Clinical and echocardiographic predictors of nonresponse to cardiac resynchronization therapy

First-Phase Ejection Fraction Predicts Response to Cardiac Resynchronization Therapy and Adverse Outcomes

OBJECTIVES

The aim of this study was to examine the value of first-phase ejection fraction (EF1), to predict response to cardiac resynchronization therapy (CRT) and clinical outcomes after CRT.

BACKGROUND

CRT is an important treatment for patients with chronic heart failure. However, even in carefully selected cases, up to 40% of patients fail to respond. EF1, the ejection fraction up to the time of maximal ventricular contraction, is a novel sensitive echocardiographic measure of early systolic function and might relate to response to CRT.

METHODS

An initial retrospective study was performed in 197 patients who underwent CRT between 2009 and 2018 and were followed to determine clinical outcomes at King's Health Partners in London. A validation study (n = 100) was performed in patients undergoing CRT at Barts Heart Centre in London.

RESULTS

Volumetric response rate (reduction in end-systolic volume ≥15%) was 92.3% and 12.1% for those with EF1 in the highest and lowest tertiles (P < 0.001). A cutoff value of 11.9% for EF1 had >85% sensitivity and specificity for prediction of response to CRT; on multivariate binary logistic regression analysis incorporating previously defined predictors, EF1 was the strongest predictor of response (odds ratio [OR]: 1.56 per 1% change in EF1; 95% CI: 1.37-1.78; P < 0.001). EF1 was also the strongest predictor of improvement in clinical composite score (OR: 1.11; 95% CI: 1.04-1.19; P = 0.001). Improvement in EF1 at 6 months after CRT implantation (6.5% ± 5.8% vs 1.8% ± 4.3% in responders vs nonresponders; P < 0.001) was the best predictor of heart failure rehospitalization and death after median follow-up period of 20.3 months (HR: 0.81; 95% CI: 0.73-0.90; P < 0.001). In the validation cohort, EF1 was a similarly 1strong predictor of response (OR: 1.45; 95% CI: 1.23-1.70; P < 0.001) as in the original cohort.

CONCLUSIONS

EF1 is a promising marker to identify patients likely to respond to CRT.

Judgement of the multidisciplinary team is an important predictor of mortality after cardiac resynchronization therapy

Aims

Cardiac resynchronization therapy (CRT) in appropriately selected patients with heart failure improves symptoms and survival. It is necessary to correctly identify patients who will benefit most from this therapy. We aimed to assess the predictive power of the multidisciplinary team's clinical judgement in the short‐term death after CRT implantation.

Methods and results

Patients with heart failure and referred for the first CRT implant were prospectively included. Prior to implantation, all patients underwent a systematic assessment with a team composed of social work, nurse, psychologist, nutritionist, and clinical cardiologist. Based on this assessment, patients could be contraindicated to CRT or referred to the procedure as favourable or unfavourable. All patients should complete 12 months of follow‐up; 172 patients were referred for CRT, 21 (12.2%) were contraindicated after the multidisciplinary team evaluation, 71 (47%) referred to CRT as non‐favourable implants, and 80 (53%) as favourable implants. All‐cause mortality occurred in only 2 (2.5%) patients in the favourable group and in 30 (42.3%) in the non‐favourable group, P < 0.001 (log rank). Among the 20 variables used as possible predictors of worse prognosis by the multidisciplinary team, four were independently associated with mortality in the follow‐up after the multivariate analysis: 1 year MAGGIC score between 40% and 49%, relative risk (RR) 5.0, 95% confidence interval (CI) 1.3–18.6, P = 0.016; poor pharmacological adherence, RR 4.9, 95% CI 1.6–15.6, P = 0.007; glomerular filtration rate <35 mL/min/1.73 m², RR 3.0, 95% CI 1.1–8.5, P = 0.041; and right ventricular dysfunction, RR 2.6, 95% CI 1.2–5.7, P = 0.018.

Conclusions

The clinical judgement before the CRT implantation performed by a multidisciplinary team through the analysis of clinical and psychosocial variables is a strong predictor of short‐term mortality.

