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Implantable loop recorders (ILR) are devices that are implanted subcutaneously on the chest, which enables the continuous monitoring of arrhythmias for up to three years. These devices have an important role in helping to make a diagnosis and supporting decisions about the best patient management. There are currently three companies that produce ILRs. The Reveal DX and XT device is produced by Medtronic. The Confirm device is produced by Abbott. The Biomonitor III device is produced by Biotronik. The established indications for ILR include the management of transient loss of consciousness and the diagnosis of undocumented palpitations; however, they are also used for less established applications, including atrial fibrillation (AF) monitoring and risk stratification in patients with previous myocardial infarction or inherited cardiomyopathies. There is also diverse literature exploring the use of these devices in other populations, including patients with conditions such as congenital heart disease, amyloidosis, stroke, obstructive sleep apnea, renal transplant and patients who undergo procedures such as AF ablation and coronary artery bypass graft. In this review, we describe how the use of ILR has been applied in different settings, including patients with cardiac and non-cardiac conditions as well as post-cardiac procedures. We then discuss the potential issues related to using ILR in these other indications. Full article

Background: Cardiovascular disease remains the leading cause of death in the United States. Coronary artery disease alone accounted for approximately 13% of deaths in the US in 2016. Some studies have suggested an increased prevalence of coronary artery disease (CAD) in chronic inflammatory conditions, such as celiac disease (CD). Chronic subclinical systemic inflammation, decreased absorption of cardio-protective nutrients and drugs have all been postulated as the driving mechanisms for this increased risk of CAD. Methods: We reviewed a Nationwide Inpatient Sample from 2007 to 2017, using Acute Coronary syndrome as a principal diagnosis with CD as the secondary diagnosis, utilizing validated ICD-9-CM and ICD-10 codes. We examined the annual trends in the number of cases and hospitalization charges yearly and used survey regression to calculate adjusted odds ratios (aOR) for hospital mortality and other outcomes. Results: We identified a total of 8,036,307 ACS hospitalizations from 2007 to 2017, of which 5917 (0.07%) had a diagnosis for CD. The proportion of patients with CD in ACS hospitalizations increased from 0.015% in 2007 to 0.076% in 2017. These patients were significantly older (70.3 vs. 67.4 years, p < 0.02), more likely female (51.9% vs. 39.5%, p < 0.01), and more likely to be white (93.8% vs. 76.6%; p < 0.01) than ACS patients without CD. After adjusting for age, gender, race, Charlson Comorbidity index and hospital level characteristics, ACS hospitalizations for CD patients had a lower odds ratio for hospital mortality (aOR = 0.39; 95% CI = 0.23–0.67; p < 0.01). Additionally, length of stay in this patient population was shorter (4.53 vs. 4.84 days, p < 0.01) but the mean hospitalization charges were higher (USD 64,058 vs. USD 60,223, p < 0.01). Conclusion: We found that the number of ACS-related admissions in CD patients has risen more than five-fold between 2007 and 2017. However, the odds of in-hospital mortality in these patients is not higher than patients without CD. The results of our study demonstrate that although the systemic inflammation related to CD is associated with an increasing prevalence of ACS hospitalizations, on the contrary, the mortality rate is significantly higher in patients without celiac disease. Full article

Atrial fibrillation (AF), a heart condition, has been a well-researched topic for the past few decades. This multidisciplinary field of study deals with signal processing, finite element analysis, mathematical modeling, optimization, and clinical procedure. This article is focused on a comprehensive review of journal articles published in the field of AF. Topics from the age-old fundamental concepts to specialized modern techniques involved in today’s AF research are discussed. It was found that a lot of research articles have already been published in modeling and simulation of AF. In comparison to that, the diagnosis and post-operative procedures for AF patients have not yet been totally understood or explored by the researchers. The simulation and modeling of AF have been investigated by many researchers in this field. Cellular model, tissue model, and geometric model among others have been used to simulate AF. Due to a very complex nature, the causes of AF have not been fully perceived to date, but the simulated results are validated with real-life patient data. Many algorithms have been proposed to detect the source of AF in human atria. There are many ablation strategies for AF patients, but the search for more efficient ablation strategies is still going on. AF management for patients with different stages of AF has been discussed in the literature as well but is somehow limited mostly to the patients with persistent AF. The authors hope that this study helps to find existing research gaps in the analysis and the diagnosis of AF. Full article

The NOTION trial compares transcatheter aortic valve implantation versus surgical aortic valve replacement in low-risk patients. Looking carefully at the outcomes of this trial, there is no doubt that the transcatheter aortic valve implantation results were outstanding. The same thing cannot be said for the results of the surgery. We tried to understand the reason for that. Full article

