Mechanisms of arrhythmias and conduction disorders in older adults

Immune cells and arrhythmias

Cardiac arrhythmias are a significant cause of morbidity and mortality worldwide. Emerging evidence has demonstrated that resident and infiltrating cardiac immune cells play direct, mechanistic roles in arrhythmia onset and progression. In this review, we provide a comprehensive summary and expert commentary on the role of each immune cell subtype in the pathogenesis of atrial and ventricular arrhythmias.

Longevity mechanisms in cardiac aging: exploring calcium dysregulation and senescence

Cardiac aging is a multistep process that results in a loss of various structural and functional heart abilities, increasing the risk of heart disease. Since its remarkable discovery in the early 1800s, when limestone is heated, calcium's importance has been defined in numerous ways. It can help stiffen shells and bones, function as a reducing agent in chemical reactions, and play a central role in cellular signalling. The movement of calcium ions in and out of cells and between those is referred to as calcium signalling. It influences the binding of the ligand, enzyme activity, electrochemical gradients, and other cellular processes. Calcium signalling is critical for both contraction and relaxation under the sliding filament model of heart muscle. However, with age, the heart undergoes changes that lead to increases in cardiac dysfunction, such as myocardial fibrosis, decreased cardiomyocyte function, and noxious disturbances in calcium homeostasis. Additionally, when cardiac tissues age, cellular senescence, a state of irreversible cell cycle arrest, accumulates and begins to exacerbate tissue inflammation and fibrosis. This review explores the most recent discoveries regarding the role of senescent cell accumulation and calcium signalling perturbances in cardiac aging. Additionally, new treatment strategies are used to reduce aged-related heart dysfunction by targeting senescent cells and modulating calcium homeostasis.

Congestive Heart Failure and Arrhythmias Among Hospitalized Patients With Carcinoid Syndrome

Introduction Carcinoid syndrome (CS) represents the most common functional syndrome in patients with neuroendocrine tumors which may be in an advanced tumor state. The pathophysiology of congestive heart failure (CHF) and arrhythmia in CS is poorly understood; however, chronic exposure to excessive circulating serotonin is considered one of the most important factors contributing to increased morbidity and mortality in this population. Despite recognition, international consensus guidelines specifically addressing the diagnosis and management of CHF and arrhythmia in CS are lacking. This study focused on hospitalized patients once they represent more severe disease states requiring intensive management, thereby providing a clearer understanding of factors influencing adverse clinical outcomes.  Methods This retrospective cohort study utilized the Healthcare Cost and Utilization Project National Inpatient Sample to identify predictors of congestive heart failure and arrhythmia in hospitalized CS patients from 2016 to 2018.  Results Initially, a total of 1,859 patients were included. After stratification, 606 patients had CHF and arrhythmia diagnosis with variables analyzed using multivariate logistic regression. Among 606 patients, 360 had CHF with advanced age, male sex, non-Hispanic Black race, Medicare insurance, and prolonged hospital stays, all of which were identified as significant predictors. Similarly, 246 patients diagnosed with arrhythmias were more prevalent in older and male patients and were associated with increased mortality and prolonged hospitalization. Conclusion These results highlight critical patient-related factors influencing mortality in CS patients with CHF and arrhythmia. Strategies aimed at early recognition, including clinical scoring systems, and biomarker assessment, could improve risk stratification and patient outcomes. Our findings underscore the importance of early risk stratification and targeted interventions to mitigate cardiac complications in CS patients. Additionally, incorporating our data into clinical practice has the potential to improve early recognition, promoting timely interventions for CS patients with CFH and arrhythmia. Developing consensus guidelines for managing CS-related cardiac complications, based on these insights, will further standardize care and improve patient outcomes.

Leucocyte telomere length and conduction system ageing

BACKGROUND

Deterioration of the cardiac conduction system is an important manifestation of cardiac ageing. Cellular ageing is accompanied by telomere shortening and telomere length (TL) is often regarded as a marker of biological ageing, potentially adding information regarding conduction disease over and above chronological age. We therefore sought to evaluate the association between leucocyte telomere length (LTL) on two related, but distinct aspects of the cardiac conduction system: ECG measures of conduction (PR interval and QRS duration) and incident pacemaker implantation in a large population-based cohort.

METHODS

In the UK Biobank, we measured PR interval and QRS duration from signal-averaged ECG waveforms in 59 868 and 62 266 participants, respectively. Incident pacemaker implantation was ascertained using hospital episode data from 420 071 participants. Associations with LTL were evaluated in (Cox) multivariable regression analyses adjusted for potential confounders. Putative causal effects of LTL were investigated by mendelian randomisation (MR).

RESULTS

Mean PR interval and QRS duration were 144.2 ms (± 20.4) and 92.3 ms (± 7.8), respectively, and there were 7169 (1.7%) incident pacemaker implantations, during a median follow-up period of 13.6 (IQR 1.5) years. LTL was significantly associated with PR interval (0.19 ms (95% CI: 0.03 to 0.35), per 1 SD shorter LTL, p=0.021), but not QRS duration. After adjusting for age, sex and cardiovascular risk factors, shorter LTL remained associated with an increased risk for incident pacemaker implantation (HR per SD decrease in LTL: 1.03 (95% CI: 1.01 to 1.06), p=0.012). MR analysis showed a trend towards an association of shorter LTL with longer PR interval and higher risk of pacemaker implantation but was likely to be underpowered.

CONCLUSIONS

Shorter LTL was significantly, and possibly causally, associated with prolongation of atrioventricular conduction and pacemaker implantation, independent of traditional cardiovascular risk factors. Our findings support further research to explore the role of ageing on cardiac conduction beyond chronological age.

