Epidemiology of arrhythmias and conduction disorders in older adults

Obstructive Sleep Apnea Screening in Patients With Atrial Fibrillation: Missed Opportunities for Early Diagnosis

BACKGROUND

"There is a high prevalence of obstructive sleep apnea (OSA) among patients with atrial fibrillation (AF). There is also strong evidence that proper OSA management can reduce AF recurrence." Polysomnography is the gold standard for OSA diagnosis, but screening tests, such as STOP-BANG, have been successful in identifying patients at risk for OSA. Our study assesses screening rates for OSA in patients with persistent AF, and willingness of patients at increased risk for OSA towards further diagnostic evaluation.

METHODS

A total of 254 persistent AF patients were surveyed regarding prior screening for OSA, and if previously unscreened, assessed with STOP-BANG. Prior cardioversions and willingness to undergo further workup was also recorded. Patients at risk for OSA were given educational brochures. Subjects with diagnosis of OSA were asked about their compliance with positive airway pressure therapy.

RESULTS

Sixty-six percent of AF patients were never screened for OSA; 75% unscreened participants (95% CI: 68-81%) were at high risk for OSA. Patients with previous hospitalizations or electrical cardioversions were more frequently screened for OSA (P = 0.02, P = 0.03, respectively). Forty-three percent of high-risk individuals had a BMI < 30. Among patients at risk for OSA (score ≥ 3), the majority (n = 99, 79%) were interested in follow-up with a sleep study (n = 93, 74%).

CONCLUSIONS

Although there is a strong OSA-associated risk for AF, which is amenable to intervention, most patients with persistent AF are not assessed for OSA. Simple to use screening questionnaires are sensitive and can reliably identify patients at high risk for OSA, reserving costlier and somewhat inconvenient nocturnal polysomnography to only those at risk. We hope our study will help to push the AF and OSA connection into the spotlight in the primary care of patients with AF.

A modified intracavitary electrocardiographic method for detecting the location of the tip of central venous catheters in atrial fibrillation patients

Introduction:

The intracavitary electrocardiographic method is recommended for assessing the location of the tip of central venous catheter when there is an identifiable P wave. Previous reports suggested that intracavitary electrocardiographic method might also be applied to patients with atrial fibrillation, considering the so-called f waves as a surrogate of the P wave.

Methods:

We studied 18 atrial fibrillation patients requiring simultaneously a central venous catheter and a trans-esophageal echocardiography. An intracavitary electrocardiographic trace was recorded with the catheter tip in three different positions defined by trans-esophageal echocardiography imaging: in the superior vena cava, 2 cm above the cavo-atrial junction; at the cavo-atrial junction; and in the right atrium, 2 cm below the cavo-atrial junction. Three different criteria of measurement of the f wave pattern in the TQ tract were used: the mean height of f waves (method A); the height of the highest f wave (method B); the difference between the highest positive peak and the lowest negative peak (method C).

Results:

There were no complications. With the tip placed at the cavo-atrial junction, the mean value of the f waves was significantly higher than in the other two positions. All three methods were effective in discriminating the tip position at the cavo-atrial junction, though method B proved to be the most accurate.

Conclusion:

A modified intracavitary electrocardiographic technique can be safely used for detecting the location of the tip of central venous catheters in atrial fibrillation patients: the highest activity of the f waves is an accurate indicator of the location of the tip at the cavo-atrial junction.

Automated beat-wise arrhythmia diagnosis using modified U-net on extended electrocardiographic recordings with heterogeneous arrhythmia types

Abnormality of the cardiac conduction system can induce arrhythmia - abnormal heart rhythm - that can frequently lead to other cardiac diseases and complications, and are sometimes life-threatening. These conduction system perturbations can manifest as morphological changes on the surface electrocardiographic (ECG) signal. Assessment of these morphological changes can be challenging and time-consuming, as ECG signal features are often low in amplitude and subtle. The main aim of this study is to develop an automated computer aided diagnostic (CAD) system that can expedite the process of arrhythmia diagnosis, as an aid to clinicians to provide appropriate and timely intervention to patients. We propose an autoencoder of ECG signals that can diagnose normal sinus beats, atrial premature beats (APB), premature ventricular contractions (PVC), left bundle branch block (LBBB) and right bundle branch block (RBBB). Apart from the first, the rest are morphological beat-to-beat elements that characterize and constitute complex arrhythmia. The novelty of this work lies in how we modified the U-net model to perform beat-wise analysis on heterogeneously segmented ECGs of variable lengths derived from the MIT-BIH arrhythmia database. The proposed system has demonstrated self-learning ability in generating class activations maps, and these generated maps faithfully reflect the cardiac conditions in each ECG cardiac cycle. It has attained a high classification accuracy of 97.32% in diagnosing cardiac conditions, and 99.3% for R peak detection using a ten-fold cross validation strategy. Our developed model can help physicians to screen ECG accurately, potentially resulting in timely intervention of patients with arrhythmia.

Dysrhythmias in patients with a complete atrioventricular septal defect: From surgery to early adulthood

Objective

Outcomes after surgical repair of complete atrioventricular septal defect (cAVSD) have improved. With advancing age, the risk of development of dysrhythmias may increase. The aims of this study were to (1) examine development of sinus node dysfunction (SND), atrial and ventricular tachyarrhythmias, and (2) study progression of atrioventricular conduction abnormalities in young adult patients with repaired cAVSD.

Study design

In this retrospective multicenter study, 74 patients (68% female) with a cAVSD repaired in childhood were included. Patients’ medical files were evaluated for occurrence of SND, atrioventricular conduction block (AVB), atrial and ventricular tachyarrhythmias.

Results

Median age at repair was 6 months (interquartile range 3‐10) and median age at last follow‐up was 24 years (interquartile range 21‐28). SND occurred after a median of 17 years (interquartile range 11‐19) after repair in 23% of patients, requiring pacemaker implantation in two patients (12%). Regular supraventricular tachycardia was observed in three patients (4%). Atrial fibrillation and ventricular tachyarrhythmias were not observed. Twenty‐seven patients (36%) had first‐degree AVB, which was self‐limiting in 16 (59%) and persistent in 10 (37%) patients. One patient developed third‐degree AVB 7 days after left atrioventricular valve replacement. Spontaneous type II second‐degree AVB occurred in a 28‐year‐old patient. Both patients underwent pacemaker implantation.

