Is mechanical dyssynchrony a therapeutic target in heart failure with preserved ejection fraction?

Clinical and prognostic implications of phenomapping in patients with heart failure receiving cardiac resynchronization therapy

BACKGROUND

Despite having an indication for cardiac resynchronization therapy according to current guidelines, patients with heart failure with reduced ejection fraction who receive cardiac resynchronization therapy do not consistently derive benefit from it.

AIM

To determine whether unsupervised clustering analysis (phenomapping) can identify distinct phenogroups of patients with differential outcomes among cardiac resynchronization therapy recipients from routine clinical practice.

METHODS

We used unsupervised hierarchical cluster analysis of phenotypic data after data reduction (55 clinical, biological and echocardiographic variables) to define new phenogroups among 328 patients with heart failure with reduced ejection fraction from routine clinical practice enrolled before cardiac resynchronization therapy. Clinical outcomes and cardiac resynchronization therapy response rate were studied according to phenogroups.

RESULTS

Although all patients met the recommended criteria for cardiac resynchronization therapy implantation, phenomapping analysis classified study participants into four phenogroups that differed distinctively in clinical, biological, electrocardiographic and echocardiographic characteristics and outcomes. Patients from phenogroups 1 and 2 had the most improved outcome in terms of mortality, associated with cardiac resynchronization therapy response rates of 81% and 78%, respectively. In contrast, patients from phenogroups 3 and 4 had cardiac resynchronization therapy response rates of 39% and 59%, respectively, and the worst outcome, with a considerably increased risk of mortality compared with patients from phenogroup 1 (hazard ratio 3.23, 95% confidence interval 1.9-5.5 and hazard ratio 2.49, 95% confidence interval 1.38-4.50, respectively).

CONCLUSIONS

Among patients with heart failure with reduced ejection fraction with an indication for cardiac resynchronization therapy from routine clinical practice, phenomapping identifies subgroups of patients with differential clinical, biological and echocardiographic features strongly linked to divergent outcomes and responses to cardiac resynchronization therapy. This approach may help to identify patients who will derive most benefit from cardiac resynchronization therapy in "individualized" clinical practice.

Usefulness and clinical relevance of left ventricular global longitudinal systolic strain in patients with heart failure with preserved ejection fraction

In recent years, several studies have shown the usefulness and clinical relevance of left ventricular global longitudinal systolic strain (GLS) in different cardiovascular diseases. In line with this, the role of GLS in patients with heart failure with preserved ejection fraction (HFpEF) has achieved great importance in this predominant form of heart failure in the last years. In this regard, GLS has shown to be not only a sensitive parameter to detect subtle myocardial abnormalities but also a parameter of clinical and prognostic relevance in patients with HFpEF. In this review, we analyze the current evidence concerning the clinical relevance of GLS in patients with HFpEF and we discuss the potential usefulness of GLS in this complex and heterogeneous condition for which so far no effective therapy exists.

Electrocardiographic characteristics in patients with heart failure and normal ejection fraction: A systematic review and meta-analysis

BACKGROUND

Little is known about ECG abnormalities in patients with heart failure and normal ejection fraction (HeFNEF) and how they relate to different etiologies or outcomes.

METHODS AND RESULTS

We searched the literature for peer-reviewed studies describing ECG abnormalities in HeFNEF other than heart rhythm alone. Thirty five studies were identified and 32,006 participants. ECG abnormalities reported in patients with HeFNEF include atrial fibrillation (prevalence 12%-46%), long PR interval (11%-20%), left ventricular hypertrophy (LVH, 10%-30%), pathological Q waves (11%-18%), RBBB (6%-16%), LBBB (0%-8%), and long JTc (3%-4%). Atrial fibrillation is more common in patients with HeFNEF compared to those with heart failure and reduced ejection fraction (HeFREF). In contrast, long PR interval, LVH, Q waves, LBBB, and long JTc are more common in patients with HeFREF. A pooled effect estimate analysis showed that QRS duration ≥120 ms, although uncommon (13%-19%), is associated with worse outcomes in patients with HeFNEF.

CONCLUSIONS

There is high variability in the prevalence of ECG abnormalities in patients with HeFNEF. Atrial fibrillation is more common in patients with HeFNEF compared to those with HeFREF. QRS duration ≥120 ms is associated with worse outcomes in patients with HeFNEF. Further studies are needed to address whether ECG abnormalities correlate with different phenotypes in HeFNEF.

