Clinical effects of cardiac contractility modulation (CCM) as a treatment for chronic heart failure

Advances in device-based treatment of heart failure with preserved ejection fraction: evidence from clinical trials

Heart failure with preserved ejection fraction (HFpEF) is a group of clinical syndromes that exhibit a remarkably heterogeneous phenotype, characterized by symptoms and signs of heart failure, left ventricular diastolic dysfunction, elevated levels of natriuretic peptides, and an ejection fraction greater than or equal to 50%. With the aging of the population and the escalating prevalence of hypertension, obesity, and diabetes, the incidence of HFpEF is progressively rising. Drug therapy options for HFpEF are currently limited, and the associated high risk of cardiovascular mortality and heart failure rehospitalization significantly impact patients' quality of life and longevity while imposing a substantial economic burden on society. Recent research indicates that certain device-based therapies may serve as valuable adjuncts to drug therapy in patients with specific phenotypes of HFpEF, effectively improving symptoms and quality of life while reducing the risk of readmission for heart failure. These include inter-atrial shunt and greater splanchnic nerve ablation to reduce left ventricular filling pressure, implantable heart failure monitor to guide diuresis, left atrial pacing to correct interatrial dyssynchrony, cardiac contractility modulation to enhance cardiac calcium handling, as well as renal denervation, baroreflex activation therapy, and vagus nerve stimulation to restore the autonomic imbalance. In this review, we provide a comprehensive overview of the mechanisms and clinical evidence pertaining to these devices, with the aim of enhancing therapeutic strategies for HFpEF.

Cost-utility of cardiac contractility modulation in patients with heart failure with reduced ejection fraction in Italy

AIMS

Cardiac contractility modulation (CCM) is a device therapy for heart failure, based on the delivery of high-voltage biphasic impulses to the right ventricular septum during the myocardial absolute refractory period. This study evaluated the cost-effectiveness of CCM therapy plus optimal medical therapy (OMT) vs. OMT alone in patients with heart failure with reduced ejection fraction.

METHODS AND RESULTS

A Markov model with a lifespan time horizon was developed to assess the cost-utility using the FIX trials as main data sources. A deterministic sensitivity analysis and a probabilistic sensitivity analysis were run to analyse the decision uncertainty in the model through cost-effectiveness acceptability curve (CEAC) and cost-effectiveness acceptability frontier (CEAF). Value of information analysis was also conducted computing the expected value of perfect information (EVPI) and the expected value of partial perfect information. The base case results showed that the CCM plus OMT option was highly cost-effective compared with OMT alone with an incremental cost-utility ratio of €7034/quality-adjusted life year (QALY). The CEAC and CEAF illustrated that for all willingness to pay levels above €5600/QALY, tested up to €50 000/QALY, CCM plus OMT alternative had the highest probability of being cost-effective. The EVPI per patient was estimated to be €124 412 on a willingness to pay threshold of €30 000/QALY.

CONCLUSIONS

For patients with heart failure with reduced ejection fraction, CCM therapy could be cost-effective when taking a lifetime horizon. Further long-term, post-approval clinical studies are needed to verify these results in a real-world context, particularly concerning the effect of CCM therapy on mortality.

One-Year Outcome of Cardiac Contractility Modulation in Patients With Reduced Ejection Fraction, Atrial Fibrillation, and Previous Resynchronization: A Pilot Study

BACKGROUND

After 6 months of therapy, cardiac contractility modulation (CCM) has been shown to improve symptoms, exercise tolerance, and quality of life as well as reduce the rate of hospitalizations in patients with heart failure with reduced left ventricular ejection fraction (HFrEF), but long-term effects data are lacking, with no randomized trial to date.

STUDY QUESTION

What is the long-term benefit of the CCM device implantation in symptomatic patients with severe, optimally treated HFrEF?

STUDY DESIGN

We conducted a prospective trial involving patients with symptomatic HFrEF [New York Heart Association (NYHA) Class III or IV, left ventricular ejection fraction (LVEF) ≤35%] who were supported by a CCM device.

RESULTS

Twenty patients (19 men), aged 66.5 ± 6.9 years, were provided with CCM therapy and followed up for an average duration of 321.7 ± 113.5 days. The etiology of heart failure was ischemic in 16 patients (80%), 9 patients (45%) had atrial fibrillation, 6 patients (30%) had diabetes mellitus, and mean creatinine clearance value was 54.8 ± 13.0 mL/min. Eleven patients (60%) had LVEF ≤25%. Although all the patients had an implanted cardioverter-defibrillator, 6 of them (30%) also had resynchronization therapy. The pharmacological treatment has been optimized in all patients. One year after implantation, the LVEF increased from 24.68% ± 4.5 to 34.6 ± 5 ( P < 0.0001), NYHA class improved from 3.2 ± 0.5 to 1.4 ± 0.5 ( P < 0.0001), and exercise tolerance evaluated with a 6-Minute Walk Test increased (from 307.9 ± 74.1 m to 567 ± 99.5 m; P < 0.00001). These improvements were largely seen in the first 6 months.

