBBB the most reliable one (sensitivity = 97.24%; specificity = 98.86%).

Conclusions

Female gender, NICM, LBBB and NYHA class II are baseline variables with an apparent capability to independently predict response to CRT, being LBBB the most reliable one.

Cardiac resynchronization therapy: Current status and near-future prospects

Cardiac resynchronization therapy (CRT) has been established as a standard treatment for heart failure. The effectiveness of CRT has been shown in many clinical trials and realized in actual clinical practice. Nevertheless, underutilization of CRT is a major problem in the treatment of heart failure. One factor leading to underutilization is the existence of CRT non-responders. CRT non-response has been discussed for approximately 20 years, since CRT was introduced. Since the beginning, the CRT non-response rate has been reported to be 30%. However, we are now undergoing a major transformation in the thinking about CRT response. First, heart failure is a progressive disease. Like many medications for heart failure, CRT does not cure the underlying disease of heart failure. Considering the natural course of heart failure, it is easy to understand that there will definitely be non-responders. There might have been misunderstandings about how to determine CRT response. Although CRT is a treatment for heart failure, it does not cure heart failure or myocardial tissue damage. Instead, by correcting conduction disorders and dyssynchrony, it modifies factors that exacerbate heart failure, which contributes to improvement. In addition, it is important to realize that pacing is the only treatment for correcting conduction disorders. Thus, in theory, CRT is an essential treatment for heart failure at any stage, regardless of severity, when it is accompanied by conduction disorder. Here, we consider the current state of CRT and the causes of underutilization. Returning to the origin of CRT, reconsidering the effects of CRT and the thinking about response, and spreading a new way of thinking will lead to the proper utilization of CRT.

Very Long-Term Follow-Up in Cardiac Resynchronization Therapy: Wider Paced QRS Equals Worse Prognosis

Background: Different electrocardiogram (ECG) findings are known to be independent predictors of clinical response to cardiac resynchronization therapy (CRT). It remains unknown how these findings influence very long-term prognosis. Methods and Results: A total of 102 consecutive patients (75 males, mean age 65 ± 10 years) referred to our center for CRT implantation had previously been included in this prospective observational study. The same patient group was now re-evaluated for death from all causes over a prolonged median follow-up of 10.3 years (interquartile range 9.4–12.5 years). During follow-up, 55 patients died, and 82% of the clinical non-responders (n = 23) and 44% of the responders (n = 79) were deceased. We screened for univariate associations and found QRS width during biventricular (BIV) pacing (p = 0.02), left ventricular (LV) pacing (p < 0.01), Δ LV paced–right ventricular (RV) paced (p = 0.03), age (p = 0.03), New York Heart Association (NYHA) class (p < 0.01), CHA₂DS₂-Vasc score (p < 0.01), glomerular filtration rate (p < 0.01), coronary artery disease (p < 0.01), non-ischemic cardiomyopathy (NICM) (p = 0.01), arterial hypertension (p < 0.01), NT-proBNP (p < 0.01), and clinical response to CRT (p < 0.01) to be significantly associated with mortality. In the multivariate analysis, NICM, the lower NYHA class, and smaller QRS width during BIV pacing were independent predictors of better outcomes. Conclusion: Our data show that QRS width duration during biventricular pacing, an ECG parameter easily obtainable during LV lead placement, is an independent predictor of mortality in a long-term follow-up. Our data add further evidence that NICM and lower NYHA class are independent predictors for better outcome after CRT implantation.

Upgrade from implantable cardioverter-defibrillator vs. de novo implantation of cardiac resynchronization therapy: long-term outcomes

AIMS

To assess and compare long-term mortality and predictors thereof in de novo cardiac resynchronization therapy defibrillators (CRT-D) vs. upgrade from an implantable cardioverter-defibrillator (ICD) to CRT-D.