MultiPole pacing in non-responders to cardiac resynchronization therapy: Results from the QP ExCELs/MPP sub-study

BACKGROUND

Multisite LV stimulation therapy allows for stimulation of two different left ventricular pacing vectors within a single LV lead and may improve responsiveness to cardiac resynchronization therapy (CRT). This study prospectively evaluated the safety and efficacy of the MultiPole Pacing (MPP) feature in CRT non-responder patients.

METHODS AND RESULTS

CRT non-responders with a standard CRT-D indication were eligible for enrollment into the MPP Sub-Study. Patient status, NYHA classification, Patient Global Assessment (PGA), and adverse events were collected at follow-up. A clinical composite score (CCS) was determined at the 6 month follow-up visit. The primary objective was defined as the proportion of patients with an improved CCS. Safety was evaluated as freedom from MPP system related adverse events requiring additional invasive intervention to resolve. A total of 53 patients were enrolled across 26 U.S. centers. The cumulative follow-up duration was 24.1 years. CCS was improved in 35.6% of patients (p < .0001 when compared to a performance goal of 3%) after 6 months of MPP therapy. When incorporating patient feedback into a modified CCS, 60.0% of patients showed an improvement. Three patients (5.7%) experienced hospitalization for heart failure, and three patient deaths occurred over the follow-up period. No MPP system-related events were reported for an AE-free rate of 100% (95% CI 93.28% to 100.0%).

CONCLUSIONS

The results of this small, non-randomized study suggest that the MPP feature is safe, and may be effective at converting a percentage of CRT non-responders to responders. Larger, randomized studies are needed to confirm this result.

Predictors of response to cardiac resynchronization therapy in patients with chronic right ventricular pacing

Background

The benefits of de novo cardiac resynchronization therapy (CRT) in patients with QRS-prolongation and impaired left-ventricular function (LVEF) are well established. Current guidelines also recommend CRT-upgrade in patients requiring permanent or frequent right ventricular pacing (RVP) with symptomatic heart failure and reduced LVEF. Whereas several predictors of response to de novo CRT-implantation such as female gender, QRS-duration, non-ischemic cardiomyopathy (NICM) are known due to large prospective trials, similar factors regarding CRT-upgrade are currently lacking.

Methods and results

We examine 114 patients 3–6 months after CRT-upgrade due to frequent RVP (> 50%) and symptomatic heart failure. Response to CRT was evaluated by improvement in NYHA class referring to the Minnesota Living With Heart Failure Questionnaire. Only cardiomyopathy type and use of Angiotensin-converting-enzyme (ACE) inhibitor had an impact on response to CRT-upgrade in a linear regression model. Patients with NICM presented a greater responder rate than patients with ischemic cardiomyopathy (ICM) (80.4 vs. 60.3%, p < 0.05). Other traditional response predictors in de novo CRT recipients (e.g. QRS-width, female gender) showed no effect on CRT-response in this cohort.

Conclusion

Only underlying heart disease (NICM vs. ICM) and the use of ACE inhibitor were significant predictors of response to CRT-upgrade. In contrast to de novo CRT-recipients, where pre-implant QRS-duration is a key predictor, QRS-duration during RV-pacing has no significant impact on CRT-response in this cohort.

Graphic abstract

Cardiac resynchronisation therapy in patients with left bundle branch block with residual conduction

Aim

To evaluate whether left bundle branch block with residual conduction (rLBBB) is associated with worse outcomes after cardiac resynchronisation therapy (CRT).

Methods

All consecutive CRT implants at our institution between 2006 and 2013 were identified from our local device registry. Pre- and post-implant patient specific data were extracted from clinical records.

