Improvement of long-term survival by cardiac contractility modulation in heart failure patients: A case-control study

HF Etiology and cardiac contractility modulation therapy

OBJECTIVES

Our study aimed to assess the safety and efficacy of cardiac contractility modulation (CCM) therapy in patients with heart failure with reduced ejection fraction (HFrEF) depending on HF etiology.

METHODS

We enrolled 166 patients with optimal medical therapy-resistant HFrEF (median age 59 years, 83.7% males, median NYHA class - 2, median left ventricular ejection fraction (LVEF) - 29.0%) who underwent CCM therapy device implantation from 2013 to 2019 in four medical centers in Russia. The HF etiology was determined based on invasive coronary angiography or cardiac MRI data. Transthoracic echocardiography (TTE), 6-minute walking test (6MWT), and NTproBNP-tests were performed at a baseline and 12 months after the implantation.

RESULTS

The ischemic etiology of HF was revealed in 100 patients (61.5%) (ICM group); the non-ischemic group (NICM) evolved 66 patients (38.5%). Patients in the ICM group were significantly older (61[57-69] vs. 55 [42.8-61], p < 0.001), more frequently had hypertension (79% vs. 42.4%, p < 0.001) and chronic kidney disease (43% vs. 22.7%, p = 0.012). Patients in the NICM group had significantly more often atrial fibrillation (AF) (58% vs. 74%, p = 0.048), larger end-diastolic volume (EDV) (249 [208-309] vs. 220 [192-271], p = 0.019) and end-systolic volume (ESV) (183 [147-230] vs. 154 [128-199], p = 0.003). There were no significant differences in mortality between ICM and NICM groups (14.4 vs. 10.8%, p = 0.51). In 12 months, there was a significant increase in LVEF in the NICM group (+ 2.0 [2-6] vs. +7.7 [2-12], p < 0.001), while the improvement in the 6MWT (+ 75 [22-108] vs. +80 [10-160], p = 0.851) and NYHA class did not reach the level of significance. The subanalysis between patients with improved NYHA class and those without improvement revealed that patients without improvement more frequently had AF (56% vs. 89%; p < 0.01), chronic obstructive lung disease (18% vs. 35% p = 0.047), higher blood pressure (110 [105-120] vs. 120[110-129]; p = 0.032).

CONCLUSION

In this multicenter retrospective study, patients with non-ischemic HFrEF showed a significantly higher improvement in LVEF and LV reverse remodeling following CCM therapy device implantation. There was no significant association between HF etiology and survival in drug-resistant HFrEF patients following CCM therapy.

Cardiac contractility modulation in patients with heart failure - A review of the literature

Experimental in vivo and in vitro studies showed that electric currents applied during the absolute refractory period can modulate cardiac contractility. In preclinical studies, cardiac contractility modulation (CCM) was found to improve calcium handling, reverse the foetal myocyte gene programming associated with heart failure (HF), and facilitate reverse remodeling. Randomized control trials and observational studies have provided evidence about the safety and efficacy of CCM in patients with HF. Clinically, CCM therapy is indicated to improve the 6-min hall walk, quality of life, and functional status of HF patients who remain symptomatic despite guideline-directed medical treatment without an indication for cardiac resynchronization therapy (CRT) and have a left ventricular ejection fraction (LVEF) ranging from 25 to 45%. Although there are promising results about the role of CCM in HF patients with preserved LVEF (HFpEF), further studies are needed to elucidate the role of CCM therapy in this population. Late gadolinium enhancement (LGE) assessment before CCM implantation has been proposed for guiding the lead placement. Furthermore, the optimal duration of CCM application needs further investigation. This review aims to present the existing evidence regarding the role of CCM therapy in HF patients and identify gaps and challenges that require further studies.