Conclusions

Clinically significant dysrhythmias were uncommon in young adult patients after cAVSD repair. However, three patients required pacemaker implantation for either progression of SND or spontaneous type II second‐degree AVB. Longer follow‐up should point out whether dysrhythmias will progress or become more prevalent with increasing age.

The Economic Burden of Heart Conditions in Brazil

Background

Heart conditions impose physical, social, financial and health-related quality of life limitations on individuals in Brazil.

Objectives

This study assessed the economic burden of four main heart conditions in Brazil: hypertension, heart failure, myocardial infarction, and atrial fibrillation. In addition, the cost-effectiveness of telemedicine and structured telephone support for the management of heart failure was assessed.

Methods

A standard cost of illness framework was used to assess the costs associated with the four conditions in 2015. The analysis assessed the prevalence of the four conditions and, in the case of myocardial infarction, also its incidence. It further assessed the conditions’ associated expenditures on healthcare treatment, productivity losses from reduced employment, costs of providing formal and informal care, and lost wellbeing. The analysis was informed by a targeted literature review, data scan and modelling. All inputs and methods were validated by consulting 15 clinicians and other stakeholders in Brazil. The cost-effectiveness analysis was based on a meta-analysis and economic evaluation of post-discharge programs in patients with heart failure, assessed from the perspective of the Brazilian Unified Healthcare System (Sistema Unico de Saude).

Results

Myocardial infarction imposes the greatest financial cost (22.4 billion reais/6.9 billion USD), followed by heart failure (22.1 billion reais/6.8 billion USD), hypertension (8 billion reais/2.5 billion USD) and, finally, atrial fibrillation (3.9 billion reais/1.2 billion USD). Telemedicine and structured telephone support are cost-effective interventions for achieving improvements in the management of heart failure.

Conclusions

Heart conditions impose substantial loss of wellbeing and financial costs in Brazil and should be a public health priority.

Can Intradetrusor OnabotulinumtoxinA Injections Alter Heart Function in Patients with Cardiac Arrhythmia?

The prevalence of overactive bladder (OAB) increases with age and can be associated with other co-morbidities, such as cardiac arrhythmia. Unfortunately, commonly used anticholinergic drugs for OAB can affect the cardiovascular system, leading to tachycardia. However, there are no data, which consider the influence of intradetrusor onabotulinumtoxinA injections on heart function in idiopathic OAB patients. The aim of the present study was to evaluate the influence of intradetrusor onabotulinumtoxinA injections on electrocardiogram (ECG) parameters. Additionally, changes in ECG were analyzed in OAB patients without cardiac arrhythmia. Thirty-one patients with cardiac arrhythmia and 31 participants without irregular heart rate (HR) completed the study. ECG measurements were performed in supine positions 2 h before onabotulinumtoxinA injections, 1 h after treatment, and at 2 weeks of follow-up. At week 6, a phone-call survey was conducted to collect data about adverse events. OnabotulinumtoxinA injections were performed with rigid cystoscopy under local anesthesia. We did not observe any clinically significant changes in the analyzed ECG parameters between consecutive measurements. While a slight increase of HR was observed in patients without cardiac arrhythmia, it remained within normal range. Intravesical onabotulinumtoxinA injections are, hence, safe for female patients with cardiac arrhythmia and do not significantly influence changes in ECG.

Anxiety, age, education and activities of daily living as predictive factors of the occurrence of frailty syndrome in patients with heart rhythm disorders

OBJECTIVES

Frailty is one of the geriatric syndromes that are caused by subclinical impairment of many organs, leading to the loss of reserves and the ability to maintain homeostasis. Aim of the study was to assess which factors including anxiety and depression can be predictive factors for the occurrence of frailty syndrome in patients with heart rhythm disorders.

METHODS

The study included 171 consecutive patients >64 years (73.91 ± 6.72; 48.5% W) with diagnosed cardiac arrhythmias who had been qualified for pacemaker implantation. The Tilburg Frailty Indicator scale as well as the Hospital Anxiety and Depresion Scale (HADS) were used.

RESULTS

The average HADS results in the frailty group was significantly higher 7.42 ± 2.63 compared to the robust patients 6.33 ± 2.83; p =0.0019. Similar results were observed in patients with atrio-ventricular blocks (AVB): HADS-A: frail 8.23 ± 2.13 vs. robust 6.62 ± 2.27; p = 0.0036 and HADS-D: frail 8.84 ± 2.85 vs. robust 7.17 ± 2.48; p =0.0086. The multiple regression model showed that age (p =0.0023), education (p =0.0001), ADL (p =0.0001) and the severity of the anxiety (p = 0.0414) were important predictors of the dependent variable and predicted higher levels of frailty syndrome.

CONCLUSION

Anxiety, age, education and the activities of daily living can be predictive factors of the occurrence of frailty syndrome in patients with heart rhythm disorders who have been qualified for pacemaker implantation.

Association of Arrhythmia in Patients with Cervical Spondylosis: A Nationwide Population-Based Cohort Study

BACKGROUND

Sympathetic activity, including cervical ganglia, is involved in the development of cardiac arrhythmias.

OBJECTIVE

The present study investigated the association between cervical spondylosis and arrhythmia, which has never been reported before.

METHODS

Patients newly diagnosed with cervical spondylosis (CS) with an index date between 2000 and 2011 were identified from the National Health Insurance Research Database. We performed a 1:1 case-control matched analysis. Cases were matched to controls according to their estimated propensity scores, based on demographics and existing risk factors. Cox proportional hazard models were applied to assess the association between CS and arrhythmia.

RESULTS

The CS cohort comprised 22,236 patients (males, 42.6%; mean age, 54.4 years) and non-CS cohort comprised 22,236 matched controls. There were 1441 events of arrhythmia in CS cohort and 537 events of arrhythmia in non-CS cohort, which 252 and 127 events of atrial fibrillation in CS and non-CS cohort, 33 and 12 events of ventricular tachycardia in CS cohort and non-CS cohort, 78 and 35 events of supraventricular tachycardia in CS cohort and non-CS cohort. The CS cohort had an arrhythmia incidence of 11.1 per 1000 person-years and a higher risk [adjusted hazard ratio (aHR) = 3.10, 95% confidence interval (CI) = 2.80⁻3.42] of arrhythmia, 2.54-fold aHR of ventricular tachycardia (95% CI = 1.70⁻3.79), and 2.22-fold aHR of atrial fibrillation (95% CI = 1.79⁻2.76) compared with non-CS cohort.

