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

[Electrocardiographic and hemodynamic profile of patients with psychotic disorder]

INTRODUCTION

Cardiac mortality among patients diagnosed with mental disorders is higher compared to the general population. Some authors suggest that cardiovascular risk is related to intrinsic factors specific to psychiatric disease. Nevertheless, the interpretation of these results is limited by the concomitant prescription of antipsychotics which have a cardiovascular effect. Studies evaluating the hemodynamic and electrocardiographic profile of drug naïve or drug-free patients suffering from mental disorders remain few.

AIMS

The aims of this work were to study the electrocardiographic and hemodynamic profile of drug naïve or drug-free patients with mental disorders and to determine clinical and biological factors associated with any electrocardiographic abnormalities.

SUBJECTS AND METHODS

It was a descriptive and evaluative cross-sectional study. We enrolled drug naïve or drug-free patients for at least two months. All subjects were inpatients and had at admission clinical, biological and electrocardiographic evaluation.

RESULTS

Forty-four percent of the sample had asymptomatic electrocardiographic abnormalities. These subjects had lower serum thyroid hormone levels compared to healthy group (P=0.066). Hemodynamic profile showed that 12% of the population had orthostatic hypotension.

CONCLUSION

Electrocardiographic and hemodynamic abnormalities are common among drug-free or drug naïve patients diagnosed with psychotic disorders. The association of electrocardiographic abnormalities with low levels of thyroxin requires more investigation.

Congenital myopathies are mainly associated with a mild cardiac phenotype

BACKGROUND

To evaluate the prevalence of cardiac involvement in patients with congenital myopathies and the association to specific genotypes.

METHODS

We evaluated patients with physical examination, electrocardiogram, echocardiography, and 48-h Holter monitoring. Follow-up was performed for major events.

RESULTS

We included 130 patients, 55 men (42%), with a mean age of 34 ± 17 years. A genetic diagnosis was established in 97 patients (75%). Right bundle branch block was observed in three patients: 2/34 patients with a ryanodine receptor 1 (RYR1) and 1/6 with a tropomyosin two gene (TPM2) gene mutation. Echocardiography showed left-ventricular hypertrophy in five patients: 2/17 and 3/34 patients with a Dynamin 2 (DNM2) and a RYR1 mutation, respectively. One patient with a myosin heavy-chain (MYH7) mutation had dilated cardiomyopathy and heart failure. On Holter monitoring, frequent ventricular premature contractions were observed in one patient with a DNM2 mutation. Two patients with a TPM2 and a RYR1 mutation, respectively, had a single short run of non-sustained ventricular tachycardia. Atrioventricular nodal re-entry tachycardia was observed in a 20-year-old man with an actin 1 gene mutation. During follow-up (median 8.4 years), four patients died, all of non-cardiac causes.

CONCLUSION

Congenital myopathies are generally associated with a mild cardiac phenotype. Our findings substantiate the literature and indicate that, except for patients with specific genotypes, such as MYH7 and TTN mutations, repeated cardiac assessments can be minimized, given a normal initial cardiac screening at time of diagnosis.

Conduction Abnormalities After Transcatheter Aortic Valve Replacement

Transcatheter aortic valve replacement (TAVR) has been established as a therapeutic option for patients with severe symptomatic aortic stenosis who are of intermediate or higher surgical risk. Several periprocedural complications are reduced with newer transcatheter heart valve generations; however, conduction abnormalities and the need for permanent pacemaker implantation have remained unchanged and are the most frequent TAVR complications. The close relationship of the atrioventricular node and left bundle branch to the subaortic region explains these potential conduction abnormalities. This article highlights conduction abnormalities after TAVR with a focus on basic conduction system anatomy in relation to the aortic valve, the mechanism, incidence, predisposing factors for occurrence, impact on mortality and finally, proposed treatment algorithms for management.

Clinical features, predictors, and long-term prognosis of pacing-induced cardiomyopathy

AIMS

We investigated the clinical features, predictors, and long-term prognosis of pacing-induced cardiomyopathy (PiCM).

METHODS AND RESULTS

From a retrospective analysis of 1418 consecutive pacemaker patients, 618 were found to have a preserved baseline left ventricular ejection fraction (LVEF), follow-up echocardiographic data, and no history of heart failure (HF). PiCM was defined as a reduction in LVEF (< 50%) along with either (i) a ≥ 10% decrease in LVEF, or (ii) new-onset regional wall motion abnormality unrelated to coronary artery disease. PiCM occurred in 87 of 618 patients (14.1%), with a decrease in mean LVEF from 60.5% to 40.1%. The median time to PiCM was 4.7 years. Baseline left bundle branch block, wider paced QRS duration (≥ 155 ms), and higher ventricular pacing percentage (≥ 86%) were identified as independent predictors of PiCM in multivariate logistic regression analysis. The risk of PiCM increased gradually with the number of identified predictors, becoming more significant in the presence of two or more predictors (P < 0.001). During the entire follow-up (median 7.2 years), the risk of all-cause death or HF admission was significantly higher in patients with PiCM compared to those without PiCM (38.3% vs. 54.0%, adjusted hazard ratio 2.93; 95% confidence interval 1.82-4.72; P < 0.001).

CONCLUSION

Pacing-induced cardiomyopathy patients showed a worse long-term prognosis than those without PiCM. Therefore, patients with multiple risk factors of PiCM should be monitored carefully even if their left ventricular systolic function is preserved initially. A timely upgrade to a biventricular or His-bundle pacing device needs to be considered in patients with PiCM.

ECG clues for false ST-segment elevation myocardial infarction activations

BACKGROUND

Rapid diagnosis of ST-segment elevation myocardial infarction (STEMI) is crucial for appropriate management. Catheterization for a false STEMI activation has risks including exposure to contrast agent and radiation, increased healthcare costs and delay in treatment of the primary medical condition.

PATIENTS AND METHODS

This was a single center retrospective study including all 'cath alerts' between January 2012 and December 2015. 'Cath alert' is a term used to activate the interventional cardiology team when STEMI is suspected by the emergency department physicians based on review of the initial ECG. We reviewed all STEMI alerts to understand ECG differences between true and false STEMI.

RESULTS

Our study population (N = 361) included 221 (61%) men and 140 (39%) women, with average age 60 ± 4.2 years. Among the 361 STEMI alerts, 82 (22.7%) did not have acute coronary syndrome. Common ECG causes of misdiagnosis included left ventricular hypertrophy (LVH, found in 40/82, 49%), early repolarization changes (20/82, 24%), right bundle branch block (RBBB) (13/82, 16%), and Brugada pattern (3/82, 4%). Multivariate regression analysis showed that LVH and RBBB were independent predictors of nonacute coronary syndrome false STEMI (odds ratio: 0.54; 95% confidence interval: 0.32-0.93; P = 0.03 for LVH, and odds ratio: 0.26, 95% confidence interval: 0.1-0.62, P = 0.004 for RBBB).

CONCLUSION

The incidence of false STEMI alerts was almost 23% at our center. This number might be reduced with additional training of emergency department physicians in ECG interpretation, and recognition of common causes of misdiagnosis such as LVH, early repolarization changes, RBBB, and Brugada pattern.

Donor health assessment - When is blood donation safe?