Cardiac Contractility Modulation for Heart Failure: Current and Future Directions

Cardiac contractility modulation (CCM) is a Food and Drug Administration-approved device-based therapy for patients with heart failure. The system delivers biphasic electric stimulation to the ventricular myocardium during the absolute refractory period to augment left ventricular contraction. CCM therapy promotes acute and chronic changes at the cellular level, leading to favorable remodeling throughout the myocardium. CCM improves quality of life, New York Heart Association class, left ventricular ejection fraction, peak oxygen uptake, and the composite end point of cardiovascular death and heart failure hospitalizations. This review will focus on the biological basis, indications, and evidence for CCM, as well as the future applications of this technology.

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.

Efficacy of the New Inotropic Agent Istaroxime in Acute Heart Failure

Current therapeutic strategies for acute heart failure (AHF) are based on traditional inotropic agents that are often associated with untoward effects; therefore, finding new effective approaches with a safer profile is dramatically needed. Istaroxime is a novel compound, chemically unrelated to cardiac glycosides, that is currently being studied for the treatment of AHF. Its effects are essentially related to its inotropic and lusitropic positive properties exerted through a dual mechanism of action: activation of the sarcoplasmic reticulum Ca2+ ATPase isoform 2a (SERCA2a) and inhibition of the Na+/K+-ATPase (NKA) activity. The advantages of istaroxime over the available inotropic agents include its lower arrhythmogenic action combined with its capability of increasing systolic blood pressure without augmenting heart rate. However, it has a limited half-life (1 hour) and is associated with adverse effects including pain at the injection site and gastrointestinal issues. Herein, we describe the main mechanism of action of istaroxime and we present a systematic overview of both clinical and preclinical trials testing this drug, underlining the latest insights regarding its adoption in clinical practice for AHF.

Cardiac contractility modulation in heart failure with reduced ejection fraction treatment

Heart failure with reduced left ventricular ejection fraction (LV EF) (HFrEF) is a significant issue of health care due to increasing indexes of morbidity and mortality. The emergence of a number of drugs and implantable devices for the treatment of HFrEF has allowed improvement of patients’ well-being and prognosis. However, high mortality and recurrent decompensated heart failure remain a substantial issue and stimulate the search for new methods of CHF treatment. Cardiac contractility modulation (CCM) is a method of managing patients with HFrEF. Available data from randomized clinical trials (RCT) indicate the efficacy of CCM in improvement of patients’ well-being and quality of life. The question remains open: what effect does CCM have on LV reverse remodeling? Experimental data and results of observational studies suggest a possibility of reverse remodeling by CCM; however, this has not been confirmed in RCT. Also, it remains unclear how CCM influences the frequency of hospitalizations for decompensated heart failure and the death rate of patients with HFrEF. Results of both RCTs and observational studies have shown a moderate improvement of quality of life associated with CCM. Furthermore, RCTs have not found any increase in LV EF due to the therapy, nor has a meta-analysis of RCTs revealed any improvement of the prognosis associated with CCM.  Further RCTs are needed to evaluate the effect of CCM on reverse remodeling, survival rate, and to determine the place of CCM in the treatment of patients with CHF.

SV, Saidova MA, Zhirov IV, Tereshchenko SN. Myocardial remodeling in patients with chronic heart failure and implanted cardiac contractility modulators

Aim. To study the effect of cardiac contractility modulation on reverse remodeling and myocardial function in patients with chronic heart failure (HF) according to echocardiography (EchoCG). Materials and methods. In a group of 40 patients with a combination of chronic HF and atrial fibrillation (AF), the dynamics of standard EchoCG parameters and the effectiveness of myocardial work of the left ventricle (LV) against the background of 12-month therapy of cardiac contractility modulation (CCM) were analyzed. Results. The results obtained indicate a statistically significant positive effect of CCM on LV remodeling parameters and the effectiveness of myocardial work according to EchoCG. Conclusion. Transthoracic echocardiography is the main imaging method and provides great opportunities for evaluating the effectiveness of HF treatment, including non-drug methods such as CCM. Evaluation of LV myocardial function in patients with HF and implanted CCM devices is a promising scientific and practical research method.