CONCLUSIONS

Over the course of a year, CCM therapy was associated with improved LVEF and NYHA class, as well as significantly better exercise tolerance, even in patients with atrial fibrillation and cardiac resynchronization therapy and did not seem to be associated with additional significant device-related problems.

Improved Physical Function After Cardiac Contractility Modulation Therapy in 10 Patients With Chronic Heart Failure

BACKGROUND

A new generation of therapeutic devices has expanded the options for managing advanced heart failure. We examined the outcomes of cardiac contractility therapy in a series of 10 patients with chronic heart failure.

METHODS

Ten patients with chronic heart failure were nonrandomly selected to receive cardiac contractility modulation therapy. Hemodynamics, left ventricular ejection fraction, functional capacity, and clinical outcomes were evaluated at baseline and after 6 months of therapy.

RESULTS

Eight male and 2 female patients (mean [SD] age, 63.4 [9.4] years) received cardiac contractility modulation therapy. Between baseline and 6-month follow-up, mean (SD) left ventricular ejection fraction improved from 27.1% (4.18%) to 35.1% (9.89%), New York Heart Association class declined from 3.9 (0.32) to 2.44 (0.52), and 6-minute walk test distance increased from 159.2 (93.79) m to 212.4 (87.24) m. Furthermore, the mean (SD) number of hospital admissions within the 6 months before cardiac contractility modulation therapy was 2.4 (2.27) compared with 1 (1.52) during the 6 months after therapy.

CONCLUSION

Cardiac contractility modulation therapy improved physical functioning and reduced hospital admissions in these patients.

Role of Cardiac Contractility Modulation in Heart Failure With a Higher Ejection Fraction

Cardiac contractility modulation (also known as CCM) is a novel device therapy that delivers nonexcitatory electric stimulation to cardiac myocytes during the absolute refractory period, and it has been shown to improve functional status and clinical outcomes in patients with heart failure (HF) with reduced ejection fraction (HFrEF). CCM therapy is currently recommended for a subset of patients with advanced HFrEF who are not candidates for cardiac resynchronization therapy. A growing body of evidence demonstrates the benefit of CCM therapy in patients with HFrEF and with ejection fraction at the upper end of the spectrum and in patients with HF and with mildly reduced ejection fraction (HFmrEF). Experimental studies have also observed reversal of pathological biomolecular intracellular changes with CCM therapy in HF with preserved ejection fraction (HFpEF), indicating the potential for clinically meaningful benefits of CCM therapy in these patients. In this review, we sought to discuss the basis of CCM therapy and its potential for management of patients with HF with higher ejection fractions.

Cardiac contractility modulation therapy improves health status in patients with heart failure with preserved ejection fraction: a pilot study (CCM-HFpEF)

AIMS

This pilot study aimed to assess the potential benefits of cardiac contractility modulation (CCM) in patients with heart failure with preserved ejection fraction (HFpEF).

METHODS AND RESULTS

This was a prospective, multicentre, single-arm, pilot study of CCM therapy in patients with HFpEF and New York Heart Association (NYHA) class II or III. Echocardiographic parameters were measured by an echo core laboratory to determine study eligibility. After CCM device implantation, patients were followed for 24 weeks. Overall, 47 patients (mean age 74.3 ± 4.4 years, 70.2% female) were enrolled, with left ventricular ejection fraction of 59 ± 4.4%, 63.8% with hypertension, 46.8% with atrial fibrillation, 40.4% with diabetes, 31.9% with at least one heart failure hospitalization in the prior year, 61.7% in NYHA class III, and Kansas City Cardiomyopathy Questionnaire (KCCQ) overall summary score of 48.9 ± 21.7. The primary efficacy endpoint (mean change in the KCCQ overall summary score) improved by 18.0 ± 16.6 points (p < 0.001) and there was an event-free rate of 93.6% for the primary safety endpoint (device- and procedure-related complications), as adjudicated by an independent physician committee.

CONCLUSION

This pilot study demonstrates that the benefits of CCM may extend to the HFpEF patient population. The significant improvement in health status observed, with no obvious impact on safety, suggests that utilization of CCM for patients with HFpEF could prove to be promising.

Cardiac Contractility Modulation in Patients with Heart Failure with Reduced Left Ventricular Ejection Fraction

Cardiac contractility modulation is an innovative therapy conceived for the treatment of heart failure. It is a device-based therapy, employing multiple electrodes to deliver relatively high-voltage (~7.5 V) biphasic signals to the endocardium of the right ventricular septum, in order to improve heart failure symptoms, exercise capacity and quality of life. Multiple clinical and mechanistic studies have been conducted to investigate the potential usefulness of this technology and, as of now, they suggest that it could have a place in therapy and meet a relevant medical need for a specific sub-category of underserved heart failure patients with reduced left ventricular ejection fraction. More studies are needed to further investigate its effect on outcomes such as mortality and rate of hospitalizations.