CONCLUSIONS

Cervical spondylosis is associated with a higher risk of arrhythmia.

Impact of high-grade atrioventricular block and cumulative frequent pacing on atrial arrhythmias

BACKGROUND

The relationship between high-grade atrioventricular block (HGAVB) with cumulative frequent pacing and risk of atrial arrhythmias (AAs) has not been well characterized. We hypothesized HGAVB and pacing may have significant impact on incidence and prevalence of AAs by modulating atrial substrate.

OBJECTIVE

To determine impact of HGAVB and pacing on AAs including atrial fibrillation (AF), atrial flutter (AFL), and atrial tachycardia (AT).

METHODS

All consecutive patients who underwent dual-chamber pacemaker implantation for HGAVB from 2005 to 2011 at the University of Chicago were included. AAs and percent of pacing were detected through device interrogation. Patients' data were collected from electronic medical records and clinic visits.

RESULTS

A total of 166 patients (mean age 71 ± 15 years; 54% female, 56% African American) were studied. AF was documented in 27% of patients before pacemaker implantation. During a mean 5.8 ± 2.2 years of follow-up, 47% had device-detected AF, 10% AFL, and 26% AT. New-onset AF was documented in 40 of the 122 patients without prior AF (33%). Continuous (≥ 99%) right ventricular pacing was associated with significantly decreased AF prevalence (34% vs 59%, P = 0.005), and correlated with lower incidence (26% vs 41%, P = 0.22). Pacing suppressed AF in 14% of patients with baseline AF; those patients had lower atrial pacing (3.2% vs 45%, P < 0.0001). Left atrial dilation was the only independent predictor of AF with frequent pacing (P = 0.009).

CONCLUSIONS

HGAVB is associated with high incidence and prevalence of AAs with and without pacing. Cumulative frequent (≥99%) ventricular pacing reduces risk of AF in patients with HGAVB.

Automated diagnosis of arrhythmia using combination of CNN and LSTM techniques with variable length heart beats

Arrhythmia is a cardiac conduction disorder characterized by irregular heartbeats. Abnormalities in the conduction system can manifest in the electrocardiographic (ECG) signal. However, it can be challenging and time-consuming to visually assess the ECG signals due to the very low amplitudes. Implementing an automated system in the clinical setting can potentially help expedite diagnosis of arrhythmia, and improve the accuracies. In this paper, we propose an automated system using a combination of convolutional neural network (CNN) and long short-term memory (LSTM) for diagnosis of normal sinus rhythm, left bundle branch block (LBBB), right bundle branch block (RBBB), atrial premature beats (APB) and premature ventricular contraction (PVC) on ECG signals. The novelty of this work is that we used ECG segments of variable length from the MIT-BIT arrhythmia physio bank database. The proposed system demonstrated high classification performance in the handling of variable-length data, achieving an accuracy of 98.10%, sensitivity of 97.50% and specificity of 98.70% using ten-fold cross validation strategy. Our proposed model can aid clinicians to detect common arrhythmias accurately on routine screening ECG.

Electrocardiograms: a guide to rhythm recognition for emergency nurses

Electrocardiogram (ECG) is one of the most commonly performed investigations in emergency departments (EDs), and is an extremely useful adjunct that guides diagnosis, prognosis and treatment. In most cases nurses are the first healthcare professional to assess patients and record an ECG, yet anecdotal evidence suggests that few emergency nurses review, interpret and act on ECG findings. Research suggests this may be due to lack of confidence in, or knowledge about, interpretation of results, often because of inadequate training. This article aims to help emergency nurses understand and interpret the cardiac rhythms commonly encountered on ECGs in EDs, to enable them to support earlier diagnosis and treatment. It describes a simple, five-step method for evaluating the main components of cardiac rhythm.

Cardiac Arrhythmia Classification by Multi-Layer Perceptron and Convolution Neural Networks

The electrocardiogram (ECG) plays an imperative role in the medical field, as it records heart signal over time and is used to discover numerous cardiovascular diseases. If a documented ECG signal has a certain irregularity in its predefined features, this is called arrhythmia, the types of which include tachycardia, bradycardia, supraventricular arrhythmias, and ventricular, etc. This has encouraged us to do research that consists of distinguishing between several arrhythmias by using deep neural network algorithms such as multi-layer perceptron (MLP) and convolution neural network (CNN). The TensorFlow library that was established by Google for deep learning and machine learning is used in python to acquire the algorithms proposed here. The ECG databases accessible at PhysioBank.com and kaggle.com were used for training, testing, and validation of the MLP and CNN algorithms. The proposed algorithm consists of four hidden layers with weights, biases in MLP, and four-layer convolution neural networks which map ECG samples to the different classes of arrhythmia. The accuracy of the algorithm surpasses the performance of the current algorithms that have been developed by other cardiologists in both sensitivity and precision.

Evaluation of left and right ventricular systolic and diastolic electromechanical synchrony in older people: a population-based observational study

It is unknown whether physiological ageing also goes along with electromechanical asynchrony of contraction. Aim of the study was to evaluate synchrony of contraction in older people with ("non-healthy") or without ("healthy") evidence for structural cardiac disease. In 547 persons (age 76.7+/-5.5 years, 306 male, 241 female) recruited from a population-based cohort of the ActiFE-Ulm study including a random sample of people >/=65 years old living in the region of Ulm, Germany, various PW- and TDI-Doppler based markers for asynchrony were obtained by echocardiography. Within a subgroup of 84 healthy subjects, at most minimal systolic and diastolic asynchrony was found. Concerning systolic asynchrony, similar observations were made within the non-healthy subgroup. However, extent of diastolic left ventricular intraventricular asynchrony and also - by tendency - diastolic interventricular asynchrony was increased in comparison to the healthy subgroup. To conclude, no evidence that physiological ageing might go along with relevant left or right ventricular systolic or diastolic electromechanical asynchrony was found in our study. Furthermore, our population-based data support the results from other clinical studies with rather selected cohorts that structural heart diseases might go along with increased diastolic asynchrony.