Blood donation is a highly regulated practice in the world, ensuring the safety and efficacy of collected blood and its components whether used as irreplaceable parts of modern transfusion medicine, as a therapeutic modality or additional support to other clinical therapies. In Norway blood donation is regulated by governmental regulations ("Blodforskriften") and further instructed by national guidelines, "Veileder for transfusjonstjenesten" [1], providing an aid for assessment of donor health. This concise review touches upon: definitions of donor health and disease; some important pitfalls; and the handling of some common and less common pathophysiological conditions; with an example from the Blood center of Oslo University Hospital, Norway's largest blood center. I also comment on some medications used by a number of blood donors, although wounds, ulcers and surgery are not included. Considering the panorama of conditions blood donors can suffer from, blood donation can never be completely safe for everybody, as zero risk does not exist, but it is our task through donor evaluation to identify and reduce risk as much as possible.

Registry report of the prevalence of ECG abnormalities and their relation to patient characteristics in an asymptomatic population

BACKGROUND

Cardiovascular disease is the leading cause of morbidity and mortality in developed countries. Many patients do not experience symptoms before a first major cardiovascular event. Resting electrocardiogram (ECG) may help identify asymptomatic individuals with a high risk of cardiovascular disease.

OBJECTIVE

We sought to determine the prevalence of ECG abnormalities in an apparently symptom-free adult population within a prospective registry.

METHODS

The registry consisted of 4739 consecutive apparently healthy individuals [age 62.8 ± 6.2 (SD) years; 54% female], referred by their General Practitioners between 2009 and 2013. Patient demographics, and clinical data were obtained, alongside blood tests and a resting ECG.

RESULTS

ECG abnormalities were present in 1509 (31.8%) subjects and were commoner with increasing age (F = 0.161, p = 0.01), systolic (F = 0.134, p = 0.01) and diastolic (F = 0.44, p = 0.01) blood pressure and waist circumference (F = 0.53, p = 0.01). Left ventricular hypertrophy (LVH) was the most common abnormality (n = 281) and was positively associated with systolic (F = 0.12, p = 0.01) and diastolic blood pressure (F = 0.99, p = 0.01) and male gender (X2 = 60.5, p < 0.01). All ECG abnormalities (except for LVH) were associated with an increasing age, while right bundle branch block (F = 0.041, p = 0.01) and atrial fibrillation (n = 29; F = 0.036, p = 0.05) were associated with the presence of diabetes mellitus (n = 211). Only left bundle branch block (n = 50) was associated with angina (F = 0.05, p = 0.01).

CONCLUSIONS

Unrecognized cardiac abnormalities are common in middle-aged men and women with no overt symptoms. ECG offers the potential to identify these abnormalities and provide earlier intervention and treatment, and possibly improve cardiovascular outcome.

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.

Electrocardiographic characteristics, anthropometric features, and cardiovascular risk factors in a large cohort of adolescents

Aims

The characteristics of electrocardiographic (ECG) patterns in the general population of adolescents are insufficiently defined. The purpose of this study is to report ECG patterns and their association with anthropometric characteristics.

Methods and results

Twenty-four thousand and sixty-two students of Roman schools, aged 12–19, were screened with ECG and physical examinations. Electrocardiographic abnormalities were classified as either minor/non-clinically relevant or major, and anthropometric measures were evaluated per age class. Obesity prevalence was 20.9%, with a higher rate in younger students (P < 0.008 for all comparisons, except for the pair 16–17 vs. 18–19 years). Stage 1 hypertension was found in 3.14% of adolescents, Stage 2 hypertension in 0.45% of adolescents, and isolated systolic hypertension in 11.7% of adolescents. Heart rate and QT interval corrected for heart rate (QTc) decreased with increasing age. The QTc was longer in females than in males over 14 years. A higher rate of incomplete right bundle branch block (RBBB) was observed in underweight students (21.58% vs. 15.10% in non-underweight students, P < 0.0001). Complete RBBB was the most common major ECG abnormality (1.6%). It was associated with height irrespective of age, sex, and body mass index (odds ratio 17.9; 95% confidence interval 5.0–64.6) and more frequent in students regularly practicing physical activity (1.80% vs. 1.02%, P = 0.0009).

Conclusion

Heart rate and QTc decreased with increasing age. The QTc was longer in females than in males over 14 years. RBBB was the most common major abnormality and was associated with higher stature. The prevalence of some cardiovascular risk factors in adolescents is provided.

Right bundle branch block in patients with suspected myocardial infarction

Aims:

The new European Society of Cardiology guideline for ST-segment elevation myocardial infarction recommends that left and right bundle branch block should be considered equal for recommending urgent angiography in patients with suspected myocardial infarction. We aimed to evaluate this novel recommendation in two prospective studies of patients with suspected myocardial infarction.

Methods and results:

We included 4067 patients presenting to the emergency department with suspected myocardial infarction. All patients had an ECG recorded immediately upon admission. Patients were classified as having right bundle branch block (RBBB), left bundle branch block (LBBB), bifascicular block (BFB) or no bundle branch block. All patients were followed for up to two years to assess mortality. In the overall population 125 (3.1%) patients had RBBB, 281 (6.9%) LBBB and 60 (1.5%) BFB. The final diagnosis of myocardial infarction was adjudicated in 20.8% (RBBB), 28.5% (LBBB), 23.3% (BFB) and 21.6% (no complete block) of patients. The mortality rate after one year was 10.7% (RBBB), 7% (LBBB), 17.5% (BFB) and 3.2% (no complete block). The adjusted hazard ratios were 1.29 (95% confidence interval (CI) 0.71–2.34; P=0.40) for RBBB, 1.71 (95% CI 1.17–2.50; P=0.006) for LBBB and 2.27 (95% CI 1.28–4.05; P=0.005) for BFB.

Conclusion:

Our results support the new European Society of Cardiology ST-segment elevation myocardial infarction guideline describing RBBB as a high risk for mortality in patients with suspected myocardial infarction. However, the data challenge the concept of RBBB as a trigger of acute angiography because the likelihood of myocardial infarction in a chest pain unit setting is equally frequent in patients without bundle branch block.

Association between decreasing estimated glomerular filtration rate and risk of cardiac conduction defects in patients with type 2 diabetes

AIM

We aimed to assess the association between decreasing estimated glomerular filtration rate (eGFR) or abnormal albuminuria and the risk of certain cardiac conduction defects in patients with type 2 diabetes mellitus (T2DM).

METHODS

We examined a hospital-based sample of 923 patients with T2DM discharged from our Division of Endocrinology over the years 2007-2014. Standard electrocardiograms (ECGs) were performed in all patients. eGFR was estimated by using the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, whilst albuminuria was measured by an immuno-nephelometric method on morning spot urine samples.

RESULTS

A total of 253 (27.4%) patients had some type of cardiac conduction defects on standard ECGs (defined as at least one heart block among first-degree atrioventricular block, second-degree block, third-degree block, left bundle branch block, right bundle branch block, left anterior hemi-block or left posterior hemi-block). Prevalence of patients with eGFR_CKD-EPI < 30 mL/min/1.73 m², eGFR_CKD-EPI 59-30 mL/min/1.73 m² or abnormal albuminuria (i.e. urinary albumin-to-creatinine ratio ≥ 30 mg/g) were 7.0%, 29.4% and 41.3%, respectively. After adjustment for known cardiovascular risk factors, diabetes-related variables and potential confounders, there was a significant, graded association between decreasing eGFR values and risk of any cardiac conduction defects [adjusted-odds ratios of 2.05 (95% CI: 1.2-3.5), 2.85 (95% CI: 1.6-5.1) and 3.62 (95% CI: 1.6-8.1) for eGFR_CKD-EPI 89-60, eGFR_CKD-EPI 59-30 and eGFR_CKD-EPI < 30 mL/min/1.73 m², respectively]. Conversely, abnormal albuminuria was not independently associated with an increased risk of any conduction defects (adjusted-odds ratio: 1.09, 95% CI: 0.7-1.6).