Device-based treatment options for heart failure with preserved ejection fraction

Heart failure with preserved ejection fraction (HFpEF) is a syndrome with an unfavorable prognosis, and the number of the patients continues to grow. Because there is no effective therapy established as a standard, including pharmacological treatments, a movement to develop and evaluate device-based therapies is an important emerging area in the treatment of HFpEF patients. Many devices have set their target to reduce the left atrial pressure or pulmonary capillary wedge pressure because they are strongly related to the symptoms and prognosis of HFpEF, but the methodology to achieve it varies based on the devices. In this review, we summarize and categorize these devices into the following: (1) interatrial shunt devices, (2) left ventricle expander, (3) electrical therapy, (4) left ventricular assist devices, and (5) mechanical circulatory support devices under development. Here, we describe the features and specifications of device-based therapies currently under development and those at more advanced stages of preclinical testing. Advantages and limitations of these technologies, with insights on their safety and feasibility for HFpEF patients, are described.

How many patients with heart failure are eligible for cardiac contractility modulation therapy?

BACKGROUND

Increasing evidence exists suggesting that cardiac contractility modulation therapy (CCM) improves symptoms in heart failure patients if various selection criteria are fulfilled. The aim of this study is to analyse an unselected sample of heart failure patients to establish what percentage of patients would meet the current criteria for CCM therapy.

METHODS

All patients admitted to two district general hospitals in the UK in 2018 with a diagnosis of heart failure were audited for eligibility for CCM therapy. The selection criteria were (a) ejection fraction (EF) 25%-45%, (b) QRS duration less than 130 ms, (c) New York Heart Association (NYHA) class 3-4 and (d) treated for heart failure for at least 90 days and on stable medications. Exclusion criteria included: (a) significant valvular disease, (b) permanent or persistent atrial fibrillation, (c) biventricular pacing system implanted or QRS duration more than 130 ms and (4) patients not suitable for device therapy as a result of palliative treatment intent.

RESULTS

A total of 475 patients were admitted with heart failure during the study period. From this group, 24 (5.1%) patients fulfilled the criteria for CCM therapy. The mean age and ejection fraction were 70.8 ± 10.2 and 32.5% ± 7.4%. The majority of patients were men (71%) and had an ischaemic cardiomyopathy (75%). If patients with atrial fibrillation were included, an additional 18 (3.8%) patients potentially may be eligible for CCM.

CONCLUSION

Only 5.1% of all patients presenting with heart failure might benefit from cardiac CCM. This is a small proportion of the overall heart failure population. However, this population has no other current option for device therapy of their condition.

Clinical effects of cardiac contractility modulation in heart failure with mildly reduced systolic function

AIMS

Increasing attention is being given to patients with heart failure and 'mid-range' left ventricular ejection fraction (LVEF, ≥40% and <50%) for whom there are no approved therapies that improve prognosis. We aim to assess for the first time the effects of cardiac contractility modulation (CCM) therapy in this patient population.

METHODS AND RESULTS

We assessed the effects of 6-  month CCM therapy on functional status, exercise tolerance and quality of life in a subgroup of 53 patients with a LVEF of 40-45% recruited in previous CCM studies, including 37 patients in the CCM group and 16 in the control group. New York Heart Association classification improved by ≥1 class from baseline to 24 weeks in 80.6% (95% confidence interval [62.5%, 92.5%]) of patients in the CCM group compared with 57.1% in the control group (95% confidence interval [28.9%, 82.3%], P = 0.15). Six-minute walk distance increased significantly in the CCM group with a net between-group treatment effect of 53.9 ± 74.2 m (P = 0.05). Peak VO₂ improved in the CCM group with a net between-group treatment effect of 2.0 ± 2.8 mL/kg/min (P = 0.02). Minnesota Living with Heart Failure Questionnaire score decreased from baseline to 24 weeks with a net between-group treatment effect of -13.1 ± 21.0 (P = 0.10). There were no significant differences in the adverse event rate between the CCM and control groups.

CONCLUSIONS

These preliminary results suggest that CCM exerts favourable effects on exercise tolerance and quality of life in patients with LVEF in the range of 40-45% with an acceptable safety profile. Further randomized controlled studies are planned to prove these effects.

Cardiac contractility modulation for patient with refractory heart failure: an updated evidence-based review

Heart failure is the cardiovascular epidemic of the twenty-first century, with poor prognosis and quality of life despite optimized medical treatment. Despite over the last decade significant improvements, with a major impact on morbidity and mortality, have been made in therapy for heart failure with reduced ejection fraction, little progress was made in the development of devices, with the implantable defibrillator indicated for patients with left ventricle ejection fraction ≤ 35% and cardiac resynchronization therapy for those with QRS ≥ 130 ms and evidence of left bundle branch block. Nevertheless, only a third of patients meet these criteria and a high percentage of patients are non-responders in terms of improving symptoms. Nowadays, in patients with symptomatic heart failure with ejection fraction between 25% and 45% and QRS < 130 ms, not eligible for cardiac resynchronization, the cardiac contractility modulation (CCM) represents a concrete therapeutic option, having proved to be safe and effective in reducing hospitalizations for heart failure and improving symptoms, functional capacity, and quality of life. The aim of this review is therefore to summarize the pathophysiological mechanisms, the current indications, and the recent developments regarding the new applications of the CCM for patients with chronic heart failure.