Non-syndromic cardiac progeria in a patient with the rare pathogenic p.Asp300Asn variant in the LMNA gene

Background

Mutations in LMNA gene, encoding Lamin A/C, cause a diverse array of phenotypes, collectively referred to as laminopathies. The most common manifestation is dilated cardiomyopathy (DCM), occurring in conjunction with variable skeletal muscle involvement but without involvement of the coronary arteries. Much less commonly, LMNA mutations cause progeroid syndromes, whereby an early-onset coronary artery disease (CAD) is the hallmark of the disease. We report a hitherto unreported compound cardiac phenotype, dubbed as “non-syndromic cardiac progeria”, in a young patient who carried a rare pathogenic variant in the LMNA gene and developed progressive degeneration of various cardiac structures, as seen in the elderly. The phenotype resembled the progeroid syndromes, except that it was restricted to the heart and did not involve other organs.

Case presentation

The patient was a well-developed Caucasian female who presented at age 29 years with an acute myocardial infarction (MI) and was found to have extensive CAD. She had none of the conventional risk factors for atherosclerosis. She underwent coronary artery bypass surgery but continued to require multiple percutaneous coronary interventions for symptomatic obstructive coronary lesions. During the course of next 10 years, she developed mitral regurgitation, degenerative mitral and aortic valve diseases, atrial flutter, and progressive conduction defects. She died from progressive heart failure with predominant involvement of the right ventricle and severe tricuspid regurgitation. Cardiac phenotype in this young patient resembled degenerative cardiac diseases of the elderly and the progeroid syndromes. However, in contrast to the progeroid syndromes, the phenotype was restricted to the heart and did not involve other organs. Thus, the phenotype was dubbed as a non-syndromic cardiac progeria.

Genetic screening of several cardiomyopathy genes, including LMNA, which is a causal gene for progeroid syndromes, led to identification of a very rare pathogenic p.Asp300Asn variant in the LMNA gene.

Conclusions

We infer that the LMNA p.Asp300Asn mutation is pathogenic in non-syndromic cardiac progeria. Mutations involving codon 300 in the LMNA gene have been associated with progeroid syndromes involving multiple organs. Collectively, the data provide credence to the causal role of p.Asp300Asn mutation in the pathogenesis of non-syndromic cardiac progeria.

Electronic supplementary material

The online version of this article (10.1186/s12881-017-0480-x) contains supplementary material, which is available to authorized users.

Aging-related mitochondrial dysfunction facilitates the occurrence of serious arrhythmia after myocardial infarction

BACKGROUND

During aging a mosaic of normal cells and cells with mitochondrial deficiency develops in various tissues including the heart. Whether this contributes to higher susceptibility for arrhythmia following myocardial infarction (MI) is unknown.

METHODS AND RESULTS

Myocardial cryoinfarction was performed in 12-month-old transgenic mice with accelerated accumulation of deletions in mitochondrial DNA. Occurrence and pathogenesis of arrhythmia was investigated after two weeks. Holter-ECG recordings revealed higher rates of premature ventricular complexes (incidence > 10/24 h: 100% vs. 20%; p = 0.048) and more severe spontaneous arrhythmia during stress test in mutant mice with MI as compared to control mice with MI. Mice with mitochondrial dysfunction exhibited longer spontaneous AV-blocks (467 ± 26 ms vs. 377 ± 24 ms; p = 0.013), an increased probability for induction of ventricular tachycardia during in vivo electrophysiological investigation (22% vs. 9%; p = 0.044), and a reduced conduction velocity in the infarct borderzone (38.5 ± 0.5 cm/s vs. 55.3 ± 0.9 cm/s; p = 0.001). Furthermore, mutant mice exhibited a significant reduction of the phospho-Cx43/Cx43 ratio in right (0.59 ± 0.04 vs. 0.85 ± 0.01; p = 0.027) and left ventricular myocardium (0.72 ± 0.01 vs. 0.86 ± 0.02; p = 0.023).

CONCLUSIONS

Aging-related cardiac mosaic respiratory chain dysfunction facilitates the occurrence of spontaneous and inducible cardiac arrhythmia after myocardial infarction and is associated with slowing of electrical impulse propagation in the infarct borderzone.

Atrioventricular Conduction Delay Predicts Impaired Exercise Capacity in Patients with Heart Failure with Reduced Ejection Fraction

Background

Atrioventricular conduction delay (AVCD) impairs left ventricular (LV) filling and consequently leads to a reduction of cardiac output. We hypothesized that in patients with severely depressed LV function and coexisting intraventricular conduction disturbances (IVCD), AVCD can affect exercise performance. Therefore, we evaluated the association of AVCD and exercise capacity in patients with heart failure (HFREF) and coexisting IVCD.

Material/Methods

We included patients with stable, chronic HFREF, LVEF <35%, sinus rhythm, and QRS ≥120 ms. PR interval and peak oxygen consumption (VO_{2 peak}) were specifically investigated. Multiple regression analysis was used to adjust the association between PR interval and VO_{2 peak} for possible confounders.

Results

Most (57.5%) of the 40 included patients [20% female, aged 63±12, 47.5% of ischemic etiology (IHD)] were in NYHA class III. Mean PR interval was 196±38.1 ms. There were 26 (65%) patients with PR interval ≤200 ms and 14 (35%) with >200 ms. Groups were similar in clinical, laboratory, echocardiographic parameters, QRS morphology, and treatment regimens. VO_{2 peak} was lower in patients with longer PR interval group as compared to shorter PR interval group (12.3±4.1 vs. 17.06±4.4, p=0.002). In the regression model, PR interval, female sex, and IHD remained important predictors of VO_{2 peak} (_partial=−0.50, p=0.003; r_partial=−0.48, p=0.005; r_partial=−0.44, p=0.01; R²=0.61).

Conclusions

Delayed AV conduction contributes to decreased exercise capacity in patients with HFREF and coexisting IVCD.

