Determining whether LV filling time contributes to HF symptoms in different widths of QRS in LBBB patients: A clinical study

OBJECTIVES

Accurate assessment of left ventricular (LV) function is essential for managing patients with left bundle branch block (LBBB). This study aimed to evaluate the relationship between LV systolic function, left ventricular diastolic filling time (LVFT), QRS duration, and heart failure symptoms in patients with LBBB.

METHODS

This study was conducted between June 2021 and June 2022. Patients with LBBB and sinus rhythm who were referred to the echocardiography department were included in the study. All the patients underwent electrocardiogram-gated echocardiography using the same machine. In this study, the LVFT value was measured in absolute terms and as a ratio to the R-R interval (LVFT/RR).

RESULTS

A total of sixty-five patients were included, forty-two (64.6%) were women, and the mean age was 60.71 ± 8.72. We performed three one-way ANOVA tests that showed that LV filling time/RR ratio, QRS duration, and ejection fraction were significantly different between heart failure classes (p = 0.008, p = 0.001, and p < 0.001, respectively). A weak correlation was observed between LVEF and LVFT/RR (r = 0.349, p = 0.004). Additionally, QRS duration was negatively correlated with LVEF (r =  - 0.395, p = 0.004) and LVFT/RR (r =  - 0.350, p = 0.004), although these correlations were weak.

CONCLUSION

We showed that LVFT/RR ratio differed significantly between HF functional classes and was lower in patients with more severe HF symptoms. Additionally, QRS duration was negatively correlated with LVEF and LVFT/RR, and patients with more severe HF symptoms had longer QRS durations.

Difference of cardiac rehabilitation in the morning or evening on indexes of left ventricular and N-terminal pro-brain natriuretic peptide: a randomized controlled trial

The present study aimed to evaluate the effects a cardiac rehabilitation program (CRP) performed in the morning or evening on left ventricular (LV) filling indices and the level of N-terminal fragment of pro-brain natriuretic peptide (NT-proBNP) in patients undergoing percutaneous coronary angioplasty during the COVID-19 pandemic.

Methods

This was a randomized controlled single-blinded clinical trial. Ninety-six patients (mean age: 50.2 ± 8.1 years, 36 women and 44 men) with percutaneous coronary angioplasty were divided into two groups of intervention and control. In each group, the CRP was performed in either morning or evening. The CRP included walking and performing push-ups and sit-ups for 8 weeks. The participants of the control groups received routine care. The functional indices of LV, including LV ejection fraction, systolic function, and diastolic function (i.e. the transmitral flow), the E/e' to left atrium peak strain ratio (as an estimation for LA stiffness), and NT-proBNP level were measured in all participants before starting and at the end of the CRP.

Results

In the intervention group, the individuals performing the CRP in the evening had significantly higher E-wave (0.76±0.02 vs. 0.75±0.03; P=0.008), ejection fraction (52.5±5.64 vs. 55.5±3.59; P=0.011), and diastolic function velocity (E/A ratio, 1.03±0.06 vs. 1.05±0.03; P=0.014) and significantly lower A-wave (0.72±0.02 vs. 0.71±0.01; P=0.041), E/e' ratio (6.74±0.29 vs. 6.51±0.38; P=0.038), and NT-proBNP level (2007.9±214.24 vs. 1933.9±253.13; P=0.045) compared with those performing the program in the morning.

Conclusions

A supervised CRP performed in the evening compared with morning was more effective in improving LV functional indices. Therefore, such home-based interventions are recommended to be performed in the evening during the COVID-19 pandemic.

Complications of Vascular Disease

Vascular diseases and their sequelae increase perioperative risk for noncardiac surgical patients. In this review, the authors discuss vascular diseases, their epidemiology and pathophysiology, risk stratification, and management strategies to reduce adverse perioperative outcomes.