Results

A total of 690 CRT implants were identified during the study period. Prior to CRT, 52.2% of patients had true left bundle branch block (LBBB), 19.1% a pacing-induced LBBB (pLBBB), 11.2% a rLBBB, 0.8% a right bundle branch block (RBBB), and 16.5% had a nonspecific intraventricular conduction delay (IVCD) electrocardiogram pattern. Mean age at implant was 67.5 years (standard deviation [SD] = 10.6), mean left ventricular ejection fraction (LV EF) was 25.7% (SD = 7.9%), and mean QRS duration was 158.4 ms (SD = 32 ms). After CRT, QRS duration was significantly reduced in the LBBB (p < 0.001), pLBBB (p < 0.001), rLBBB (p < 0.001), RBBB (p = 0.04), and IVCD groups (p = 0.03). LV EF significantly improved in the LBBB (p < 0.001), rLBBB (p = 0.002), and pLBBB (p < 0.001) groups, but the RBBB and IVCD groups showed no improvement. There was no significant difference in mortality between the LBBB and rLBBB groups. LV EF post-CRT, chronic kidney disease, hyperkalaemia, hypernatremia, and age at implant were significant predictors of mortality.

Conclusion

CRT in patients with rLBBB results in improved LV EF and similar mortality rates to CRT patients with complete LBBB. Predictors of mortality post-CRT include post-CRT LV EF, presence of CKD, hyperkalaemia, hypernatremia, and older age at implant.

A novel risk model for mortality and hospitalization following cardiac resynchronization therapy in patients with non-ischemic cardiomyopathy: the alpha-score

Background

Non-ischemic cardiomyopathy (NICM) has been associated with a better left ventricle reverse remodeling response and improved clinical outcomes after cardiac resynchronization therapy (CRT). The aims of our study were to identify the predictors of mortality and heart failure hospitalization in patients treated with CRT and design a risk score for prognosis.

Methods

A cohort of 422 consecutive NICM patients with CRT was retrospectively enrolled between January 2010 and December 2017. The primary endpoint was all-cause mortality and heart transplantation.

Results

In a multivariate analysis, the predictors of all-cause death were left atrial diameter [Hazard ratio (HR): 1.056, 95% confidence interval (CI): 1.020–1.093, P = 0.002]; non-left bundle branch block [HR: 1.793, 95% CI: 1.131–2.844, P = 0.013]; high sensitivity C-reactive protein [HR: 1.081, 95% CI: 1.029–1.134 P = 0.002]; and N-terminal pro-B-type natriuretic peptide [HR: 1.018, 95% CI: 1.007–1.030, P = 0.002]; and New York Heart Association class IV [HR: 1.018, 95% CI: 1.007–1.030, P = 0.002]. The Alpha-score (Atrial diameter, non-LBBB, Pro-BNP, Hs-CRP, NYHA class IV) was derived from each independent risk factor. The novel score had good calibration (Hosmer-Lemeshow test, P > 0.05) and discrimination for both primary endpoints [c-statistics: 0.749 (95% CI: 0.694–0.804), P < 0.001] or heart failure hospitalization [c-statistics: 0.692 (95% CI: 0.639–0.745), P < 0.001].

Conclusion

The Alpha-score may enable improved discrimination and accurate prediction of long-term outcomes among NICM patients with CRT.

Comparison of triple-site ventricular pacing versus conventional cardiac resynchronization therapy in patients with systolic heart failure: A meta-analysis of randomized and observational studies

Background

Conventional cardiac resynchronization therapy (CRT, Bi‐V) is associated with no response in about 40% patients due to an insufficient resynchronization. Some studies showed triple‐site ventricular (Tri‐V) pacing had greater benefits compared with Bi‐V pacing, but the results of these studies were conflicting. We hypothesized that Tri‐V pacing had greater benefits on long‐term outcomes compared with Bi‐V pacing in patients with heart failure.

Methods

PubMed, EMBASE, and the Cochrane Library were searched for clinical studies with related outcomes. Weighted mean differences (WMD) and 95% confidence intervals (CIs) were calculated to compare the change in left ventricular ejection fraction (LVEF), left ventricular geometry, functional capacity, and quality of life between Tri‐V pacing group and control group.

