Bundle branch block patterns and long-term outcomes in heart failure

Abnormal electrocardiogram and poor prognosis in heart failure with preserved ejection fraction

PURPOSE

Electrocardiogram (ECG) is generally performed in patients with heart failure with preserved ejection fraction (HFpEF), but the prognostic value of abnormal ECG is not fully understood. We aim to explore the prognostic value of abnormal ECG at baseline in HFpEF using data from the TOPCAT trial.

METHODS

A total of 1736 patients from TOPCAT-Americas were included and divided into normal versus abnormal ECG groups. Survival analyses were performed for the following outcomes: the primary endpoint [a composite of cardiovascular death, heart failure (HF) hospitalization, and aborted cardiac arrest], all-cause death, cardiovascular death, and HF hospitalization.

RESULTS

Abnormal ECG was significantly associated with higher risks of the primary endpoint [hazard ratio (HR): 1.480, P = 0.001] and HF hospitalization (HR: 1.400, P = 0.015), and borderline significantly with cardiovascular death (HR: 1.453, P = 0.052) in patients with HFpEF after multivariate adjustment. As for specific ECG abnormalities, bundle branch block was associated with the primary endpoint (HR: 1.278, P = 0.020) and HF hospitalization (HR: 1.333, P = 0.016), whereas atrial fibrillation/flutter was associated with all-cause death (HR: 1.345, P = 0.051) and cardiovascular death (HR: 1.570, P = 0.023), but ventricular paced rhythm, pathological Q waves, and left ventricular hypertrophy were not of prognostic significance. Besides, other unspecific abnormalities together were associated with the primary endpoint (HR: 1.213, P = 0.032).

CONCLUSION

Abnormal ECG at baseline could be associated with poor prognosis in patients with HFpEF. Physicians are encouraged to pay more attention to HFpEF patients who present an abnormal ECG instead of ignoring those obscure abnormalities. Key messages What is already known on this topic Electrocardiogram (ECG) is a basic and easily accessible examination for patients with heart failure with preserved ejection fraction (HFpEF). Some findings from ECG such as frontal QRS-T angle, QTc interval, and the Cornell product have been shown to be associated with the prognosis of HFpEF but these results are from studies with relatively small sample sizes. What this study adds Using data from TOPCAT-Americas, this study found that an overall estimation of abnormal ECG significantly predicted poor prognosis in patients with HFpEF. As for specific abnormalities in ECG, bundle branch block mainly predicted heart failure hospitalization and atrial fibrillation mainly predicted death. How this study might affect research, practice, or policy This study reminds physicians to pay more attention to HFpEF patients who present an abnormal ECG.

Early left bundle branch pacing in heart failure with mildly reduced ejection fraction and left bundle branch block

BACKGROUND

Left bundle branch pacing (LBBP) achieves resynchrony and improves cardiac function in heart failure (HF) patients with reduced ejection fraction (EF) by correcting left bundle branch block (LBBB). Few data on the efficacy of early LBBP in HF with mildly reduced EF (HFmrEF) and LBBB have been reported.

OBJECTIVE

The purpose of this study was to explore the efficacy of early LBBP in patients with HFmrEF and LBBB.

METHODS

Consecutive patients with HFmrEF (left ventricular EF [LVEF] 35%-50%) and LBBB were prospectively enrolled to receive LBBP (Early-LBBP group) plus guideline-directed medical therapy (GDMT) or GDMT alone (GDMT group). Study outcomes included changes in LVEF, LV end-diastolic diameter (LVEDD), New York Heart Association (NYHA) functional classification, and N-terminal pro-brain natriuretic peptide (NT-proBNP), and clinical events (HF rehospitalization or syncope). Subgroup analysis compared efficacy of LBBP between patients with LBBB only without comorbidities or late gadolinium enhancement (LGE) (LBBB-Only group) and patients with either comorbidities or LGE (LBBB-Combined group).

RESULTS

Fifty-four patients were enrolled and analyzed (37 Early-LBBP group; 15 GDMT group). LBBP achieved greater improvement in LVEF (+14.75% ± 7.37% vs -2.42% ± 2.84%; P <.001), reduction of LVEDD (-7.51 ± 5.40 mm vs -0.87 ± 4.36 mm; P <.001) and NYHA classification (-0.84 ± 0.76 vs -0.13 ± 0.74; P = .004), and similar reduction of NT-proBNP (-408.83 ± 920.29 pg/mL vs -229.05 ± 1579.17 pg/mL; P = .610) at 6 months. Early LBBP showed significantly reduced clinical events (0.0% vs 40.0%; P <.001) after 20.68 ± 13.55 months of follow-up. Subgroup analysis showed patients in the LBBB-Only group benefited more from LBBP with regard to LVEF improvement and LVEDD reduction than the LBBB-Combined group.

CONCLUSION

Early LBBP with GDMT demonstrated greater improvement of cardiac function and reduced clinical events than GDMT alone in patients with HFmrEF and LBBB.