CONCLUSION

Decreasing eGFR is independently associated with an increased risk of cardiac conduction defects in hospitalized patients with T2DM.

Permanent pacemaker implantation after transcatheter aortic valve replacement in bicuspid aortic valve patients

BACKGROUND

Studies of permanent pacemaker implantation (PPI) after transcatheter aortic valve replacement (TAVR) specifically for bicuspid aortic valve (BAV) patients are lacking. We aim to delineate possible aspects that might affect the incidence of PPI in a retrospective cohort of BAV patients treated with early-generation self-expanding devices.

METHODS

A total of 80 patients with bicuspid morphology who successfully underwent TAVR by self-expanding devices without prior PPI were included. Baseline clinical, echocardiographic, and angiographic characteristics, procedural and post-procedural details were collected.

RESULTS

The incidence of PPI after early-generation self-expanding valves in this BAV cohort was 26.3%. Baseline characteristics were comparable between patients requiring PPI post-TAVR or not. Perimeter oversizing greater than 20% significantly increased the risk of PPI compared with an oversizing of 10-20% (OR 5.08 [1.22, 21.07], P = 0.03). The proportion of patients with a depth of implantation greater than 6 mm was significantly higher in those who required PPI (82.4% vs 54.3%, P = 0.04). When testing the impact of depth of implantation >6 mm and oversizing in different morphologies, only in type 1 bicuspid patients and by oversizing>20% increased the risk of PPI (OR 12.00 [1.25, 115.36], P = 0.03) compared with an oversizing of 10-20%.

CONCLUSIONS

Excessive perimeter oversizing in relation to aortic annulus and depth of implantation greater than 6 mm should be avoided to improve PPI post-TAVR for BAV patients receiving self-expanding devices, especially for type 1 BAV.

Incidence of arrhythmias and impact of permanent pacemaker implantation in hospitalizations with transcatheter aortic valve replacement

BACKGROUND

This study sought to analyze in-hospital outcomes associated with preexisting and newly implanted permanent pacemaker (PPM) in patients who underwent transcatheter aortic valve replacement (TAVR). PPM implantation following the development of conduction abnormalities is a common adverse event following TAVR. Furthermore, PPM implantation rates are higher in TAVR hospitalizations compared with the surgical alternative, thus we have analyzed the predictors of pacing post-TAVR.

HYPOTHESIS

We hypothesize that incidence of arrhythmias are high post-TAVR and have worse adverse outcomes after receiving PPM.

METHODS

The study population was identified from the National Inpatient Sample database between 2012 and 2014. TAVR population was identified using ICD-9-CM procedure codes 35.05 and 35.06. Hospitalizations were divided into 3 group: (1) with preexisting PPM, (2) with newly implanted PPM, and (3) without any PPM.

RESULTS

Overall, 0.8% of hospitalizations presented with preexisting PPM and 23.7% of hospitalizations received new PPM. The overall incidence of atrial fibrillation was 44.5%, left bundle branch block 8.9%, complete atrioventricular block 9.5%, and right bundle branch block 2.7%. In-hospital mortality was higher in hospitalizations receiving PPM compared with those without (4.9% vs 4.0%; P = 0.05). Length of stay and cost were higher in the group receiving new PPM. Female sex, atrial fibrillation, left bundle branch block, and second-degree and complete atrioventricular block were significant predictors for receiving PPM after TAVR.

CONCLUSIONS

A risk stratification for hospitalizations with conduction disorders is necessary to avoid longer hospital stays, added costs, and mortality. Further research is warranted to investigate additional predictors for PPM after TAVR.

Severe brady-arrhythmias in systemic lupus erythematosus: prevalence, etiology and associated factors

Background

Severe brady-arrhythmias, requiring a permanent pacemaker (PPM), have been sparsely reported in systemic lupus erythematosus (SLE). The aim of this study was to describe the characteristics of such arrhythmias in a defined lupus cohort.

Patients and methods

The database of the Toronto Lupus Clinic ( n = 1366) was searched for patients who received a PPM. Demographic, clinical, immunological and therapeutic variables along with electrocardiographic (ECG) and echocardiographic findings (based on the last available test prior to PPM) were analyzed. Patients with a PPM (cases) were compared with age-, sex- and disease duration-matched patients without a PPM (controls). Analysis was performed with SAS 9.0; p < 0.05 was considered significant.

Results

Eighteen patients were identified, 13 (0.95%) with complete atrioventricular block and 5 (0.37%) with sick sinus syndrome. Disease duration at PPM implantation was 22 ± 12 years. Compared to controls, cases had more frequently coronary artery disease, hypertension, dyslipidemia and longer antimalarial (AM) treatment duration. The prevalence of first-degree atrioventricular block, right bundle branch block, left anterior fascicular block and septal hypertrophy was also higher. AM treatment was significantly associated with brady-arrhythmias (OR = 1.128, 95% CI = 1.003–1.267, p = 0.044). Nine patients had prior heart disease and one received a PPM two years after renal transplantation. Eight patients did not have any potential risk factors; prolonged AM therapy (mean 22 years) might have been the cause.

Conclusions

Apart from known causes, prolonged AM treatment may be associated with severe brady-arrhythmias in SLE. Certain ECG and echocardiographic characteristics may represent indicators of an ongoing damage in the conduction system.

Electrocardiogram Abnormalities Suggest Aberrant Cardiac Conduction in Huntington's Disease

Background

There is increasing evidence that the effects of Huntington's disease (HD) extend beyond the central nervous system. In particular, significant cardiac dysfunction has been described in transgenic mouse models and suggested in symptomatic patients, in whom cardiac involvement could provide an independent risk for sudden cardiac death.

Methods

Standard 12-lead electrocardiograms (ECGs) obtained at screening from 590 early symptomatic (Stage 1 and 2) HD patients participating in a multi-site Phase III study were analyzed.

Results

Evaluating only those ECGs in individuals not on medications or with potentially contributing medical conditions, the prevalence of bradycardia was 28.3% (marked in 5.8%), prolonged QRS 4.9%, intraventricular conduction delay 3.4%, right bundle branch block 1.3%, and QTc prolongation 3.7%.

Conclusion

Significant cardiac abnormalities, characterized primarily by conduction abnormalities, were found in a larger than expected number of patients. Abnormal intraventricular conduction may lead to increased risk for arrhythmia and may be compounded by prescription of QT-prolonging medications.

Prevalence of electrocardiographic abnormalities in primary care patients according to sex and age group. A retrospective observational study

BACKGROUND

Knowledge of the prevalence of electrocardiographic abnormalities in a population is useful for interpreting the findings. The aim here was to assess the prevalence of electrocardiographic abnormalities and self-reported comorbidities and cardiovascular risk factors according to sex and age group among Brazilian primary care patients.

DESIGN AND SETTING

Observational retrospective study on consecutive primary care patients in 658 cities in the state of Minas Gerais, Brazil, whose digital electrocardiograms (ECGs) were sent for analysis to the team of the Telehealth Network of Minas Gerais (TNMG).

METHODS

All ECGs analyzed by the TNMG team in 2011 were included. Clinical data were self-reported and electrocardiographic abnormalities were stratified according to sex and age group.

RESULTS

A total of 264,324 patients underwent ECG examinations. Comorbidities and cardiovascular risk factors were more frequent among women, except for smoking. Atrial fibrillation and flutter, premature beats, intraventricular blocks, complete right bundle branch block and left ventricular hypertrophy were more frequent among men, and nonspecific ventricular repolarization abnormalities and complete left bundle branch block among women.