Tadalafil treatment improves cardiac, renal and lower urinary tract dysfunctions in rats with heart failure

Tadalafil, a phosphodiesterase-5 (PDE5) inhibitor, shown to exert a protection to heart failure (HF) associated damage or lower urinary tract symptoms (LUTS). Thus, we investigated the contribution of tadalafil chronic treatment in the alterations of LUTS in HF rats. Male rats were subjected to aortocaval fistula model for HF induction. Echocardiography, cystometric, renal function and redox cell balance, as well as concentration-response curves to carbachol, KCl, ATP and frequency-response curves to electrical field stimulation (EFS) were evaluated in Sham, HF, Tadalafil and HF-Tadalafil (12 weeks endpoint) groups. HF group to present increased in left-ventricle (LV) mass and in LV end-diastolic- and LV end-systolic volume, with a decreased ejection fraction. Tadalafil treatment was able to decrease in hypertrophy and improve the LV function restoring cardiac function. For micturition function (in vivo), HF animals shown an increase in basal pressure, threshold pressure, no-voiding contractions and decreased bladder capacity, being that the tadalafil treatment restored the cystometric parameters. Contractile mechanism response (in vitro) to carbachol, KCl, ATP and EFS in the detrusor muscles (DM) were increased in the HF group, when compared to Sham group. However, tadalafil treatment restored the DM hypercontractility in the HF animals. Moreover, renal function as well as the oxidative mechanism was impaired in the HF animals, and the tadalafil treatment improved all renal and oxidative parameters in HF group. Our data shown that tadalafil has potential as multi-therapeutic drug and may be used as a pharmacological strategy for the treatment of cardiovascular, renal and urinary dysfunctions associated with HF.

Predictive value of frontal QRS-T angle after cardiac resynchronization therapy

OBJECTIVE

It is practical and useful to detect patients who benefit from cardiac resynchronization therapy (CRT) by electrocardiographic (ECG) methods. In this study, the predictive role of the frontal QRS-T angle and other ECG parameters was evaluated in CRT responder patients.

METHOD

Seventy-seven consecutive patients with left ventricular ejection fraction (LVEF) ≤ 35%, New York Heart Association (NYHA) classes II-III, ambulatory class IV and normal sinus rhythm, who had complete left bundle branch block and were treated with CRT were included in this study. Patients were classified as "CRT responders" and "CRT non responders" according to their LVEF improvement. The frontal QRS-T angle was calculated as the absolute value of the difference between the QRS and T wave axes [frontal QRS-T angle = (QRS axis-T axis)].

RESULTS

The mean age of the patients was 64.5 ± 9.1 years, and the average follow-up was 28 (12-47) months. The post-implantation LVEF was higher in the patients CRT responders group (p < 0.001). Post-implantation frontal QRS-T angle (p = 0.003), QRS duration (p = 0.008) and cQT interval (p = 0.012) values were much shorter in the CRT responder group. Multivariable regression analyses showed that the frontal QRS-T angle and age were independent risk factors for CRT response (p = 0.009). The results of the receiver operating characteristic curve analyses (ROC) showed that the predictive optimal cut-off value of CRT response for the frontal QRS-T angle was <135 degrees (AUC: 0.69, 95% CI 0.575-0.814, p = 0.004).

CONCLUSION

The narrowed frontal QRS-T angle (<135 degrees), QRS duration and cQT interval were associated with CRT response in heart failure patients. The frontal QRS-T angle can be an independent predictor of CRT response.

Electronic healthcare records and external outcome data for hospitalized patients with heart failure

Heart failure is one of the most important reasons for hospitalization among elderly individuals and is associated with significant mortality and morbidity. Epidemiological studies require the establishment of high-quality databases. Several datasets that primarily involve heart failure populations have been established in Western countries and have generated many high-quality studies. However, no such dataset is available from China. Due to differences in genetic background and healthcare systems between China and Western countries, the establishment of a heart failure database for the Chinese population is urgently needed. We performed a retrospective single-center observational study to collect data regarding the characteristics of heart failure patients in China by integrating electronic healthcare records and follow-up outcome data. The study collected information for a total of 2,008 patients with heart failure, containing 166 attributes.

Health State Utilities of Patients with Heart Failure: A Systematic Literature Review

BACKGROUND AND OBJECTIVES

New treatments and interventions are in development to address clinical needs in heart failure. To support decision making on reimbursement, cost-effectiveness analyses are frequently required. A systematic literature review was conducted to identify and summarize heart failure utility values for use in economic evaluations.

METHODS

Databases were searched for articles published until June 2019 that reported health utility values for patients with heart failure. Publications were reviewed with specific attention to study design; reported values were categorized according to the health states, 'chronic heart failure', 'hospitalized', and 'other acute heart failure'. Interquartile limits (25th percentile 'Q1', 75th percentile 'Q3') were calculated for health states and heart failure subgroups where there were sufficient data.