QTc and QRS Abnormalities are Associated with Outcome in Pediatric Heart Failure

Adult studies have shown that depolarization and repolarization abnormalities are associated with worsening heart failure; however, this relationship is not well understood in pediatric congenital heart disease. We evaluated the association between QTc and QRS duration to systolic function and outcome in children with heart failure and reduced ejection fraction (HFrEF). We performed a retrospective, single-center, 14-year cohort study of HFrEF children. Clinical records, echocardiograms, and electrocardiograms were reviewed for every clinical encounter. Diagnosis, interventions, outcomes, QRS and QTc duration, and systolic function were collected. Repeated-measure ANOVA evaluated the association between depolarization and repolarization to cardiac function. Cox regression analysis examined the effects of age, time since diagnosis, and measured and change in QTc and QRS duration on time to transplant/death. We enrolled 136 cardiomyopathy (CM) and 47 structural heart disease (SHD) patients. Prolonged QRS (p = 0.0001) and QTc (p = 0.02) were associated with systolic dysfunction. This association was significant in SHD group (QRS p < 0.0001, QTc p = 0.048), but not CM group (QRS p = 0.5, QTc p = 0.3). Progressive lengthening of QTc was significantly associated with transplant or death in the overall cohort (HR 1.02, CI 1.011-1.028), SHD, (HR 1.020, CI 1.001-1.039), and CM (HR 1.017, CI 1.007-1.027). QTc and QRS prolongation are each associated with ventricular dysfunction in pediatric SHD with heart failure. QTc prolongation is an indication for poor outcomes in SHD and CM groups, leading to a higher risk of death or transplantation. Progressive lengthening of QTc over time in children with HFrEF may indicate increased risk in this population.

Prevalence, Related Factors and Association of Left Bundle Branch Block With Prognosis in Patients With Acute Heart Failure: a Simultaneous Analysis in 3 Independent Cohorts

OBJECTIVES

To determine the prevalence, characteristics and association with prognosis of left bundle branch block (LBBB) in 3 different cohorts of patients with acute heart failure (AHF).

METHODS AND RESULTS

We retrospectively analyzed 12,950 patients with AHF who were included in the EAHFE (Epidemiology Acute Heart Failure Emergency), RICA (National Heart Failure Registry of the Spanish Internal Medicine Society), and BASEL-V (Basics in Acute Shortness of Breath Evaluation of Switzerland) registries. We independently analyzed the relationship between baseline and clinical characteristics and the presence of LBBB and the potential association of LBBB with 1-year all-cause mortality and a 90-day postdischarge combined endpoint (Emergency Department reconsultation, hospitalization or death). The prevalence of LBBB was 13.5% (95% confidence interval: 12.9%-14.0%). In all registries, patients with LBBB more commonly had coronary artery disease and previous episodes of AHF, were taking chronic spironolactone treatment, had lower left ventricular ejection fraction and systolic blood pressure values and higher NT-proBNP levels. There were no differences in risk for patients with LBBB in any cohort, with adjusted hazard ratios (95% confidence interval) for 1-year mortality in EAHFE/RICA/BASEL-V cohorts of 1.02 (0.89-1.17), 1.15 (0.95-1.38) and 1.32 (0.94-1.86), respectively, and for 90-day postdischarge combined endpoint of 1.00 (0.88-1.14), 1.14 (0.92-1.40) and 1.26 (0.84-1.89). These results were consistent in sensitivity analyses.

CONCLUSIONS

Less than 20% of patients with AHF present LBBB, which is consistently associated with cardiovascular comorbidities, reduced left ventricular ejection fraction and more severe decompensations. Nonetheless, after taking these factors into account, LBBB in patients with AHF is not associated with worse outcomes.

Association between atrial fibrillation and bundle branch block

BACKGROUND

The association between atrial fibrillation (Afib) and sinus and AV nodal dysfunction has previously been reported. However, no data are available regarding the association between Afib and bundle branch block (BBB).

METHODS

Patient data were obtained from the Nationwide Inpatient Sample (NIS) database between years 2009 and 2015. Patients with a diagnosis of Afib and BBB were identified using validated International Classification of Diseases, 9th revision, and Clinical Modification (ICD-9-CM) codes. Statistical analysis using the chi-square test and multivariate linear regression analysis were performed to determine the association between Afib and BBB.

RESULTS

The total number of patients with BBB was 3,116,204 (1.5%). Patients with BBB had a mean age of 73.5 ± 13.5 years, 53.6% were males, 39.1% belonged to the age group ≥80 years, and 72.9% were Caucasians. The prevalence of Afib was higher in the BBB group, as compared to the non-BBB group (29% vs 11.8%, p value<.001). This association remained significant in multivariate regression analysis with an odds ratio of 1.25 (CI: 1.24-1.25, P < .001). Among the subtypes of BBB, Afib was comparatively more associated with RBBB (1.32, CI 1.31-1.33, p value<.0001) than LBBB (1.17, CI 1.16-1.18, p value<.0001). The mean cost was higher among Afib with BBB, compared with Afib patients without BBB ($15 795 vs $14 391, p value<.0001). There was no significant difference in the mean length of stay (5.6 vs 5.9 days, p value<.0001) or inpatient mortality (4.9% vs 4.8%).

CONCLUSION

This study demonstrates that prevalence of Afib is higher in patients with BBB than without BBB. Cost are higher for Afib patients with BBB, compared to those without BBB, with no significant increase in mortality or length of stay.