CONCLUSION

Electrocardiographic abnormalities were relatively common findings, even in the younger age groups. The prevalence of electrocardiographic abnormalities increased with age and was higher among men in all age groups, although women had higher frequency of self-reported comorbidities.

Assessment of potential heart donors: A statement from the French heart transplant community

Assessment of potential donors is an essential part of heart transplantation. Despite the shortage of donor hearts, donor heart procurement from brain-dead organ donors remains low in France, which may be explained by the increasing proportion of high-risk donors, as well as the mismatch between donor assessment and the transplant team's expectations. Improving donor and donor heart assessment is essential to improve the low utilization rate of available donor hearts without increasing post-transplant recipient mortality. This document provides information to practitioners involved in brain-dead donor management, evaluation and selection, concerning the place of medical history, electrocardiography, cardiac imaging, biomarkers and haemodynamic and arrhythmia assessment in the characterization of potential heart donors.

Relation of elevated serum uric acid levels to first-degree heart block and other cardiac conduction defects in hospitalized patients with type 2 diabetes

AIMS

Several studies have reported that moderately elevated serum uric acid levels are associated with an increased risk of tachyarrhythmias (mainly atrial fibrillation) in patients with and without type 2 diabetes mellitus (T2DM). It is currently unknown whether an association also exists between elevated serum uric acid levels and cardiac conduction defects in patients with T2DM.

METHODS

We retrospectively analyzed a hospital-based sample of 967 patients with T2DM discharged from our Division of Endocrinology over the years 2007-2014. Standard electrocardiograms were performed on all patients and were interpreted by expert cardiologists.

RESULTS

Overall, 267 (27.6%) patients had some type of conduction defects on electrocardiograms (defined as at least one block among first-degree atrio-ventricular block, second-degree block, third-degree block, left bundle branch block, right bundle branch block, left anterior hemi-block or left posterior hemi-block). Patients in the 3rd serum uric acid tertile had a higher prevalence of any cardiac conduction defects than those belonging to 2nd or 1st tertile, respectively (35.8% vs. 25.0% vs. 22.6%; p<0.0001). Elevated serum uric acid levels were associated with a nearly twofold increased risk of cardiac conduction defects after adjustment for age, sex, hemoglobin A1c, diabetes duration, metabolic syndrome, chronic kidney disease, chronic obstructive pulmonary disease, ischemic heart disease, valvular heart disease and medication use (adjusted-odds ratio 1.84, 95% confidence intervals 1.2-2.9; p=0.009).

CONCLUSIONS

Moderately elevated serum uric acid levels are associated with an increased prevalence of any cardiac conduction defects in hospitalized patients with T2DM, independent of multiple risk factors and potential confounding variables.

Nonalcoholic fatty liver disease is associated with an increased risk of heart block in hospitalized patients with type 2 diabetes mellitus

Recent studies suggested that nonalcoholic fatty liver disease (NAFLD) is associated with an increased risk of cardiac tachyarrhythmias (mainly atrial fibrillation) in patients with and without type 2 diabetes mellitus. The aim of this study was to examine whether an association also exists between NAFLD and heart block. We have retrospectively evaluated a hospital-based cohort of 751 patients with type 2 diabetes discharged from our Division of Diabetes and Endocrinology during years 2007–2014. Standard electrocardiograms were performed on all patients. Diagnosis of NAFLD was based on ultrasonography, whereas the severity of advanced hepatic fibrosis was based on the fibrosis (FIB)-4 score and other non-invasive fibrosis markers. Overall, 524 (69.8%) patients had NAFLD and 202 (26.9%) had heart block (defined as at least one block among first-degree atrio-ventricular block, second-degree block, third-degree block, left bundle branch block, right bundle branch block, left anterior hemi-block or left posterior hemi-block) on electrocardiograms. Patients with NAFLD had a remarkably higher prevalence of any persistent heart block than those without NAFLD (31.3% vs. 16.7%, p<0.001); this prevalence was particularly increased among those with higher FIB-4 score. NAFLD was associated with a threefold increased risk of prevalent heart block (adjusted-odds ratio 3.04, 95% CI 1.81–5.10), independently of age, sex, hypertension, prior ischemic heart disease, hemoglobin A1c, microvascular complication status, use of medications and other potentially confounding factors. In conclusion, this is the largest cross-sectional study to show that NAFLD and its severity are independently associated with an increased risk of prevalent heart block in hospitalized patients with type 2 diabetes.

Nonalcoholic Fatty Liver Disease (NAFLD) and Risk of Cardiac Arrhythmias: A New Aspect of the Liver-heart Axis

Nonalcoholic fatty liver disease (NAFLD) is a pathologic condition frequently observed in clinical practice. To date, the prevalence of NAFLD is approximately 25-30% among adults of the general population in Western countries but increases to approximately 70-75% among patients with type 2 diabetes mellitus. In the last decade, accumulating evidence has clearly demonstrated that patients with NAFLD have not only an increased liver-related morbidity and mortality but also an increased risk of fatal and non-fatal cardiovascular events. In particular, several studies have documented the existence of an independent association among NAFLD and cardiac changes in structure and function in both non-diabetic and diabetic patients. In addition, mounting evidence also suggests that there is a strong relationship between NAFLD and cardiac arrhythmias, such as atrial fibrillation, QTc prolongation and ventricular arrhythmias. This is of clinical interest, as it could explain, at least in part, the increased risk of death for cardiovascular disease in patients with NAFLD. Therefore, seeing that cardiovascular disease complications are the leading cause of disability and death in NAFLD patients, the recent European clinical practice guidelines advised to check the cardiovascular system in all patients with NAFLD. This clinical mini review will briefly describe the increasing body of evidence regarding the association between NAFLD and cardiac arrhythmias, and discuss the potential biological mechanisms underlying this association.

Population-based values and abnormalities of the electrocardiogram in the general Dutch population: The LifeLines Cohort Study

BACKGROUND

Our aim is to present average values and prevalence of electrocardiographic (ECG) abnormalities among the general Dutch population in the LifeLines Cohort.

HYPOTHESIS

The ECG values previously studied in the Caucasian population of smaller cohorts will be confirmed with ECG data from LifeLines.

METHODS

ECG data of 152 180 individuals age 18 to 93 years were available. Individuals with cardiovascular risk factors were excluded to analyze the healthy population. Average values of the ECG for the healthy population were presented as means with 95% and 99% confidence intervals and as medians with first and 99th percentiles.

RESULTS

Median heart rate was highest in the youngest and oldest individuals of the healthy population. Median duration of P wave, PQ interval, and QRS duration were longer in males compared with females. In contrast, median QT interval corrected for heart rate was higher in females. In general, the above-mentioned parameters increased with age. The prevalences of ECG abnormalities adjusted for the Dutch population were 0.9% for atrial fibrillation or flutter, 1.4% for premature atrial complexes, 0.5% for myocardial infarction, 2.1% for ventricular premature complexes, 1.0% for left ventricular hypertrophy, 8.1% for P-R interval >200 ms, and 0.8% for bundle branch block.

CONCLUSIONS

Our study provides an overview of average values and ECG abnormalities and confirms data of previous smaller studies. In addition, we evaluate the age- and sex-dependent normal limits of the P wave and QRS duration and confirm in detail the frontal plane QRS-T angle on the ECG.

The prevalence of electrocardiogram abnormalities in professional divers

BACKGROUND

The underwater environment presents physiological challenges for the cardiovascular, renal and pulmonary systems. Increases in external hydrostatic pressure reduce the capacity of the venous compartment and cause blood to move toward the lung. The aim of this study was to evaluate retrospectively electrocardiographic (ECG) changes in a cohort of professional divers.