Cardiac Contractility Modulation Attenuates Chronic Heart Failure in a Rabbit Model via the PI3K/AKT Pathway

The Akt plays an important role in regulating cardiac growth, myocardial angiogenesis, and cell death in cardiac myocytes. However, there are few studies to focus on the responses of the Akt pathway to cardiac contractility modulation (CCM) in a chronic heart failure (HF) model. In this study, the effects of CCM on the treatment of HF in a rabbit model were investigated. Thirty six-month-old rabbits were randomly separated into control, HF, and CCM groups. The rabbits in HF and CCM groups were pressure uploaded, which can cause an aortic constriction. Then, CCM was gradually injected to the myocardium of rabbits in the CCM group, and this process lasted for four weeks with six hours per day. Rabbit body weight, heart weight, and heart beating rates were recorded during the experiment. To assess the CCM impacts, rabbit myocardial histology was examined as well. Additionally, western blot analysis was employed to measure the protein levels of Akt, FOXO3, Beclin, Pi3k, mTOR, GSK-3β, and TORC2 in the myocardial histology of rabbits. Results showed that the body and heart weight of rabbits decreased significantly after suffering HF when compared with those in the control group. However, they gradually recovered after CCM application. The CCM significantly decreased collagen volume fraction in myocardial histology of HF rabbits, indicating that CCM therapy attenuated myocardial fibrosis and collagen deposition. The levels of Akt, FOXO3, Beclin, mTOR, GSK-3β, and TORC2 were significantly downregulated, but Pi3k concentration was greatly upregulated after CCM utilization. Based on these findings, it was concluded that CCM could elicit positive effects on HF therapy, which was potentially due to the variation in the Pi3k/Akt signaling pathway.

Therapy for heart failure with preserved ejection fraction: current status, unique challenges, and future directions

Heart failure (HF) with preserved ejection fraction (HFpEF) is the most common form of HF. Among elderly women, HFpEF comprises more than 80% of incident HF cases. Adverse outcomes-exercise intolerance, poor quality of life, frequent hospitalizations, and reduced survival-approach those of classic HF with reduced EF (HFrEF). However, despite its importance, our understanding of the pathophysiology of HFpEF is incomplete, and despite intensive efforts, optimal therapy remains uncertain, as most trials to date have been negative. This is in stark contrast to management of HFrEF, where dozens of positive trials have established a broad array of effective, guidelines-based therapies that definitively improve a range of clinically meaningful outcomes. In addition to providing an overview of current management status, we examine evolving data that may help explain this paradox, overcome past challenges, provide a roadmap for future success, and that underpin a wave of new trials that will test novel approaches based on these insights.

[Device-device interaction]

With a continuous increase in the approval of cardiac implantable electronic devices (CIED), not only pacemakers (PM) and implantable cardioverter defibrillators (ICD) but especially devices for treating chronic heart failure, more and more possibilities of device-device interactions arise, which in isolated cases can lead to death of the patient. Because of the still low numbers of patients overall, there are very few scientific studies and only isolated case reports on this topic. Devices which are at risk of interaction with a previously implanted PM are wearable cardioverter defibrillators (WCD) and subcutaneous ICDs (S-ICD). These two devices both use the surface electrocardiogram (ECG) in their algorithm for detecting ventricular arrhythmia. These surface ECGs seem to be prone to unipolar pacemaker stimulation artefacts. By correct programming of implanted pacemakers in the bipolar stimulation mode it is possible to avoid ECG artefacts and inadequate treatment. In baroreceptor activation therapy (BAT) there seem to be no device interactions so far, even though this device shows substantial highly frequent artefacts in the ECG. The cardiac contractility modulation (CCM) system has also until now not shown interactions with transvenous or subcutaneous ICD devices, even though randomized trials are missing.

Possibilities and perspectives of using cardiac contractility modulation in patients with chronic heart failure and atrial fibrillation

Heart failure is one of the main health care problems all over the world. Although, there are many drugs with proven effectiveness and hi-tech devices, there is a continuous process of searching new possibilities in heart failure prophylaxis going on because of huge economic burden and impact on life quality. Developing of atrial fibrillation in heart failure patients increases the risks of hospitalization and all-cause mortality. Appearance of new Optimizer Smart® system of cardiac contractility modulation is a perspective way of treatment in patients with heart failure and atrial fibrillation, who are not a candidate or have not got a good result from cardiac resynchronization therapy (CRT).