METHODS AND RESULTS

Study population consisted of 595 consecutive patients with CRT-D implanted between 2002 and 2015 in a tertiary care, university hospital, in a densely inhabited, urban region of Poland [480 subjects (84.3%) with CRT-D de novo implantation; 115 patients (15.7%) upgraded from ICD to CRT-D]. In a median observation of 1692 days (range 457-3067), all-cause mortality for de novo CRT-D vs. CRT-D upgrade was 35.5% vs. 43.5%, respectively (P = 0.045). On multivariable regression analysis including all CRT recipients, the previously implanted ICD was an independent predictor for death [hazard ratio (HR) 1.58, 95% confidence interval (CI) 1.10-2.29, P = 0.02]. For those, who were upgraded from ICD to CRT-D, the independent predictors for all-cause death were as follows: creatinine level (HR 1.01, 95% CI 1.00-1.02, P = 0.01), left ventricular end-systolic diameter (HR 1.07, 95% CI 1.02-1.11, P = 0.002), New York Heart Association (NYHA) IV class at baseline (HR 2.36, 95% CI 1.00-5.53, P = 0.049) and cardiac device-related infective endocarditis during follow-up (HR 2.42, 95% CI 1.02-5.75, P = 0.046). A new CRT scale (Creatinine ≥150 μmol/L; Remodelling, left ventricular end-systolic ≥59 mm; Threshold for NYHA, NYHA = IV) showed high prediction for mortality in CRT-D upgrades (AUC 0.70, 95% CI 0.59-0.80, P = 0.0007).

CONCLUSION

All-cause mortality in patients upgraded from ICD is significantly higher compared with de novo CRT-D implantations and reaches almost 45% within 4.5 years. A new CRT scale (Creatinine; Remodelling; Threshold for NYHA) has been proposed to help survival prediction following CRT upgrade.

Association of QRS narrowing with response to cardiac resynchronization therapy-a systematic review and meta-analysis of observational studies

Prolonged QRS duration, which reflects a higher degree of mechanical dysynchrony, is a predictor of response to CRT. However, the association of QRS narrowing after biventricular pacing with CRT response rates is not clear. Our aim was to conduct a systematic review and meta-analysis on the association between QRS narrowing after cardiac resynchronization therapy (CRT) and clinical and echocardiographic response to CRT in patients with heart failure. Two independent investigators searched MedLine and EMBASE databases through July 2018 without any limitations. Studies providing estimates (continuous data) on the association of QRS shortening with either clinical (defined as New York Heart Association (NYHA) reduction ≥ 1) or echocardiographic (defined as left ventricular end-systolic volume (LVESV) reduction ≥ 15%) response to CRT were finally included in the quantitative synthesis. We included 32 studies (14 studies (1274 patients mean age 64 years old, males 79.3%) using clinical CRT response and 18 studies (1270 patients, mean age 64 years old, males 69.1%) using echocardiographic CRT response). A significant association between QRS narrowing and shorter attained QRS duration with clinical and echocardiographic CRT response was observed. The observed association was independent of the timing of QRS width measurement after CRT implantation. Acute and late improvement of electrical dysynchrony as depicted by QRS narrowing following biventricular pacing is associated with clinical and echocardiographic response to CRT. However, large prospective studies are needed to further examine our findings.

Clinical Significance of Global Wasted Work in Patients with Heart Failure Receiving Cardiac Resynchronization Therapy

BACKGROUND

The relationship between myocardial work assessment using pressure-strain loops by echocardiography before cardiac resynchronization therapy (CRT) and response to CRT has been recently revealed. Among myocardial work parameters, the impact of left ventricular myocardial global wasted work (GWW) on response to CRT and outcome following CRT has been seldom studied. Hence, the authors evaluated the relationship between preprocedural GWW and outcome in a large prospective cohort of patients with heart failure (HF) and reduced ejection fraction receiving CRT.

METHODS

The study included 249 patients with HF. Myocardial work indices including GWW were calculated using speckle-tracking strain two-dimensional echocardiography using pressure-strain loops. End points of the study were (1) response to CRT, defined as left ventricular reverse remodeling and/or absence of hospitalization for HF, and (2) all-cause death during follow-up.

