Impact of Mitral Regurgitation on Reverse Remodeling and Outcome in Patients Undergoing Cardiac Resynchronization Therapy

Evolution and prognosis of tricuspid and mitral regurgitation following cardiac implantable electronic devices: a systematic review and meta-analysis

AIMS

Significant changes in tricuspid regurgitation (TR) and mitral regurgitation (MR) post-cardiac implantable electronic devices (CIEDs) are increasingly recognized. However, uncertainty remains as to whether the risk of CIED-associated TR and MR differs with right ventricular pacing (RVP) via CIED with trans-tricuspid RV leads, compared with cardiac resynchronization therapy (CRT), conduction system pacing (CSP), and leadless pacing (LP). The study aims to synthesize extant data on risk and prognosis of significant post-CIED TR and MR across pacing strategies.

METHODS AND RESULTS

We searched PubMed, EMBASE, and Cochrane Library databases published until 31 October 2023. Significant post-CIED TR and MR were defined as ≥ moderate. Fifty-seven TR studies (n = 13 723 patients) and 90 MR studies (n = 14 387 patients) were included. For all CIED, the risk of post-CIED TR increased [pooled odds ratio (OR) = 2.46 and 95% CI = 1.88-3.22], while the risk of post-CIED MR reduced (OR = 0.74, 95% CI = 0.58-0.94) after 12 and 6 months of median follow-up, respectively. Right ventricular pacing via CIED with trans-tricuspid RV leads was associated with increased risk of post-CIED TR (OR = 4.54, 95% CI = 3.14-6.57) and post-CIED MR (OR = 2.24, 95% CI = 1.18-4.26). Binarily, CSP did not alter TR risk (OR = 0.37, 95% CI = 0.13-1.02), but significantly reduced MR (OR = 0.15, 95% CI = 0.03-0.62). Cardiac resynchronization therapy did not significantly change TR risk (OR = 1.09, 95% CI = 0.55-2.17), but significantly reduced MR with prevalence pre-CRT of 43%, decreasing post-CRT to 22% (OR = 0.49, 95% CI = 0.40-0.61). There was no significant association of LP with post-CIED TR (OR = 1.15, 95% CI = 0.83-1.59) or MR (OR = 1.31, 95% CI = 0.72-2.39). Cardiac implantable electronic device-associated TR was independently predictive of all-cause mortality [pooled hazard ratio (HR) = 1.64, 95% CI = 1.40-1.90] after median of 53 months. Mitral regurgitation persisting post-CRT independently predicted all-cause mortality (HR = 2.00, 95% CI = 1.57-2.55) after 38 months.

CONCLUSION

Our findings suggest that, when possible, adoption of pacing strategies that avoid isolated trans-tricuspid RV leads may be beneficial in preventing incident or deteriorating atrioventricular valvular regurgitation and might reduce mortality.

Outcomes of mitral TEER in non-responders to cardiac resynchronization therapy: A systematic review and meta-analysis

BACKGROUND

Secondary mitral regurgitation (MR) worsens in 10-15 % of heart failure (HF) patients receiving cardiac resynchronization therapy (CRT). Transcatheter edge-to-edge repair (TEER) with Mitra-Clip (Abbot Vascular, Santa Clara, CA, USA) therapy is associated with improved survival and decreased rates of hospitalization for HF in selected patients with secondary MR. Data on TEER outcomes in CRT-non-responders are limited. The purpose of this meta-analysis was to evaluate outcomes of mitral TEER with Mitra-Clip in CRT-non-responders.

METHODS

Cochrane, Scopus, MEDLINE, and EMBASE were searched for studies discussing outcomes of Mitra-Clip in CRT non-responders. Two reviewers were independently involved in screening studies and extracting relevant data. Individual study incidence rate estimates underwent logit transformation to calculate the weighted summary proportion under the random effect model.

RESULTS

A total of eight reports met the inclusion criteria (439 patients). Mitra-Clip improved MR grade to ≤2+ in 83.8 % and 86.8 % of CRT non-responders at six months and one year, respectively. Symptomatic improvement (New York Heart Association class ≤II) was also found in 71 % and 78.1 % of CRT non-responders at six months and one year, respectively. The pooled overall incidence estimates of mortality at 30 days, 6 months, 1 year, and 2 years were 3.6 %, 9.2 %, 17.8 %, and 25.9 %, respectively.

CONCLUSION

TEER with Mitra-Clip in patients with significant secondary MR who do not respond to CRT was associated with MR improvement, alleviation of symptoms, and mortality rates similar to those in the COAPT trial.

Persistence of significant secondary mitral regurgitation post-cardiac resynchronization therapy and survival: a systematic review and meta-analysis : Mitral regurgitation and mortality post-CRT

Cardiac resynchronization therapy (CRT) significantly reduces secondary mitral regurgitation (MR) in patients with severe left ventricular systolic dysfunction. However, uncertainty remains as to whether improvement in secondary MR correlates with improvement with mortality seen in CRT. We conducted a meta-analysis to determine the association of persistent unimproved significant secondary MR (defined as moderate or moderate-to-severe or severe MR) compared to improved MR (no MR or mild MR) post-CRT with all-cause mortality, cardiovascular mortality, and heart failure hospitalization. A systematic search of PubMed, EMBASE, and Cochrane Library databases till July 31, 2022 identified studies reporting clinical outcomes by post-CRT secondary MR status. In 12 prospective studies of 4954 patients (weighted mean age 66.8 years, men 77.8%), the median duration of follow-up post-CRT at which patients were re-evaluated for significant secondary MR was 6 months and showed significant relative risk reduction of 30% compared to pre-CRT. The median duration of follow-up post-CRT for ascertainment of main clinical outcomes was 38 months. The random effects pooled hazard ratio (95% confidence interval) of all-cause mortality in patients with unimproved secondary MR compared to improved secondary MR was 2.00 (1.57-2.55); p < 0.001). There was insufficient data to evaluate secondary outcomes in a meta-analysis, but limited data that examined the relationship showed significant association of unimproved secondary MR with increased cardiovascular mortality and heart failure hospitalization. The findings of this meta-analysis suggest that lack of improvement in secondary MR post-CRT is associated with significantly elevated risk of all-cause mortality and possibly cardiovascular mortality and heart failure hospitalization. Future studies may investigate approaches to address persistent secondary MR post-CRT to help improved outcome in this population.