Cardiac contractility modulation improves long-term survival and hospitalizations in heart failure with reduced ejection fraction

AIMS

Cardiac contractility modulation (CCM) improves symptoms and exercise tolerance and reduces heart failure (HF) hospitalizations over 6-month follow-up in patients with New York Heart Association (NYHA) class III or IV symptoms, QRS < 130 ms and 25% ≤ left ventricular ejection fraction (LVEF) ≤ 45% (FIX-HF-5C study). The current prospective registry study (CCM-REG) aimed to assess the longer-term impact of CCM on hospitalizations and mortality in real-world experience in this same population.

METHODS AND RESULTS

A total of 140 patients with 25% ≤ LVEF ≤ 45% receiving CCM therapy (CCM-REG_25-45 ) for clinical indications were included. Cardiovascular and HF hospitalizations, Minnesota Living with Heart Failure Questionnaire (MLHFQ) and NYHA class were assessed over 2 years. Mortality was tracked through 3 years and compared with predictions by the Seattle Heart Failure Model (SHFM). A separate analysis was performed on patients with 35% ≤ LVEF ≤ 45% (CCM-REG_35-45 ) and 25% ≤ LVEF < 35% (CCM-REG_25-34 ). Hospitalizations decreased by 75% (from 1.2/patient-year the year before, to 0.35/patient-year during the 2 years following CCM, P < 0.0001) in CCM-REG_25-45 and by a similar amount in CCM-REG_35-45 (P < 0.0001) and CCM-REG_25-34 . MLHFQ and NYHA class improved in all three cohorts_, with progressive improvements over time (P < 0.002). Three-year survival in CCM-REG_25-45 (82.8%) and CCM-REG_24-34 (79.4%) were similar to those predicted by SHFM (76.7%, P = 0.16; 78.0%, P = 0.81, respectively) and was better than predicted in CCM-REG_35-45 (88.0% vs. 74.7%, P = 0.046).

CONCLUSION

In real-world experience, CCM produces results similar to those of previous studies in subjects with 25% ≤ LVEF ≤ 45% and QRS < 130 ms; cardiovascular and HF hospitalizations are reduced and MLHFQ and NYHA class are improved. Overall mortality was comparable to that predicted by the SHFM but was lower than predicted in patients with 35% ≤ LVEF ≤ 45%.

Cardiac contractility modulation: mechanisms of action in heart failure with reduced ejection fraction and beyond

Heart failure (HF) is responsible for substantial morbidity and mortality and is increasing in prevalence. Although there has been remarkable progress in the treatment of HF with reduced ejection fraction (HFrEF), morbidity and mortality are still substantial. Cardiac contractility modulation (CCM) signals, consisting of biphasic high-voltage bipolar signals delivered to the right ventricular septum during the absolute refractory period, have been shown to improve symptoms, exercise tolerance and quality of life and reduce the rate of HF hospitalizations in patients with ejection fractions (EF) between 25% and 45%. CCM therapy is currently approved in the European Union, China, India, Australia and Brazil for use in symptomatic HFrEF patients with normal or slightly prolonged QRS duration. CCM is particularly beneficial in patients with baseline EF between 35% and 45%, which includes half the range of HF patients with mid-range EFs (HFmrEF). At the cellular level, CCM has been shown in HFrEF patients to improve calcium handling, to reverse the foetal myocyte gene programme associated with HF, and to facilitate reverse remodelling. This review highlights the preclinical and clinical literature related to CCM in HFrEF and HFmrEF and outlines the potential of CCM for HF with preserved EF, concluding that CCM may fill an important unmet need in the therapeutic approach to HF across the range of EFs.

A Randomized Controlled Trial to Evaluate the Safety and Efficacy of Cardiac Contractility Modulation

OBJECTIVES

This study sought to confirm a subgroup analysis of the prior FIX-HF-5 (Evaluate Safety and Efficacy of the OPTIMIZER System in Subjects With Moderate-to-Severe Heart Failure) study showing that cardiac contractility modulation (CCM) improved exercise tolerance (ET) and quality of life in patients with ejection fractions between 25% and 45%.

BACKGROUND

CCM therapy for New York Heart Association (NYHA) functional class III and IV heart failure (HF) patients consists of nonexcitatory electrical signals delivered to the heart during the absolute refractory period.

METHODS

A total of 160 patients with NYHA functional class III or IV symptoms, QRS duration <130 ms, and ejection fraction ≥25% and ≤45% were randomized to continued medical therapy (control, n = 86) or CCM (treatment, n = 74, unblinded) for 24 weeks. Peak Vo₂ (primary endpoint), Minnesota Living With Heart Failure questionnaire, NYHA functional class, and 6-min hall walk were measured at baseline and at 12 and 24 weeks. Bayesian repeated measures linear modeling was used for the primary endpoint analysis with 30% borrowing from the FIX-HF-5 subgroup. Safety was assessed by the percentage of patients free of device-related adverse events with a pre-specified lower bound of 70%.