Device treatment of heart failure

Background: The incidence of heart failure (HF) is rapidly increasing, introducing a significant burden and challenges in clinical practice. Non-pharmacological cardiac device therapy has been established as an essential component of optimal HF management, particularly for the prevention of sudden cardiac death and the improvement of HF symptoms, left ventricular (LV) systolic function, quality of life, and eventually survival.Current Concepts: Cardiac resynchronization therapy (CRT) can correct atrioventricular or inter/intraventricular dyssynchrony, thereby improving LV systolic function. Recently, the concept of CRT is being expanded, including His bundle (HB), HB-optimized LV, left bundle branch (LBB), and LBB optimized LV pacing CRTs. Newly introduced CRT approaches by stimulating the cardiac conduction system are expected to correct dyssynchrony better and consequently exhibit better CRT outcomes than the conventional biventricular pacing CRT. The current versions of implantable cardioverter-defibrillators (ICDs) or CRT devices can continuously monitor multiple biosignals. CRT/ICD can calculate a single index by combining these multiple bio-signal data for early detection of HF aggravation. Recently, subcutaneous and transvenous ICDs showed comparable safety and efficacy in HF patients. In drug-refractory HF patients without LV dyssynchrony, cardiac contractility modulation therapy provides some promising results.Discussion and Conclusion: Recent technological advancements have improved the efficacy and safety of cardiac device therapy. Therefore, cardiac device therapy should be used more actively to manage HF patients better.

Optimizer Smart System for the treatment of chronic heart failure: Overview of its safety and efficacy

Introduction: Heart failure (HF) is a major cause of morbidity and mortality throughout the world. Despite the significant progress in the prevention and treatment of HF, mortality rates still remain high. Device therapy for HF includes cardiac resynchronization therapy (CRT) and the use of an implantable cardioverter-defibrillator (ICD). Recently, a new device therapy for the treatment of HF became available, called cardiac contractility modulation (CCM). CCM is a new device therapy for patients with HF who do not qualify for CRT. It is implanted in a minimally invasive manner to improve the patient's morbidity. Optimizer Smart System is a new device that delivers CCM therapy.Areas covered: We review the function of the Optimizer Smart System, the data from the recent clinical trials, and discuss its efficacy and future projections in the treatment for HF.Expert opinion: CCM therapy provided with the Optimizer® Smart System is safe, feasible, and applicable to a wide range of patients with HF. To demonstrate the effectiveness of the Optimizer Smart System's use merits further large multicenter randomized controlled trials.

Cardiac Contractility Modulation in Patients with Ischemic versus Non-ischemic Cardiomyopathy: Results from the MAINTAINED Observational Study

BACKGROUND

Cardiac contractility modulation (CCM) is an FDA-approved device-based therapy for patients with systolic heart failure and normal QRS width who are symptomatic despite optimal drug therapy. The purpose of this study was to compare the long-term therapeutic effects of CCM therapy in patients with ischemic (ICM) versus non-ischemic cardiomyopathy (NICM).

METHODS

Changes in NYHA class, KDIGO CKD stage, left ventricular ejection fraction (LVEF), tricuspid annular plane systolic excursion (TAPSE), and NT-proBNP levels were compared as functional parameters. Moreover, observed mortality rates at 1 and 3 years were compared to those predicted by the MAGGIC heart failure risk score, and observed mortality rates were compared between groups for the entire follow-up period.

RESULTS

One hundred and seventy-four consecutive patients with chronic heart failure and CCM device implantation between 2002 and 2019 were included in this retrospective analysis. LVEF was significantly higher in NICM patients after 3 years of CCM therapy (35 ± 9 vs. 30 ± 9%; p = 0.0211), and after 5 years, also TAPSE of NICM patients was significantly higher (21 ± 5 vs. 18 ± 5%; p = 0.0437). There were no differences in other effectiveness parameters. Over the entire follow-up period, 35% of all patients died (p = 0.81); only in ICM patients, mortality was lower than predicted at 3 years (35 vs. 43%, p = 0.0395).