METHODS

Between January 2009 and January 2012, 225 randomly selected professional divers, 204 male (91%) and 21 female (9%) attended our clinic for their biannual diving medical assessment. Their ECG records were evaluated retrospectively.

RESULTS

The most common ECG abnormality observed was incomplete right bundle branch block (IRBBB) in 30 divers (13.3%). Eleven divers (4.9%) showed right QRS axis deviation (seven with IRBBB). Six divers had a sinus tachycardia; in four divers there was early repolarization; three divers had ventricular extrasystoles; one diver had ST elevation in lead V3; there was one with sinus arrhythmia and another with T-wave inversion in leads V2, V3 and aVF. These ECG changes were evaluated retrospectively by a cardiologist who made various recommendations for further review including bubble contrast echocardiography for IRBBB.

CONCLUSIONS

No serious ECG abnormalities were identified, but IRBBB should be further investigated because of its association with persistent (patent) foramen ovale. Rapid cardiological review of ECGs could be achieved using modern communications technology, such as telecardiography, and further clinical investigations directed by specialist recommendation arranged promptly if indicated.

Transcatheter Heart Valve Selection and Permanent Pacemaker Implantation in Patients With Pre-Existent Right Bundle Branch Block

Background

Right bundle branch block is an established predictor for new conduction disturbances and need for a permanent pacemaker (PPM) after transcatheter aortic valve replacement. The aim of the study was to evaluate the absolute rates of transcatheter aortic valve replacement related PPM implantations in patients with pre‐existent right bundle branch block and categorize for different transcatheter heart valves.

Methods and Results

We pooled data on 306 transcatheter aortic valve replacement patients from 4 high‐volume centers in Europe and selected those with right bundle branch block at baseline without a previously implanted PPM. Logistic regression was used to evaluate whether PPM rate differed among transcatheter heart valves after adjustment for confounders. Mean age was 83±7 years and 63% were male. Median Society of Thoracic Surgeons score was 6.3 (interquartile range, 4.1–10.2). The following transcatheter valve designs were used: Medtronic CoreValve (n=130; Medtronic, Minneapolis, MN); Edwards Sapien XT (ES‐XT; n=124) and Edwards Sapien 3 (ES‐3; n=32; Edwards Lifesciences, Irvine, CA); and Boston Scientific Lotus (n=20; Boston Scientific Corporation, Marlborough, MA). Overall permanent pacemaker implantation rate post‐transcatheter aortic valve replacement was 41%, and per valve design: 75% with Lotus, 46% with CoreValve, 32% with ES‐XT, and 34% with ES‐3. The indication for PPM implantation was total atrioventricular block in 98% of the cases. Lotus was associated with a higher PPM rate than all other valves. PPM rate did not differ between ES‐XT and ES‐3. Ventricular paced rhythm at 30‐day and 1‐year follow‐up was present in 81% at 89%, respectively.

Conclusions

Right bundle branch block at baseline is associated with a high incidence of PPM implantation for all transcatheter heart valves. PPM rate was highest for Lotus and lowest for ES‐XT and ES‐3. Pacemaker dependency remained high during follow‐up.

Is screening for abnormal ECG patterns justified in long-term follow-up of childhood cancer survivors treated with anthracyclines?

BACKGROUND

ECG and echocardiography are noninvasive screening tools to detect subclinical cardiotoxicity in childhood cancer survivors (CCSs). Our aims were as follows: (1) assess the prevalence of abnormal ECG patterns, (2) determine the agreement between abnormal ECG patterns and echocardiographic abnormalities; and (3) determine whether ECG screening for subclinical cardiotoxicity in CCSs is justified.

PROCEDURE

We retrospectively studied ECG and echocardiography in asymptomatic CCSs more than 5 years after anthracycline treatment. Exclusion criteria were abnormal ECG and/or echocardiogram at the start of therapy, incomplete follow-up data, clinical heart failure, cardiac medication, and congenital heart disease. ECG abnormalities were classified using the Minnesota Code. Level of agreement between ECG and echocardiography was calculated with Cohen kappa.

RESULTS

We included 340 survivors with a mean follow-up of 14.5 years (range 5-32). ECG was abnormal in 73 survivors (21.5%), with ventricular conduction disorders, sinus bradycardia, and high-amplitude R waves being most common. Prolonged QTc (>0.45 msec) was found in two survivors, both with a cumulative anthracycline dose of 300 mg/m² or higher. Echocardiography showed abnormalities in 44 survivors (12.9%), mostly mild valvular abnormalities. The level of agreement between ECG and echocardiography was low (kappa 0.09). Male survivors more often had an abnormal ECG (corrected odds ratio: 3.00, 95% confidence interval: 1.68-5.37).

CONCLUSIONS

Abnormal ECG patterns were present in 21% of asymptomatic long-term CCSs. Lack of agreement between abnormal ECG patterns and echocardiographic abnormalities may suggest that ECG is valuable in long-term follow-up of CCSs. However, it is not clear whether these abnormal ECG patterns will be clinically relevant.

Twelve-lead electrocardiogram and mortality in young adults after ischaemic stroke

Introduction

Ischaemic stroke at young age carries an increased risk for mortality in comparison to the general population, but factors associated with mortality have been poorly studied. We studied the role of electrocardiogram in mortality risk stratification in young stroke patients.

Patients and methods

The Helsinki Young Stroke Registry encompasses 1008 patients aged <50 years with ischaemic stroke. We included 690 patients for this electrocardiogram substudy. Our endpoints were all-cause and cardiovascular mortality. Cox regression models - adjusted for clinical and demographic characteristics - were used to identify the electrocardiogram parameters associated with these endpoints.

Results

At a mean follow-up of 8.8 years, cumulative all-cause and cardiovascular mortality were 16.1 and 9.1%, respectively. Factors associated with both endpoints included diabetes (type 1 for all-cause, type 2 for cardiovascular mortality), heavy drinking, malignancy, as well as stroke severity and aetiology. Of the electrocardiogram parameters, higher heart rate (hazard ratio 1.35 per 10/min, 95% confidence interval 1.21-1.49), a shorter P-wave (hazard ratio 0.78 per 10 ms decrement, 0.64-0.92) and longer QTc interval (1.09 per 10 ms, 1.03-1.16) were associated with increased all-cause mortality. Only a higher heart rate (1.42 per 10/min, 1.24-1.60) was associated with death from cardiovascular causes.

Conclusions

A higher heart rate during the subacute phase after stroke is associated with an elevated risk of all-cause and cardiovascular mortality in young adults. A longer QTc interval is associated only with higher all-cause mortality. P-wave characteristics and their possible association with mortality need further studies.

Association between right ventricular systolic function and electromechanical delay in patients with right bundle branch block

BACKGROUND

Elevated right ventricle (RV) pressure and/or volume can place stress on the right bundle branch block (RBBB) and its associated Purkinje network, which can affect its electrical properties, resulting in conduction delay or block. We hypothesized that prolonged R' wave duration in lead V1 would extend the later portion of the QRS complex and can act as an indicator of reduced RV function in patients with RBBB.

METHOD

Kosin University Gospel Hospital echocardiography and electrocardiography (ECG) database was reviewed to identify patients with complete RBBB between 2013 and 2015. ECGs recorded closest to the time of the echocardiography were carefully reviewed, and QRS and R' wave duration were measured. RV systolic dysfunction was defined as an RV fractional area change (FAC) less than 35%, as indicated by echocardiography guidelines.