RESULTS

The systematic literature review identified 161 publications based on data from 142 studies. Utility values for chronic heart failure were reported by 128 publications; 39 publications published values for hospitalized and three for other acute heart failure. There was substantial heterogeneity in the specifics of the study populations, methods of elicitation, and summary statistics, which is reflected in the wide range of utility values reported. EQ-5D was the most used instrument; the interquartile limit for mean EQ-5D values for chronic heart failure was 0.64-0.72.

CONCLUSIONS

There is a wealth of published utility values for heart failure to support economic evaluations. Data are heterogenous owing to specificities of the study population and methodology of utility value elicitation and analysis. Choice of value(s) to support economic models must be carefully justified to ensure a robust economic analysis.

Prevalence and incidence of intra-ventricular conduction delays and outcomes in patients with heart failure and reduced ejection fraction: insights from PARADIGM-HF and ATMOSPHERE

AIMS

The importance of intra-ventricular conduction delay (IVCD), the incidence of new IVCD and its relationship to outcomes in heart failure and reduced ejection fraction (HFrEF) are not well studied. We addressed these questions in the PARADIGM-HF and ATMOSPHERE trials.

METHODS AND RESULTS

The risk of the primary composite outcome of cardiovascular death or heart failure hospitalization and all-cause mortality were estimated by use of Cox regression according to baseline QRS duration and morphology in 11 861 patients without an intracardiac device. At baseline, 1789 (15.1%) patients had left bundle branch block (LBBB), 524 (4.4%) right bundle branch block (RBBB), 454 (3.8%) non-specific IVCD, 2588 (21.8%) 'mildly abnormal' QRS (110-129 ms) and 6506 (54.9%) QRS <110 ms. During a median follow-up of 2.5 years, the risk of the primary composite endpoint was higher among those with a wide QRS, irrespective of morphology: hazard ratios (95% confidence interval) LBBB 1.36 (1.23-1.50), RBBB 1.54 (1.31-1.79), non-specific IVCD 1.65 (1.40-1.94) and QRS 110-129 ms 1.35 (1.23-1.47), compared with QRS duration <110 ms. A total of 1234 (15.6%) patients developed new-onset QRS widening ≥130 ms (6.1 per 100 patient-years). Incident LBBB occurred in 495 (6.3%) patients (2.4 per 100 patient-years) and was associated with a higher risk of the primary composite outcome [hazard ratio 1.42 (1.12-1.82)].

CONCLUSION

In patients with HFrEF, a wide QRS was associated with worse clinical outcomes irrespective of morphology. The annual incidence of new-onset LBBB was around 2.5%, and associated with a higher risk of adverse outcomes, highlighting the importance of repeat electrocardiogram review.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT0083658 (ATMOSPHERE) and NCT01035255 (PARADIGM-HF).

Cardiac resynchronization therapy in New York Heart Association class-IV patients dependent on intravenous drugs or invasive supportive treatments

Aims

We sought to evaluate the effectiveness of cardiac resynchronization therapy (CRT) in far‐advanced heart failure (FA‐HF) patients with New York Heart Association (NYHA) class‐IV status and dependency on intravenous drugs (IVDs) and/or invasive supportive treatments (ISTs).

Methods and results

Among 305 patients who underwent CRT implantation between October 2005 to December 2019, we identified 17 FA‐HF patients with NYHA class‐IV status and dependency on IVDs (inotropes, diuretics, vasopressors, or vasodilators) and/or ISTs (extracorporeal membranous oxygenator or continuous renal replacement therapy). All patients (median age = 68.7 years, non‐ischaemic cardiomyopathy = 15) remained dependent on several IVDs (2.2 ± 1.3 per patient) and/or ISTs for 11.3 ± 7.8 days due to multiple tapering failure (4.3 ± 3.2 per patient) before CRT implantation. However, 14 (82%) patients were successfully weaned from IVDs/ISTs within 5.2 ± 5.3 days following CRT, and 12 (71%) stayed alive for more than 1 year free of ventricular assist device or heart transplantation with symptom improvement (≥1 NYHA class) and a reduced annual HF hospitalization rate (P = 0.002). Considerable improvements in ventricular systolic function (P = 0.004) and volumetric reverse remodelling (P = 0.007) were noticed during the long‐term follow‐up period (35 ± 15 months post‐CRT). The ventricular assist device/heart transplantation/death‐free survival rate post‐CRT was 71% and 65% at 1 and 3 years, respectively.