Valvular heart disease and cardiomyopathy: reappraisal of their interplay

Cardiomyopathies and valvular heart diseases are typically considered distinct diagnostic categories with dedicated guidelines for their management. However, the interplay between these conditions is increasingly being recognized and they frequently coexist, as in the paradigmatic examples of dilated cardiomyopathy and hypertrophic cardiomyopathy, which are often complicated by the occurrence of mitral regurgitation. Moreover, cardiomyopathies and valvular heart diseases can have a shared aetiology because several genetic or acquired diseases can affect both the cardiac valves and the myocardium. In addition, the association between cardiomyopathies and valvular heart diseases has important prognostic and therapeutic implications. Therefore, a better understanding of their shared pathophysiological mechanisms, as well as of the prevalence and predisposing factors to their association, might lead to a different approach in the risk stratification and management of these diseases. In this Review, we discuss the different scenarios in which valvular heart diseases and cardiomyopathies coexist, highlighting the need for an improved classification and clustering of these diseases with potential repercussions in the clinical management and, particularly, personalized therapeutic approaches.

Medical Therapy for Functional Mitral Regurgitation

Functional mitral regurgitation (FMR) can be broadly categorized into 2 main groups: ventricular and atrial, which often coexist. The former is secondary to left ventricular remodeling usually in the setting of heart failure with reduced ejection fraction or less frequently due to ischemic papillary muscle remodeling. Atrial FMR develops due to atrial and annular dilatation related to atrial fibrillation/flutter or from increased atrial pressures in the setting of heart failure with preserved ejection fraction. Guideline-directed medical therapy is the first step and prevails as the mainstay in the treatment of FMR. In this review, we address the medical therapeutic options for FMR management and highlight a targeted approach for each FMR category. We further address important clinical and echocardiographic characteristics to aid in determining when medical therapy is expected to have a low yield and an appropriate window for effective interventional approaches exists.

The Role of Cardiac Resynchronization Therapy for the Management of Functional Mitral Regurgitation

Valve leaflets and chordae structurally normal characterize functional mitral regurgitation (FMR), which in heart failure (HF) setting results from an imbalance between closing and tethering forces secondary to alterations in the left ventricle (LV) and left atrium geometry. In this context, FMR impacts the quality of life and increases mortality. Despite multiple medical and surgical attempts to treat FMR, to date, there is no univocal treatment for many patients. The pathophysiology of FMR is highly complex and involves several underlying mechanisms. Left ventricle dyssynchrony may contribute to FMR onset and worsening and represents an important target for FMR management. In this article, we discuss the mechanisms of FMR and review the potential therapeutic role of CRT, providing a comprehensive review of the available data coming from clinical studies and trials.

Percutaneous Edge-to-Edge Mitral Valve Repair for Functional Mitral Regurgitation

The presence and severity of functional mitral regurgitation (FMR) is associated with worse outcomes in patients with heart failure and reduced ejection fraction. Prior to the availability of percutaneous mitral valve repair, management for FMR has been limited to medical therapy, cardiac resynchronization therapy for a specific subset of patients and surgery which has yet to demonstrate mortality benefits. Transcatheter edge-to-edge repair (TEER) of the mitral valve has emerged in the past decade as an invaluable member of the armamentarium against FMR with the 2 landmark randomized controlled trials providing deep insights on patient selection. In addition, TEER has spurred the rapid advancement in our understanding of FMR. This article seeks to provide an overview as well as our current understanding on the role of TEER in FMR.

Epidemiology, Pathophysiology, and Management of Native Atrioventricular Valve Regurgitation in Heart Failure Patients

Atrioventricular regurgitation is frequent in the setting of heart failure. It is due to atrial and ventricular remodelling, as well as rhythmic disturbances and loss of synchrony. Once atrioventricular regurgitation develops, it can aggravate the underlying heart failure, and further participate and aggravate its own severity. Its presence is therefore concomitantly a surrogate of advance disease and a predictor of mortality. Heart failure management, including medical therapy, cardiac resynchronization therapy, and restoration of sinus rhythm, are the initial steps to reduce atrioventricular regurgitation. In the current review, we analyse the current data assessing the epidemiology, pathophysiology, and impact of non-valvular intervention on atrioventricular regurgitation including medical treatment, cardiac resynchronization and atrial fibrillation ablation.