RESULTS

Median follow-up duration was 48 months (interquartile range, 43-54 months). Median preoperative GWW was 281 mm Hg% (interquartile range, 184-388 mm Hg%). Preoperative GWW was associated with CRT response (area under the curve, 0.74; P < .0001), and a 200 mm Hg% threshold discriminated CRT nonresponders from responders with 85% specificity and 50% sensitivity, even after adjustment for known predictors of CRT response (adjusted odds ratio, 4.03; 95% CI, 1.91-8.68; P < .001). After adjustment for established predictors of outcome in patients with HF with reduced ejection fraction receiving CRT, GWW < 200 mm Hg% remained associated with a relative increased risk for all-cause death compared with GWW ≥ 200 mm Hg% (adjusted hazard ratio, 2.0; 95% CI, 1.1-3.9; P = .0245). Adding GWW to a baseline model including known predictors of outcome in CRT resulted in an improvement of this model (χ² to improve 4.85, P = .028). The relationship between GWW and CRT response and outcome was stronger in terms of size effect and statistical significance than for other myocardial work indices.

CONCLUSIONS

Low preoperative GWW (<200 mm Hg%) is associated with absence of CRT response in CRT candidates and with a relative increased risk for all-cause death. GWW appears to be a promising parameter to improve selection for CRT of patients with HF with reduced ejection fraction.

What Are the Expectations for Cardiac Resynchronization Therapy? A Validation of Two Response Definitions

BACKGROUND

The definition of response to cardiac resynchronization therapy (CRT) varies across clinical trials. There are two main definitions, i.e., echocardiographic response and functional response. We assessed which definition was more reasonable.

METHODS

In this study of 260 patients who had undergone CRT, an echocardiographic response was defined as a reduction in a left ventricular end-systolic volume of greater than or equal to 15% or an improvement in left ventricular ejection fraction of greater than or equal to 5%. A functional response was defined as an improvement of at least one class category in the New York Heart Association functional classification. We assessed the response to CRT at 6 months after device implantation, based on each definition, and investigated the relationship between response and clinical outcomes.

RESULTS

The echocardiographic response rate was 74.2%. The functional response rate was 86.9%. Non-responder status, based on both definitions, was associated with higher all-cause mortality. Cardiac death was only associated with functional non-responder status (hazard ratio (HR) 2.65, 95% confidence interval (CI) 1.19-5.46, p = 0.0186) and heart failure hospitalization (HR 2.78, 95% CI, 1.29-5.26, p = 0.0111).

CONCLUSION

After CRT implantation, the functional response definition of CRT response is associated with a higher response rate and better clinical outcomes than that of the echocardiographic response definition, and therefore it is reasonable to use the functional definition to assess CRT response.

Correlation of newer indices of dyssynchrony with clinical response in patients undergoing cardiac resynchronisation therapy

The benefits of CRT in select subsets of systolic heart failure patients with LBBB are proven. We prospectively evaluated conventional and newer echocardiographic parameters of left ventricular dyssynchrony in 35 patients who underwent CRT and were followed up after 6 months. Of the 33 surviving patients, 21 were echocardiographic responders and 24 were clinical responders. The parameters in clinical responders and non-responders were compared. The anatomic M Mode parameters of delays improved, while the radial strain and the mitral valve velocity time integral (MVVTI) did not show any significant change after CRT.

Clinical significance of left ventricular reverse remodeling after catheter ablation of atrial fibrillation in patients with left ventricular systolic dysfunction

BACKGROUND

Left ventricular (LV) reverse remodeling (LVRR) after catheter ablation of atrial fibrillation (AFCA) has not been fully described. This study investigated the predictors and clinical outcomes of LVRR after AFCA in patients with LV systolic dysfunction.

METHODS

Of 3319 consecutive patients who underwent first-time AFCA between January 2012 and October 2019, 376 with a baseline LV ejection fraction of <50% were retrospectively evaluated. They were subjected to 256-slice multidetector computed tomography (MDCT) scanning at baseline and 3 months after AFCA. The LVRR was defined as a decrease in the LV end-systolic volume of ≥15%.