Conclusions

Cardiac resynchronization therapy implantation may be a feasible treatment that can offer short‐term and long‐term clinical benefits for NYHA class‐IV FA‐HF patients who are dependent on IVDs/ISTs. When considering treatment options, CRT should not be prematurely excluded solely based on a patient's dependency on IVDs/ISTs without first attempting to identify favourable CRT response factors.

Implications of Kidney Disease in the Cardiac Patient

Cardiovascular and renal diseases share common pathophysiological grounds, risk factors, and therapies. The 2 entities are closely interlinked and often coexist. The prevalence of kidney disease among cardiac patients is increasing. Patients have an atypical clinical presentation and variable disease manifestation versus the general population. Renal impairment limits therapeutic options and worsens prognosis. Meticulous treatment and close monitoring are required to ensure safety and avoid deterioration of kidney and heart functions. This review highlights recent advances in the diagnosis and treatment of cardiac pathologies, including coronary artery disease, arrhythmia, and heart failure, in patients with decreased renal function.

One-Year Mortality Risk Stratification in Patients Hospitalized for Acute Decompensated Heart Failure: Construction of TSOC-HFrEF Risk Scoring Model

Background

Most previous risk prediction models in patients hospitalized for heart failure (HF) are derived from populations in Western countries, and it is unclear whether these models are applicable to Asian populations. This study aimed to construct a risk score system for predicting one-year mortality risk in Asian patients and to compare the applicability of this risk score system with the 3C-HF score system.

Methods

We used the population in the Taiwan Society of Cardiology-Heart Failure with Reduced Ejection Fraction (TSOC-HFrEF) registry, which is a prospective cohort of patients admitted for acute decompensated heart failure (ADHF) in Taiwan. The risk score system was constructed using multivariate Cox-model derived coefficients. A bootstrapping procedure was also used for bias-corrected evaluations. Comparisons between this constructed model and the 3C-HF score prediction model were evaluated using calibration plots and area under curve (AUC)/receiver operating characteristic (ROC) curve.

Results

Patients with complete data (n = 1127) in the TSOC-HFrEF registry were analyzed. During one year of follow-up, 14.5% (n = 163) of the patients died. A risk score system was constructed with the following predictors: body mass index, diastolic blood pressure, dyslipidemia, diabetes, aortic regurgitation, QRS duration, hemoglobin concentration, and digoxin usage. Compared to the 3C-HF score system, this risk score system had a similar discriminatory ability (AUC/ROC values of 0.675 and 0.636, p = 0.127) and both were well-calibrated in the Taiwan population.

Conclusions

The proposed risk score system for predicting one-year all-cause mortality in Taiwanese patients with ADHF may facilitate risk stratification in Asian patients with HF.

Mildly symptomatic heart failure with reduced ejection fraction: diagnostic and therapeutic considerations

Aims

Whereas up to about half of patients with heart failure with reduced ejection fraction (HFrEF) report no or only mild symptoms and are considered as clinically stable, the progressive nature of HFrEF, often silent, renders clinical stability a misleading situation, especially if disease progression is unrecognized. We highlight the challenges in the definition of clinical stability and mild symptomatic status in HFrEF, outline clinical characteristics and available diagnostic tools, and discuss evidence and gaps in the current guidelines for the management of these patients.

Methods and Results

This is a state‐of‐the‐art review that focuses on clinical, diagnostic, and therapeutic aspects in mildly symptomatic HFrEF patients; summarizes the challenges; and proposes directions for future research in this group of patients. The New York Heart Association classification has been widely used as a measure of prognosis in HFrEF, but it lacks objectivity and reproducibility in terms of symptoms assessment. The definition of clinical stability as described in current guidelines is vague and may often lead to underdiagnosis of disease progression in patients who appear to be ‘stable' but in fact are at an increased risk of clinical worsening, hospitalization, or death. Although an increasing number of clinical trials proved that the efficacy of HFrEF therapies was unrelated to the symptomatic status of patients and led to their implementation early in the course of the disease, clinical inertia in terms of under‐prescription or underdosing of guideline‐recommended medications in mildly symptomatic HFrEF patients is still a challenging issue to deal with.

Conclusions

Mildly symptomatic status in a patient with HFrEF is very frequent; it should not be ignored and should not be regarded as an index of disease stability. The application of risk scores designed to predict mortality and mode of death should be engaged among mildly symptomatic patients, not only to identify the most suitable HF candidates for cardioverter defibrillator implantation, but also to identify patients who might benefit from early intensification of medical treatment before the implementation of more interventional approaches.