RESULTS

The difference in peak Vo₂ between groups was 0.84 (95% Bayesian credible interval: 0.123 to 1.552) ml O₂/kg/min, satisfying the primary endpoint. Minnesota Living With Heart Failure questionnaire (p < 0.001), NYHA functional class (p < 0.001), and 6-min hall walk (p = 0.02) were all better in the treatment versus control group. There were 7 device-related events, yielding a lower bound of 80% of patients free of events, satisfying the primary safety endpoint. The composite of cardiovascular death and HF hospitalizations was reduced from 10.8% to 2.9% (p = 0.048).

CONCLUSIONS

CCM is safe, improves exercise tolerance and quality of life in the specified group of HF patients, and leads to fewer HF hospitalizations. (Evaluate Safety and Efficacy of the OPTIMIZER System in Subjects With Moderate-to-Severe Heart Failure; NCT01381172).

Cardiac contractility modulation: a novel approach for the treatment of heart failure

Heart failure is a major health problem worldwide and, despite effective therapies, is expected to grow by almost 50 % over the next 15 years. Five-year mortality remains high at 50 % over 5 years. Because of the economic burden and large impact on quality of life, substantial effort has focused on treatments with multiple medical (beta-blockers, angiotensin-converting enzyme inhibitors and angiotensin receptor blockers (ARB), aldosterone antagonists, and combination of ARB/neprilysin blockers, ivabradine) and device therapies (ICD, CRT) which have been implemented to reduce disease burden and mortality. However, in the past decade only two new medical therapies and no devices have been approved by the US FDA for the treatment of heart failure. This review highlights the preclinical and clinical literature, and the implantation procedure, related to a relatively new therapeutic device for heart failure; cardiac contractility modulation (CCM). CCM delivers a biphasic high-voltage bipolar signal to the RV septum during the absolute refractory period, eliciting an acute increase in global contractility, and chronically producing a sustained improvement in quality of life, exercise tolerance, and heart failure symptoms. The technology is used commercially in Europe with nearly 3000 patients implanted worldwide. Indications include patients with reduced EF and normal or slightly prolonged QRS duration, thus filling an important therapeutic gap among the 2/3 of patients with heart failure who do not meet criteria for CRT. The mechanism by which CCM provides benefit can be seen at the cellular level where improved calcium handling (phosphorylation of phospholamban, upregulation of SERCA-2A), reversal of the fetal myocyte gene program associated with heart failure, and reverse remodeling are observed. Recent retrospective studies indicate a long-term mortality benefit. A pivotal randomized controlled study is currently being completed in the USA. CCM appears to be an effective, safe technology for the treatment of heart failure with reduced ejection fraction.

Heart failure with preserved ejection fraction: current management and future strategies : Expert opinion on the behalf of the Nucleus of the "Heart Failure Working Group" of the German Society of Cardiology (DKG)

About 50% of all patients suffering from heart failure (HF) exhibit a reduced ejection fraction (EF ≤ 40%), termed HFrEF. The others may be classified into HF with midrange EF (HFmrEF 40-50%) or preserved ejection fraction (HFpEF, EF ≥ 50%). Presentation and pathophysiology of HFpEF is heterogeneous and its management remains a challenge since evidence of therapeutic benefits on outcome is scarce. Up to now, there are no therapies improving survival in patients with HFpEF. Thus, the treatment targets symptom relief, quality of life and reduction of cardiac decompensations by controlling fluid retention and managing risk factors and comorbidities. As such, renin-angiotensin-aldosterone inhibitors, diuretics, calcium channel blockers (CBB) and beta-blockers, diet and exercise recommendations are still important in HFpEF, although these interventions are not proven to reduce mortality in large randomized controlled trials. Recently, numerous new treatment targets have been identified, which are further investigated in studies using, e.g. soluble guanylate cyclase stimulators, inorganic nitrates, the angiotensin receptor neprilysin inhibitor LCZ 696, and SGLT2 inhibitors. In addition, several devices such as the CardioMEMS, interatrial septal devices (IASD), cardiac contractility modulation (CCM), renal denervation, and baroreflex activation therapy (BAT) were investigated in different forms of HFpEF populations and some of them have the potency to offer new hopes for patients suffering from HFpEF. On the basic research field side, lot of new disease-modifying strategies are under development including anti-inflammatory drugs, mitochondrial-targeted antioxidants, new anti-fibrotic and microRNA-guided interventions are under investigation and showed already promising results. This review addresses available data of current best clinical practice and management approaches based on expert experiences and summarizes novel approaches towards HFpEF.

Clinical effects of long-term cardiac contractility modulation (CCM) in subjects with heart failure caused by left ventricular systolic dysfunction

Introduction

Heart failure is a major cause of morbidity and mortality throughout the world. Despite advances in therapy, nearly half of patients receiving guideline-directed medical therapy remain limited by symptoms. Cardiac contractility modulation (CCM) can improve symptoms in this population, but efficacy and safety in prospective studies has been limited to 12 months of follow-up. We report on the first 2 year multi-site evaluation of CCM in patients with heart failure.