RESULTS

Compared to patients with normal RV function (n=241), patients with RV dysfunction (n=123) showed prolonged QRS duration (145.3±19.3ms vs. 132.2±13.4ms, p<0.001), predominantly due to R' prolongation (84.8±13.0ms vs. 102.9±12.0ms, p<0.001). R' duration was significantly associated with RV FAC (r=-0.609, p<0.001), RV systolic pressure (r=0.142, p=0.008), RV dimension (r=0.193, p<0.001), and RV myocardial performance index (r=0.199, p<0.001). On receiving operator characteristic curve analysis, V1 R' duration ≥93ms was associated with RV dysfunction with 90% sensitivity and 87% specificity (area under the curve: 0.883, 95% confidence interval=0.845-0.914, p<0.001).

CONCLUSION

Prolonged R' wave duration in lead V1 is an indicator of RV dysfunction and pressure and/or volume overload in patients with RBBB.

Cardiovascular outcomes in patients with intraventricular conduction blocks: A sixteen-year follow-up in a state-wide database

BACKGROUND

To assess the adverse clinical effects of left anterior hemiblock alone or in combination with right bundle branch block and of complete left bundle branch block in comparison with isolated right bundle branch block and the relationship of these effects with altered mechanoelectric factors resulting in left ventricular dysfunction.

METHODS

In a 16-year follow-up study using a statewide database, we studied the occurrence of mortal and morbid cardiovascular (CV) events among patients without apparent ischemic heart disease who had left anterior hemiblock (LAHB, n=4273, right bundle branch block (RBBB) with LAHB (BFBB, n=1857) and left bundle branch block (LBBB, n=9484 compared to isolated RBBB (n=25288).

RESULTS

After adjustment for demographics, co-morbidities and insurance, LAHB was associated with a significant excess risk of all-cause death (HR 1.134, 95% CI 1.061-1.213, p=0.0002) and CV death (HR 1.329, 95% CI 1.174-1.501, p<0.0001). BFBB was associated with excess HF (HR 1.190, 95% CI 1.048-1.351, p<0.0071), all-cause death (HR 1.440, 95% CI 1.045-1.252, p=0.0036) and CV death (HR 1.210, 95% CI 1.020-1.436, p<0.0001). LBBB was associated with an excess risk of MR (HR 1.307, 95% CI 1.116-1.530, p<0.0009), HF 1.177, 95% CI1.097-1.263, p<0.0001) and CV death (HR 1.220, 95% CI 1.106-1.345, p<0.0001).

CONCLUSIONS

In patients without apparent ischemic heart disease, the presence of LAHB alone or in combination with RBBB imparts increased risk of CV and all-cause death compared to isolated RBBB. BFBB is also associated with an increased risk of HF.

Sleep-disordered breathing and daytime cardiac conduction abnormalities on 12-lead electrocardiogram in community-dwelling older men

PURPOSE

Nocturnal cardiac conduction abnormalities are commonly observed in patients with sleep-disordered breathing (SDB). However, few population-based studies have examined the association between SDB and daytime cardiac conduction abnormalities.

METHODS

We examined a random sample of 471 community-dwelling men, aged ≥67 years, enrolled in the multi-center Outcomes of Sleep Disorders in Older Men (MrOS Sleep) study. SDB severity was categorized using percent of total sleep time with oxygen saturation <90 % (%TST < 90) and apnea hypopnea index (AHI). Cardiac conduction parameters were assessed by resting 12-lead electrocardiography (ECG). All analyses were adjusted for age, site, β-blocker use, coronary heart disease, calcium channel blocker use, and use of antiarrhythmic medications.

RESULTS

Mean age was 77 ± 6 years, median %TST < 90 was 0.7 (IQR 0.00-3.40), and median AHI was 7.06 (IQR 2.55-15.32). Men with greater nocturnal hypoxemia (%TST < 90 ≥ 3.5 %) compared with those without hypoxemia (%TST < 90 < 1.0 %) had a lower odds of bradycardia (OR 0.55 [0.32-0.94]) and right bundle branch block (RBBB) (OR 0.24 [0.08-0.75]) but a higher odds of ventricular paced rhythm (OR 4.42 [1.29-15.19]). Heart rate (HR) increased in a graded manner with increasing %TST < 90 (p-trend 0.01) and increasing AHI (p-trend 0.006), but these gradients were small in absolute magnitude. There were no associations of SDB measures with other ECG conduction parameters.

CONCLUSIONS

Greater nocturnal hypoxemia in older men was associated with a lower prevalence of daytime sinus bradycardia and RBBB, a higher prevalence of ventricular paced rhythm, and higher resting HR.

A Three-Decade Survival Analysis of Intraventricular Conduction Delay in Adults Without Ischemic Heart Disease

BACKGROUND

The prognosis of an incidental finding of intraventricular conduction delay in individuals without ischemic heart disease is debatable. Intraventricular conduction delay presents electrocardiographically as bundle branch block or nonspecific intraventricular conduction delay. We aimed to assess the long-term survival of an incidental intraventricular conduction delay finding in a cohort of individuals without ischemic heart disease, followed up for 3 decades.

METHODS

A randomized stratified cohort of the adult Israeli population underwent medical examinations and electrocardiography between 1976 and 1982. Patients with ischemic heart disease were excluded, and the cohort was followed for all-cause mortality for a median of 30.4 years. Major intraventricular conduction delay was defined as having complete bundle branch block or nonspecific intraventricular conduction delay, and minor intraventricular conduction delay was defined as having incomplete bundle branch block. Cox proportional hazard model was performed, comparing individuals by electrocardiogram finding, adjusting for demographic, clinical, and electrocardiographic variables.

RESULTS

Of 2465 subjects, 2385 (96.8%) were without intraventricular conduction delay, 38 (1.5%) had minor intraventricular conduction delay, and 42 (1.7%) had major intraventricular conduction delay. All-cause mortality rates were higher among minor and major intraventricular conduction delay groups (57.9% and 66.7%, P = .43 and P = .04, respectively) compared with no intraventricular conduction delay (52.1%). By controlling for sex, age, and body mass index, intraventricular conduction delay was not associated with all-cause mortality: hazard ratios, 0.82 (95% confidence interval, 0.52-1.25) and 1.06 (95% confidence interval, 0.72-1.54) for minor and major intraventricular conduction delay, respectively.

CONCLUSIONS

Intraventricular conduction delay was not found to be an independent risk factor for all-cause mortality in individuals without ischemic heart disease.

Are 12-lead ECG findings associated with the risk of cardiovascular events after ischemic stroke in young adults?

INTRODUCTION

Ischemic stroke (IS) in a young patient is a disaster and recurrent cardiovascular events could add further impairment. Identifying patients with high risk of such events is therefore important. The prognostic relevance of ECG for this population is unknown.

MATERIALS AND METHODS

A total of 690 IS patients aged 15-49 years were included. A 12-lead ECG was obtained 1-14 d after the onset of stroke. We adjusted for demographic factors, comorbidities, and stroke characteristics, Cox regression models were used to identify independent ECG parameters associated with long-term risks of (1) any cardiovascular event, (2) cardiac events, and (3) recurrent stroke.

RESULTS

Median follow-up time was 8.8 years. About 26.4% of patients experienced a cardiovascular event, 14.5% had cardiac events, and 14.6% recurrent strokes. ECG parameters associated with recurrent cardiovascular events were bundle branch blocks, P-terminal force, left ventricular hypertrophy, and a broader QRS complex. Furthermore, more leftward P-wave axis, prolonged QTc, and P-wave duration >120 ms were associated with increased risks of cardiac events. No ECG parameters were independently associated with recurrent stroke.