Myocardial work is a predictor of exercise tolerance in patients with dilated cardiomyopathy and left ventricular dyssynchrony

The assessment of myocardial work (MW) by pressure-strain loops is a recently introduced tool for the assessment of myocardial performance. Aim of the present study is to evaluate the relationship between myocardial work and exercise tolerance in patients with dilated cardiomyopathy (DCM). 51 patients with DCM (mean age 57 ± 13 years, left ventricular ejection fraction: 32 ± 9%) underwent cardiopulmonary exercise test (CPET) to assess exercise performance. 22 patients (43%) had left or right bundle branch block with QRS duration > 120 ms. Trans-thoracic echocardiography (TTE) was performed before CPET. The following indices of myocardial work (MW) were measured regionally and globally: constructive work (CW), wasted work (WW), and work efficiency (WE). Left ventricular dyssynchrony (LV-DYS) was defined by the presence of septal flash or apical rocking at TTE. LV-DYS was observed in 16 (31%) patients and associated with lower LV ejection fraction (LVEF), lower global and septal WE, and higher global and septal WW. In patients with LV-DYS, septal WE was the only predictor of exercise capacity at multivariable analysis (β = 0.68, p = 0.03), whereas LVEF (β = 0.47, p = 0.05) and age (β = - 0.42, p = 0.04) were predictors of exercise capacity in patients without LV-DYS. In patients with DCM, LV-DYS is associated with an heterogeneous distribution of myocardial work. Septal WE is the best predictor of exercise performance in these patients.

Cardiac Resynchronization Therapy in Preserved to Mildly Reduced Systolic Function

Cardiac resynchronization therapy has been proven to be clearly beneficial for patients with heart failure, a prolonged QRS duration, and a left ventricular ejection fraction ≤35%. Ejection fraction cutoff, however, is arbitrary and very likely excludes many patients who could benefit from cardiac resynchronization. This article describes the major detrimental effects of left bundle branch block and summarizes the data regarding the potential beneficial effects of cardiac resynchronization in patients with a left ventricular ejection fraction greater than 35%.

Myocardial Strain and Dyssynchrony: Incremental Value?

Heart failure (HF) has evolved in an epidemic manner and constitutes a major public health issue. Currently, several prognostic markers and treatment options exist to guide treatment of HF with reduced ejection fraction, but echocardiographic deformation imaging suggests novel pathophysiologic aspects that could help optimize treatment further. Even though no formal treatment options currently exist for patients with HF with preserved ejection fraction, some HF medication does seem to attenuate strain measures. Speckle tracking has furthermore helped characterize this condition and to confer prognostic information. Thus, strain imaging could facilitate novel trials, and thereby hopefully introduce treatment opportunities.

Left ventricular longitudinal systolic function analysed by 2D speckle-tracking echocardiography in heart failure with preserved ejection fraction: a meta-analysis

BACKGROUND

The purpose of this meta-analysis was to confirm if the global longitudinal systolic function of the left ventricle (LV) is altered in patients with heart failure with preserved ejection fraction (HFpEF).

METHODS

We searched in different databases (Medline, Embase and Cochrane) studies that analysed LV global longitudinal systolic strain (GLS) in patients with HFpEF and in controls (such as healthy subjects or asymptomatic patients with arterial hypertension, diabetes mellitus or coronary artery disease).

RESULTS

Twenty-two studies (2284 patients with HFpEF and 2302 controls) were included in the final analysis. Patients with HFpEF had significantly lower GLS than healthy subjects (mean -15.7% (range -12% to -18.9%) vs mean -19.9% (range -17.1% to -21.5%), weighted mean difference -4.2% (95% CI -3.3% to -5.0%), p < 0.001, respectively). In addition, patients with HFpEF had also significantly lower GLS than asymptomatic patients (mean -15.5% (range -13.4% to -18.4%) vs mean -18.3% (range -15.1% to -20.4%), weighted mean difference -2.8%(95% CI -1.9% to -3.6%), p < 0.001, respectively). In line, 10 studies showed that the rate of abnormal GLS was significantly higher in patients with HFpEF (mean 65.4% (range 37%-95%)) than in asymptomatic subjects (mean 13% (range 0%-29.6%)). Regarding the prognostic relevance of abnormal GLS in HFpEF, two multicentre studies with large sample size (447 and 348) and high number of events (115 and 177) showed that patients with abnormal GLS had worse cardiovascular (CV) outcomes than those with normal GLS (HR for CV mortality and HF hospitalisation 2.14 (95% CI 1.26 to 3.66) and 1.94 (95% CI 1.22 to 3.07)), even adjusting these analyses for multiples clinical and echocardiographic variables.