Methods

One hundred and forty-three subjects with heart failure and reduced ejection fraction were followed via clinical registry for 24 months recording NYHA class, MLWHFQ score, 6 min walk distance, LVEF, and peak VO₂ at baseline and 6 month intervals as clinically indicated. Serious adverse events, and all cause as well as cardiovascular mortality were recorded. Data are presented stratified by LVEF (all subjects, LVEF <35%, LVEF ≥35%).

Results

One hundred and six subjects from 24 sites completed the 24 month follow-up. Baseline parameters were similar among LVEF groups. NYHA and MLWHFQ improved in all 3 groups at each time point. LVEF in the entire cohort improved 2.5, 2.9, 5.0, and 4.9% at 6, 12, 18, and 24 months, respectively. Insufficient numbers of subjects had follow-up data for 6 min walk or peak VO₂ assessment, precluding comparative analysis. Serious adverse events (n = 193) were observed in 91 subjects and similarly distributed between groups with LVEF <35% and LVEF ≥35%, and similar to other device trials for heart failure. Eighteen deaths (7 cardiovascularly related) over 2 years. Overall survival at 2 years was 86.4% (95% confidence intervals: 79.3, 91.2%).

Conclusion

Cardiac contractility modulation provides safe and effective long-term symptomatic and functional improvement in heart failure. These benefits were independent of baseline LVEF and were associated with a safety profile similar to published device trials.

Low Intensity Epicardial Pacing During the Absolute Refractory Period Augments Left Ventricular Function Mediated by Local Catecholamine Release

BACKGROUND

Biventricular epicardial (Epi) pacing can augment left ventricular (LV) function in heart failure. We postulated that these effects might involve catecholamine release from local autonomic nerve activation. To evaluate this hypothesis we applied low intensity Epi electrical stimuli during the absolute refractory period (ARP), thus avoiding altered activation sequence.

METHODS

Anesthetized pigs (n = 6) were instrumented with an LV pressure (LVP) transducer, left atrial (LA) and LV Epi pacing electrodes, and sonomicrometer segment length (SL) gauges placed proximal and remote to the LV stimulation site. A catheter was placed into the great cardiac vein adjacent to the LV pacing site for norepinephrine (NE) analysis. During LA pacing at constant rate, 3 pulses (0.8 milliseconds, 2-3x threshold) were applied to the LV Epi electrodes during the ARP. An experimental run consisted of baseline, stimulation (10 minutes), and recovery (5 minutes), repeated 3 times before and after β1 - receptor blockade (BB, metoprolol).

RESULTS

ARP stimulation produced significant increases in cardiac function reflected by elevated LVP, LV, dP/dtmax , and reduced time to LV dP/dtmax . This was accompanied by increased coronary NE levels and increases in LVP versus SL loop area in the remote myocardial segment. In contrast, the proximal segment exhibited early shortening and decreased loop area. BB abolished the changes in SL and LV function despite continued NE release.

CONCLUSION

These results demonstrate that ARP EPI stimulation induces NE release mediating augmented global LV function. This effect may contribute to the beneficial effect of biventricular Epi pacing in heart failure in some patients.

Heart Failure With Reduced Ejection Fraction And A Narrow QRS Complex: Combination Of A Subcutaneous Defibrillator With Cardiac Contractility Modulation

Cardiac contractility modulation (CCM) is a relatively new electrical therapy for heart failure patients with reduced ejection fraction. The majority of patients eligible for CCM will also need an implantable cardioverter-defibrillator (ICD). To-date, three pacing electrodes are mandatory for CCM therapy because the current CCM signal delivery algorithm requires sequential intracardiac sensing of a p-wave, followed by appropriately timed ventricular activation by the two ventricular septal leads. As there is no device combining CCM with ICD functions, most CCM patients will need multiple intracardiac electrodes, which increase the cumulative risk for complications such as systemic infections, thrombosis of central venous lines, insulation failures or lead fractures. The long-term complications associated with trans-venous ICD leads have led to the development of a totally subcutaneous implantable cardioverter-defibrillator (S-ICD). In this essay the two technologies CCM and S-ICD are reviewed. Additionally, we present their successful combination on the basis of a case report on the first patient receiving both devices.

[New therapy concepts for heart failure with preserved ejection fraction]

The management of patients with heart failure and preserved ejection fraction (HFpEF) remains challenging and requires an accurate diagnosis. Although currently no convincing therapy that can prolong survival in patients with HFpEF has been established, treatment of fluid retention, heart rate and control of comorbidities are important cornerstones to improve the quality of life and symptoms. In recent years many new therapy targets have been tested for development of successful interventional strategies for HFpEF. Insights into new mechanisms of HFpEF have shown that heart failure is associated with dysregulation of the nitric oxide-cyclic guanosine monophosphate-protein kinase (NO-cGMP-PK) pathway. Two new drugs are currently under investigation to test whether this pathway can be significantly improved by either the neprilysin inhibitor LCZ 696 due to an increase in natriuretic peptides or by the soluble guanylate cyclase stimulator vericiguat, which is also able to increase cGMP. In addition, several preclinical or early phase studies which are currently investigating new mechanisms for matrix, intracellular calcium and energy regulation including the role of microRNAs and new devices are presented and discussed.