CONCLUSION

A 12-lead ECG can be used for risk prediction of cardiovascular events but not for recurrent stroke in young IS patients. KEY MESSAGES ECG is an easy, inexpensive, and useful tool for identifying young ischemic stroke patients with a high risk for recurrent cardiovascular events and it has a statistically significant association with these events even after adjusting for confounding factors. Bundle branch blocks, P-terminal force, broader QRS complex, LVH according to Cornell voltage duration criteria, more leftward P-wave axis, prolonged QTc, and P-wave duration >120 ms are predictors for future cardiovascular or cardiac events in these patients. No ECG parameters were independently associated with recurrent stroke.

Right ventricular failure predicted from right bundle branch block: cardiac magnetic resonance imaging validation

BACKGROUND

Right ventricular (RV) failure has proven to be independently associated with adverse outcomes. Electrocardiographic parameters assessing RV function are largely unknown, making echocardiography the first line for RV function assessment. It is however, limited by geometrical assumptions and is inferior to cardiac magnetic resonance imaging (CMRI) which is widely regarded as the most accurate tool for assessing RV function.

METHODS

We seek to determine the correlation of ECG parameters of right bundle branch block (RBBB) with RV ejection fraction (EF) and RV dimensions using the CMRI. QRS duration, R amplitude and R' duration were obtained from precordial lead V1; S duration and amplitude were obtained from lead I and AVL. RV systolic dysfunction was defined as RV EF <40%. RV systolic dysfunction group (mean EF of 24±10%) were compared with normal RV systolic function group which acted as control (mean EF of 48±8%). CMRI and ECG parameters were compared between the two groups. Rank correlations and scatter diagrams between individual CMRI parameters and ECG parameters were done using medcalc for windows, version 12.5. Sensitivity, specificity and area under the curve (AUC) were calculated.

RESULTS

RV systolic dysfunction group was found to have larger RV end systolic volumes (90±42 vs. 59±40 mL, P=0.02). ECG evaluation of RV dysfunction group revealed longer R' duration (103±22 vs. 84±18 msec, P=0.005) as compared to the control group. The specificity of R' duration >100 msec to detect RV systolic dysfunction was found to be 93%. R' duration was found to have an inverse correlation with RV EF (r=-0.49, P=0.007).

CONCLUSIONS

Larger RV end systolic volumes seen with RV dysfunction can affect the latter part of right bundle branch leading to prolonged R' duration. We here found prolonged R' duration in lead V1 to have a highly specific inverse correlation to RV systolic function. ECG can be used as an inexpensive tool for RV function assessment and should be used alongside echocardiography to evaluate RV dysfunction when CMRI is not available.

Prevalence and Prognostic Implications of Bundle Branch Block in Comatose Survivors of Out-of-Hospital Cardiac Arrest

This study reports the prevalence and prognostic impact of right bundle branch block (RBBB) and left bundle branch block (LBBB) in the admission electrocardiogram (ECG) of comatose survivors of out-of-hospital cardiac arrest (OHCA). The present study is part of the predefined electrocardiographic substudy of the prospective randomized target temperature management trial, which found no benefit of targeting 33°C over 36°C in terms of outcome. Six-hundred eighty-two patients were included in the substudy. An admission ECG, which defined the present study population, was available in 602 patients (88%). These ECGs were stratified by the presence of LBBB, RBBB, or no-BBB (reference) on admission. End points were mortality and neurologic outcome 6 months after OHCA. RBBB was present in 79 patients (13%) and LBBB in 65 patients (11%), and the majority of BBBs (92%) had resolved 4 hours after admission. RBBB was associated with significantly higher 6 months mortality (RBBB: hazard ratio [HR]_unadjusted 1.78, 95% confidence interval [CI] 1.30 to 2.43; LBBB: HR_unadjusted 1.26, 95% CI 0.87 to 1.81), but this did not reach a level of significance in the adjusted model (HR_adjusted 1.33, 95% CI 0.94 to 1.87). Similar findings were seen for neurologic outcome in the unadjusted and adjusted analyses. RBBB was further independently associated with higher odds of unfavorable neurologic outcome (RBBB: adjusted odds ratio 1.97, 95% CI 1.05 to 3.71). In conclusion, BBBs after OHCA were transient in most patients, and RBBB was directly associated with higher mortality and independently associated with higher odds of unfavorable neurologic outcome. RBBB is seemingly an early indicator of an unfavorable prognosis after OHCA.

Effects of Fine Particulate Matter (PM2.5) on Systemic Oxidative Stress and Cardiac Function in ApoE(-/-) Mice

Aim: In this study, we aimed to explore the toxic mechanisms of cardiovascular injuries induced by ambient fine particulate matter (PM_2.5) in atherosclerotic-susceptible ApoE^−/− mice. An acute toxicological animal experiment was designed with PM_2.5 exposure once a day, every other day, for three days. Methods: ApoE^−/− and C57BL/6 mice were randomly categorized into four groups, respectively (n = 6): one control group, three groups exposed to PM_2.5 alone at low-, mid-, and high-dose (3, 10, or 30 mg/kg b.w.). Heart rate (HR) and electrocardiogram (ECG) were monitored before instillation of PM_2.5 and 24 h after the last instillation, respectively. Cardiac function was monitored by echocardiography (Echo) after the last instillation. Biomarkers of systemic oxidative injuries (MDA, SOD), heart oxidative stress (MDA, SOD), and NAD(P)H oxidase subunits (p22phox, p47phox) mRNA and protein expression were analyzed in mice. The results showed that PM_2.5 exposure could trigger the significant increase of MDA, and induce the decrease of heart rate variability (HRV), a marker of cardiac autonomic nervous system (ANS) function with a dose–response manner. Meanwhile, abnormal ECG types were monitored in mice after exposure to PM_2.5. The expression of cytokines related with oxidative injuries, and mRNA and protein expression of NADPH, increased significantly in ApoE^−/− mice in the high-dose group when compared with the dose-matched C57BL6 mice, but no significant difference was observed at Echo. In conclusion, PM_2.5 exposure could cause oxidative and ANS injuries, and ApoE^−/− mice displayed more severe oxidative effects induced by PM_2.5.

Electrocardiographic Abnormalities and Treatment with Benznidazole among Children with Chronic Infection by Trypanosoma cruzi: A Retrospective Cohort Study

Background

Chronic infection by Trypanosoma cruzi could cause heart conduction disturbances. We sought to analyze electrocardiographic abnormalities among children with chronic T. cruzi infection with and without trypanocidal treatment with benznidazole.

Methodology/Principal Findings

We studied 111 children 6–16 years of age with asymptomatic chronic T. cruzi infection who were recruited in 1991–1992 in Salta, Argentina. Most children were randomly assigned to benznidazole 5 mg/Kg/day (n = 47) or matching placebo (n = 48) for 60 days. Remaining children (n = 16) received treatment with benznidazole 5 mg/Kg/day open-label. Electrocardiograms were obtained at baseline and in 1995–1996, 1998, 2000 and 2005, and were analyzed using the Buenos Aires method. Among the 94 children with an electrocardiogram at baseline, 8 (8.5%) had electrocardiographic abnormalities, including 4 (4.7%) children with right bundle branch block. Proportion of abnormal electrocardiograms in the full population (n = 111) remained constant over time (media follow-up 8.6 years). Multivariable adjusted prevalence ratios (95% confidence interval [95%CI]) for electrocardiographic abnormalities in 1995–1996, 1998, 2000 and 2005 comparing children treated with benznidazole versus those not treated were 2.76 (0.66, 11.60), 2.33 (0.44, 12.31), 3.06 (0.48, 19.56), and 1.94 (0.33, 11.25), respectively. Among the 86 children with a normal electrocardiogram at baseline, 16 (18.6%) developed electrocardiographic abnormalities during follow-up. The multivariable adjusted hazard ratio for incident electrocardiographic abnormalities comparing children treated with benznidazole versus those not treated was 0.68 (95%CI: 0.25, 1.88).