Right bundle branch block is not associated with worse short- and mid-term outcome after transcatheter aortic valve implantation

Background

Transcatheter aortic valve implantation (TAVI) is the standard treatment option for patients with severe aortic stenosis (AS) at intermediate or high surgical risk. Preexisting right bundle branch block (RBBB) is a strong predictor of new pacemaker implantation (PPM) after TAVI, and previous data indicate a worse short- and long-term outcome of patients. The aim of this study was to investigate whether preexisting RBBB has an effect on the short- and mid-term outcome of patients undergoing TAVI in a German high-volume TAVI center.

Methods

For the present retrospective analysis, a total of 1,891 patients with native severe AS with successful TAVI without preexisting PPM were included. The primary endpoint was all-cause mortality after 30 days and 12 months. Baseline RBBB was present in 190 (10.1%) of cases.

Results

Patients with preexisting RBBB had a considerably higher rate of new PPM after TAVI compared with patients without RBBB (87/190 [45.8%] vs. 219/1,701 [12.9%]; p<0.001). RBBB had no impact on all-cause mortality at 30 days (2.1% vs. 2.7%; p = 0.625) and at 12 months (14.4% vs. 13.6%; p = 0.765). Further stratification according to the presence of new PPM showed a difference in mid-term survival rates between the four groups, with the worst outcome for patients without RBBB and new PPM (log rank p = 0.024). However, no difference in mid-term cardiovascular survival was found.

Conclusion

Preexisting RBBB is a common finding in patients with severe AS undergoing TAVI and is associated with considerably higher PPM rates but not with worse short- and mid-term outcome.

Percutaneous Coronary Intervention in Transcatheter Aortic Valve Implantation Patients: Overview and Practical Management

Coronary artery disease (CAD) is present in 40-75% of patients undergoing transcatheter aortic valve implantation (TAVI) for severe symptomatic aortic stenosis. Currently, the indication for TAVI is expanding toward younger patients at lower surgical risk. Given the progressive nature of CAD, the necessity for coronary angiography (CA), including percutaneous coronary intervention (PCI), will subsequently increase as in the future TAVI patients will be younger and have a longer life expectancy. Data on the impact of PCI in patients with severe CAD scheduled for TAVI are controversial, and although European and US guidelines recommend PCI before TAVI, the optimal timing for PCI remains unclear due to a lack of evidence. Depending on the valve type, position, and axial alignment of the implanted device, CA and/or PCI after TAVI can be challenging. Hence, every interventionalist should be familiar with the different types of transcatheter heart valves and their characteristics and technical issues that can arise during invasive coronary procedures. This review provides an overview of current data regarding the prevalence and clinical implications of CAD and PCI in TAVI patients and includes useful guidance for practical management in the clinical routine.

Impact of Baseline Right Bundle Branch Block on Outcomes After Pulmonary Vein Isolation in Patients With Atrial Fibrillation

Right bundle branch block (RBBB) is one of the most frequent alterations of the electrocardiogram. Several studies have shown that RBBB is a risk factor of cardiovascular diseases. However, the clinical outcomes after pulmonary vein isolation (PVI) in patients with RBBB remain unclear. We enrolled consecutive atrial fibrillation (AF) patients who underwent PVI from the Osaka Rosai Atrial Fibrillation (ORAF) registry. We excluded patients with other wide QRS morphologies (left bundle branch block, ventricular pacing, and unclassified intraventricular conduction disturbances) and divided them into 2 groups: RBBB (QRS duration ≥120msec) and No-RBBB (QRS duration <120) groups. We compared the incidence of late recurrence of AF and/or atrial tachycardia (AT) (LRAF) between the 2 groups using a propensity score-matched analysis and evaluated the risk of LRAF using Cox regression model. We finally analyzed 671 consecutive AF patients. The RBBB group consisted of 50 patients (7.5%) and the No-RBBB group of 621 patients. Median follow-up duration was 734 [496, 1,049] days. Hypertension and diabetes mellitus were significantly higher in RBBB group than No-RBBB group. Among the 46 matched patients pairs, Kaplan-Meier analysis demonstrated that RBBB group had a significantly greater risk of LRAF than the No-RBBB group (p = 0.046). The Cox regression model revealed significantly higher risks of LRAF (HR, 2.30; 95% CI, 1.00 to 5.33; p=0.044) in RBBB group compared with No-RBBB group. Non-PV AF triggers were significantly higher in RBBB group than No-RBBB group (p = 0.048). In conclusion, RBBB can be an important predictor of LRAF after PVI.

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).

Clinical Impact of Preexisting Right Bundle Branch Block after Transcatheter Aortic Valve Replacement: A Systematic Review and Meta-Analysis

Introduction

Transcatheter aortic valve replacement (TAVR) is now the treatment of choice for patients with severe aortic stenosis regardless of their surgical risk. Right bundle branch block (RBBB) can be a predictor for development of significant atrioventricular (AV) block after TAVR, requiring permanent pacemaker implantation (PPI). However, data related to the risk of PPI requirement with preexisting RBBB is scarce. Hence, this systematic review and meta-analysis aims to assess clinical outcomes of patients undergoing TAVR with RBBB on preexisting electrocardiogram.

Methods

We performed a systematic literature review to identify randomized and nonrandomized clinical studies that reported any clinical impact of patients undergoing TAVR with preexisting RBBB. A total of eight databases including PubMed (Medline), Embase, Cochrane Library, ACP Journal Club, Scopus, DARE, and Ovid containing articles from January 2000 to May 2020 were analyzed.