Cardiac implantable electronic device (CIED) implants are rising in an older, more co-morbid population. The prevalence of CIED infection ranges from 1–4%. Whilst complete extraction of all transvenous hardware is recommended for infected, eroded, or pre-eroding CIEDs, this approach is not without risk and may be unacceptable to some patients. Long-term data on a more conservative strategy is lacking. We report on our experience of conservative management with pocket revision as a primary strategy in carefully selected patients. Method: A retrospective review of all CIED revision procedures was undertaken at a large tertiary center, over a 7-year period, with a mean follow-up timeframe of 39 months. Results: A total of 86 patients underwent 96 revision procedures; 7 patients required further revisions and 13 went on to undergo CIED extraction by the end of the follow-up period. The overall rate of mortality at 12 months was 8.1%, increasing to 24.4% at the end of the follow-up period. Conclusion: Our data provide important outcome information on an alternative strategy to lead extraction in carefully selected patients where the risk of extraction is perceived to be unacceptable. The absence of systemic infection appears to predict better outcomes than previously reported, and over two-thirds of patients remained complication-free at 12 months. Full article

Background: Bundle branch re-entrant ventricular tachycardia (BBRVT) is a monomorphic ventricular arrhythmia with wide QRS complexes caused by re-entrant tachycardia between both bundle branches. BBRVT can occur in a variety of cardiac pathologies with His–Purkinje system (HPS) conduction abnormalities such as dilated cardiomyopathy, coronary artery disease, hypertrophic cardiomyopathy, valvular heart disease and even after aortic valve surgery. Case report: A 62-year-old male patient with an ischemic cardiomyopathy and implantable cardioverter defibrillator (ICD) underwent minimal invasive aortic valve replacement (Yil-AVR) and coronary artery bypass graft (CABG). He was remitted a week later because of relapsing sustained ventricular tachycardia (VT). Electrocardiogram showed a wide QRS tachycardia, which was remarkably similar to the patient’s sinus rhythm. Analysis of ICD revealed the presence of BBRVT. Catheter ablation of the right bundle branch (RBB) was performed. He is currently in clinical follow-up and no reoccurrence of VT has been recorded so far. Conclusion: Patients with known cardiomyopathy can develop BBRVT early after cardiac surgery. To our knowledge, this is the first time that BBRVT occurred after Yil-AVR. Full article

Objectives: We sought to investigate the rates of same-day discharge (SDD) post elective percutaneous coronary intervention (PCI) at our institution and review its safety by examining clinical outcomes. We also performed an economic analysis evaluating our hospital’s cost data for SDD following PCI. Methods: Patients undergoing elective PCI at St George Hospital, Australia, from January 2017 to December 2019 were evaluated. Primary outcomes included 7-day major adverse cardiovascular endpoints (MACEs) and readmission to hospital within 30 days. Results: Among 502 patients who underwent elective PCI, 421 patients (83.8%) were managed with SDD. There was one case of acute stent thrombosis and one case of coronary wire-induced perforation requiring a pericardial drain that occurred following elective PCI with SDD (0.54%). Unplanned cardiac re-hospitalisation at 30 days following elective PCI was 5.2%. SDD after elective PCI was associated with a healthcare cost saving of AUD 4817 per case. Conclusion: SDD following elective PCI was demonstrated to be a safe and effective strategy that was also associated with significant cost savings. SDD following elective PCI warrants more widespread use as it lowers healthcare costs, has equivalent patient outcomes and improves patient satisfaction. Full article

The purpose of this literature review is to gain an overview of the role of platelet-activating factor (PAF) within each of the body systems and how it contributes to normal and pathophysiological states. The review showed that there are multiple functions of PAF that are common to several body systems; however, there is little evidence to explain why PAF has this affect across multiple systems. Interestingly, there seems to be conflicting research as to whether PAF is an overall protective or pathogenic pathway. Within this research, it was found that there are different pathways depending on the specific body system, as well as between body systems. However, one universal function reported in the literature is of PAF as a pro-inflammatory molecule. Overall, this review identified five major functions of PAF: vasoconstriction, increased inflammation, vascular remodeling, increased edema, and endothelial permeability. Full article