CONCLUSIONS

Regarding improvement of biventricular systolic function, patients with NICM appear to benefit particularly from CCM therapy.

Possibilities of Evaluating the Dynamics of Left Ventricular Perfusion and Contractility in Patients with Chronic Heart Failure after Implantation of a Heart Contractility Modulator Using Perfusion Single-Photon Emission Computed Tomography

Perfusion scintigraphy and single-photon emission tomography of the myocardium are promising methods for complex assessment of the state of the left ventricle myocardium in patients with chronic heart failure. These methods of nuclear cardiology can be performed in patients with reduced renal function, as well as the presence of implanted devices such as implantable cardioverters-defibrillators, resynchronizing devices and cardiac modulating therapy, which is their undeniable advantage. The reproducibility of the method is ensured bu fully automated calculation of parameters of myocardial perfusion and contractility. To date, there are no data in the literature on the use of nuclear cardiology methods as an imaging technique in patients with cardiac contractility modulation devises. This paper describes the current possibilities and prospects of nuclear medicine methods in patients with chronic heart failure after implantation of a heart contractility modulator.

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.

[Modulation of cardiac contractility in patients with chronic heart failure and atrial fibrillation]

AIM

to evaluate the effectiveness of cardiac contractility modulation (MSS) in patients with chronic heart failure (CHF) and atrial fibrillation (AF).

MATERIALS AND METHODS

The following studies were performed in 40 patients with CHF and AF before implantation of the MSS device and after 2 and 6 months of follow-up: 12-channel ECG, transthoracic EchoCG, 6-minute walk test, determination of the level of Pro-natriuretic N-terminal peptide (NT-proBNP), daily ECG monitoring, and a questionnaire based on the Minnesota quality of life questionnaire for patients with CHF (MHFLQ). All patients received long-term optimal drug therapy for CHF before surgery.

RESULTS

The results obtained indicate a statistically significant positive effect of the use of MSS in patients with CHF and AF on LV FV, the functional class of CHF, and levels of NT-proBNP regardless of the etiology of CHF.

CONCLUSION

The use of MSS may be promising for the treatment of heart failure in patients with CHF and AF.

Cardiac contractility modulation for the treatment of heart failure with reduced ejection fraction

There has been a progressive evolution in the management of patients with chronic heart failure and reduced ejection fraction (HFrEF), including cardiac resynchronisation therapy (CRT) in those that fulfil pre-defined criteria. However, there exists a significant proportion with refractory symptoms in whom CRT devices are not clinically indicated or ineffective. Cardiac contractility modulation (CCM) is a novel therapy that incorporates administration of non-excitatory electrical impulses to the interventricular septum during the absolute refractory period. Implantation is analogous to a traditional transvenous pacemaker system, but with the use of two right ventricular leads. Mechanistic studies have shown augmentation of left ventricular contractility and beneficial global effects on reverse remodeling, primarily through alterations in calcium handling. This appears to occur without increasing myocardial oxygen consumption. Data from clinical trials have shown translational improvements in functional capacity and quality of life, though long-term outcome data are lacking. This review explores the rationale, evidence base and limitations of this nascent technology.

Cardiac contractility modulation in left ventricular systolic dysfunction: one-year experience in a pilot study and design of a prospective registry

BACKGROUND

Cardiac contractility modulation (CCM) is a treatment option for patients suffering symptomatic chronic heart failure (CHF) with reduced left ventricular ejection fraction (LVEF) who are not eligible for cardiac resynchronization. Data on mid-term follow-up are limited to small observational studies. The aim of this study was to assess the impact of CCM on quality of life, symptoms, exercise tolerance and left ventricular function in patients with CHF and moderate-to-severe left ventricular systolic dysfunction.