CONCLUSION

The present meta-analysis analysing 2284 patients with HFpEF and 2302 controls confirms that the longitudinal systolic function of the LV is significantly altered in high proportion of patients with HFpEF. Further large multicentre studies with the aim to confirm the prognostic role of abnormal GLS in HFpEF are warranted.

Heart Failure With Preserved Ejection Fraction and Atrial Fibrillation: Vicious Twins

Heart failure with preserved ejection fraction (HFpEF) and atrial fibrillation (AF) are age-related conditions that are increasing in prevalence, commonly coexist, and share clinical features. This review provides a practical update on the epidemiology, pathophysiology, diagnosis, and management of patients with concomitant HFpEF and AF. Epidemiological studies highlight the close and complex links between HFpEF and AF, the shared risk factors, the high AF occurrence in the natural history of HFpEF, and the independent contribution of each condition to poor outcomes. Diagnosis of HFpEF in the setting of AF is challenging because the symptoms overlap. AF is associated with changes in echocardiographic parameters and circulating natriuretic peptides that confound HFpEF diagnosis. Symptomatic improvement with diuretic therapy supports the presence of HFpEF in patients with concomitant AF. Important knowledge gaps need to be addressed by a multidisciplinary and translational research approach to develop novel therapies that can improve prognosis.

Prognostic importance of left ventricular mechanical dyssynchrony in heart failure with preserved ejection fraction

AIMS

Left ventricular mechanical dyssynchrony has been described in heart failure with preserved ejection fraction (HFpEF), but its prognostic significance is not known.

METHODS AND RESULTS

Of 3445 patients with HFpEF enrolled in the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial, dyssynchrony analysis was performed on 424 patients (12%) by multiple speckle tracking echocardiography strain-based criteria. The primary dyssynchrony analysis was the standard deviation of the time to peak longitudinal strain (SD T2P LS). Cox proportional hazards models assessed the association of dyssynchrony with the composite outcome of cardiovascular death or heart failure hospitalization. Mean age was 70 ± 10 years, LVEF was 60 ± 8%, and QRS duration was 101 ± 27 ms. Worse dyssynchrony, reflected in SD T2P LS, was associated with wider QRS, prior myocardial infarction, larger LV volume and mass, and worse systolic (lower LVEF and global longitudinal strain) and diastolic (lower e' and higher E/e') function. During a median follow-up of 2.6 (interquartile range 1.5-3.8) years, 107 patients experienced the composite outcome. Worse dyssynchrony was associated with the composite outcome in unadjusted analysis [hazard ratio (HR) 1.04, 95% confidence interval (CI) 1.01-1.07; P = 0.021, per 10 ms increase], but not after adjusting for clinical characteristics, or after further adjustment for LVEF, AF, NYHA class, stroke, heart rate, creatinine, haematocrit, and QRS duration (HR 1.03, 95% CI 0.99-1.06; P = 0.16, per 10 ms increase).

CONCLUSION

Worse LV mechanical dyssynchrony, assessed by speckle tracking echocardiography, is not an independent predictor of adverse outcomes in HFpEF, suggesting that mechanical dyssynchrony is unlikely to be an important mechanism underlying this syndrome. These findings warrant validation in an independent study specifically designed to assess the prognostic utility of mechanical dyssynchrony in HFpEF.

TRIAL REGISTRATION

NCT00094302.

Clinical outcomes according to QRS duration and morphology in the irbesartan in patients with heart failure and preserved systolic function (I-PRESERVE) trial

BACKGROUND

The aims of this study were to describe the prevalence of QRS prolongation and abnormal QRS morphology in patients with heart failure and preserved ejection fraction (HF-PEF) and to examine the relationship between these QRS abnormalities and clinical outcomes.