Efficacy and survival in patients with cardiac contractility modulation: long-term single center experience in 81 patients

AIMS

To analyze long-term efficacy and survival in patients with chronic heart failure treated with cardiac contractility modulation.

METHODS

81 patients implanted with a CCM device between 2004 and 2012 were included in this retrospective analysis. Changes in NYHA class, ejection fraction (EF), Minnesota Living with Heart Failure Questionnaire, NT-proBNP and peak VO₂ were analyzed during a mean follow up of 34.2 ± 28 months (6-123 months). Observed mortality rate was compared with that predicted by the MAGGIC Score.

RESULTS

Patients were 61 ± 12 years old with EF 23 ± 7%. Heart failure was due to ischemic (n=48, 59.3%) or idiopathic dilated (n=33, 40.7%) cardiomyopathy. EF increased from 23.1 ± 7.9 to 29.4 ± 8.6% (p<0.05), mean NT-proBNP decreased from 4395 ± 3818 to 2762 ± 3490 ng/l (p<0.05) and mean peak VO2 increased from 13.9 ± 3.3 to 14.6 ± 3.5 ml/kg/min (p=0.1). The overall clinical responder rate (at least 1 class improvement of NYHA within 6 months or last follow-up) was 74.1%. 21 (25.9%) patients died during follow up, 11 (52.4%) due to cardiac conditions and 10 (47.6%) due to non-cardiac conditions. Mortality rates at 1 and 3 years were 5.2% and 29.5% compared to mortality rates estimated from the MAGGIC risk score of 18.4% (p<0.001) and 40% (p=ns), respectively. Log-Rank analysis of all events through 3 years of follow-up, however, was significantly less than predicted (p=0.022).

CONCLUSIONS

CCM therapy improved quality of life, exercise capacity, NYHA class, EF and NT-proBNP levels during long-term follow up. Mortality rates appeared to be lower than estimated from the MAGGIC score.

A randomized controlled trial to evaluate the safety and efficacy of cardiac contractility modulation in patients with moderately reduced left ventricular ejection fraction and a narrow QRS duration: study rationale and design

Cardiac contractility modulation (CCM) signals are nonexcitatory electrical signals delivered during the cardiac absolute refractory period that enhance the strength of cardiac muscular contraction. The FIX-HF-5 study was a prospective randomized study comparing CCM plus optimal medical therapy (OMT) to OMT alone that included 428 New York Heart Association (NYHA) functional class III or IV heart failure patients with ejection fraction (EF) ≤45% according to core laboratory assessment. The study met its primary safety end point, but did not reach its primary efficacy end point: a responders analysis of changes in ventilatory anaerobic threshold (VAT). However, in a prespecified subgroup analysis, significant improvements in primary and secondary end points, including the responder VAT end point, were observed in patients with EFs ranging from 25% to 45%, who constituted about one-half of the study subjects. We therefore designed a new study to prospectively confirm the efficacy of CCM in this population. A hierarchic bayesian statistical analysis plan was developed to take advantage of the data already available from the first study. In addition, based on technical difficulties encountered in reliably quantifying VAT and the relatively large amount of nonquantifiable studies, the primary efficacy end point was changed to peak VO2, with significant measures incorporated to minimize the influence of placebo effect. In this paper, we provide the details and rationale of the FIX-HF-5C study design to study CCM plus OMT compared with OMT alone in subjects with normal QRS duration, NYHA functional class III or IV, and EF 25%-45%. This study is registered on www.clinicaltrials.gov with identifier no. NCT01381172.

Long term impact of cardiac contractility modulation on QRS duration

BACKGROUND AND PURPOSE

Cardiac contractility modulation (CCM) is an implantable device treatment for heart failure with reduced ejection fraction. CCM therapy improves patient functional status but its effect on intra-ventricular conduction remains unknown.

METHODS

70 patients treated with CCM between 12/2002 and 5/2013 had 12-vector-ECG recordings made at baseline and final follow-up visits. QRS complex duration was measured at each time point.

RESULTS

Mean follow-up was 2.8 years. Mean QRS duration was unchanged from baseline (112.0 ms) to last follow up (112.9 ms, p=n.s.). These results are strikingly different from comparative published data of several studies with heart failure patients without CCM, consistently indicating an increase in QRS duration (6.0-23.4 ms) over a similar time period.

CONCLUSIONS

CCM prevents chronic ventricular depolarization delay that occurs in heart failure and that is associated with poorer outcomes. This supports the safety of long-term CCM therapy and suggests a possible long-term benefit in maintaining QRS duration.