Optimized implementation of cardiac resynchronization therapy: a call for action for referral and optimization of care

Cardiac resynchronization therapy (CRT) is one of the most effective therapies for heart failure with reduced ejection fraction and leads to improved quality of life, reductions in heart failure hospitalization rates and all-cause mortality. Nevertheless, up to two-thirds of eligible patients are not referred for CRT. Furthermore, post-implantation follow-up is often fragmented and suboptimal, hampering the potential maximal treatment effect. This joint position statement from three European Society of Cardiology Associations, Heart Failure Association (HFA), European Heart Rhythm Association (EHRA) and European Association of Cardiovascular Imaging (EACVI), focuses on optimized implementation of CRT. We offer theoretical and practical strategies to achieve more comprehensive CRT referral and post-procedural care by focusing on four actionable domains: (i) overcoming CRT under-utilization, (ii) better understanding of pre-implant characteristics, (iii) abandoning the term 'non-response' and replacing this by the concept of disease modification, and (iv) implementing a dedicated post-implant CRT care pathway.

Optimized implementation of cardiac resynchronization therapy: a call for action for referral and optimization of care: A joint position statement from the Heart Failure Association (HFA), European Heart Rhythm Association (EHRA), and European Association of Cardiovascular Imaging (EACVI) of the European Society of Cardiology

Cardiac resynchronization therapy (CRT) is one of the most effective therapies for heart failure with reduced ejection fraction and leads to improved quality of life, reductions in heart failure hospitalization rates and all-cause mortality. Nevertheless, up to two-thirds of eligible patients are not referred for CRT. Furthermore, post-implantation follow-up is often fragmented and suboptimal, hampering the potential maximal treatment effect. This joint position statement from three European Society of Cardiology Associations, Heart Failure Association (HFA), European Heart Rhythm Association (EHRA) and European Association of Cardiovascular Imaging (EACVI), focuses on optimized implementation of CRT. We offer theoretical and practical strategies to achieve more comprehensive CRT referral and post-procedural care by focusing on four actionable domains: (i) overcoming CRT under-utilization, (ii) better understanding of pre-implant characteristics, (iii) abandoning the term 'non-response' and replacing this by the concept of disease modification, and (iv) implementing a dedicated post-implant CRT care pathway.

Left ventricular remodelling and prognosis after discharge in new-onset acute heart failure with reduced ejection fraction

Aims

This study aimed to investigate the left ventricular (LV) remodelling and long‐term prognosis of patients with new‐onset acute heart failure (HF) with reduced ejection fraction who were pharmacologically managed and survived until hospital discharge. We compared patients with ischaemic and non‐ischaemic aetiology.

Methods and results

This cohort study consisted of 111 patients admitted with new‐onset acute HF in the period 2008–2016 [62% non‐ischaemic aetiology, 48% supported by inotropes, vasopressors, or short‐term mechanical circulatory devices, and left ventricular ejection fraction (LVEF) at discharge 28% (interquartile range 22–34)]. LV dimensions, LVEF, and mitral valve regurgitation were used as markers for LV remodelling during up to 3 years of follow‐up. Both patients with non‐ischaemic and ischaemic HF had significant improvement in LVEF (P < 0.001 and P = 0.004, respectively) with significant higher improvement in those with non‐ischaemic HF (17% vs. 6%, P < 0.001). Patients with non‐ischaemic HF had reduction in LV end‐diastolic and end‐systolic diameters (6 and 10 mm, both P < 0.001), but this was not found in those with ischaemic HF [+3 mm (P = 0.09) and +2 mm (P = 0.07), respectively]. During a median follow‐up of 4.6 years, 98 patients (88%) did not reach the composite endpoint of LV assist device implantation, heart transplantation, or all‐cause mortality, with no difference between with ischaemic and non‐ischaemic HF [hazard ratio 0.69 (95% confidence interval 0.19–2.45)].

Conclusions

Patients with new‐onset acute HF with reduced ejection fraction discharged on optimal medical treatment have a good prognosis. We observed a considerable LV remodelling with improvement in LV function and dimensions, starting already at 6 months in patients with non‐ischaemic HF but not in their ischaemic counterparts.

Ischemic Mitral Regurgitation: A Multifaceted Syndrome with Evolving Therapies

Dysfunction of the left ventricle (LV) with impaired contractility following chronic ischemia or acute myocardial infarction (AMI) is the main cause of ischemic mitral regurgitation (IMR), leading to moderate and moderate-to-severe mitral regurgitation (MR). The site of AMI exerts a specific influence determining different patterns of adverse LV remodeling. In general, inferior-posterior AMI is more frequently associated with regional structural changes than the anterolateral one, which is associated with global adverse LV remodeling, ultimately leading to different phenotypes of IMR. In this narrative review, starting from the aforementioned categorization, we proceed to describe current knowledge regarding surgical approaches in the management of IMR.

The mechanism and prognosis of acute and late improvement in mitral regurgitation after cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) improves functional mitral regurgitation (MR); however, the mechanism and differences in acute and late improvement in MR are unclear. We aimed to evaluate the factors associated with the acute and late MR improvements and the prognosis of MR improvement after CRT. This retrospective study included 121 patients who underwent CRT implantation with full echocardiography assessment at baseline, 1 week, and 6 months after implantation. MR severity was classified into five grades (0: none to 4: severe). Two-dimensional speckle-tracking echocardiography with radial strain was used to assess dyssynchrony, and the time difference between the lateral and inferior segments at papillary muscle levels (TD_late-inf) was calculated. The MR improved 1 week and 6 months after CRT in 40 (33%) and 45 (37%) patients, respectively. On multivariate analyses, TD_late-inf (baseline-1 week) and SPWMD were independently associated with acute MR improvement. The %reduction in left ventricular end-systolic volume (LVESV) (baseline-6 months) and TD_late-inf (baseline-1 week) were independently correlated with late MR improvement. The patients with pre-MR grades 2-4 and improved MR after CRT showed significantly better prognosis in heart failure hospitalization. Cutoff values of ≥ 19.5 ms of the reduction of TD_late-inf and ≥ 30.8% of the %reduction of LVESV were significantly associated with the decrease in heart failure hospitalization. The improved interpapillary muscle activation time delay and volume reduction after CRT were associated with acute and late MR improvements. There may be different time course of recovery and distinct causes for late MR improvement.