Results

Five trials with 251 patients were included in the analysis. Patients in the Tri‐V pacing group had a greater improvement in LVEF (WMD 4.04; 95% CI 2.15‐5.92, P < .001) and NYHA classes (WMD −0.27; 95% CI −0.42 to −0.11, P = .001) compared with control group. However, there were no significant differences in left ventricular geometry, six‐min walk distance, or Minnesota Living With Heart Failure Questionnaire score between the two groups. The subgroup analyses showed there might be a greater improvement in LVEF in the Tri‐V pacing group in patients with QRS duration ≥ 155 ms (WMD 5.60; 95% CI 3.09‐8.10, P < .001).

Conclusions

The present analysis suggests that Tri‐V pacing has greater benefits in terms of an improvement in LVEF and functional capacity in patients with systolic heart failure, especially in patients with the duration of QRS ≥ 155 ms.

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.

Cardiac resynchronization therapy and its role in the management of heart failure

The prevalence of heart failure is increasing and it is associated with significant mortality and morbidity. Optimal medical therapy improves outcome, but heart failure continues to have a substantial impact on both the individual patient and wider society. Over the last two decades, cardiac resynchronization therapy has revolutionized the treatment of selected patients who have heart failure. Cardiac resynchronization therapy significantly reduces mortality and hospitalization through reverse cardiac remodelling. This review informs non-specialists about cardiac resynchronization therapy and for which patients it should be considered.

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.

Long-Term Follow-Up of Isolated Epicardial Left Ventricular Lead Implant Using a Minithoracotomy Approach for Cardiac Resynchronization Therapy

BACKGROUND

Transvenous left ventricular (LV) lead placement for cardiac resynchronization therapy is unsuccessful in 5-10% of reported cases. These patients may benefit from isolated surgical placement of an epicardial LV lead via minithoracotomy approach.

AIM

To evaluate the success of this approach at long-term follow-up.

METHODS

Retrospective evaluation of all consecutive patients undergoing isolated epicardial LV lead placement after failed transvenous attempt over a 6-year period. Data collected on baseline parameters, procedural details, and outcome at follow-up (hospital stay, complications, mortality, and clinical response).

RESULTS

Forty-two patients underwent epicardial lead implant. Five died within 1 year (11.9%): two (4.8%) died within 30-days post op (one from intraoperative hemorrhage, the other from multiple organ failure); 39 (95.1%) were admitted to the high dependency unit and transferred to the ward <24 hours. Median hospital stay was 3.4 ± 1.9 days. The overall complication rate was 17.5% (n = 7): 15.0% (n = 6) short term and 2.5% (n = 1) long term; these included three (7.5%) LV noncapture events all treated with reprogramming. There were two (5.0%) wound infections requiring oral antibiotics and two (5.0%) device infections requiring intravenous antibiotics (one had device resiting, the other developed septic shock requiring intensive care admission). Assessment of clinical response was possible in 34 (81.0%) at follow-up: 21 (61.8%) were responders and 13 (28.2%) nonresponders with no significant differences between these groups; no clinical predictors of response were identified.

CONCLUSION

Isolated epicardial LV lead implant using minithoracotomy is relatively safe and effective at successful LV pacing. Response rate and postoperative recovery at long-term follow-up are reasonable in these high-risk patients.

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.

Incidence, definition, diagnosis, and management of the cardiac resynchronization therapy nonresponder

PURPOSE OF REVIEW

Cardiac resynchronization therapy (CRT) reduces morbidity and mortality in patients with mild-to-severe heart failure. However, up to 40% of CRT recipients are nonresponders. This review addresses important aspects with regard to the identification and management of CRT nonresponders.

RECENT FINDINGS

Mid-term clinical or echocardiographic nonresponse is associated with worse clinical outcomes during the extended follow-up. A number of predictors are indicative of CRT response, which include patient characteristics, electrical determinants, and imaging techniques from preimplant to postimplant period, and can be grouped as modifiable and nonmodifiable contributors to treatment response. Advanced age, male sex, ischemic cause, end-stage heart failure, inadequate electrical delay, and absence of mechanical dyssynchrony are regarded as unfavorable but nonmodifiable factors, for which considering underutilization of CRT by refining patient selection is reasonable. On the contrary, more efforts should be made to optimize patient management by correcting those modifiable factors, such as suboptimal medical therapy, uncontrolled atrial fibrillation, left ventricular lead dislodgement or inappropriate location, loss of biventricular capture, and lack of device optimization.