Results

We identified and screened 224 potential eligible publications through the databases and found 14 relevant clinical trials for a total of 15,319 participants. There was an increased 30-day pacemaker implantation rate of 38.1% in the RBBB group compared to 11.4% in the no RBBB group with a risk ratio of 3.56 (RR 3.56 (95% CI 3.21–3.93, p < 0.01)). There was an increased 30-day all-cause mortality in the RBBB group of 9.5% compared with 6.3% in the no RBBB group with an odds ratio of 1.60 (OR 1.60 (95% CI 1.14–2.25, p < 0.01)).

Conclusion

This study indicates that patients with preexisting RBBB have higher incidence of PPI and all-cause mortality after TAVR compared with patients without RBBB. Further trials are needed to compare the clinical outcomes based on TAVR valve types and assess the benefit of PPI in patients with new-onset RBBB after TAVR.

Prognostic impact of right bundle branch block in hospitalized patients with idiopathic dilated cardiomyopathy: a single-center cohort study

Objective

Idiopathic dilated cardiomyopathy (IDCM) is a primary myocardial disease resulting in symptoms of heart failure. Right bundle branch block (RBBB) is associated with increased cardiovascular risk and all-cause mortality. Therefore, the present study was performed to identify the prognostic impact of RBBB in patients with IDCM.

Methods

In total, 165 hospitalized patients with IDCM were evaluated. Receiver operating characteristic curve analysis was used to determine the cutoff point, and Cox regression was used to assess risk factors.

Results

After a median follow-up of 73.1 months (interquartile range, 36.1–88.7 months), 59 (35.8%) patients had died. All-cause mortality was significantly higher in patients with than without RBBB (log-rank χ2 = 9.400), P<0.05. Significant independent predictors of all-cause mortality in patients with IDCM were RBBB (hazard ratio, 2.898; 95% confidence interval, 1.201–6.995) and the left ventricular end-diastolic dimension (LVEDD) (hazard ratio, 1.034; 95% confidence interval, 1.004–1.066) at admission. Patients with RBBB and an LVEDD of ≥63 mm had the highest mortality (log-rank χ2 = 14.854), P<0.05.

Conclusion

RBBB was an independent predictor of all-cause mortality, and the combination of RBBB and LVEDD provided more clinically relevant information than RBBB alone for assessing the risk of all-cause mortality in patients with IDCM.

Clinical Presentations and Outcomes in Patients Presenting With Acute Cardiac Events and Right Bundle Branch Block

We conducted a retrospective analysis of 50 974 patients admitted with acute cardiac events with and without right bundle branch block (RBBB) over 23 years. Compared to non-RBBB, patients with RBBB (n = 386; 0.8%) were 3 years older ( P = .001), more likely to present with breathlessness rather than chest pain ( P = .001), and had more diabetes mellitus ( P = .001). Patients with RBBB had significantly higher cardiac enzymes ( P = .001); however, there were no significant differences in the presentation with ST-segment elevation myocardial infarction (24.6% vs 22.2%), non-ST-segment elevation myocardial infarction (23.7% vs 22.4%), and unstable angina (51.7% vs 55.4%). Patients with RBBB were more likely to have congestive heart failure (CHF; 9.6% vs 3.2%, P = .001), cardiogenic shock (10.6% vs 1.7%, P = .001), and ventricular tachyarrhythmias (7.3% vs 2.2%, P = .001). Left ventricular ejection fraction and hospital length of stay were comparable between the groups. All-cause mortality was 5 times greater in patients with RBBB (21% vs 4.2%, P = .001). Right bundle branch block was independent predictor of mortality (adjusted odd ratio 5.14; 95% confidence interval: 3.90-6.70). Subanalysis comparing normal QRS, RBBB, and left BBB showed that RBBB was associated with the worst outcomes except for CHF. Although RBBB presents in only about 1% of patients with cardiac disease, it was found to be an independent predictor of hospital mortality.

Diagnosis of right bundle branch block: a concordance study

BACKGROUND

Right bundle branch block is one of the most common electrocardiographic abnormalities. Most cases of right bundle branch block are detected in asymptomatic patients in primary care, so a correct interpretation of electrocardiograms (ECGs) at this level is necessary. The objective of this research is to determine the degree of concordance in the diagnosis of incomplete and complete right bundle branch block between four primary care researchers and a cardiologist.

METHODS

The research design is a retrospective cohort study of patients over 18 years of ages of patients over 18 years of ages who underwent an ECG for any reason and were diagnosed with right bundle branch block by their physician. The physicians participating, 4 primary care researchers and a cardiologist were specialized in interpreting electrocardiographic records. The diagnosis of incomplete and complete right bundle branch block was recorded and other secondary variables were analysed. In case of diagnostic discordance between the researchers, the ECGs were reviewed by an expert cardiologist, who interpreted them, established the diagnosis and analysed the possible causes for the discrepancy.

RESULTS

We studied 160 patients diagnosed with right bundle branch block by their general practise. The patients had a mean age of 64.8 years and 54% of them were men. The concordance in the diagnosis of incomplete right bundle branch block showed a Fleiss' kappa index (k) of 0.71 among the five researchers and of 0.85 among only the primary care researchers. The k for complete right bundle branch block was 0.93 among the five researchers and 0.96 among only the primary care researchers.

CONCLUSION

The interobserver agreement in the diagnosis of right bundle branch block performed by physicians specialized in ECG interpretation (primary care physicians and a cardiologist) was very good. The variability was greater for the diagnosis of incomplete right bundle branch block.