METHODS

Patients suffering CHF with LVEF <45% and NYHA class >II despite optimal medical therapy, underwent CCM implantation. Enrolled patients underwent baseline and 3, 6 and 12-months evaluation with ECG, echocardiogram, clinical assessment, 6-minute walking test and Minnesota Living with Heart Failure Questionnaire (MLWHFQ).

RESULTS

Ten patients underwent CCM implantation. All patients were actively treated with the optimal pharmacological therapy as tolerated and had at least one hospitalization for worsening heart failure during the previous year. After a mean follow-up of 15 months, 9 patients were alive, while one patient died for worsening heart failure precipitated by pneumonia. Among the remaining 9 patients, LVEF improved non-significantly from 29.4±8% to 32.2±10% (P=0.092), 6-minute walking test distance improved from 179±73 m to 304±99 m (P<0.001), NYHA class reduced from 3.0±0.4 to 1.6±0.5 (P=0.003) and MLWHFQ score improved from 59.6±49 to 34.2±32 (P=0.037). Only 2 patients have been hospitalized during the 12 months. Overall, a net clinical benefit was detected in 6 out of 9 patients.

CONCLUSIONS

CCM could be effective in improving quality of life, symptoms and exercise tolerance, and reduces hospitalizations in patients with symptomatic CHF on top of optimal medical and electrical therapy. A prospective registry has been designed to identify the subsets of patients gaining more benefit, and to assess the long-term effect of CCM on those clinical endpoints.

Safety, Performance, and Efficacy of Cardiac Contractility Modulation Delivered by the 2-Lead Optimizer Smart System

Background:

Prior studies of cardiac contractility modulation (CCM) employed a 3-lead Optimizer system. A new 2-lead system eliminated the need for an atrial lead. This study tested the safety and effectiveness of this 2-lead system compared with the 3-lead system.

Methods:

Patients with New York Heart Association III/IVa symptoms despite medical therapy, left ventricular ejection fraction 25% to 45%, and not eligible for cardiac resynchronization therapy could participate. All subjects received an Optimizer 2-lead implant. The primary end point was the estimated difference in the change of peak VO 2 from baseline to 24 weeks between FIX-HF-5C2 (2-lead system) subjects relative to control subjects from the prior FIX-HF-5C (3-lead system) study. Changes in New York Heart Association were a secondary end point. The primary safety end point was a comparison of device-related adverse events between FIX-HF-5C2 and FIX-HF-5C subjects.

Results:

Sixty subjects, 88% male, 66±9 years old with left ventricular ejection fraction 34±6% were included. Baseline characteristics were similar between FIX-HF-5C and FIX-HF-5C2 subjects except that 15% of FIX-HF-5C2 subjects had permanent atrial fibrillation versus 0% in FIX-HF-5C. CCM delivery did not differ significantly between 2- and 3-lead systems (19 892±3472 versus 19 583±4998 CCM signals/day, CI of difference [−1228 to 1847]). The change of peak VO 2 from baseline to 24 weeks was 1.72 (95% Bayesian credible interval, 1.02–2.42) mL/kg per minute greater in the 2-lead device group versus controls. 83.1% of 2-lead subjects compared with 42.7% of controls experienced ≥1 class New York Heart Association improvement ( P <0.001). There were decreased Optimizer-related adverse events with the 2-lead system compared with the 3-lead system (0% versus 8%; P =0.03).

Conclusions:

The 2-lead system effectively delivers comparable amount of CCM signals (including in subjects with atrial fibrillation) as the 3-lead system, is equally safe and improves peak VO 2 and New York Heart Association. Device-related adverse effects are less with the 2-lead system.

Registration:

URL: https://www.clinicaltrials.gov ; Unique identifier: NCT03339310

Outcomes of Cardiac Contractility Modulation: A Systematic Review and Meta-Analysis of Randomized Clinical Trials

Background

Cardiac contractility modulation (CCM) is a device therapy for systolic heart failure (HF) in patients with narrow QRS. We aimed to perform an updated meta-analysis of the randomized clinical trials (RCTs) to assess the efficacy and safety of CCM therapy.