Outcome and presentation of heart failure in breast cancer patients: findings from a Swedish register-based study

AIMS

Heart failure (HF) patients diagnosed with breast cancer (BC) may have a higher risk of death, and different HF presentation and treatment than patients without BC.

METHODS AND RESULTS

A total of 14 998 women with incident HF (iHF) or prevalent HF (pHF) enrolled in the Swedish HF Registry within and after 1 month since HF diagnosis, respectively, between 2008 and 2013. Patients were linked with the National Patient-, Cancer-, and Cause-of-Death Registry. Two hundred and ninety-four iHF and 338 pHF patients with BC were age-matched to 1470 iHF and 1690 pHF patients without BC. Comorbidity and treatment characteristics were compared using the χ2 tests for categories. Cox proportional hazard models assessed the hazard ratio (HR) and 95% confidence intervals (95% CIs) of all-cause and cardiovascular mortality among HF patients with and without BC. In the pHF group, BC patients had less often myocardial infarction (21.6% vs. 28.6%, P < 0.01) and received less often aspirin (47.6% vs. 55.1%, P = 0.01), coronary revascularization (11.8% vs. 16.2%, P < 0.01), or device therapy (0.9% vs. 3.0%, P = 0.03). After median follow-up of 2 years, risk of all-cause mortality (iHF: HR = 1.04, 95% CI = 0.83-1.29 and pHF: HR = 0.94, 95% CI = 0.79-1.12), cardiovascular mortality (iHF: HR = 0.94, 95% CI = 0.71-1.24 and pHF: HR = 0.89, 95% CI = 0.71-1.10), and HF mortality (iHF: HR = 0.80, 95% CI = 0.34-1.90 and pHF: HR = 0.75, 95% CI = 0.43-1.29) were similar for patients with and without BC in the iHF and pHF groups.

CONCLUSION

Risk of all-cause and cardiovascular mortality in HF patients did not differ by BC status. Differences in pre-existing myocardial infarction and HF treatment among pHF patients with and without BC may suggest differences in pathogenesis of HF.

Cost-Effectiveness Analysis of Patiromer and Spironolactone Therapy in Heart Failure Patients with Hyperkalemia

BACKGROUND AND OBJECTIVE

Certain patients with heart failure (HF) are unable to tolerate spironolactone therapy due to hyperkalemia. Patiromer is a novel agent used to treat hyperkalemia and has been shown to be efficacious, safe, and well-tolerated. The potential clinical outcomes and economic value of using patiromer and spironolactone in patients with HF unable to otherwise tolerate spironolactone due to hyperkalemia are unclear. The objective of this analysis was to model the potential pharmacoeconomic value of using patiromer and spironolactone in patients with a history of hyperkalemia that prevents them from utilizing spironolactone.

METHODS

We performed a cost-effectiveness analysis of treatment with patiromer, spironolactone, and an angiotensin-converting enzyme inhibitor (ACEI) in patients with New York Heart Association (NYHA) class III-IV HF compared with ACEI alone. A Markov model was constructed to simulate a cohort of 65-year-old patients diagnosed with HF from the payer perspective across the lifetime horizon. Clinical inputs were derived from the RALES and OPAL-HK randomized trials of spironolactone and patiromer, respectively. Utility estimates and costs were derived from the literature and list prices. Outcomes assessed included hospitalization, life expectancy, and quality-adjusted life-years (QALYs), costs, and the incremental cost-effectiveness ratio (ICER). One-way and probability sensitivity analyses were performed to test the robustness of the model findings.

RESULTS

Treatment with patiromer-spironolactone-ACEI was projected to increase longevity compared with ACEI alone (5.29 vs. 4.62 life-years gained, respectively), greater QALYs (2.79 vs. 2.60), and costs (US$28,200 vs. US$18,200), giving an ICER of US$52,700 per QALY gained. The ICERs ranged from US$40,000 to US$85,800 per QALY gained in 1-way sensitivity analyses.

CONCLUSION

Our results suggest that the use of spironolactone-patiromer-ACEI may provide clinical benefit and good economic value in patients with NYHA class III-IV HF unable to tolerate spironolactone due to hyperkalemia.