Transcatheter Mitral Valve Repair in Patients With and Without Cardiac Resynchronization Therapy: The COAPT Trial

BACKGROUND

In the COAPT trial (Cardiovascular Outcomes Assessment of the MitraClip Percutaneous Therapy for Heart Failure Patients With Functional Mitral Regurgitation), treatment of heart failure (HF) patients with moderate-severe or severe secondary mitral regurgitation with transcatheter mitral valve repair (TMVr) using the MitraClip plus guideline-directed medical therapy (GDMT) reduced 2-year rates of HF hospitalization and all-cause mortality compared with GDMT alone. Whether the benefits of the MitraClip extend to patients with previously implanted cardiac resynchronization therapy (CRT) is unknown. We sought to examine the effect of prior CRT in patients enrolled in COAPT.

METHODS

Patients (N=614) with moderate-severe or severe secondary mitral regurgitation who remained symptomatic despite maximally tolerated doses of GDMT were randomized 1:1 to the MitraClip (TMVr arm) versus GDMT only (control arm). Outcomes were assessed according to prior CRT use.

RESULTS

Among 614 patients, 224 (36.5%) had prior CRT (115 and 109 randomized to TMVr and control, respectively) and 390 (63.5%) had no CRT (187 and 203 randomized to TMVr and control, respectively). Patients with CRT had similar 2-year rates of the composite of death or HF hospitalization compared with those without CRT (57.6% versus 55%, P=0.32). Death or HF hospitalization at 2 years was lower with TMVr versus control treatment in patients with prior CRT (48.6% versus 67.2%, hazard ratio, 0.60 [95% CI, 0.42-0.86]) and without CRT (42.5% versus 66.9%, hazard ratio, 0.52 [95% CI, 0.39-0.69]; adjusted P_interaction=0.23). The effects of TMVr with the MitraClip on reducing the 2-year rates of all-cause death (adjusted P_interaction=0.14) and HF hospitalization (adjusted P_interaction=0.82) were also consistent in patients with and without CRT as were improvements in quality-of-life and exercise capacity.

CONCLUSIONS

In the COAPT trial, TMVr with the MitraClip improved the 2-year prognosis of patients with HF and moderate-severe or severe secondary mitral regurgitation who remained symptomatic despite maximally tolerated GDMT, regardless of prior CRT implantation. Registration: URL: https://www.clinicaltrials.gov. Unique identifier: NCT01626079.

Functional mitral regurgitation and cardiac resynchronization therapy in the "era" of trans-catheter interventions: Is it time to move from a staged strategy to a tailored therapy?

Cardiac resynchronization therapy (CRT) has been associated to left ventricle (LV) remodelling, reduction of functional mitral regurgitation (FMR) and clinical improvement in patients with heart failure and reduced ejection fraction (HFrEF). The prevalence of significant FMR in patients with LV dyssynchrony that are candidate to CRT is up to 40%. Current approach in patients with FMR undergoing CRT consists of re-evaluation of the amount of FMR following a waiting period of at least 3 months after the implant. In case of persistent significant FMR despite CRT and guideline directed medical therapy, trancatheter Mitral Valve repair (TMVR) is an important option to improve quality of life and prognosis. This stepwise approach does not take into account the probability of the individual response to CRT and the availability of TMVR solutions that are safe and effective in high risk patients. We reviewed the effects of CRT on FMR, the prognostic role of persistence of FMR after CRT treatment and the impact of treatment of FMR in patients CRT non responders. We aimed to point out the limits of current step-wised approach in light on more recent evidence regarding FMR treatment. A new, "tailored" approached is proposed.

Survival and Cardiovascular Outcomes of Patients With Secondary Mitral Regurgitation: A Systematic Review and Meta-analysis

Importance

The outcomes of patients with left ventricular (LV) dysfunction and secondary mitral regurgitation (SMR) are still controversial.

Objective

To clarify the role of SMR in the outcomes of patients with ischemic or idiopathic cardiomyopathies.

Data Sources

MEDLINE, ISI Web of Science, and Scopus databases were searched for studies published up to March 2017.

Study Selection

Studies reporting data on outcomes in patients with SMR were included. Duplicate publication data, studies lacking data on SMR grade and its correlation with outcomes, mixed data on SMR and primary mitral regurgitation, studies not clearly reporting the outcome of interest, and studies with fewer than 100 patients were excluded. Of the initial 3820 articles identified, 1.4% were finally included.

Data Extraction and Synthesis

The study met PRISMA requirements. Two of us independently screened articles for fulfillment of inclusion criteria.

Main Outcomes and Measures

The primary outcome, set after data collection, was the incidence of all-cause mortality in patients with and without SMR. Secondary outcomes included hospitalization for heart failure (HF), cardiac mortality, and a composite end point of death, HF hospitalization, and cardiac transplant.