Prognostic Implication of Ventricular Conduction Disturbance Pattern in Hospitalized Patients with Acute Heart Failure Syndrome

Background and Objectives

Conflicting data exist regarding the prognostic implication of ventricular conduction disturbance pattern in patients with heart failure (HF). This study investigated the prognostic impact of ventricular conduction pattern in hospitalized patients with acute HF.

Methods

Data from the Korean Acute Heart Failure registry were used. Patients were categorized into four groups: narrow QRS (<120 ms), right bundle branch block (RBBB), left bundle branch block (LBBB), and nonspecific intraventricular conduction delay (NICD). The NICD was defined as prolonged QRS (≥120 ms) without typical features of LBBB or RBBB. The primary endpoint was the composite of all-cause mortality or rehospitalization for HF aggravation within 1 year after discharge.

Results

This study included 5,157 patients. The primary endpoint occurred in 39.7% of study population. The LBBB group showed the highest incidence of primary endpoint followed by NICD, RBBB, and narrow QRS groups (52.5% vs. 49.7% vs. 44.4% vs. 37.5%, p<0.001). In a multivariable Cox-proportional hazards regression analysis, LBBB and NICD were associated with 39% and 28% increased risk for primary endpoint (LBBB hazard ratio [HR], 1.392; 95% confidence interval [CI], 1.152–1.681; NICD HR, 1.278; 95% CI, 1.074–1.520) compared with narrow QRS group. The HR of RBBB for the primary endpoint was 1.103 (95% CI, 0.915–1.329).

Conclusions

LBBB and NICD were independently associated with an increased risk of 1-year adverse event in hospitalized patients with HF, whereas the prognostic impacts of RBBB were limited.

Trial Registration

ClinicalTrials.gov Identifier: NCT01389843

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%.

Right bundle branch block and cardiovascular morbidity and mortality in healthy patients

The clinical significance of a right bundle branch block (RBBB) in an asymptomatic adult without evidence of cardiovascular disease is controversial. To establish the relationship between the appearance of the RBBB and the increase of cardiovascular morbidity and mortality in healthy patients, we have carried out a literature review of documents available until September 2017 through a systematic search on the Pubmed database, Cochrane library and a manual search of the mentioned literature and related articles. From the 29 articles included in the study sample, eight showed mortality and 16 morbidity outcomes. An increase of risk of death is observed is eight articles and an increase of cardiovascular events is observed in 11 articles. The most recent publications suggest that the appearance of an RBBB in healthy individuals should not be underestimated, thus further studies are needed to analyse the type of follow-up that should be carried out in these patients.

Prophylactic implantable cardioverter defibrillator in heart failure: the growing evidence for all or Primum non nocere for some?

Heart failure (HF) is a common health problem and has reached epidemic in many western countries. Despite the current era of HF treatment, the risk of sudden cardiac death (SCD) in HF remains significant. Implantable cardioverter defibrillator (ICD) support has been shown to reduce the risk of SCD in patients with HF and impaired left ventricular function. Prophylactic ICD implantation in HF patients seems a logical step to reduce mortality through a reduction in SCD. However, ICD implantation is an invasive procedure, and both short- and long-term complications can occur. This needs to be carefully considered when evaluating the risk-benefit ratio of ICD implantation for individual patients. As the severity of HF increases, the proportion of SCD compared with HF-related deaths decreases. The challenge lies in identifying patients with HF who are at significant risk of SCD and who would most benefit from an ICD in addition to other anti-arrhythmic strategies. This review offers insight on the applicability and practicability of ICD for this growing population.

Mechanical dispersion is associated with poor outcome in heart failure with a severely depressed left ventricular function and bundle branch blocks

OBJECTIVES

Bundle branch blocks (BBB)-related mechanical dyssynchrony and dispersion may improve patient selection for device therapy, but their effect on the natural history of this patient population is unknown.

METHODS

A total of 155 patients with LVEF ≤ 35% and BBB, not treated with device therapy, were included. Mechanical dyssynchrony was defined as the presence of either septal flash or apical rocking. Contraction duration was assessed as time interval from the electrocardiographic R-(Q-)wave to peak longitudinal strain in each of 17 left ventricular segments. Mechanical dispersion was defined as either the standard deviation of all time intervals (dispersion_SD) or as the difference between the longest and shortest time intervals (dispersion_delta). Patients were followed for cardiac mortality during a median period of 33 months.

RESULTS

Mechanical dyssynchrony was not associated with survival. More pronounced mechanical dispersion_delta was found in patients with dyssynchrony than in those without. In the multivariate regression analysis, patients' functional class, diabetes mellitus and dispersion_delta were independently associated with mortality.

CONCLUSIONS

Mechanical dispersion, but not dyssynchrony, was independently associated with mortality and it may be useful for risk stratification of patients with heart failure (HF) and BBB. Key Messages Mechanical dispersion, measured by strain echocardiography, is associated with poor outcome in heart failure with a severely depressed left ventricular function and bundle branch blocks. Mechanical dispersion may be useful for risk stratification of patients with heart failure and bundle branch blocks.