High resolution 3-Dimensional imaging of the human cardiac conduction system from microanatomy to mathematical modeling

Cardiac arrhythmias and conduction disturbances are accompanied by structural remodelling of the specialised cardiomyocytes known collectively as the cardiac conduction system. Here, using contrast enhanced micro-computed tomography, we present, in attitudinally appropriate fashion, the first 3-dimensional representations of the cardiac conduction system within the intact human heart. We show that cardiomyocyte orientation can be extracted from these datasets at spatial resolutions approaching the single cell. These data show that commonly accepted anatomical representations are oversimplified. We have incorporated the high-resolution anatomical data into mathematical simulations of cardiac electrical depolarisation. The data presented should have multidisciplinary impact. Since the rate of depolarisation is dictated by cardiac microstructure, and the precise orientation of the cardiomyocytes, our data should improve the fidelity of mathematical models. By showing the precise 3-dimensional relationships between the cardiac conduction system and surrounding structures, we provide new insights relevant to valvar replacement surgery and ablation therapies. We also offer a practical method for investigation of remodelling in disease, and thus, virtual pathology and archiving. Such data presented as 3D images or 3D printed models, will inform discussions between medical teams and their patients, and aid the education of medical and surgical trainees.

Nonenhanced MR angiography of the pulmonary arteries using single-shot radial quiescent-interval slice-selective (QISS): a technical feasibility study

BACKGROUND

For evaluation of the pulmonary arteries in patients suspected of pulmonary embolism, CT angiography (CTA) is the first-line imaging test with contrast-enhanced MR angiography (CEMRA) a potential alternative. Disadvantages of CTA include exposure to ionizing radiation and an iodinated contrast agent, while CEMRA is sensitive to respiratory motion and requires a gadolinium-based contrast agent. The primary goal of our technical feasibility study was to evaluate pulmonary arterial conspicuity using breath-hold and free-breathing implementations of a recently-developed nonenhanced approach, single-shot radial quiescent-interval slice-selective (QISS) MRA.

METHODS

Breath-hold and free-breathing, navigator-gated versions of radial QISS MRA were evaluated at 1.5 Tesla in three healthy subjects and 11 patients without pulmonary embolism or arterial occlusion by CTA. Images were scored by three readers for conspicuity of the pulmonary arteries through the level of the segmental branches. In addition, one patient with pulmonary embolism was imaged.

RESULTS

Scan time for a 54-slice acquisition spanning the pulmonary arteries was less than 2 minutes for breath-hold QISS, and less than 3.4 min using free-breathing QISS. Pulmonary artery branches through the segmental level were conspicuous with either approach. Free-breathing scans showed only mild blurring compared with breath-hold scans. For both readers, less than 1% of pulmonary arterial segments were rated as "not seen" for breath-hold and navigator-gated QISS, respectively. In subjects with atrial fibrillation, single-shot radial QISS consistently depicted the pulmonary artery branches, whereas navigator-gated 3D balanced steady-state free precession showed motion artifacts. In one patient with pulmonary embolism, radial QISS demonstrated central pulmonary emboli comparably to CEMRA and CTA. The thrombi were highly conspicuous on radial QISS images, but appeared subtle and were not prospectively identified on scout images acquired using a single-shot bSSFP acquisition.

CONCLUSIONS

In this technical feasibility study, both breath-hold and free-breathing single-shot radial QISS MRA enabled rapid, consistent demonstration of the pulmonary arteries through the level of the segmental branches, with only minimal artifacts from respiratory motion and cardiac arrhythmias. Based on these promising initial results, further evaluation in patients with suspected pulmonary embolism appears warranted.

High-Sensitivity Troponin as a Biomarker in Heart Rhythm Disease

Biomarkers are important prognostic tools in various cardiovascular conditions, including coronary artery disease and heart failure. Although their utility in cardiac electrophysiology (EP) is less established, biomarkers may guide EP clinical practice by identifying patients at risk for developing arrhythmias and their complications, in addition to augmenting therapeutic decisions by targeting appropriate pharmacologic and interventional therapies to patients who may benefit most. In this review, we focus on the prognostic role of high-sensitivity cardiac troponin (hs-cTn) assays-which detect subclinical cardiac myocyte damage-in cardiac arrhythmias and their sequelae. We review the current literature on hs-cTn and its impact on various arrhythmia disease states and also provide suggestions for future research in this field. In conclusion, although the utility of hs-cTn assays remains at an investigational stage in cardiac EP, studies to date have suggested value as a prognostic biomarker in atrial fibrillation and as a screening marker for patients at high risk of sudden cardiac death (both in the general population and among those with hypertrophic cardiomyopathy).

Transcatheter Aortic Valve Replacement Outcomes in Nonagenarians Stratified by Transfemoral and Transapical Approach

BACKGROUND

Survival and other outcomes of nonagenarians undergoing transcatheter aortic valve replacement (TAVR) in the Medicare population are unclear.

METHODS

Patients aged 65 years and older who underwent TAVR from November 2011 through 2013 were considered for inclusion.

RESULTS

The study consisted of 18,283 patients and 19.3% were aged 90 years or older. Compared with patients younger than 90 years, patients 90 years or older were less likely to have a number of comorbidities, including previous myocardial infarction (17.5% versus 21.8%), previous coronary artery bypass grafting (20.0% versus 35.0%), and chronic obstructive pulmonary disease (25.4% versus 39.0%) among others. The 30-day and 1-year mortality rates were 8.4% versus 5.9% (p = 0.0001) and 25.4% versus 21.5% (p = 0.0001) in the older and younger groups, respectively (odds ratio [OR] 1.47, 95% confidence interval [CI]: 1.28 to 1.70, p = 0.0001). Patients 90 years and older were more likely to undergo pacemaker insertion (11.1% versus 8.3%, p = 0.0001). Among nonagenarians, compared with the transapical group, patients undergoing transfemoral TAVR had lower 30-day (7.2% versus 13.6%, p = 0.0001) and 1-year (23.8% versus 31.6%, p = 0.0001) mortality rates, were more likely to be discharged home (54.4% versus 34.1%, p = 0.0001), and had lower 30-day readmission rates (23.8% versus 31.8%, p = 0.0001). After adjustment for patient characteristics, transapical TAVR was an independent predictor of 30-day mortality rate (OR 1.94, 95% CI: 1.48 to 2.56, p = 0.0001) and readmission (OR 1.46, 95% CI: 1.19 to 1.80, p = 0.0003).

CONCLUSIONS

In patients undergoing TAVR, although 30-day and 1-year mortality rates were slightly worse for nonagenarians than their younger counterparts, long-term survival was still encouraging, with 75% of nonagenarians living to 1 year. Transapical TAVR was associated with worse outcomes in nonagenarians.