Results

Fifty-three studies and 45 900 patients were included in the meta-analysis. The mean (SD) length of follow-up was 40.8 (22.2) months. In 26 of 36 studies reporting LV function by SMR grade, increasing SMR severity was associated with worse LV function. When SMR was categorized as present or absent, all-cause mortality was significantly higher in the patients with SMR (17 studies, 26 359 patients; risk ratio [RR],1.79; 95% CI, 1.47-2.18; P < .001, I2 = 85%); when SMR was qualitatively graded, the incidence of all-cause mortality was significantly increased in patients having any degree of SMR compared with patients not having SMR (21 studies, 21 081 patients; RR, 1.96; 95% CI, 1.67-2.31; P < .001, I2 = 74%). Finally, when SMR was quantitatively graded, it remained associated with an increased all-cause mortality rate (9 studies, 3649 patients; RR, 1.97; 95% CI, 1.71-2.27; P < .001, I2 = 0%). Moreover, SMR was associated with an increased risk of hospitalization for HF (16 studies, 10 171 patients; RR, 2.26; 95% CI, 1.92-2.67; P < .001, I2 = 41%), cardiac mortality (12 studies, 11 896 patients; RR, 2.62; 95% CI, 1.87-3.69; P < .001, I2 = 74%), and death, HF, and transplant (11 studies, 8256 patients; RR, 1.63; 95% CI, 1.33-1.99; P < .001, I2 = 78%).

Conclusions and Relevance

To our knowledge, this study is the first meta-analysis to date to demonstrate that SMR, even when mild, correlates with adverse outcomes in patients with ischemic or idiopathic cardiomyopathies. Because SMR is an intrinsic consequence of LV dysfunction, causality between SMR and mortality should not be implied.

Effect of Functional Mitral Regurgitation on Outcome in Patients Receiving Cardiac Resynchronization Therapy for Heart Failure

Functional mitral regurgitation (FMR) is common in heart failure (HF), and negatively impacts prognosis. Cardiac resynchronization therapy (CRT) can improve FMR, but the long-term changes in and impact of FMR after CRT are still unclear. The present study investigated the prevalence, evolution and impact on mortality of FMR before and after CRT in patients with HF. A total of 1,313 patients (66 ± 11 years, 77% male, 59% ischemic heart disease) treated with CRT were evaluated. Patients were divided into 4 groups of FMR according to the evolution at 6 months after CRT: no or mild FMR at baseline which remained unchanged at 6 months (grade 0-1 FMR unchanged, n = 609 [51%]), no or mild FMR which worsened to moderate to severe (grade 0-1 FMR worsened, n = 66 [6%)]), moderate to severe FMR which improved to no or mild (grade 2-4 improved, n = 209 [18%]), and moderate to severe FMR which remained unchanged (grade 2-4 unchanged, n = 309 [26%]). Over a mean follow-up of 51 ± 38 months, 297 (25%) patients died. Those with baseline FMR grade 0-1 which remained unchanged at 6-month follow-up, as well as baseline FMR grade 2-4 which improved, had lower mortality rates than patients with 6-month FMR grade 2-4 regardless of baseline FMR grade (p <0.001). Baseline FMR grade 2-4 that remained unchanged at 6-month follow-up was associated with increased mortality, independent of the clinical and left ventricular volumetric responses to CRT (hazard ratio, 1.77; 95% confidence interval, 1.41-2.22, p <0.001). In conclusion, moderate to severe FMR at baseline which remains unchanged at 6 months after CRT implantation is strongly associated with long-term mortality in patients with HF.

[Leadless endocardial ultrasound based left ventricular stimulation : WISE CRT System: alternative to conventional methods]

There are still several limitations in delivering cardiac resynchronisation therapy (CRT). After 6 months, 20-40% of patients fail to have clinical benefit due to various reasons. Endocardial stimulation rather than conventional epicardial pacing has been shown to be more physiological, improves electrical stimulation of the left ventricle (LV), has less dispersion of electrical activity and results in better resynchronisation. The WiSE™ CRT System ("Wireless stimulation endocardial system"; EBR Systems, Sunnyvale, CA, USA) provides an option for wireless, LV endocardial pacing triggered by a conventional right ventricular pacing spike from a co-implant. The feasibility of the WiSE™ CRT System has been successfully demonstrated in a population of failed cardiac resynchronisation patients with either failed implantation of a conventional system, nonresponse to conventional therapy or upgrade from pacemaker or defibrillator, where a conventional system was not an option. The WiSE™ CRT System is an innovative technology with promising safety, performance and preliminary efficacy.

Assessment of dyssynchrony by gated myocardial perfusion imaging does not improve patient management

Clinical trials have demonstrated improved outcomes with cardiac resynchronization therapy in patients with heart failure and electrical evidence of dyssynchrony. There has been intense effort at developing imaging markers of dyssynchrony with the aim of improved risk stratification. However, these efforts have not been fruitful to date. This article discusses mechanisms of cardiac dyssynchrony, reviews clinical data supporting resynchronization therapy, and addresses the lack of convincing evidence to support the use of noninvasive imaging measures of dyssynchrony in improving patient management.

Time course of secondary mitral regurgitation in patients with heart failure receiving cardiac resynchronization therapy: Impact on long-term outcome beyond left ventricular reverse remodelling

BACKGROUND

The prognostic value of secondary mitral regurgitation (MR) at baseline versus immediately after and several months after cardiac resynchronization therapy (CRT), beyond left ventricular (LV) reverse remodelling, has yet to be investigated.

AIM

To evaluate the clinical significance of secondary MR before and at two timepoints after CRT in a large cohort of consecutive patients with heart failure (HF) and reduced LV ejection fraction.

METHODS

A total of 198 patients were recruited prospectively into a registry, and underwent echocardiography at baseline and immediately after CRT (on the day of hospital discharge). Echocardiography was also performed 9 months after CRT in 172 patients. The impact of significant secondary MR (≥moderate) on all-cause death, cardiovascular death and hospitalization for HF was studied at each stage.