Clinical outcomes according to QRS duration and morphology in the Eplerenone in Mild Patients: Hospitalization and SurvIval Study in Heart Failure (EMPHASIS-HF)

AIMS

We examined the relationship between different degrees of QRS prolongation and different QRS morphologies and clinical outcomes in patients with heart failure, reduced ejection fraction (HF-REF), and mild symptoms in the Eplerenone in Mild Patients Hospitalization and SurvIval Study in Heart Failure trial (EMPHASIS-HF). We also evaluated the effect of eplerenone in these patients according to QRS duration/morphology.

METHODS AND RESULTS

Patients were categorized as: QRS duration (ms) (i) <120 (n = 1375); (ii) 120-149 (n = 517); and (iii) ≥150 (n = 383), and QRS morphology (i) normal (n = 1252); (ii) left bundle branch block (BBB) (n = 608); and (iii) right BBB/intraventricular conduction defect (IVCD) (n = 415). The outcomes examined were the composite of cardiovascular death or heart failure hospitalization and all-cause mortality. Both abnormal QRS duration and QRS morphology were associated with higher risk, e.g. the rates of the composite outcome were: 10.2, 17.6, and 15.5 per 100 patient-years in the <120, 120-149, and ≥150 ms groups, respectively. Eplerenone reduced the risk of the primary outcome and mortality, compared with placebo, consistently across the QRS duration/morphology subgroups.

CONCLUSION

We found that even moderate prolongation of QRS duration and right BBB/IVCD were associated with a high risk of adverse outcomes in HF-REF. Eplerenone was similarly effective, irrespective of QRS duration/morphology.

Ventricular conduction abnormalities as predictors of long-term survival in acute de novo and decompensated chronic heart failure

Aims

Data on the prognostic role of left and right bundle branch blocks (LBBB and RBBB), and nonspecific intraventricular conduction delay (IVCD; QRS ≥ 110 ms, no BBB) in acute heart failure (AHF) are controversial. Our aim was to investigate electrocardiographic predictors of long‐term survival in patients with de novo AHF and acutely decompensated chronic heart failure (ADCHF).

Methods and Results

We analysed the admission electrocardiogram of 982 patients from a multicenter European cohort of AHF with 3.9 years' mean follow‐up. Half (51.5%, n = 506) of the patients had de novo AHF. LBBB, and IVCD were more common in ADCHF than in de novo AHF: 17.2% vs. 8.7% (P < 0.001) and 20.6% vs. 13.2% (P = 0.001), respectively, and RBBB was almost equally common (6.9% and 8.1%; P = 0.5), respectively. Mortality during the follow‐up was higher in patients with RBBB (85.4%) and IVCD (73.7%) compared with patients with normal ventricular conduction (57.0%); P < 0.001 for both. The impact of RBBB on prognosis was prominent in de novo AHF (adjusted HR 1.93, 1.03–3.60; P = 0.04), and IVCD independently predicted death in ADCHF (adjusted HR 1.79, 1.28–2.52; P = 0.001). Both findings were pronounced in patients with reduced ejection fraction. LBBB showed no association with increased mortality in either of the subgroups. The main results were confirmed in a validation cohort of 1511 AHF patients with 5.9 years' mean follow‐up.

Conclusions

Conduction abnormalities predict long‐term survival differently in de novo AHF and ADCHF. RBBB predicts mortality in de novo AHF, and IVCD in ADCHF. LBBB has no additive predictive value in AHF requiring hospitalization.

The Prognostic Significance of Right Bundle Branch Block: A Meta-analysis of Prospective Cohort Studies

BACKGROUND

The prognostic significance of right bundle branch block (RBBB) is inconsistent across studies. We aimed to assess the association between RBBB (in general population and patients with heart disease) and risk of all-cause mortality, cardiac death, acute myocardial infarction (MI), and heart failure (HF).

HYPOTHESIS

RBBB may be associated with increased risk of death.

METHODS

PubMed, EMBASE, and the Cochrane Library up to February 2015 were searched for prospective cohort studies that reported RBBB at baseline and all-cause mortality, cardiac death, MI, and HF at follow-up. A meta-analysis of published data was undertaken primarily by means of fixed-effects models.

RESULTS

Nineteen cohort studies including 201 437 participants were included with a mean follow-up period ranging from 1 to 246 months. For general population with RBBB, the pooled adjusted hazard ratio (HR) for all-cause mortality was 1.17 (95% confidence interval [CI]: 1.03-1.33) compared with no BBB. General population with RBBB had an increased risk of cardiac death (HR: 1.43, 95% CI: 1.17-1.74). For patients with RBBB and acute MI, the pooled risk ratio was 2.31 (95% CI: 2.13-2.49) for in-hospital mortality, 2.85 (95% CI: 2.46-3.30) for 30-day mortality, and 1.96 (95% CI: 1.59-2.42) for longer-term mortality. For acute HF patients, the pooled risk ratio of all-cause mortality was 1.11 (95% CI: 1.06-1.16), and for chronic HF patients it was 1.75 (95% CI: 1.38-2.22).

CONCLUSIONS

Right bundle branch block is associated with an increased risk of mortality in general population and patients with heart disease.

Real world effectiveness of primary implantable cardioverter defibrillators implanted during hospital admissions for exacerbation of heart failure or other acute co-morbidities: cohort study of older patients with heart failure

OBJECTIVES

To examine the effectiveness of primary implantable cardioverter defibrillators (ICDs) in elderly patients receiving the device during a hospital admission for exacerbation of heart failure or other acute co-morbidities, with an emphasis on adjustment for early mortality and other factors reflecting healthy candidate bias rather than the effect of the ICD.