RESULTS

The prevalence of LVRR was 83% (n = 306). Multivariate logistic regression analysis including age, body mass index, diabetic status, beta-blocker use, and LV diastolic diameter revealed that the predictors of LVRR were non-paroxysmal atrial fibrillation (AF) (odds ratio, 2.68; 95% confidence interval, 1.42-5.05; p = 0.002) and absence of apparent underlying structural heart disease (4.81; 2.31-10.0; p <0.001). The prevalence of LVRR differed depending on AF recurrence pattern prior to the post-MDCT [no episode vs. paroxysmal episode (lasting <7 days) vs. persistent episode (lasting ≥7 days), 84% vs. 81% vs. 63%, respectively, p = 0.023]. During a median follow-up of 32 months, the incidence of paroxysmal form of AF recurrence was similar, whereas persistent form of AF recurrence was less frequent in patients with LVRR (10.5% vs. 18.6%, p = 0.018). Heart failure hospitalizations (2.3% vs. 15.7%, p <0.001), cardiovascular deaths (0.7% vs. 4.3%, p = 0.015), and all-cause deaths (1.3% vs. 5.7%, p = 0.018) were similarly less frequent in those with LVRR.

CONCLUSIONS

LVRR after AFCA, which was predicted by non-paroxysmal AF without any apparent structural heart disease at baseline, was associated with persistent form of AF recurrence prior to the evaluation. LVRR was associated with favorable clinical outcomes.

Improvement in circulating endothelial progenitor cells pool after cardiac resynchronization therapy: increasing the list of benefits

Background

Recent studies suggest that circulating endothelial progenitor cells (EPCs) may influence the response to cardiac resynchronization therapy (CRT). The aim of this study was to evaluate the effect of CRT on EPC levels and to assess the impact of EPCs on long-term clinical outcomes.

Population and methods

Prospective study of 50 patients submitted to CRT. Two populations of circulating EPCs were quantified previously to CRT implantation: CD34⁺KDR⁺ and CD133⁺KDR⁺ cells. EPC levels were reassessed 6 months after CRT. Endpoints during the long-term follow-up were all-cause mortality, heart transplantation, and hospitalization for heart failure (HF) management.

Results

The proportion of non-responders to CRT was 42% and tended to be higher in patients with an ischemic vs non-ischemic etiology (64% vs 35%, p = 0.098). Patients with ischemic cardiomyopathy (ICM) showed significantly lower CD34⁺KDR⁺ EPC levels when compared to non-ischemic dilated cardiomyopathy patients (DCM) (0.0010 ± 0.0007 vs 0.0030 ± 0.0024 cells/100 leukocytes, p = 0.032). There were no significant differences in baseline EPC levels between survivors and non-survivors nor between patients who were rehospitalized for HF management during follow-up or not. At 6-month follow-up, circulating EPC levels were significantly higher than baseline levels (0.0024 ± 0.0023 vs 0.0047 ± 0.0041 CD34⁺KDR⁺ cells/100 leukocytes, p = 0.010 and 0.0007 ± 0.0004 vs 0.0016 vs 0.0013 CD133⁺/KDR⁺ cells/100 leukocytes, p = 0.007).

Conclusions

Patients with ICM showed significantly lower levels of circulating EPCs when compared to their counterparts. CRT seems to improve the pool of endogenously circulating EPCs and reduced baseline EPC levels seem not to influence long-term outcomes after CRT.

Graphical abstract

Prognostic effect and modulation of cardiac sympathetic function in heart failure patients treated with cardiac resynchronization therapy

BACKGROUND

Cardiac autonomic dysfunction as assessed by 123I-metaiodobenzylguanidine (123I-mIBG) scintigraphy is associated with poor prognosis in heart failure (HF) patients. Although cardiac resynchronization therapy (CRT) has emerged as an effective therapy in improving outcomes on HF patients, its effect on cardiac sympathetic nervous function is still not fully understood. We aimed to study the value of pre-implantation 123I-mIBG late heart-to-mediastinum ratio (HMR) as a predictor of response and outcomes after CRT and to correlate modification in this parameter with CRT response and functional improvement.