RESULTS

The frequency of significant secondary MR decreased from 23% (n=45) to 8% (n=16) immediately after CRT. Among the 172 patients who underwent echocardiography 9 months after CRT, 17 (10%) had significant secondary MR. During a median follow-up of 48 months, 49 patients died and 36 were hospitalized for HF. Patients with significant secondary MR immediately after or 9 months after CRT had an increased risk of all-cause death, cardiovascular death and hospitalization for HF during follow-up (P<0.05 for all endpoints). After adjustment for LV reverse remodelling, significant secondary MR 9 months after CRT remained associated with an increased risk of all-cause death (adjusted hazard ratio [HR] 3.77; P=0.014), cardiovascular death (adjusted HR 5.36; P=0.037), and hospitalization for HF (adjusted HR 7.33; P=0.001).

CONCLUSIONS

Significant secondary MR despite CRT provides important prognostic information beyond LV reverse remodelling. Further studies are needed to evaluate the potential role of new percutaneous procedures for mitral valve repair in improving outcome in these very high-risk patients.

Minimally invasive mitral valve annuloplasty confers a long-term survival benefit compared with state-of-the-art treatment in heart failure with functional mitral regurgitation

BACKGROUND

Clinical impact of the minimally invasive surgical mitral valve annuloplasty (MVA) of functional mitral regurgitation (FMR) in systolic heart failure on top of the state-of-the-art standards of care remains controversial. Therefore, we aimed to compare clinical outcomes of isolated MVA using the mini-invasive videothoracoscopic approach versus the state-of-the-art (CON=conservative) treatment in patients with chronic systolic heart failure and symptomatic FMR.

METHODS

The study population consisted of 379 patients (age 68.9±11.0years, 62.8% males) with left ventricular (LV) systolic dysfunction, symptomatic FMR and previous heart failure hospitalization. A total of 167 patients underwent undersized MVA and 212 patients were treated conservatively. A concomitant MAZE was performed in 53 (31.7%) patients.

RESULTS

In the MVA group, the periprocedural and the 30-day mortality were 1.2% and 4.8%, respectively. During the median follow-up of 7.1years (IQR 3.5-9.8years) a total of 74 (44.3%) and 138 (65.1%) died in the MVA and the CON group, respectively (p<0.001). The lowest mortality was observed in MVA combined with MAZE (22.6%; p<0.01). In Cox regression analysis, age, MVA with MAZE emerged as independent predictors of both all-cause mortality and rehospitalizations for heart failure (all p<0.05). MVA was associated with significantly greater symptomatic improvement and reduction of FMR than the conservative treatment (both p<0.001). Reverse LV remodeling was observed only in the MVA combined with MAZE group (p<0.01).

CONCLUSIONS

In patients with symptomatic FMR, minimally invasive MVA, in particular in combination with MAZE, confers an independent long-term survival benefit compared with the state-of-the-art treatment.

Longer Left Ventricular Electric Delay Reduces Mitral Regurgitation After Cardiac Resynchronization Therapy: Mechanistic Insights From the SMART-AV Study (SmartDelay Determined AV Optimization: A Comparison to Other AV Delay Methods Used in Cardiac Resynchronization Therapy)

BACKGROUND

Mitral regurgitation (MR) is associated with worse survival in those undergoing cardiac resynchronization therapy (CRT). Left ventricular (LV) lead position in CRT may ameliorate mechanisms of MR. We examine the association between a longer LV electric delay (QLV) at the LV stimulation site and MR reduction after CRT.

METHODS AND RESULTS

QLV was assessed retrospectively in 426 patients enrolled in the SMART-AV study (SmartDelay Determined AV Optimization: A Comparison to Other AV Delay Methods Used in CRT). QLV was defined as the time from QRS onset to the first large peak of the LV electrogram. Linear regression and logistic regression were used to assess the association between baseline QLV and MR reduction at 6 months (absolute change in vena contracta width and odds of ≥1 grade reduction in MR). At baseline, there was no difference in MR grade, LV dyssynchrony, or LV volumes in those with QLV above versus below the median (95 ms). After multivariable adjustment, increasing QLV was an independent predictor of MR reduction at 6 months as reflected by an increased odds of MR response (odds ratio: 1.13 [1.03-1.25]/10 ms increase QLV; P=0.02) and a decrease in vena contracta width (P<0.001). At 3 months, longer QLV (≥median) was associated with significant decrease in LV end-systolic volume (ΔLV end-systolic volume -28.2±38.9 versus -4.9±33.8 mL, P<0.001). Adjustment for 3-month ΔLV end-systolic volume attenuated the association between QLV and 6-month MR reduction.

CONCLUSIONS

In patients undergoing CRT, longer QLV was an independent predictor of MR reduction at 6 months and associated with interval 3-month LV reverse remodeling. These findings provide a mechanistic basis for using an electric-targeting LV lead strategy at the time of CRT implant.

Very Late Continued Reverse Remodelling After Cardiac Resynchronization Therapy in Patients With Extreme Left Ventricular Dilatation

Response to cardiac resynchronization therapy (CRT) varies greatly among patients. We present 2 patients with severe heart failure symptoms (New York Heart Association class IV) and extreme initial left ventricular (LV) dilatation (LV end-diastolic diameter of 92 mm and 80 mm, respectively) and severe functional mitral regurgitation who underwent CRT device implantation. Long-term follow-up showed late (≥ 4 years) normalization of LV ejection fraction (LVEF), LV dimensions, and functional status. In a subgroup of patients with nonischemic dilated cardiomyopathy and complete left bundle branch block, late continued LV reverse remodelling may lead to normalization of LV volumes and LVEF and significant improvement in functional class.