The Relationship Between Cardiac Conduction Times, Cardiovascular Risk Factors, and Inflammation in Patients with Early Arthritis

Objective.

To investigate the prevalence of conduction disorders in patients with early arthritis and the relationship with inflammation and traditional cardiovascular (CV) risk factors.

Methods.

Patients with rheumatoid arthritis (RA) have a 2-fold higher risk of sudden cardiac death, possibly owing to conduction disorders. This increased risk might already be present at the clinical onset of arthritis. Therefore, we assessed electrocardiography, blood pressure, 28-joint Disease Activity Score (DAS28), lipid profile, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level in 480 patients with early arthritis at baseline and after 1 year.

Results.

The prevalence of conduction disorders was 12.5%. Conduction times at baseline were not associated with DAS28, ESR, or CRP levels and did not change during antirheumatic treatment. Baseline and the improvement in DAS28 (European League Against Rheumatism response), ESR, and CRP were significantly associated with heart rate, lipid profile, and blood pressure. Elevated total cholesterol and blood pressure were associated with an increased QRS time. The change in heart rate differed 7.3 bpm between patients with the least versus largest DAS improvement.

Conclusion.

The prevalence of conduction disorders in patients with early arthritis was 12.5%, which is similar to the general population and was not associated with changes in inflammation markers. However, a high cholesterol was associated with a prolonged QRS time. Therefore, the emphasis of CV risk management in arthritis should not be only on treatment of disease activity but also on traditional CV risk factors. The relationship between the improvement in disease activity and heart rate is remarkable because this could imply a 10-year CV mortality risk difference of 24%.

Proarrhythmia liability assessment and the comprehensive in vitro Proarrhythmia Assay (CiPA): An industry survey on current practice

INTRODUCTION

The Safety Pharmacology Society (SPS) has conducted a survey of its membership to identify industry practices related to testing considered in the Comprehensive In vitro Proarrhythmia Assay (CiPA).

METHODS

Survey topics included nonclinical approaches to address proarrhythmia issues, conduct of in silico studies, in vitro ion channel testing methods used, drugs used as positive controls during the conduct of cardiac ion channel studies, types of arrhythmias observed in non-clinical studies and use of the anticipated CiPA ion channel assay.

RESULTS

In silico studies were used to evaluate effects on ventricular action potentials by only 15% of responders. In vitro assays were used mostly to assess QT prolongation (95%), cardiac Ca²⁺ and Na⁺ channel blockade (82%) and QT shortening or QRS prolongation (53%). For de-risking of candidate drugs for proarrhythmia, those assays most relevant to CiPA including cell lines stably expressing ion channels used to determine potency of drug block were most frequently used (89%) and human stem cell-derived or induced pluripotent stem cell cardiomyocytes (46%). Those in vivo assays related to general proarrhythmia derisking include ECG recording using implanted telemetry technology (88%), jacketed external telemetry (62%) and anesthetized animal models (53%). While the CiPA initiative was supported by 92% of responders, there may be some disconnect between current practice and future expectations, as explained.

DISCUSSION

Proarrhythmia liability assessment in drug development presently includes study types consistent with CiPA. It is anticipated that CiPA will develop into a workable solution to the concern that proarrhythmia liability testing remains suboptimal.

[Remodeling of the aging heart : Sinus node dysfunction and atrial fibrillation]

The incidence of both sinus node dysfunction (SND) and atrial fibrillation (AF) increases with age. SND and AF frequently coexist. Likewise, they are often associated with cardiovascular diseases. Both arrhythmias share similar pathomechanisms such as structural and functional remodeling, i. e., degenerative fibrosis and altered Ca²⁺ handling, respectively. A growing body of evidence suggests an important role for the CamKII (Ca²⁺/calmodulin-dependent protein kinase II) in structural as well as in functional remodeling. In the sinus node, remodeling leads to degenerative fibrosis and as a consequence to sinus node arrest or to reentry (brady/tachycardia). In the atrium, remodeling sets the conditions for reentry and its triggering mechanisms, especially the conditions for triggered activity on the basis of delayed afterdepolarizations (DAD). Thus, SND and AF seem to be different phenotypes of related pathophysiological mechanisms. On the other hand, it remains controversial as to whether SND causes AF or vice versa.

Atrial fibrillation detected by external loop recording for seven days or two-day simultaneous Holter recording: A comparison in patients with ischemic stroke or transient ischemic attack

Atrial fibrillation (AF) is the most common cardiac cause of ischemic stroke and transient ischemic attack (IS/TIA).

AIM

To compare the diagnostic value of seven-day external loop recording (ELR) and two-day Holter recording for detecting AF after IS/TIA.

METHODS

191 IS/TIA patients without AF history. Endpoint was AF >30s. We started two-day Holter recording and seven-day ELR simultaneously.

RESULTS

Seven-day ELR and two-day Holter recording detected the same three AF patients. ELR detected another six patients with AF adjudicated by cardiologists, four detections after Holter (3 vs. 7, p=0.125) and two false-positive detections during Holter. Seven-day ELR automatically classified 50/191 patients (26%) with AF, but only 7/50 (14%) were confirmed as AF by cardiologists.

CONCLUSION

Seven-day ELR did not detect significantly more patients with AF than two-day Holter recording. 86% of patients with ELR-classified AF were false positives, indicating a poor performance of the automatic AF detection algorithm used.

The association of uncoupling protein 2 (UCP2) exon 8 insertion/deletion polymorphism and ECG derived QRS duration: A cross-sectional study in an Australian rural population

BACKGROUND

Associations between inherited mitochondrial disease and cardiac conduction have been previously described. However, there are no available studies exploring the mitochondrial uncoupling protein 2 gene (UCP2) insertion/deletion (I/D) polymorphisms interaction on cardiac electrical conduction. Our aim was to determine if ECG-derived QRS duration is associated with UCP2 DD genotype in a cross-sectional Australian aging rural population.

METHODS

A retrospective study design utilizing a rural health diabetic screening clinic data-base containing observational data from September 2011 to September 2014. Inclusion criteria included were having ECG parameters such as QRS duration measures and a DNA sample within the same subject. Genomic DNA was extracted and subjects were genotyped for the 45-bp I/D polymorphism in the 3'-untranslated region of UCP2.