DESIGN

Retrospective cohort study.

SETTING

Linked data from the Centers for Medicare and Medicaid Services and American College of Cardiology-National Cardiovascular Data Registry ICD registry, nationwide heart failure registry, and Medicare claims data 2004-09.

POPULATION

23,111 patients aged ≥ 66 who were admitted to hospital for exacerbation of heart failure or other acute co-morbidities and eligible for primary ICDs.

MAIN OUTCOME MEASURES

All cause mortality and sudden cardiac death. Latency analyses with Cox regression were used to derive crude hazard ratios and hazard ratios adjusted for high dimension propensity score for outcomes after 180 days from index implantation or discharge.

RESULTS

Patients who received an ICD during a hospital admission had lower crude mortality risk than patients who did not receive an ICD (40% v 60% at three years); however, with conditioning on 180 day survival and with adjustment for high dimension propensity score, the apparent benefit with ICD was no longer evident for sudden cardiac death (adjusted hazard ratio 0.95, 95% confidence interval 0.78 to 1.17) and had a diminished impact on total mortality (0.91, 0.82 to 1.00). There were trends towards a benefit with ICD in reducing mortality or sudden cardiac death in patients who had had a myocardial infarction more than 40 days previously, left bundle branch block, or low serum B type natriuretic peptide; however, these trends did not reach significance.

CONCLUSION

After adjustment for healthy candidate bias and confounding, the benefits of primary ICD therapy seen in pivotal trials were not apparent in patients aged 66 or over who received ICDs during a hospital admission for exacerbation of heart failure or other acute co-morbidities. Future research is warranted to further identify subgroups of elderly patients who are more likely to benefit from ICDs. Recognition of those patients whose dominant risk factors are from decompensated heart failure and non-cardiac co-morbidities will allow better focus on ICDs in those patients for whom the device offers the most benefit and provides meaningful prolonging of life.

Use of Cardiac Resynchronisation Therapy - Change of Clinical Settings

Current guidelines recommend cardiac resynchronisation therapy (CRT) for patients with severe left ventricular dysfunction (left ventricular ejection fraction [LVEF] ≤35 %), QRS duration of ≥120-150 ms (Class IA and IB indications) on surface electrocardiogram (ECG) and New York Heart Association (NYHA) class III or IV heart failure (HF) symptoms. Ongoing studies aim to expand the use of CRT in patients with asymptomatic or minimal symptoms left ventricular dysfunction. There have been studies that have shown benefit of CRT extended to this group of patients. There have also been different implications of the role of CRT in patients with atrial fibrillation (AF), patients with narrow QRS duration or with right bundle branch block (RBBB) on surface ECG, as well as patients with end-stage renal failure on dialysis therapy. This article aims to review the current body of evidence of expanding use of CRT in these populations.

ECG in patients with acute heart failure can predict in-hospital and long-term mortality

Initial risk stratification in patients with acute heart failure (AHF) is poorly validated. Previous studies tended to evaluate the prognostic significance of only one or two selected ECG parameters. The aim of this study was to evaluate the impact of multiple ECG parameters on mortality in AHF. The Acute Heart Failure Database (AHEAD) registry collected data from 4,153 patients admitted for AHF to seven hospitals with Catheter Laboratory facilities. Clinical variables, heart rate, duration of QRS, QT and QTC intervals, type of rhythm and ST-T segment changes on admission were collected in a web-based database. 12.7 % patients died during hospitalisation, the remainder were discharged and followed for a median of 16.2 months. The most important parameters were a prolonged QRS and a junctional rhythm, which independently predict both in-hospital mortality [QRS > 100 ms, odds ratio (OR) 1.329, 95 % CI 1.052-1.680; junctional rhythm, OR 3.715, 95 % CI 1.748-7.896] and long-term mortality (QRS > 120 ms, OR 1.428, 95 % CI 1.160-1.757; junctional rhythm, OR 2.629, 95 % CI 1.538-4.496). Increased hospitalisation mortality is predicted by ST segment elevation (OR 1.771, 95 % CI 1.383-2.269) and prolonged QTC interval >475 ms (OR 1.483, 95 % CI 1.016-2.164). Presence of atrial fibrillation and bundle branch block is associated with increased unadjusted long-term mortality, but mostly reflects more advanced heart disease, and their predictive significance is attenuated in the multivariate analysis. ECG in patients admitted for acute heart failure carries significant short- and long-term prognostic information, and should be carefully evaluated.

Prognostic significance of ECG abnormalities for mortality risk in acute heart failure: insight from the Sub-Saharan Africa Survey of Heart Failure (THESUS-HF)

OBJECTIVE

The aim of this study was to assess the predictive utility of 12-lead electrocardiogram (ECG) abnormalities among Africans with acute heart failure (HF).