Background: Percutaneous closure of patent foramen ovale (PFO) and atrial septal defects (ASD) is being more commonly performed due to changes in international guidelines supporting its use. This study was performed to determine the clinical outcomes, safety and cost implications of same-day discharge (SDD) following such procedures and place this in an Australian context. Methods: This was a retrospective, observational study of patients undergoing elective percutaneous PFO or ASD closure at St. George Hospital, Australia between January 2011 and January 2020. Primary outcomes included 30-day major adverse cardiovascular endpoints (MACE) and readmission to hospital within 30 days. Results: Twenty-four patients were included in the primary analysis. Ten (41.7%) patients underwent elective ASD closure while 14 (58.3%) underwent PFO closure. Among the 24 patients who underwent elective percutaneous closure of structural heart disease, 23 patients (95.8%) were managed with SDD. There were no MACE outcomes at 30 days. No patients were re-admitted to hospital at 30 days following these procedures. When compared to overnight admission to hospital post-elective percutaneous structural heart condition closure, SDD yielded a cost saving of AUD 5999 per case. Conclusion: SDD following elective percutaneous closure of ASD and PFO was demonstrated to be a safe and effective strategy for managing patients. With more widespread use, it can lead to significant cost savings for hospitals without compromising patient care. Full article

Body surface potential mapping (BSPM) is a noninvasive modality to assess cardiac bioelectric activity with a rich history of practical applications for both research and clinical investigation. BSPM provides comprehensive acquisition of bioelectric signals across the entire thorax, allowing for more complex and extensive analysis than the standard electrocardiogram (ECG). Despite its advantages, BSPM is not a common clinical tool. BSPM does, however, serve as a valuable research tool and as an input for other modes of analysis such as electrocardiographic imaging and, more recently, machine learning and artificial intelligence. In this report, we examine contemporary uses of BSPM, and provide an assessment of its future prospects in both clinical and research environments. We assess the state of the art of BSPM implementations and explore modern applications of advanced modeling and statistical analysis of BSPM data. We predict that BSPM will continue to be a valuable research tool, and will find clinical utility at the intersection of computational modeling approaches and artificial intelligence. Full article

Since its inception, the electrocardiogram (ECG) has been an essential tool in medicine. The ECG is more than a mere tracing of cardiac electrical activity; it can detect and diagnose various pathologies including arrhythmias, pericardial and myocardial disease, electrolyte disturbances, and pulmonary disease. The ECG is a simple, non-invasive, rapid, and cost-effective diagnostic tool in medicine; however, its clinical utility relies on the accuracy of its interpretation. Computer ECG analysis has become so widespread and relied upon that ECG literacy among clinicians is waning. With recent technological advances, the application of artificial intelligence-augmented ECG (AI-ECG) algorithms has demonstrated the potential to risk stratify, diagnose, and even interpret ECGs—all of which can have a tremendous impact on patient care and clinical workflow. In this review, we examine (i) the utility and importance of the ECG in clinical practice, (ii) the accuracy and limitations of current ECG interpretation methods, (iii) existing challenges in ECG education, and (iv) the potential use of AI-ECG algorithms for comprehensive ECG interpretation. Full article

Syncope of cardiac origin may be associated with an increased risk of sudden cardiac death if not treated in a timely and appropriate manner. The diagnostic approach of syncope imposes a significant economic burden on society. The investigation and elucidation of the pathogenetic mechanism of syncope are of great clinical importance, as both prognosis and appropriate therapeutic approaches depend on these factors. The responsible mechanism of presyncope or syncope can only be revealed through the patient history, baseline clinical examination and electrocardiogram. The percentage of patients who are diagnosed with these tests alone exceeds 50%. In patients with a history of organic or acquired heart disease or/and the presence of abnormal findings on the electrocardiogram, a further diagnostic electrophysiology inclusive approach should be followed to exclude life threatening arrhythmiological mechanism. However, if the patient does not suffer from underlying heart disease and does not show abnormal electrocardiographic findings in the electrocardiogram, then the probability in the electrophysiology study to find a responsible cause is small but not absent. The role of a two-step electrophysiology study inclusive risk stratification approach for the effective management of the former is thoroughly discussed in this review. Full article

The ambulatory ECG (AECG) is an important diagnostic tool for many heart electrophysiology-related cases. AECG covers a wide spectrum of devices and applications. At the core of these devices and applications are the algorithms responsible for signal conditioning, ECG beat detection and classification, and event detections. Over the years, there has been huge progress for algorithm development and implementation thanks to great efforts by researchers, engineers, and physicians, alongside the rapid development of electronics and signal processing, especially machine learning (ML). The current efforts and progress in machine learning fields are unprecedented, and many of these ML algorithms have also been successfully applied to AECG applications. This review covers some key AECG applications of ML algorithms. However, instead of doing a general review of ML algorithms, we are focusing on the central tasks of AECG and discussing what ML can bring to solve the key challenges AECG is facing. The center tasks of AECG signal processing listed in the review include signal preprocessing, beat detection and classification, event detection, and event prediction. Each AECG device/system might have different portions and forms of those signal components depending on its application and the target, but these are the topics most relevant and of greatest concern to the people working in this area. Full article