Novel Heart Failure Biomarkers Predict Improvement of Mitral Regurgitation in Patients Receiving Cardiac Resynchronization Therapy-The BIOCRT Study

BACKGROUND

Cardiac resynchronization therapy (CRT) improves mitral regurgitation (MR) in a subset of patients. We hypothesized that biomarkers (amino-terminal pro-B type natriuretic peptide, high-sensitivity troponin I, galectin-3 [gal-3], and soluble ST2) might predict MR response after CRT.

METHODS

We measured levels of biomarkers during CRT implantation in 132 patients with a subsequent 2-year follow-up. MR was graded as no-trace, mild, moderate, or severe at baseline and at 6 months.

RESULTS

In patients with baseline at least mild MR, 56% had improvement at 6 months, with lower 2-year mortality vs patients without improvement (0% vs 18%; P = 0.002). At baseline, patients with MR improvement had lower high-sensitivity troponin I and gal-3 levels compared with those without improvement (19 vs 40 pg/L; P = 0.01; 14 vs 18 ng/mL; P = 0.007). In multivariable analyses, higher log-transformed gal-3 (odds ratio, 0.15; 95% confidence interval, 0.04-0.65; P = 0.01) remained an independent predictor for MR nonimprovement. Levels of pro-B type natriuretic peptide and soluble ST2 were lower at follow-up in patients with MR improvement (potentially reflecting reduced myocardial stretch and stress) without reaching statistical significance.

CONCLUSIONS

Higher galectin levels at the time of CRT implantation are associated with MR nonresponse.

Pre-Operative Left Ventricular Torsion, QRS Width/CRT, and Post-Mitral Surgery Outcomes in Patients With Nonischemic, Chronic, Severe Secondary Mitral Regurgitation

The selection of appropriate candidates for mitral surgery among symptomatic patients with nonischemic, chronic, secondary severe mitral regurgitation (NICSMR) remains a clinical challenge. We studied 50 consecutive symptomatic NICSMR patients for a median follow-up of 2.5 years after mitral surgery and concluded that the pre-operative 2-dimensional speckle tracking echocardiography-derived left ventricular torsional profile and QRS width/cardiac resynchronization therapy are potentially important prognostic indicators for post-surgery survival and reverse remodeling.

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Determining which patients with NICSMR will benefit from MS is a clinical dilemma.

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LV torsion (which is a shear strain, not volume strain such as ejection fraction and originates in LV myocardial architectures) may reveal the myopathic conditions and reflect intra-LV electrical conduction.

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The LV torsional profile predicted post-MS outcomes in NICSMR patients with a narrow QRS but not in those with a wide QRS.

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The findings may help to resolve the clinical dilemma and identify appropriate candidates for mitral surgery (and other resources) in patients with NICSMR.

Effect of QRS Narrowing After Cardiac Resynchronization Therapy on Functional Mitral Regurgitation in Patients With Systolic Heart Failure

The determinants of improvement in functional mitral regurgitation (FMR) after cardiac resynchronization therapy (CRT) remain unclear. We evaluated the predictors of FMR improvement and hypothesized that CRT-induced change in QRS duration (ΔQRS) might have an impact on FMR response after CRT. One hundred ten CRT recipients were enrolled. CRT response (≥ 15 reduction in left ventricular end-systolic volume) and FMR response (absolute reduction in FMR volume) were assessed with echocardiography before and 6 months after CRT. The study end points included all-cause death or hospitalization assessed in 12 ± 3 months (range 1 to 18). A total of 71 patients (65%) responded to CRT at 6 months. FMR response was observed in 49 (69%) of the CRT responders and 8 (20%) of the CRT nonresponders (p <0.001). Although the baseline QRS durations were similar, the paced QRS durations were shorter (p = 0.012) and the ΔQRS values were greater (p = 0.003) in FMR responders compared with FMR nonresponders. There was a linear correlation between ΔQRS and change in regurgitant volume (r = 0.49, p <0.001). At multivariate analysis, baseline tenting area (p = 0.012) and ΔQRS (p = 0.028) independently predicted FMR response. A ΔQRS ≥ 20 ms was related to CRT response, FMR improvement, and lower rates of death or hospitalization during follow-up (p values <0.05). In conclusion, QRS narrowing after CRT independently predicts FMR response. A ΔQRS ≥ 20 ms after CRT is associated with a favorable outcome in all clinical end points.

Acute Hemodynamic Response to Cardiac Resynchronization in Dilated Cardiomyopathy: Effect on Late Mitral Regurgitation

BACKGROUND

Functional mitral regurgitation (FMR) is associated with reduced survival in dilated cardiomyopathy (DCM). Cardiac resynchronization therapy (CRT) can improve FMR. We sought to identify the predictors of FMR improvement after CRT in DCM.

METHODS

From January 2003 to December 2013, 430 DCM patients consecutively enrolled were retrospectively analyzed. Inclusion criteria were successful CRT implantation in the presence of conventional indications (i.e., left bundle branch block, left ventricular ejection fraction ≤35%, New York Heart Association functional class ≥II) and moderate-to-severe FMR at the time of procedure. Early echocardiographic evaluation after CRT implantation (median 2.5 days) has been performed in each patient. Improvement in FMR (absent/mild) at midterm (7 months; interquartile range 4-10) was considered as the primary study end point.