METHODS AND RESULTS

BETTER-HF (Benefit of exercise training therapy and cardiac resynchronization in HF patients) is a prospective randomized clinical trial including HF patients submitted CRT (mean LVEF 24 ± 8%, 74% NYHA class ≥ III) who underwent a clinical, echocardiographic, and scintigraphic assessment before and 6 months after CRT. One-hundred and twenty-one patients were included. Echocardiographic response was observed in 54% and composite outcome of cardiac mortality, cardiac transplant or heart failure hospitalization in 24% of patients. Baseline late HMR was an independent predictor of CRT response (regression coefficient 2.906, 95% CI 0.293-3.903, P .029) and outcomes (HR 0.066 95% CI 0.005-0.880, P .040). At follow-up, 123I-mIBG imaging showed positive changes in cardiac sympathetic nerve activity only in responders to CRT (1.36 ± 0.14 prior vs. 1.42 ± 0.16 after CRT, P .039). There was a significant correlation between improvement in late HMR and improvement in peak oxygen consumption (r 0.547, P < .001).

CONCLUSION

In our study, baseline cardiac denervation predicted response and clinical outcomes after CRT implantation. Cardiac sympathetic function was improved only in patients who responded to CRT and these positive changes were correlated with improvement in functional capacity.

Combination of left ventricular reverse remodeling and brain natriuretic peptide level at one year after cardiac resynchronization therapy predicts long-term clinical outcome

Introduction

The aim of this study was to investigate the predictors of long-term clinical outcome of heart failure (HF) patients who survived first year after initiation of cardiac resynchronization therapy (CRT).

Methods

This was a single-center observational cohort study of CRT patients implanted because of symptomatic HF with reduced ejection fraction between 2005 and 2013. Left ventricle (LV) diameters and ejection fraction, New York Heart Association (NYHA) class, and level of N-terminal fragment of pro-brain natriuretic peptide (NT-proBNP) were assessed at baseline and 12 months after CRT implantation. Their predictive power for long-term HF hospitalization and mortality, and cardiac and all-cause mortality was investigated.

Results

A total of 315 patients with left bundle branch block or intraventricular conduction delay who survived >1 year after CRT implantation were analyzed in the current study. During a follow-up period of 4.8±2.1 years from CRT implantation, 35.2% patients died from cardiac (19.3%) or non-cardiac (15.9%) causes. Post-CRT LV ejection fraction and LV end-systolic diameter (either 12-month value or the change from baseline) were equally predictive for clinical events. For NT-proBNP, however, the 12-month level was a stronger predictor than the change from baseline. Both reverse LV remodeling and 12-month level of NT-proBNP were independent and comparable predictors of CRT-related clinical outcome, while NT-proBNP response had the strongest association with all-cause mortality. When post-CRT relative change of LV end-systolic diameter and 12-month level of NT-proBNP (dichotomized at -12.3% and 1230 ng/L, respectively) were combined, subgroups of very-high and very-low risk patients were identified.

Conclusion

The level of NT-proBNP and reverse LV remodeling at one year after CRT are independent and complementary predictors of future clinical events. Their combination may help to improve the risk stratification of CRT patients.

Modified frailty as a novel factor in predicting the response to cardiac resynchronization in the elderly population

Background

The response to cardiac resynchronization therapy (CRT) is an important element of the treatment of advanced heart failure, especially in the geriatric population. The aim of the study was to examine the impact of frailty syndrome on the response to treatment with CRT.

Methods

Two hundred and forty-six patients of 60 years or older (aged 73.35±6.95; 22.4% women) with an implanted CRT were included in this single-center prospective study. There was a 12-month follow-up. The Tilburg Frailty Indicator was used to determine frailty (5 or more points). The response to CRT was evaluated based on an analysis of clinical criteria.

Results

One hundred and sixty-nine of 246 (68.9%) patients were found to be clinical CRT responders. Frailty syndrome was recognized in 173 (70.32%). There were 63.0% responders in the frailty-affected group, whereas there were statistically more responders (79.5%) in the robust group (P=0.0116). In the logistic regression, frailty emerged as an independent predictor of the response to CRT (OR=0.81, 95% CI=0.71–0.92; P=0.0008). The area under the curve of the ROC curve for frailty in the responders to CRT was 0.62. The cut-off value for a designation of frailty was 6 (P=0.0014).