SUMMARY

Proper management and careful selection of CRT recipients will transform a proportion of treatment nonresponders into responders, which is vital to improve patients' outcome.

Optimizing benefit from CRT: role of speckle tracking echocardiography, the importance of LV lead position and scar

Cardiac resynchronization therapy is demonstrated to be effective in patients with advanced heart failure. Correcting mechanical dyssynchrony is proposed as the predominant mechanism of response. Achieving optimum left ventricular lead position, at the site of maximal mechanical dyssynchrony but away from transmural scar, is identified as one of the main determinants of both symptomatic and prognostic benefit. Strategies employing multimodality cardiac imaging techniques have been used to identify this optimal pacing site, in addition to any potential anatomical limitations to successful implantation. Speckle tracking echocardiography offers prospective lead targeting, incorporating pathophysiological determinants of cardiac resynchronization therapy response. This review considers the key factors in defining optimum left ventricular lead location, emphasizing the role of myocardial scar. The use of speckle tracking echocardiography and the potential for this technique to be incorporated into routine practice to guide the implant strategy in an individual patient is discussed.

Adrenergic receptor gene polymorphism and left ventricular reverse remodelling after cardiac resynchronization therapy: preliminary results

AIMS

Several factors can influence the extent of left ventricular (LV) reverse remodelling after cardiac resynchronization therapy (CRT) in patients with heart failure (HF). Polymorphism in genes involved in cardiac remodelling, namely beta-adrenergic receptors (ARs), may have a role. We studied the influence of beta-1 Arg389Gly, beta-2 Arg16Gly, and beta-2 Gln27Glu ARs gene polymorphisms on the magnitude of reverse remodelling response to CRT and its possible correlations with the incidence of appropriate implantable cardioverter-defibrillator (ICD) shocks.

METHODS AND RESULTS

Beta-ARs were assessed in 101 patients with HF due to idiopathic (50.5%) or ischaemic (49.5%) dilated cardiomyopathy, undergoing CRT for standard indications [left ventricular ejection fraction (LVEF) 23.5 ± 7.5%, QRS ≥ 120 ms]. Left ventricular ejection fraction was measured by echocardiography at baseline, 6 months after CRT, and periodically afterwards. The LVEF change from baseline was of 3.1 ± 11 units among Gln27Gln, 8.3 ± 10.4 units among Gln27Glu, 11 ± 6.4 units among Glu27Glu carriers (P = 0.018 for Gln27Gln vs. Glu27Glu carriers), and 8.8 ± 9.8 units among Gln27Glu + Glu27Glu carriers (P = 0.006 vs. Gln27Gln). Gln27 homozygotes had a higher incidence of appropriate ICD shocks for fast ventricular tachycardia/ventricular fibrillation.

CONCLUSION

Beta-2 Gln27Glu ARs gene polymorphism may influence LV reverse remodelling after CRT with Glu27Glu carriers showing the greatest improvement. It may also influence the incidence of malignant ventricular tachyarrhythmias.

Implications of left bundle branch block in patient treatment

Left bundle branch block (LBBB) causes an abnormal pattern of cardiac activation and affects regional myocardial function. Although recognition of LBBB on the surface electrocardiogram is straightforward, dissecting its effect on patient treatment and outcome can be more challenging. The altered pattern of cardiac activation in LBBB causes electrical and mechanical ventricular dyssynchrony, influences ischemia detection on the surface electrocardiogram, and affects stress testing and imaging modalities dependent on wall motion and thickening. Restoration of synchrony by biventricular pacing can improve symptoms and longevity in carefully selected patients. The diagnostic, prognostic, and therapeutic implications of LBBB across this spectrum are discussed in this review.

[Advances in cardiac pacing]

This article contains a review of the current status of remote monitoring and follow-up involving cardiac pacing devices and of the latest developments in cardiac resynchronization therapy. In addition, the most important articles published in the last year are discussed.