CRT Optimization: What Is New? What Is Necessary?

Feasibility of CMR Imaging during Biventricular Pacing: Comparison with Invasive Measurement as a Pathway towards a Novel Optimization Strategy

OBJECTIVES

This prospective pilot study assessed the feasibility of cardiovascular magnetic resonance (CMR) imaging during biventricular (BIV) pacing in patients with a CMR conditional cardiac resynchronization therapy defibrillator (CRT-D) and compared the results with invasive volume measurements.

METHODS

Ten CRT-D patients underwent CMR imaging prior to device implantation (baseline) and six weeks after device implantation, including CRT-on and CRT-off modes. Left ventricular (LV) function, volumes, and strain measurements of LV dyssynchrony and dyscoordination were assessed. Invasive pressure-volume measurements were performed, matching the CRT settings used during CMR.

RESULTS

Post-implantation imaging enabled reliable cine assessment, but showed artefacts on late gadolinium enhancement images. After six weeks of CRT, significant reverse remodeling was observed, with a 22.7 ± 11% reduction in LV end-systolic volume during intrinsic rhythm (CRT-off). During CRT-on, the LV ejection fraction significantly improved from 27.4 ± 5.9% to 32.2 ± 8.7% (p < 0.01), and the strain assessment showed the abolition of the left bundle branch block contraction pattern. Invasively measured and CMR-assessed LV hemodynamics during BIV pacing were significantly associated.

CONCLUSIONS

Post-CRT implantation CMR assessing acute LV pump function is feasible and provides important insights into the effects of BIV pacing on cardiac function and contraction patterns. LV assessment during CMR may constitute a future CRT optimization strategy.

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.

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.

Aetiology of Heart Failure, Rather than Sex, Determines Reverse LV Remodelling Response to CRT

Introduction: Cardiac resynchronization therapy (CRT) is an established therapy for patients with heart failure with reduced ejection fraction (HFrEF). Women appear to respond differently to CRT, yet it remains unclear whether this is inherent to the female sex itself, or due to other patient characteristics. In this study, we aimed to investigate sex differences in response to CRT. Methods: This is a post-hoc analysis of a prospective, multicenter study (MARC) in the Netherlands, studying HFrEF patients with an indication for CRT according to the guidelines (n = 240). Primary outcome measures are left ventricular ejection fraction (LVEF) and left ventricular end systolic volume (LVESV) at 6 months follow-up. Results were validated in an independent retrospective Belgian cohort (n = 818). Results: In the MARC cohort 39% were women, and in the Belgian cohort 32% were women. In the MARC cohort, 70% of the women were responders (defined as >15% decrease in LVESV) at 6 months, compared to 55% of men (p = 0.040) (79% vs. 67% in the Belgian cohort, p = 0.002). Women showed a greater decrease in LVESV %, LVESV indexed to body surface area (BSA) %, and increase in LVEF (all p < 0.05). In regression analysis, after adjustment for BSA and etiology, female sex was no longer associated with change in LVESV % and LVESV indexed to BSA % and LVEF % (p > 0.05 for all). Results were comparable in the Belgian cohort. Conclusions: Women showed a greater echocardiographic response to CRT at 6 months follow-up. However, after adjustment for BSA and ischemic etiology, no differences were found in LV-function measures or survival, suggesting that non-ischemic etiology is responsible for greater response rates in women treated with CRT.

Cardiac Resynchronization Therapy Remote Monitoring - COVID-19 Pandemic Experiences and Future Perspectives

Cardiac resynchronization therapy (CRT) is a well-established form of the treatment for heart failure (HF) in patients with left ventricle contraction dyssynchrony. Apart from typical in-office management, remote monitoring enables constant surveillance on both the patient's and the device's condition. This way, in case of any problems, clinical decisions could be made earlier leading to better outcome of CRT patients. COVID-19 pandemic with following lockdowns in many countries resulted in getting more attention on remote monitoring systems. The aim of this paper was to gather and summarize worldwide experiences from CRT remote monitoring during COVID-19 pandemic and point out future possibilities for HF patients treated with CRT. Already published experiences from remote monitoring of CRT devices during COVID-19 restrictions confirmed previous advantages of telemedical approach, however, more publications in this area would be helpful.

Cardiac Resynchronization Therapy in Patients with Heart Failure: What is New?

Cardiac resynchronization therapy (CRT) is an established treatment of patients with medically refractory, mild-to-severe systolic heart failure (HF), impaired left ventricular function, and wide QRS complex. The pathologic activation sequence observed in patients with abnormal QRS duration and morphology results in a dyssynchronous ventricular activation and contraction leading to cardiac remodeling, worsening systolic and diastolic function, and progressive HF. In this article, the authors aim to explore the current CRT literature, focusing their attentions on the promising innovation in this field.

Real-World Economic Burden Among Patients With And Without Heart Failure Worsening After Cardiac Resynchronization Therapy

INTRODUCTION

Although cardiac resynchronization therapy (CRT) has the potential to improve cardiac function in patients with heart failure (HF), a considerable portion of patients do not respond to therapy. This study assessed the economic burden among patients with and without HF worsening after receiving CRT in real-world practice.

METHODS

In this retrospective claims-based study using Optum's de-identified Clinformatics^® Data Mart Database (January 2007-December 2018), adults who received CRT were stratified into two cohorts based on whether they showed evidence of HF worsening within 180 days post-CRT implantation. Inverse probability of treatment weighting (IPTW) was used to adjust for confounding, accounting for demographics (e.g., age, sex), the Quan-Charlson Comorbidity Index, other clinical characteristics, healthcare resource utilization (HRU), and healthcare costs during the 180 days pre-CRT (baseline period). Annualized all-cause and congestive HF-related HRU and healthcare costs from payer and patient perspectives were assessed from day 181 post-CRT (follow-up period), and compared between cohorts using incidence rate ratios (IRRs) and cost ratios (CRs).

RESULTS

This study included 12,753 patients (n = 4785 with HF worsening; n = 7968 without). Mean age was 72 years and roughly two-thirds were male. Baseline characteristics were balanced between cohorts post-IPTW. During follow-up, patients with HF worsening had significantly greater annual all-cause inpatient [adjusted IRR (95% confidence interval) = 1.55 (1.44, 1.66), p < 0.001], outpatient [adjusted IRR = 1.46 (1.32, 1.61), p < 0.001], and emergency department [adjusted IRR = 1.31 (1.22, 1.41), p < 0.001] visits. Mean annual total per patient payer-paid amounts were significantly higher for patients with HF worsening versus without HF worsening [adjusted CR = 1.68 (1.56, 1.80), p < 0.001]. Annual patient-paid medical costs were also higher for patients with HF worsening [adjusted CR = 1.31 (1.25, 1.38), p < 0.001]. Results were similar for congestive HF-related HRU and costs.

CONCLUSIONS

The incremental economic burden among patients with HF worsening following CRT is substantial. Efforts aimed at CRT optimization may help reduce this burden.