Methods

We conducted a systematic review and meta-analysis of randomized clinical trials (RCTs) between January 2001 and June 2018. Outcomes of interest were peak oxygen consumption (peak VO2), 6-Minute Walk Distance (6MWD), Minnesota Living with Heart Failure Questionnaire (MLHFQ), HF hospitalizations, cardiac arrhythmias, pacemaker/ICD malfunctioning, all-cause hospitalizations, and mortality. Data were expressed as standardized mean difference (SMD) or odds ratio (OR).

Results

Four RCTs including 801 patients (CCM n = 394) were available for analysis. The mean age was 59.63 ± 0.84 years, mean ejection fraction was 29.14 ± 1.22%, and mean QRS duration was 106.23 ± 1.65 msec. Mean follow-up duration was six months. CCM was associated with improved MLWHFQ (SMD -0.69, p = 0.0008). There were no differences in HF hospitalizations (OR 0.76, p = 0.12), 6MWD (SMD 0.67, p = 0.10), arrhythmias (OR 1.40, p = 0.14), pacemaker/ICD malfunction/sensing defect (OR 2.23, p = 0.06), all-cause hospitalizations (OR 0.73, p = 0.33), or all-cause mortality (OR 1.04, p = 0.92) between the CCM and non-CCM groups.

Conclusions

Short-term treatment with CCM may improve MLFHQ without significant difference in 6MWD, arrhythmic events, HF hospitalizations, all-cause hospitalizations, and all-cause mortality. There is a trend towards increased pacemaker/ICD device malfunction. Larger RCTs might be needed to determine if the CCM therapy will be beneficial with longer follow-up.

Modulação da Contratilidade Cardíaca

Pacientes com insufi ciência cardíaca (IC) vêm se benefi ciando da terapia elétrica por meio de marcapassos convencionais quando associada à bradicardia e à terapia de ressincronização cardíaca ou com fração de ejeção rebaixada e presença de QRS maior que 150 ms, principalmente na presença de bloqueio de ramo esquerdo. Outros grupos de pacientes com IC apresentam limitações ao tratamento com eletroterapia. No entanto, um conceito antigo tem tomado espaço no tratamento de um grupo de pacientes que fi ca fora das diretrizes nacionais e internacionais para eletroterapia na IC: a modulação da contração cardíaca. Este artigo tem como objetivo apresentar a revisão das evidências científi cas já produzidas e publicadas acerca dessa nova modalidade de tratamento da IC.

Modulation of Heart Contractility

Patients with heart failure (HF) are being benefi ted by electric therapy through conventional pacemakers when associated to bradycardia and cardiac resynchronization therapy or with low ejection fraction and presence of QRS longer than 150 ms, mainly in the presence of left branch block. Other groups of patients with HF present limitations regarding electrotherapy. However, an old concept has gained space in the treatment of patients who are outside the national and international guidelines for electrotherapy in HF: the modulation of heart contractility. This article has the purpose of presenting a review of already produced scientifi c evidence regarding this new modality for HF treatment

Device therapy in heart failure with reduced ejection fraction-cardiac resynchronization therapy and more

In patients with heart failure with reduced ejection fraction (HFrEF), optimal medical treatment includes beta-blockers, ACE inhibitors/angiotensinreceptor-neprilysin inhibitors (ARNI), mineralocorticoid receptor antagonists, and ivabradine when indicated. In device therapy of HFrEF, implantable cardioverter-defibrillators and cardiac resynchronization therapy (CRT) have been established for many years. CRT is the therapy of choice (class I indication) in symptomatic patients with HFrEF and a broad QRS complex with a left bundle branch block (LBBB) morphology. However, the vast majority of heart failure patients show a narrow QRS complex or a non-LBBB morphology. These patients are not candidates for CRT and alternative electrical therapies such as baroreflex activation therapy (BAT) and cardiac contractility modulation (CCM) may be considered. BAT modulates vegetative dysregulation in heart failure. CCM improves contractility, functional capacity, and symptoms. Although a broad data set is available for BAT and CCM, mortality data are still lacking for both methods. This article provides an overview of the device-based therapeutic options for patients with HFrEF.