Conclusion

Frailty is a novel independent factor that can be used to predict the clinical response to CRT in the elderly population. Modifying the level of recognition in the Tilburg Frailty Indicator can improve the prediction of a response to CRT.

Prediction of clinical outcome in patients treated with cardiac resynchronization therapy - the role of NT-ProBNP and a combined response score

BACKGROUND

Cardiac resynchronization therapy (CRT) is an established therapy for appropriately selected patients with heart failure. Response to CRT has been heterogeneously defined using both clinical and echocardiographic measures, with poor correlation between the two.

METHODS

The study cohort was comprised of 202 CRT-treated patients and CRT response was defined at 6 months post-implant. Echocardiographic response (E+) was defined as a reduction in LVESV ≥ 15%, clinical response as an improvement of ≥ 1 NYHA class (C+), and biomarker response as a ≥ 25% reduction in NT-proBNP(B+). The association of response measures (E+, B+, C+; response score range 0-3) and clinical endpoints at 3 years was assessed in landmarked Cox models.

RESULTS

Echo and clinical responders demonstrated greater declines in NT-proBNP than non-responders (median [E+/B+]: -52%, [E+]: -27%, [C+]: -39% and [E-/C-]: -13%; p = 0.01 for trend). Biomarker (HR 0.43 [95% CI: 0.22-0.86], p = 0.02) and clinical (HR 0.40 [0.23-0.70] p = 0.001) response were associated with a significantly reduced risk of the primary endpoint. When integrating each response measure into a composite score, each 1 point increase was associated with a 31% decreased risk for a composite endpoint of mortality, LVAD, transplant and HF hospitalization (HR 0.69 [95% CI: 0.50-0.96], p = 0.03), and a 52% decreased risk of all-cause mortality (HR 0.48 [95% CI: 0.26-0.89], p = 0.02).

CONCLUSION

Serial changes in NT-proBNP are associated with clinical outcomes following CRT implant. Integration of biomarker, clinical, and echocardiographic response may discriminate CRT responders versus non-responders in a clinically meaningful way, and with higher accuracy.

TRIAL REGISTRATION

The cohort was combined from study NCT01949246 and the study based on local review board approval 2011/550 in Lund, Sweden.

Assessment of left ventricular dyssynchrony by three-dimensional echocardiography: Prognostic value in patients undergoing cardiac resynchronization therapy

BACKGROUND

Systolic dyssynchrony index (SDI) using three-dimensional echocardiography (3DE) was shown to be a reliable measure of left ventricular (LV) dyssynchrony. However, the prognostic value of SDI on long-term outcomes after cardiac resynchronization therapy (CRT) remains unknown.

METHODS AND RESULTS

A total of 414 patients (mean age 67 ± 10 years, 60% ischemic etiology) with 3DE evaluation before CRT implantation were included. SDI was evaluated as continuous value and in quartiles. The study endpoint was combined all-cause mortality, heart transplantation, and LV assist device implantation. At baseline, median SDI was 8.0% (IQR 5.6-11.3%). During a median follow-up of 45 months (IQR 25-59 months), the endpoint was observed in 94 (23%) patients. SDI was independently associated with the endpoint together with ischemic etiology, diabetes, and renal function (HR 0.914, P = 0.003) after adjustment for age, atrial fibrillation, hemoglobin level, NYHA functional class, and posterolateral LV lead position. Patients from the 1st, 2nd, and 3rd SDI quartiles showed similar survival and superior as compared to the 4th quartile with the lowest SDI values (≤5.5%; χ²: 30.4, log-rank P < 0.001). From receiver operating characteristic curve analysis, the optimal SDI cut-off value associated with the endpoint was >6.8% (area under the curve 0.634). Finally, a subgroup analysis (293 patients) demonstrated that a more pronounced reduction in SDI immediately after CRT (resynchronization) was independently associated with superior survival (HR 0.461, P = 0.011) after adjustment for prognostic relevant parameters.

CONCLUSION

SDI is independently associated with long-term prognosis after CRT and might therefore be important to optimize risk-stratification in these patients.