Lessons learned in acute heart failure

Acute heart failure (HF) is a global pandemic with more than one million admissions to hospital annually in the US and millions more worldwide. Post-discharge mortality and readmission rates remain unchanged and unacceptably high. Although recent drug development programmes have failed to deliver novel therapies capable of reducing cardiovascular morbidity and mortality in patients hospitalized for worsening chronic HF, hospitalized HF registries and clinical trial databases have generated a wealth of information improving our collective understanding of the HF syndrome. This review will summarize key insights from clinical trials in acute HF and hospitalized HF registries over the last several decades, focusing on improving the management of patients with HF and reduced ejection fraction.

Registry-Based Pragmatic Trials in Heart Failure: Current Experience and Future Directions

PURPOSE OF REVIEW

Randomized controlled trials (RCTs) in heart failure (HF) are becoming increasingly complex and expensive to conduct and if positive deliver expensive therapy tested only in selected populations.

RECENT FINDINGS

Electronic health records and clinical cardiovascular quality registries are providing opportunities for pragmatic and registry-based prospective randomized clinical trials (RRCTs). Simplified regulatory, ethics, and consent procedures; recruitment integrated into real-world care; and simplified or automated baseline and outcome collection allow assessment of study power and feasibility, fast and efficient recruitment, delivery of generalizable findings at low cost, and potentially evidence-based and novel use of generic drugs with low costs to society. There have been no RRCTs in HF to date. Major challenges include generating funding, international collaboration, and the monitoring of safety and adherence for chronic HF treatments. Here, we use the Spironolactone Initiation Registry Randomized Interventional Trial in Heart Failure with Preserved Ejection Fraction (SPIRRIT-HFpEF), to be conducted in the Swedish Heart Failure Registry, to exemplify the advantages and challenges of HF RRCTs.

Electro-echocardiographic Indices to Predict Cardiac Resynchronization Therapy Non-response on Non-ischemic Cardiomyopathy

Cardiac resynchronization therapy (CRT) threw lights on heart failure treatment, however, parts of patients showed nonresponse to CRT. Unfortunately, it lacks effective parameters to predict CRT non-response. In present study, we try to seek effective electro-echocardiographic predictors on CRT non-response. This is a retrospective study to review a total of 227 patients of dyssynchronous heart failure underwent CRT implantation. Logistic analysis was performed between CRT responders and CRT non-responders. The primary outcome was the occurrence of improved left ventricular ejection fraction 1 year after CRT implantation. We concluded that LVEDV > 255 mL (OR = 2.236; 95% CI, 1.016-4.923) rather than LVESV > 160 mL (OR = 1.18; 95% CI, 0.544-2.56) and TpTe/QTc > 0.203 (OR = 5.206; 95% CI, 1.89-14.34) significantly predicted CRT non-response. Oppositely, S wave > 5.7 cm/s (OR = 0.242; 95% CI, 0.089-0.657), E/A > 1 (OR = 0.211; 95% CI, 0.079-0.566), E'/A' > 1 (OR = 0.054; 95% CI, 0.017-0.172), CLBBB (OR = 0.141; 95% CI, 0.048-0.409), and QRS duration >160 ms (OR = 0.52; 95% CI, 0.305-0.922) surprisingly predicted low-probability of CRT non-response.

Cardiac resynchronization therapy: results, challenges and perspectives for the future

Heart failure (HF) is considered as an epidemic and affects 2% of the population in the Western world. About 15-30% of patients with HF and reduced ejection fraction (HFrEF) also have prolonged QRS duration on the surface ECG, most commonly as a result of left-bundle branch block (LBBB). Increased QRS duration is a marker of a dyssynchronous activation, and subsequent contraction, pattern in the left ventricle (LV). When dyssynchrony is superimposed on the failing heart it further reduced systolic function and ultimately worsens outcome. During the past 15 years several randomized controlled clinical trials have documented that resynchronization of the dyssynchronous failing heart with a biventricular pacemaker - cardiac resynchronization therapy (CRT) - which can restore a more synchronous activation and contraction pattern. This translates in halted or reversed disease progression and improved clinical outcome, including reduced mortality. In this review, we will discuss several aspects of CRT including mechanisms of dyssynchrony and resynchronization in the failing heart, evidence of CRT efficacy derived from clinical trials and current challenges in CRT including patient selection and optimization of therapy delivery. Last, we will discuss future perspectives including the role of CRT to prevent adverse events in patients with an indication for antibradycardia pacing, the role of leadless pacing in the CRT setting as well as a new clinical arena where dyssynchrony and resynchronization may be important.