Conclusions/Significance

Electrocardiographic abnormalities are frequent among children with chronic T. cruzi infection. Treatment with benznidazole for 60 days may not be associated with less electrocardiographic abnormalities.

There are few data available on the natural history of electrocardiographic abnormalities among children with chronic Trypanosoma cruzi infection. Also, few studies analyzed the effect of benznidazole to prevent electrocardiographic abnormalities in this population. In the current study, electrocardiographic abnormalities were frequent among children with chronic T. cruzi infection. Results from the current study also suggest that treatment with benznidazole may not be associated with less electrocardiographic abnormalities. The current study highlights the need of further research to prevent cardiovascular manifestations associated with chronic T. cruzi infection.

Right Bundle Branch Block and Electromechanical Coupling of the Right Ventricle: An Echocardiographic Study

Background:

A growing body of evidence suggests that the presence of a right bundle branch block (RBBB) is a negative prognostic indicator in patients with and without preexisting heart disease. Even though electromechanical activation of the right ventricle (RV) in patients with RBBB and pulmonary hypertension (PH) has been investigated; a direct comparison of the presence of RBBB, on the duration of RV mechanical systole using echocardiography has not been studied.

Materials and Methods:

In this retrospective study, we analyzed the echocardiograms of 40 patients by measuring the magnitude and timing of tricuspid annulus plane systolic excursion (TAPSE) and tricuspid annulus systolic velocity (TA S’). Patients were selected to form four groups of ten patients based on the presence or absence of RBBB and PH to determine if RBBB has any effect on the time-to-peak of TAPSE or TA S’, which for our purposes serves as a measure of duration of RV mechanical systole.

Results:

Our results demonstrate that RBBB leads to a measurable prolongation of TAPSE and TA S’ in patients without PH. Time-to-peak of TAPSE or TA S’ was not significantly prolonged in patients with PH.

Conclusions:

The results of this pilot study show that RV mechanical systole is prolonged in patients with RBBB, and the addition of PH attenuates this change. Additional prospective studies are now required to elucidate further the electrical and mechanical dyssynchrony that occurs as a result of RBBB, and how these new echocardiographic measurements can be applied clinically to risk stratify patients with RBBB and PH.

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.

Faulty cardiac repolarization reserve in alternating hemiplegia of childhood broadens the phenotype

Alternating hemiplegia of childhood is a rare disorder caused by de novo mutations in the ATP1A3 gene, expressed in neurons and cardiomyocytes. As affected individuals may survive into adulthood, we use the term 'alternating hemiplegia'. The disorder is characterized by early-onset, recurrent, often alternating, hemiplegic episodes; seizures and non-paroxysmal neurological features also occur. Dysautonomia may occur during hemiplegia or in isolation. Premature mortality can occur in this patient group and is not fully explained. Preventable cardiorespiratory arrest from underlying cardiac dysrhythmia may be a cause. We analysed ECG recordings of 52 patients with alternating hemiplegia from nine countries: all had whole-exome, whole-genome, or direct Sanger sequencing of ATP1A3. Data on autonomic dysfunction, cardiac symptoms, medication, and family history of cardiac disease or sudden death were collected. All had 12-lead electrocardiogram recordings available for cardiac axis, cardiac interval, repolarization pattern, and J-point analysis. Where available, historical and prolonged single-lead electrocardiogram recordings during electrocardiogram-videotelemetry were analysed. Half the cohort (26/52) had resting 12-lead electrocardiogram abnormalities: 25/26 had repolarization (T wave) abnormalities. These abnormalities were significantly more common in people with alternating hemiplegia than in an age-matched disease control group of 52 people with epilepsy. The average corrected QT interval was significantly shorter in people with alternating hemiplegia than in the disease control group. J wave or J-point changes were seen in six people with alternating hemiplegia. Over half the affected cohort (28/52) had intraventricular conduction delay, or incomplete right bundle branch block, a much higher proportion than in the normal population or disease control cohort (P = 0.0164). Abnormalities in alternating hemiplegia were more common in those ≥16 years old, compared with those <16 (P = 0.0095), even with a specific mutation (p.D801N; P = 0.045). Dynamic, beat-to-beat or electrocardiogram-to-electrocardiogram, changes were noted, suggesting the prevalence of abnormalities was underestimated. Electrocardiogram changes occurred independently of seizures or plegic episodes. Electrocardiogram abnormalities are common in alternating hemiplegia, have characteristics reflecting those of inherited cardiac channelopathies and most likely amount to impaired repolarization reserve. The dynamic electrocardiogram and neurological features point to periodic systemic decompensation in ATP1A3-expressing organs. Cardiac dysfunction may account for some of the unexplained premature mortality of alternating hemiplegia. Systematic cardiac investigation is warranted in alternating hemiplegia of childhood, as cardiac arrhythmic morbidity and mortality are potentially preventable.

Significance of an isolated new right bundle branch block in a patient with chest pain

Chest pain is a common presenting symptom in emergency departments, and a typical manifestation of acute myocardial infarction (AMI). Recognition of ECG changes in AMI is essential for timely diagnosis and treatment. Right bundle branch block (RBBB) may be an isolated sign of AMI, and was previously considered as a criterion for fibrinolytic therapy. Since the most recent European Society of Cardiology and American Heart Association guidelines in 2013, RBBB alone is no longer considered a diagnostic criterion of AMI, even if it occurs in the context of acute chest pain, as RBBB does not usually interfere with the interpretation of ST-segment alteration. Our case illustrates an acute septal myocardial infarction with an isolated RBBB, and thus the importance of recognising this pattern in order to permit timely diagnosis and treatment.

A wide QRS/T angle in bundle branch blocks is associated with increased risk for coronary heart disease and all-cause mortality in the Atherosclerosis Risk in Communities (ARIC) Study

BACKGROUND

Repolarization abnormality in bundle branch blocks (BBB) is traditionally ignored. This study evaluated the prognostic value of QRS/T angle for mortality in the presence and absence of BBB.

METHODS AND RESULTS

Total 15,408 participants (mean age 54 years, 55.2% women, 26.9% blacks, 2.8% with BBB) were from the Arteriosclerosis Risk in Communities Study. Sex stratified Cox regression models were used to compute hazard ratios (HRs) with 95% confidence intervals (CIs) for coronary heart disease (CHD) and all-cause mortality for wide spatial QRS/T angle with and without BBB including right BBB (RBBB), left BBB (LBBB) and indetermined-type ventricular conduction defect (IVCD) and RBBB combined with left anterior fascicular block. During a median 22-year follow-up, 4767 deaths occurred, 728 of them CHD deaths. Using the No-BBB with QRS/T angle below median value as gender-specific reference groups, the mortality risk increase was significant for both women and men with No-BBB and QRS/T angle above the median value. In the pooled ICVD/LBBB group, the risk for CHD death was increased 15.9-fold in women and 6.04 fold in men, and for all-cause deaths 3.01-fold in women and 1.84-fold in men. However, the mortality risk in isolated RBBB group was only significantly increased in women but not in men.

CONCLUSION

A wide spatial QRS/T angle in BBB is associated with increased risk for CHD and all-cause mortality over and above the predictive value for BBB alone. The risk for women is as high as or higher than that in men.