Predictors of Total Mortality and Echocardiographic Response for Cardiac Resynchronization Therapy: A Cohort Study

Background

Clinical studies demonstrate that up to 40% of patients do not respond to cardiac resynchronization therapy (CRT), thus, appropriate patient selection is critical to the success of CRT in heart failure.

Objective

Evaluation of mortality predictors and response to CRT in the Brazilian scenario.

Methods

Retrospective cohort study including patients submitted to CRT in a tertiary hospital in southern Brazil from 2008 to 2014. Survival was assessed through a database of the State Department of Health (RS). Predictors of echocardiographic response were evaluated using Poisson regression. Survival analysis was performed by Cox regression and Kaplan Meyer curves. A two-tailed p value less than 0.05 was considered statistically significant.

Results

A total of 170 patients with an average follow-up of 1011 ± 632 days were included. The total mortality was 30%. The independent predictors of mortality were age (hazard ratio [HR] of 1.05, p = 0.027), previous acute myocardial infarction (AMI) (HR of 2.17, p = 0.049) and chronic obstructive pulmonary disease (COPD) (HR of 3.13, p = 0.015). The percentage of biventricular stimulation at 6 months was identified as protective factor of mortality ([HR] 0.97, p = 0.048). The independent predictors associated with the echocardiographic response were absence of mitral insufficiency, presence of left bundle branch block and percentage of biventricular stimulation.

Conclusion

Mortality in patients submitted to CRT in a tertiary hospital was independently associated with age, presence of COPD and previous AMI. The percentage of biventricular pacing evaluated 6 months after resynchronizer implantation was independently associated with improved survival and echocardiographic response.

Echocardiographic Predictors of Worse Outcome After Cardiac Resynchronization Therapy

BACKGROUND

Cardiac resynchronization therapy (CRT) is the recommended treatment by leading global guidelines. However, 30%-40% of selected patients are non-responders.

OBJECTIVE

To develop an echocardiographic model to predict cardiac death or transplantation (Tx) 1 year after CRT.

METHOD

Observational, prospective study, with the inclusion of 116 patients, aged 64.89 ± 11.18 years, 69.8% male, 68,1% in NYHA FC III and 31,9% in FC IV, 71.55% with left bundle-branch block, and median ejection fraction (EF) of 29%. Evaluations were made in the pre‑implantation period and 6-12 months after that, and correlated with cardiac mortality/Tx at the end of follow-up. Cox and logistic regression analyses were performed with ROC and Kaplan-Meier curves. The model was internally validated by bootstrapping.

RESULTS

There were 29 (25%) deaths/Tx during follow-up of 34.09 ± 17.9 months. Cardiac mortality/Tx was 16.3%. In the multivariate Cox model, EF < 30%, grade III/IV diastolic dysfunction and grade III mitral regurgitation at 6‑12 months were independently related to increased cardiac mortality or Tx, with hazard ratios of 3.1, 4.63 and 7.11, respectively. The area under the ROC curve was 0.78.

CONCLUSION

EF lower than 30%, severe diastolic dysfunction and severe mitral regurgitation indicate poor prognosis 1 year after CRT. The combination of two of those variables indicate the need for other treatment options.

Cardiac resynchronization therapy update: evolving indications, expanding benefit?

Cardiac resynchronisation therapy (CRT) is an effective intervention for appropriately selected patients with heart failure, but exactly how it works is uncertain. Recent data suggest that much, or perhaps most, of the benefits of CRT are not delivered by re-coordinating left ventricular dyssynchrony. Atrio-ventricular resynchronization, reduction in mitral regurgitation and prevention of bradycardia are other potential mechanisms of benefit that will vary from one patient to the next and over time. Because there is no single therapeutic target, it is unlikely that any single measure will accurately predict benefit. The only clinical characteristic that appears to be a useful predictor of the benefits of CRT is a QRS duration of >140 ms. Many new approaches are being developed to try to improve the effectiveness of and extend the indications for CRT. These include smart pacing algorithms, better pacing-site targeting, new sensors, multipoint pacing, remote device monitoring and leadless endocardial pacing. Whether CRT is effective in patients with atrial fibrillation or whether adding a defibrillator function to CRT improves prognosis awaits further evidence.