RESULTS

281 individuals were available for analysis. On the basis of QRS duration >140ms we found an increased percentage of our population with DD homozygotes, compared to ID heterozygotes and II homozygotes (p=0.047). For other ECG parameters; mean PQ duration, QTc across UCP2 genotypes was not significant (p=NS). QTc using a cut-off >440ms in contingency table analysis revealed no significant differences across UCP2 I/D genotypes. Mean QT dispersion (QTd) was paradoxically less in the UCP2 DD genotype compared to UCP2 II subgroup (p=0.034).

DISCUSSION

We have demonstrated an association between increasing ECG-derived QRS duration >140ms and the UCP2 DD polymorphism. The lack of association with ECG derived QTd and UCP2 DD may suggest that gene-related QRS duration prolongation is independent of cardiac hypertrophy.

Position paper for management of elderly patients with pacemakers and implantable cardiac defibrillators: Groupe de Rythmologie et Stimulation Cardiaque de la Société Française de Cardiologie and Société Française de Gériatrie et Gérontologie

Despite the increasingly high rate of implantation of pacemakers (PMs) and implantable cardioverter defibrillators (ICDs) in elderly patients, data supporting their clinical and cost-effectiveness in this age stratum are ambiguous and contradictory. We reviewed the data regarding the applicability, safety and effectiveness of conventional pacing, ICDs and cardiac resynchronization therapy (CRT) in elderly patients. Although periprocedural risk may be slightly higher in the elderly, the implantation procedure for PMs and ICDs is still relatively safe in this age group. In older patients with sinus node disease, the general consensus is that DDD pacing with the programming of an algorithm to minimize ventricular pacing is preferred. In very old patients presenting with intermittent or suspected atrioventricular block, VVI pacing may be appropriate. In terms of correcting potentially life-threatening arrhythmias, the effectiveness of ICD therapy is similar in older and younger individuals. However, the assumption of persistent ICD benefit in the elderly population is questionable, as any advantageous effect of the device on arrhythmic death may be attenuated by higher total non-arrhythmic mortality. While septuagenarians and octogenarians have higher annual all-cause mortality rates, ICD therapy may remain effective in selected patients at high risk of arrhythmic death and with minimum comorbidities despite advanced age. ICD implantation among the elderly, as a group, may not be cost-effective, but the procedure may reach cost-effectiveness in those expected to live more than 5-7years after implantation. Elderly patients usually experience significant functional improvement after CRT, similar to that observed in middle-aged patients. Management of CRT non-responders remains globally the same, while considering a less aggressive approach in terms of reinterventions (revision of left ventricular [LV] lead placement, addition of a right ventricular or LV lead, LV endocardial pacing configuration). Overall, physiological age, general status and comorbidities rather than chronological age per se should be the decisive factors in making a decision about device implantation selection for survival and well-being benefit in elderly patients.

Dofetilide: Electrophysiologic Effect, Efficacy, and Safety in Patients with Cardiac Arrhythmias

Dofetilide is a class III antiarrhythmic agent with a selective blockade of rapid component of delayed rectifier potassium current (IKr). Dofetilide was found to be safe in patients after myocardial infarction and those with congestive heart failure and left ventricular systolic dysfunction (ejection fraction of less than 35%). An important adverse effect of dofetilide is its potential proarrhythmic risk of ventricular tachyarrhythmias, mostly torsades de pointes. Because dofetilide has about an 80% renal excretion, dose adjustment is required in patients with impaired renal function. Dofetilide should not be given or discontinued if the QTc is greater than 500 ms.

Myocyte-fibroblast communication in cardiac fibrosis and arrhythmias: Mechanisms and model systems

Development of cardiac fibrosis and arrhythmias is controlled by the activity of and communication between cardiomyocytes and fibroblasts in the heart. Myocyte-fibroblast interactions occur via both direct and indirect means including paracrine mediators, extracellular matrix interactions, electrical modulators, mechanical junctions, and membrane nanotubes. In the diseased heart, cardiomyocyte and fibroblast ratios and activity, and thus myocyte-fibroblast interactions, change and are thought to contribute to the course of disease including development of fibrosis and arrhythmogenic activity. Fibroblasts have a developing role in modulating cardiomyocyte electrical and hypertrophic activity, however gaps in knowledge regarding these interactions still exist. Research in this field has necessitated the development of unique approaches to isolate and control myocyte-fibroblast interactions. Numerous methods for 2D and 3D co-culture systems have been developed, while a growing part of this field is in the use of better tools for in vivo systems including cardiomyocyte and fibroblast specific Cre mouse lines for cell type specific genetic ablation. This review will focus on (i) mechanisms of myocyte-fibroblast communication and their effects on disease features such as cardiac fibrosis and arrhythmias as well as (ii) methods being used and currently developed in this field.

DIAGNOSIS OF MULTICLASS TACHYCARDIA BEATS USING RECURRENCE QUANTIFICATION ANALYSIS AND ENSEMBLE CLASSIFIERS

Atrial Fibrillation (A-Fib), Atrial Flutter (AFL) and Ventricular Fibrillation (V-Fib) are fatal cardiac abnormalities commonly affecting people in advanced age and have indication of life-threatening condition. To detect these abnormal rhythms, Electrocardiogram (ECG) signal is most commonly visualized as a significant clinical tool. Concealed non-linearities in the ECG signal can be clearly unraveled using Recurrence Quantification Analysis (RQA) technique. In this paper, RQA features are applied for classifying four classes of ECG beats namely Normal Sinus Rhythm (NSR), A-Fib, AFL and V-Fib using ensemble classifiers. The clinically significant ([Formula: see text]) features are ranked and fed independently to three classifiers viz. Decision Tree (DT), Random Forest (RAF) and Rotation Forest (ROF) ensemble methods to select the best classifier. The training and testing of the feature set is accomplished using 10-fold cross-validation strategy. The RQA coefficients using ROF provided an overall accuracy of 98.37% against 96.29% and 94.14% for the RAF and DT, respectively. The results achieved evidently ratify the superiority of ROF ensemble classifier in the diagnosis of A-Fib, AFL and V-Fib. Precision of four classes is measured using class-specific accuracy (%) and reliability of the performance is assessed using Cohen’s kappa statistic ([Formula: see text]). The developed approach can be used in therapeutic devices and help the physicians in automatic monitoring of fatal tachycardia rhythms.