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%.

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]

Cardiac contractility modulation (CCM) is a device-based electrical therapy for the additive treatment of chronic drug-refractory heart insufficiency. High-amplitude signals are applied during the absolute refractory period and have been shown to enhance the strength of left ventricular (LV) contraction and improve exercise tolerance and quality of life. The mechanisms of action appear to involve effects on myocardial gene expression and on normalization of key myocardial proteins. So far, more than 3500 CCM devices have been implanted worldwide. For patients with therapy refractory heart insufficiency and narrow QRS complex, CCM is together with baroreceptor activation the only additive electrical therapy which had been approved in Germany. For the first time CCM has been referenced in the current guidelines on cardiac insufficiency. Prognostic data with respect to mortality have been evaluated in case series. Ongoing randomized trials and registries will address these specific endpoints and have to a significant extent already been recently published. A Food and Drug Administration (FDA) approval is expected within the next few months.

Long-term results of combined cardiac contractility modulation and subcutaneous defibrillator therapy in patients with heart failure and reduced ejection fraction

BACKGROUND

Cardiac contractility modulation (CCM) is an electrical-device therapy for patients with heart failure with reduced ejection fraction (HFrEF). Patients with left ventricular ejection fraction (LVEF) ≤35% also have indication for an implantable cardioverter-defibrillator (ICD), and in some cases subcutaneous ICD (S-ICD) is selected.

HYPOTHESIS

CCM and S-ICD can be combined to work efficaciously and safely.

METHODS

We report on 20 patients with HFrEF and LVEF ≤35% who received CCM and S-ICD. To exclude device interference, patients received intraoperative crosstalk testing, S-ICD testing, and bicycle exercise testing while CCM was activated. Clinical and QOL measures before CCM activation and at last follow-up were analyzed. S-ICD performance was evaluated while both CCM and S-ICD were active.

RESULTS

Mean follow-up was 34.3 months. NYHA class improved from 2.9 ± 0.4 to 2.1 ± 0.7 (P < 0.0001), Minnesota Living With Heart Failure Questionnaire score improved from 50.2 ± 23.7 to 29.6 ± 22.8 points (P < 0.0001), and LVEF improved from 24.4% ± 8.1% to 30.9% ± 9.6% (P = 0.002). Mean follow-up time with both devices active was 22 months. Three patients experienced a total of 6 episodes of sustained ventricular tachycardia, all successfully treated with first ICD shock. One case received an inappropriate shock unrelated to the concomitant CCM. One patient received an LVAD, so CCM and S-ICD were discontinued.

CONCLUSIONS

CCM and S-ICD can be successfully combined in patients with HFrEF. S-ICD and CCM remain efficacious when used together, with no interference affecting their function.

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.

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.

[Current impact of cardiac implantable electronic devices]

Sudden cardiac death and chronic heart failure are among the main contributors to persisting high mortality rates in Germany. In addition to removal of causal factors and guideline-conform pharmacological therapy, therapy with cardiac implantable electronic devices (CIED) is of undisputed importance. Subcutaneous defibrillators have the advantage that they do not have intracardiac electrodes but still have the same efficacy and safety. For patients with a wide QRS complex and reduced ejection fraction, cardiac resynchronization has led to a reduction of morbidity and mortality. For patients with a normal QRS complex, cardiac contractility modulation had been shown to improve the quality of life, exercise capacity and left ventricular function. As a procedure for autonomic modulation in patients with reduced cardiac strength, the data for baroreceptor stimulation are the most convincing.