RESULTS

A total of 44 patients (10% of the overall cohort) were included. A significant reduction in FMR severity was observed in 21 patients (48%) at midterm after CRT (median time 7 months). No preimplantation variables predicted FMR evolution, but FMR improvement at midterm was strongly predicted by an acute favorable hemodynamic response (persistence/development of normal right ventricular function and 10-mm Hg decrease or normalization [≤35 mm Hg] of systolic pulmonary artery pressure) at postimplantation echocardiography (odds ratio: 13.7; 95% confidence interval: 1.27-42.8; P = 0.016). FMR improvement at midterm was stable during follow-up and was associated with superior long-term transplant-free survival (P = 0.022).

CONCLUSIONS

Stable FMR improvement frequently occurs after CRT implantation in DCM and is associated with improved transplant-free survival. Echocardiographic evaluation of acute hemodynamic response to CRT is helpful to early identification of the favorable FMR evolution.

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.

Mechanistic features associated with improvement in mitral regurgitation after cardiac resynchronization therapy and their relation to long-term patient outcome

BACKGROUND

Mechanisms of mitral regurgitation (MR) reduction with cardiac resynchronization therapy (CRT) are complex, and their association with long-term outcome is unclear. We sought to elucidate mechanistic features of reduction in MR with CRT, which impact long-term patient survival.

METHODS AND RESULTS

A prospective longitudinal study of 277 patients with heart failure with QRS width ≥ 120 ms and ejection fraction ≤ 35% for CRT was performed. Quantitative echocardiography, including dyssynchrony analysis, was performed at baseline. MR was quantified by color Doppler before and 6 months after CRT. Predefined end points of death, transplant, or left ventricular assist device were tracked during 4 years. There were 114 (48%) patients with CRT with significant MR (≥ moderate) at baseline; of whom 48 (42%) patients had MR improvement, and 24 (19%) patients had MR worsening after CRT. The 66 events (47 deaths, 10 transplantations, and 9 left ventricular assist devices) were strongly associated with significant MR after CRT (hazard ratio, 3.58; 95% confidence interval, 2.18-5.87; P<0.0001). Three echocardiographic features were independently associated with amelioration of significant MR after CRT by multivariable analysis: anteroseptal to posterior wall radial strain dyssynchrony >200 ms, lack of severe left ventricular dilatation (end-systolic dimension index <29 mm/m(2)), and lack of echocardiographic scar at papillary muscle insertion sites (all P<0.05) and, when combined, were additively associated with long-term survival (P=0.0001).

CONCLUSIONS

Significant MR after CRT was strongly associated with less favorable long-term survival. Echocardiographic mechanistic features were identified that were associated with improvement in MR after CRT and favorable long-term survival.

Resynchronization: considering device-based cardiac therapy in older adults

Cardiac resynchronization therapy (CRT) is a device-based treatment available to select individuals with systolic heart failure (HF), a large proportion of whom are aged 65 and older. As the field of CRT advances, together with shifting demographics and expanded indications for implantation, there is a need for practitioners caring for older adults to understand what is and is not known about the use of CRT specifically in this population. Clinical trials demonstrating benefits for severe and mild HF have uncertain generalizability to older adults. Other studies demonstrate that device-related complications may be more common with CRT than with simpler devices and more common in older adults. CRT clinical trials also may not adequately capture outcomes and concerns specific to older adults, including quality of life and end-of-life care experiences. Informed decision-making by clinicians, policy-makers, and patients will require greater understanding of the use and outcomes of CRT in older persons.

Devices in the management of advanced, chronic heart failure

Heart failure (HF) is a global phenomenon, and the overall incidence and prevalence of the condition are steadily increasing. Medical therapies have proven efficacious, but only a small number of pharmacological options are in development. When patients cease to respond adequately to optimal medical therapy, cardiac resynchronization therapy has been shown to improve symptoms, reduce hospitalizations, promote reverse remodelling, and decrease mortality. However, challenges remain in identifying the ideal recipients for this therapy. The field of mechanical circulatory support has seen immense growth since the early 2000s, and left ventricular assist devices (LVADs) have transitioned over the past decade from large, pulsatile devices to smaller, more-compact, continuous-flow devices. Infections and haematological issues are still important areas that need to be addressed. Whereas LVADs were once approved only for 'bridge to transplantation', these devices are now used as destination therapy for critically ill patients with HF, allowing these individuals to return to the community. A host of novel strategies, including cardiac contractility modulation, implantable haemodynamic-monitoring devices, and phrenic and vagus nerve stimulation, are under investigation and might have an impact on the future care of patients with chronic HF.

Clinical, laboratory, and pacing predictors of CRT response

A decade of research has established the role of cardiac resynchronization therapy (CRT) in medically refractory, moderate to severe systolic heart failure (HF) with intraventricular conduction delay. CRT is an electrical therapy instituted to reestablish ventricular synchronization in order to improve cardiac function and favorably modulate the neurohormonal system. CRT confers a mortality benefit, improved HF hospitalizations, and functional outcome in this population, but not all patients consistently demonstrate a positive CRT response. The nonresponder rate varies from 20% to 40%, depending on the defined response criteria. Efforts to improve response to CRT have focused on a number of fronts. Methods to optimize the correction of electrical and mechanical dyssynchrony, which is the primary target of CRT, has been the focus of research, in addition to improving patient selection and optimizing post-implant care. However, a major issue in dealing with improving nonresponse rates has been finding an accurate and generally accepted definition of "response" itself. The availability of a standard consensus definition of CRT response would enable the estimation of nonresponder burden accurately and permit the development of strategies to improve CRT response. In this review, we define various aspects of "response" to CRT and outline variability in the definition criteria and the problems with its inconsistencies. We describe clinical, laboratory, and pacing predictors that influence CRT response and outcome and how to optimize response.