Evaluation of the Genetic Basis of Familial Aggregation of Pacemaker Implantation by a Large Next Generation Sequencing Panel

Background

The etiology of conduction disturbances necessitating permanent pacemaker (PPM) implantation is often unknown, although familial aggregation of PPM (faPPM) suggests a possible genetic basis. We developed a pan-cardiovascular next generation sequencing (NGS) panel to genetically characterize a selected cohort of faPPM.

Materials and Methods

We designed and validated a custom NGS panel targeting the coding and splicing regions of 246 genes with involvement in cardiac pathogenicity. We enrolled 112 PPM patients and selected nine (8%) with faPPM to be analyzed by NGS.

Results

Our NGS panel covers 95% of the intended target with an average of 229x read depth at a minimum of 15-fold depth, reaching a SNP true positive rate of 98%. The faPPM patients presented with isolated cardiac conduction disease (ICCD) or sick sinus syndrome (SSS) without overt structural heart disease or identifiable secondary etiology. Three patients (33.3%) had heterozygous deleterious variants previously reported in autosomal dominant cardiac diseases including CCD: LDB3 (p.D117N) and TRPM4 (p.G844D) variants in patient 4; TRPM4 (p.G844D) and ABCC9 (p.V734I) variants in patient 6; and SCN5A (p.T220I) and APOB (p.R3527Q) variants in patient 7.

Conclusion

FaPPM occurred in 8% of our PPM clinic population. The employment of massive parallel sequencing for a large selected panel of cardiovascular genes identified a high percentage (33.3%) of the faPPM patients with deleterious variants previously reported in autosomal dominant cardiac diseases, suggesting that genetic variants may play a role in faPPM.

Modeling the aging heart: from local respiratory defects to global rhythm disturbances

In this issue, Baris et al. (2015) describe cardiac rhythm abnormalities in a mouse model of mitochondrial dysfunction in widely distributed cells of the aging human heart. How do a few metabolically challenged cells disrupt cardiac rhythm? We suggest that these cells provide "crystallization centers" for latent dysfunctional zones to allow arrhythmia emergence.

Mosaic Deficiency in Mitochondrial Oxidative Metabolism Promotes Cardiac Arrhythmia during Aging

Aging is a progressive decline of body function, during which many tissues accumulate few cells with high levels of deleted mitochondrial DNA (mtDNA), leading to a defect of mitochondrial functions. Whether this mosaic mitochondrial deficiency contributes to organ dysfunction is unknown. To investigate this, we generated mice with an accelerated accumulation of mtDNA deletions in the myocardium, by expressing a dominant-negative mutant mitochondrial helicase. These animals accumulated few randomly distributed cardiomyocytes with compromised mitochondrial function, which led to spontaneous ventricular premature contractions and AV blocks at 18 months. These symptoms were not caused by a general mitochondrial dysfunction in the entire myocardium, and were not observed in mice at 12 months with significantly lower numbers of dysfunctional cells. Therefore, our results suggest that the disposition to arrhythmia typically found in the aged human heart might be due to the random accumulation of mtDNA deletions and the subsequent mosaic respiratory chain deficiency.

The changes in cardiac physiology with aging and the implications for the treating oncologist

The link between cancer, cardiovascular disease, and aging is well documented. In this review, we highlight the physiologic and pathologic changes associated with the cardiovascular aging process, the role they play when interfaced with various cancer therapies and the implications for the treating oncologist.

Trends in the incidence and prevalence of cardiac pacemaker insertions in an ageing population

OBJECTIVES

To determine contemporary population estimates of the prevalence of cardiac permanent pacemaker (PPM) insertions.

METHODS

A population-based observational study using linked hospital morbidity and death registry data from Western Australia (WA) to identify all incident cases of PPM insertion for adults aged 18 years or older. Prevalence rates were calculated by age and sex for the years 1995-2009 for the WA population.

RESULTS

There were 9782 PPMs inserted during 1995-2009. Prevalence rose across the study period, exceeding 1 in 50 among people aged 75 or older from 2005. This was underpinned by incidence rates which rose with age, being highest in those 85 years or older; over 500/100 000 for men throughout, and over 200/100 000 for women. Rates for patients over 75 were more than double the rates for those aged 65-74 years. Women were around 40% of cases overall. The use of dual-chamber and triple-chamber pacing increased across the study period. A cardiac resynchronisation defibrillator was implanted for 58% of patients treated with cardiac resynchronisation therapy.

CONCLUSIONS

Rates of insertion and prevalence of PPM continue to rise with the ageing population in WA. As equilibrium has probably not been reached, the demand for pacing services in similarly well-developed economies is likely to continue to grow.

Anatomical variation of pulmonary venous ostium and its relationship with atrial arrhythmia in the Saudi population

PURPOSE

To assess the anatomical variation of the ostial pattern of pulmonary veins observed on coronary computed tomography (CT) angiogram and to estimate the relationship of atrial arrhythmia with similar ostial variants in the Saudi population.

MATERIALS AND METHODS

Thin-section (0.625 mm) contrast enhanced CT scans of 151 consecutive patients obtained over a span of a two-year period (January 2009-January 2011) for the diagnosis of ischemic heart disease, aortic regurgitation, infective endocarditis, aortic aneurysm, fibrosing mediastinitis, and pericardial defect. The retrospective study was focused on the identification of the number of venous ostia on either side of the left atrium and the drainage patterns of pulmonary veins. The frequency of each pattern was tabulated, and significance of their relationship with atrial arrhythmias was assessed with the X(2) and Fisher's exact tests.

RESULTS

Out of 151 patients analyzed, 26 patients (17.2%) had anatomical variation of the pulmonary venous ostia. Atrial arrhythmia was recorded in 16 of 26(61.5%) patients (p = 0.000). The association of higher anatomical variation of pulmonary venous ostia was recorded as higher (p = 0.034) in the female group (n = 15, 57.7%).

CONCLUSION

The association between anatomically varied venous ostia and atrial arrhythmia was significant (p = 0.000) with a significantly higher anatomical variation of pulmonary venous ostia in the female Saudi population (p = 0.034).