This chapter is a review of studies that have examined false arrhythmia alarms during in-hospital electrocardiographic (ECG) monitoring in the intensive care unit. In addition, we describe an annotation effort being conducted at the UCSF School of Nursing, Center for Physiologic Research designed to improve algorithms for lethal arrhythmias (i.e., asystole, ventricular fibrillation, and ventricular tachycardia). Background: Alarm fatigue is a serious patient safety hazard among hospitalized patients. Data from the past five years, showed that alarm fatigue was responsible for over 650 deaths, which is likely lower than the actual number due to under-reporting. Arrhythmia alarms are a common source of false alarms and 90% are false. While clinical scientists have implemented a number of interventions to reduce these types of alarms (e.g., customized alarm settings; daily skin electrode changes; disposable vs. non-disposable lead wires; and education), only minor improvements have been made. This is likely as these interventions do not address the primary problem of false arrhythmia alarms, namely deficient and outdated arrhythmia algorithms. In this chapter we will describe a number of ECG features associated with false arrhythmia alarms. In addition, we briefly discuss an annotation effort our group has undertaken to improve lethal arrhythmia algorithms. Full article

Computerized electrocardiography (ECG) has been widely used and allows linkage to electronic medical records. The present study describes the development and clinical applications of an electronic cohort derived from a digital ECG database obtained by the Telehealth Network of Minas Gerais, Brazil, for the period 2010–2017, linked to the mortality data from the national information system, the Clinical Outcomes in Digital Electrocardiography (CODE) dataset. From 2,470,424 ECGs, 1,773,689 patients were identified. A total of 1,666,778 (94%) underwent a valid ECG recording for the period 2010 to 2017, with 1,558,421 patients over 16 years old; 40.2% were men, with a mean age of 51.7 [SD 17.6] years. During a mean follow-up of 3.7 years, the mortality rate was 3.3%. ECG abnormalities assessed were: atrial fibrillation (AF), right bundle branch block (RBBB), left bundle branch block (LBBB), atrioventricular block (AVB), and ventricular pre-excitation. Most ECG abnormalities (AF: Hazard ratio [HR] 2.10; 95% CI 2.03–2.17; RBBB: HR 1.32; 95%CI 1.27–1.36; LBBB: HR 1.69; 95% CI 1.62–1.76; first degree AVB: Relative survival [RS]: 0.76; 95% CI0.71–0.81; 2:1 AVB: RS 0.21 95% CI0.09–0.52; and RS 0.36; third degree AVB: 95% CI 0.26–0.49) were predictors of overall mortality, except for ventricular pre-excitation (HR 1.41; 95% CI 0.56–3.57) and Mobitz I AVB (RS 0.65; 95% CI 0.34–1.24). In conclusion, a large ECG database established by a telehealth network can be a useful tool for facilitating new advances in the fields of digital electrocardiography, clinical cardiology and cardiovascular epidemiology. Full article

This article traces the development of automated electrocardiography from its beginnings in Washington, DC around 1960 through to its current widespread application worldwide. Changes in the methodology of recording ECGs in analogue form using sizeable equipment through to digital recording, even in wearables, are included. Methods of analysis are considered from single lead to three leads to twelve leads. Some of the influential figures are mentioned while work undertaken locally is used to outline the progress of the technique mirrored in other centres. Applications of artificial intelligence are also considered so that the reader can find out how the field has been constantly evolving over the past 50 years. Full article

Interatrial blocks like other types of block may be of first degree or partial second degree, also named transient atrial block or atrial aberrancy, and third degree or advanced. In first degree, partial interatrial block (P-IAB), the electrical impulse is conducted to the left atrium, through the Bachmann’s region, but with delay. The ECG shows a P-wave ≥ 120 ms. In third-degree, advanced interatrial block (A-IAB), the electrical impulse is blocked in the upper part of the interatrial septum (Bachmann region); the breakthrough to LA has to be performed retrogradely from the AV junction zone. This explains the p ± in leads II, III and aVF. In typical cases of A-IAB, the P-wave morphology is biphasic (±) in leads II, III and aVF, because the left atrium is activated retrogradely and, therefore, the last part of the atrial activation falls in the negative hemifield of leads II, III and aVF. Recently, some atypical cases of A-IAB have been described. The presence of A-IAB is a risk factor for atrial fibrillation, stroke, dementia, and premature death. Full article