Development and Validation of Predictive Models of Cardiac Mortality and Transplantation in Resynchronization Therapy

Background

30-40% of cardiac resynchronization therapy cases do not achieve favorable outcomes.

Objective

This study aimed to develop predictive models for the combined endpoint of cardiac death and transplantation (Tx) at different stages of cardiac resynchronization therapy (CRT).

Methods

Prospective observational study of 116 patients aged 64.8 ± 11.1 years, 68.1% of whom had functional class (FC) III and 31.9% had ambulatory class IV. Clinical, electrocardiographic and echocardiographic variables were assessed by using Cox regression and Kaplan-Meier curves.

Results

The cardiac mortality/Tx rate was 16.3% during the follow-up period of 34.0 ± 17.9 months. Prior to implantation, right ventricular dysfunction (RVD), ejection fraction < 25% and use of high doses of diuretics (HDD) increased the risk of cardiac death and Tx by 3.9-, 4.8-, and 5.9-fold, respectively. In the first year after CRT, RVD, HDD and hospitalization due to congestive heart failure increased the risk of death at hazard ratios of 3.5, 5.3, and 12.5, respectively. In the second year after CRT, RVD and FC III/IV were significant risk factors of mortality in the multivariate Cox model. The accuracy rates of the models were 84.6% at preimplantation, 93% in the first year after CRT, and 90.5% in the second year after CRT. The models were validated by bootstrapping.

Conclusion

We developed predictive models of cardiac death and Tx at different stages of CRT based on the analysis of simple and easily obtainable clinical and echocardiographic variables. The models showed good accuracy and adjustment, were validated internally, and are useful in the selection, monitoring and counseling of patients indicated for CRT.

The postimplantation electrocardiogram predicts clinical response to cardiac resynchronization therapy

BACKGROUND

Biventricular (BiV) pacing for cardiac resynchronization therapy (CRT) is intended to improve left ventricular function by coordinating systolic activity of the septum and free walls. Optimal resynchronization should be manifested by 12-lead electrocardiogram (ECG) patterns consistent with resynchronized activation, a tall (≥4 mm) R wave in V1, and predominant negative deflection in lead I (RV1SI). We investigated whether the presence or absence of RV1SI predicts heart failure outcomes within 1 year of CRT implant.

METHODS

Two independent physicians reviewed the paced ECG of 213 patients post-CRT device implantation with disputes resolved by a third reviewer. The primary end points of all-cause death, unplanned hospitalization, left ventricular assist device implant, or transplant within a 1-year follow-up were blindly adjudicated according to standard definitions. Groups were compared via Kaplan-Meier estimates and Cox proportional hazards models to determine association with event-free survival.

RESULTS

Among CRT patients postimplantation, 56 (26.3%) exhibited the RV1SI pattern on ECG. Patients with the RV1SI pattern were significantly less likely to achieve the primary end point as compared to patients without the RV1SI pattern (33.9% vs 52.2%; Log Rank P = 0.022). This difference was driven by a significantly lower risk for unplanned hospitalization among patients with the RV1SI pattern (hazard ratio = 0.510; confidence interval [0.298, 0.876]). The predictive value remained after adjustment for potential confounders (P = 0.004).

CONCLUSIONS

The 12-lead ECG postimplantation predicts clinical outcomes of BiV pacing. Such prediction may be useful in predicting the need for alternative or advanced heart failure therapies. Further study into ECG patterns may help to prospectively guide CRT.

Multisite left ventricular pacing in cardiac resynchronization therapy

Cardiac resynchronization therapy is an effective treatment for selected patients with heart failure and left bundle branch block dyssynchrony. Unfortunately, about a third of patients, so-called nonresponders, do not display any symptomatic or structural improvements after the treatment. In another 5% of patients, the left ventricular lead cannot be implanted due to technical limitations. Novel quadripolar pacing lead and associated multisite pacing technology has the potential to help improve both of these problems. The technology and applications of these leads are reviewed and the novel technique of multisite pacing from two poles of one quadripolar lead is discussed. This technology may improve response to cardiac resynchronization therapy for some patients.