METHODS AND RESULTS

We used the Sub-Saharan Africa Survey of Heart Failure, a multicenter prospective cohort study of 1,006 acute HF patients, and regression models to relate baseline ECG findings to all-cause mortality and readmission during a 6-month follow-up period. Of 814 ECGs available, 523 (49.0% male) were obtained within 15 days of admission, among which 97.7% showed abnormalities. Mean age was 52.0 years and median follow-up was 180 days, with 77 deaths (Kaplan-Meier 17.5%) through day 180 and 63 patients with death or readmission to day 60. QRS width, QT duration, bundle branch block, and ischemic changes were not associated with outcomes. Increasing ventricular rate was associated with increasing risk of both outcomes (hazard ratio [HR] 1.07 per 5 beats/min increase for 60-day death or readmission, 95% confidence interval [CI] 1.02-1.12; P = .0047), and the presence of sinus rhythm was associated with lower risk (HR 0.58, 95% CI 0.34-0.97; P = .0385). There was a strong association between survival and heart rate in patients in sinus rhythm, with heart rate >119 beats/min conveying the worst mortality risk.

CONCLUSIONS

ECG abnormalities are almost universal among Africans with acute HF, which may add to the immediate diagnosis of patients presenting with dyspnea. Although some ECG findings have prognostic value for risk of adverse outcomes, most of them are nonspecific and add little to the risk stratification of these patients.

Differential clinical characteristics and prognosis of intraventricular conduction defects in patients with chronic heart failure

AIMS

Intraventricular conduction defects (IVCDs) can impair prognosis of heart failure (HF), but their specific impact is not well established. This study aimed to analyse the clinical profile and outcomes of HF patients with LBBB, right bundle branch block (RBBB), left anterior fascicular block (LAFB), and no IVCDs.

METHODS AND RESULTS

Clinical variables and outcomes after a median follow-up of 21 months were analysed in 1762 patients with chronic HF and LBBB (n = 532), RBBB (n = 134), LAFB (n = 154), and no IVCDs (n = 942). LBBB was associated with more marked LV dilation, depressed LVEF, and mitral valve regurgitation. Patients with RBBB presented overt signs of congestive HF and depressed right ventricular motion. The LAFB group presented intermediate clinical characteristics, and patients with no IVCDs were more often women with less enlarged left ventricles and less depressed LVEF. Death occurred in 332 patients (interannual mortality = 10.8%): cardiovascular in 257, extravascular in 61, and of unknown origin in 14 patients. Cardiac death occurred in 230 (pump failure in 171 and sudden death in 59). An adjusted Cox model showed higher risk of cardiac death and pump failure death in the LBBB and RBBB than in the LAFB and the no IVCD groups.

CONCLUSION

LBBB and RBBB are associated with different clinical profiles and both are independent predictors of increased risk of cardiac death in patients with HF. A more favourable prognosis was observed in patients with LAFB and in those free of IVCDs. Further research in HF patients with RBBB is warranted.

Right bundle branch block: prevalence, risk factors, and outcome in the general population: results from the Copenhagen City Heart Study

AIMS

To determine the prevalence, predictors of newly acquired, and the prognostic value of right bundle branch block (RBBB) and incomplete RBBB (IRBBB) on a resting 12-lead electrocardiogram in men and women from the general population.

METHODS AND RESULTS

We followed 18 441 participants included in the Copenhagen City Heart Study examined in 1976-2003 free from previous myocardial infarction (MI), chronic heart failure, and left bundle branch block through registry linkage until 2009 for all-cause mortality and cardiovascular outcomes. The prevalence of RBBB/IRBBB was higher in men (1.4%/4.7% in men vs. 0.5%/2.3% in women, P < 0.001). Significant predictors of newly acquired RBBB were male gender, increasing age, high systolic blood pressure, and presence of IRBBB, whereas predictors of newly acquired IRBBB were male gender, increasing age, and low BMI. Right bundle branch block was associated with significantly increased all-cause and cardiovascular mortality in both genders with age-adjusted hazard ratios (HR) of 1.31 [95% confidence interval (CI), 1.11-1.54] and 1.87 (95% CI, 1.48-2.36) in the gender pooled analysis with little attenuation after multiple adjustment. Right bundle branch block was associated with increased risk of MI with an HR of 1.67 (95% CI, 1.16-2.42) and pacemaker insertion with an HR of 2.17 (95% CI, 1.22-3.86), but not with chronic heart failure (HR 1.37; 95% CI, 0.96-1.94), atrial fibrillation (HR 1.10; 95% CI, 0.73-1.67), or chronic obstructive pulmonary disease (HR 0.99; 95% CI, 0.60-1.62). The presence of IRBBB was not associated with any adverse outcome.

CONCLUSION

In this cohort study, RBBB and IRBBB were two to three times more common among men than women. Right bundle branch block was associated with increased cardiovascular risk and all-cause mortality, whereas IRBBB was not. Contrary to common perception, RBBB in asymptomatic individuals should alert clinicians to cardiovascular risk.

Peripartum cardiomyopathy

Peripartum cardiomyopathy (PPCM) is a potentially devastating disease that affects women during the last months of pregnancy or the first months after delivery. The aetiology and pathogenesis of this disease remain unclear, but oxidative stress and the generation of a cardiotoxic fragment of prolactin may play key roles. Diagnosing PPCM remains a challenge, as symptoms may mimic those women experience during normal pregnancy and the peripartum period. A high index of suspicion is thus necessary to make the diagnosis. Patients with PPCM have a varied clinical course, as some patients achieve full recovery while others progress to end-stage heart failure and even death. Standard heart failure treatment is indicated, although special provisions are necessary in pregnant and lactating women. Additional research into the pathophysiology of this disease, including possible genetic contributions, may lead to novel treatment strategies that can improve outcomes.