METHODS AND RESULTS

We categorized patients in the Irbesartan in Heart Failure with Preserved Ejection Fraction trial (I-PRESERVE) according to QRS duration <120 vs. ≥120 ms and QRS morphology: normal, left bundle branch block (LBBB), and right bundle branch block (RBBB) or other non-specific intra-ventricular conduction defect (IVCD). The outcomes examined were the composite of cardiovascular death or heart failure hospitalization (and its components) and all-cause mortality. Of the 4128 patients enrolled in I-PRESERVE, 3754 were included in the present analyses. A total of 606 patients had a QRS duration ≥120 ms, 302 had LBBB and 742 had RBBB/IVCD. Patients with an abnormal QRS had evidence of more severe heart failure [lower left ventricular ejection fraction, lower estimated glomerular filtration rate, higher N-terminal pro-B-type natriuretic peptide (NT-proBNP)] and worse clinical status (higher New York Heart Association functional class and greater use of diuretics). Both abnormalities of QRS duration and QRS morphology were associated with worse outcomes. The rates of the composite outcome were: 6.0 and 9.3 per 100 patient years in the <120 ms and ≥120 ms groups, respectively [adjusted hazard ratio (HR) 1.32, 95% confidence interval (CI) 1.11-1.57; P = 0.002) and 6.0, 7.7 and 8.7 per 100 patient years in the normal, non-LBBB and LBBB groups, respectively (adjusted HR 1.19, 95% CI 1.00-1.42, P = 0.046; and HR 1.31, 95% CI 1.03-1.66, P = 0.026, respectively, compared with normal). The heightened risk related to QRS abnormalities persisted after adjustment for other prognostic variables, including NT-proBNP.

CONCLUSION

We found that both prolongation of QRS duration and abnormal QRS morphology were associated with a high risk of fatal and non-fatal adverse outcomes in heart failure with preserved ejection fraction.

Left ventricular regional contraction abnormalities by echocardiographic speckle tracking in combined right bundle branch with left anterior fascicular block compared to left bundle branch block

BACKGROUND

In contrast to LBBB patients less is known about patients with RBBB+LAFB regarding LV contractile abnormalities and the potential role of CRT. This study investigated whether patients with RBBB+LAFB morphology have echocardiographic mechanical strain abnormalities between the inferior and anterior LV walls, similar to abnormalities between septal and lateral walls in LBBB.

METHODS AND RESULTS

Ten healthy volunteers with no-BBB, 28 LBBB and 28 RBBB+LAFB heart failure patients were included in this retrospective study. Two-dimensional regional-strains were obtained by speckle-tracking. Scar was assessed by CMR. Response on echo was defined as normal, classical, borderline or other pattern. The number of classical patterns in LBBB was significantly higher than in RBBB+LAFB and no-BBB groups (p<0.001 for both). Contrary, the RBBB+LAFB group showed a significantly higher number of borderline patterns compared to other groups (LBBB: p=0.042, no-block: p=0.012). In addition, RBBB+LAFB patients had more scar than LBBB patients (9.9% vs 3.4%, p=0.041), and the average amount of scar in each wall was also higher in RBBB+LAFB (<5% in LBBB and <16% in RBBB+LAFB).

CONCLUSIONS

Patients with RBBB+LAFB on ECG and clinical HF demonstrate echocardiographic wall motion abnormalities between inferior and anterior LV walls, similar to abnormalities found between septal and lateral LV walls in patients with LBBB and HF. Fewer patients with RBBB+LAFB showed a classical pattern of opposing wall motion compared to LBBB. Factors that might alter strain patterns in RBBB+LAFB, including the detailed presence or absence of LV scar and coexisting block of the central fascicle, should be assessed in future studies.

Effect of Cardiac Resynchronization Therapy on Inflammation in Congestive Heart Failure: A Review

Congestive heart failure is associated with increased levels of several inflammatory mediators, and animal studies have shown that infusion of a number of cytokines can induce heart failure. However, several drugs with proven efficacy in heart failure have failed to affect inflammatory mediators, and anti-inflammatory therapy in heart failure patients has thus far been disappointing. Hence, to what extent heart failure is caused by or responsible for the increased inflammatory burden in the patient is still unclear. Over the past couple of decades, resynchronization therapy with a biventricular pacemaker has emerged as an effective treatment in a subset of heart failure patients, reducing both morbidity and mortality. Such treatment has also been shown to affect the inflammation associated with heart failure. In this study, we review recent data on the association between heart failure and inflammation, and in particular how resynchronization therapy can affect the inflammatory process.

[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.