Artificial intelligence-derived electrocardiographic aging and risk of atrial fibrillation: a multi-national study

BACKGROUND AND AIMS

Artificial intelligence (AI) algorithms in 12-lead electrocardiogram (ECG) provides promising age prediction methods. This study investigated whether the discrepancy between ECG-derived AI-predicted age (AI-ECG age) and chronological age, termed electrocardiographic aging (ECG aging), is associated with atrial fibrillation (AF) risk.

METHODS

An AI-ECG age prediction model was developed using a large-scale dataset (1 533 042 ECGs from 689 639 participants) and validated with six independent and multi-national datasets (737 133 ECGs from 330 794 participants). The AI-ECG age gap was calculated across two South Korean cohorts [mean (standard deviation) follow-up: 4.1 (4.3) years for 111 483 participants and 6.1 (3.8) years for 37 517 participants], one UK cohort [3.0 (1.6) years; 40 973 participants], and one US cohort [12.9 (8.6) years; 90 639 participants]. Participants were classified into two groups: normal group (age gap < 7 years) and ECG-aged group (age gap ≥ 7 years). The predictive capability of ECG aging for new- and early-onset AF risk was assessed.

RESULTS

The mean AI-ECG ages were 51.9 (16.2), 47.4 (12.5), 68.4 (7.8), and 56.7 (14.6) years with age gaps of .0 (6.8), -.1 (6.0), 4.7 (8.7), and -1.4 (8.9) years in the two South Korean, UK, and US cohorts, respectively. In the ECG-aged group, increased risks of new-onset AF were observed with hazard ratios (95% confidence intervals) of 2.50 (2.24-2.78), 1.89 (1.46-2.43), 1.90 (1.55-2.33), and 1.76 (1.67-1.86) in the two South Korean, UK, and US cohorts, respectively. For early-onset AF, odds ratios were 2.89 (2.47-3.37), 1.94 (1.39-2.70), 1.58 (1.06-2.35), and 1.79 (1.62-1.97) in these cohorts compared with the normal group.

CONCLUSIONS

The AI-derived ECG aging was associated with the risk of new- and early-onset AF, suggesting its potential utility to identify individuals for AF prevention across diverse populations.

Dyspnea Management in Patients Presenting to the Emergency Department at Cantonal Hospital Baselland-A Retrospective Observational Study and Medical Audit

Background/Objectives: Dyspnea, the subjective experience of breathing discomfort, accounts for approximately 5% of emergency department (ED) presentations, 10% of general ward admissions, and 20% of intensive care unit (ICU) admissions. Despite its prevalence, dyspnea remains a challenging clinical manifestation for physicians. To the best of our knowledge, there are no international guidelines for the assessment and management of patients with dyspnea coming to the ED. In this study, we aim to evaluate how dyspnea cases are assessed and managed at Cantonal Hospital Baselland in Liestal (KSBL) and to audit these practices. Methods: We conducted a retrospective, observational study of hospital records from KSBL, including all patients presenting to the ED with dyspnea as their primary symptom who were subsequently admitted to the internal medicine ward for at least one night between January and December 2022. Data on assessment and management practices were compared using the medStandards algorithm. Results: A total of 823 cases were included. The median age at admission was 76 years (with a range of 15-99), and 57% of the patients were male. Blood pressure and heart rate were documented in 93.8% of the cases, respiratory rate in 61.4%, oxygen saturation in 96.1%, and body temperature in 86.3%. The patient's subjective dyspnea description was recorded in 14.8% of the cases, while the temporal onset (timing of symptoms) was documented in 98.8%, and the intensity of effort triggering dyspnea was noted in 36.2% of cases. A dyspnea index scale was used in 7.8% and smoking status was documented in 41.1% of the cases. Lung percussion was performed in 2.6% of the cases, while a lung auscultation was performed in 94.4% and a heart auscultation was performed in 85.3% of cases. A complete blood count with a basic metabolic panel and TSH test was collected in 86.9% of the cases, while a blood gas analysis was collected in 34.0% of the cases. An ECG was reported in 87.5% of the cases. From the 337 patients who should have received an emergency ultrasound, 10.1% received one. The three most frequent final diagnoses were decompensated heart failure (28.4%), pneumonia (26.4%), and COVID-19 (17.0%). None of the three patients with a known neuromuscular disease were admitted to the shock room. Conclusions: Our findings reveal that the medStandards algorithm was only partially followed at the ED in KSBL Liestal, highlighting gaps in detailed history taking, respiratory rate measurement, lung percussion, and emergency ultrasound use. Given the frequency of dyspnea-related presentations, systematic improvements in the adherence to assessment protocols are urgently needed to enhance patient outcomes.

Trends, gender, and racial disparities in patients with mortality due to paroxysmal tachycardia: A nationwide analysis from 1999-2020

BACKGROUND

Paroxysmal tachycardia encompasses various heart rhythm disorders that cause rapid heart rates. Its episodic occurrence makes it difficult to identify and measure its prevalence and trends in the population. Additionally, there is limited data on disparities and trends in mortality due to paroxysmal tachycardia, which is essential for assessing current medical approaches and identifying at-risk populations.

METHODS

Our study examined death certificates from 1999 to 2020 using the CDC WONDER Database to identify deaths caused by paroxysmal tachycardia in individuals aged 25 and older, using the ICD-10 code I47. Age-adjusted mortality rates (AAMRs) and annual percent changes (APC) were calculated by year, gender, age group, race/ethnicity, geographic location, and urbanization status. Trends in AAMRs were analyzed using the Joinpoint Regression Program to identify significant changes and inflection points in mortality trends throughout the study period.

RESULTS

Between 1999 and 2020, 155,320 deaths were reported in patients with paroxysmal tachycardia. Overall, AAMR decreased from 4.8 to 3.7 per 100,000 population between 1999 and 2020, despite showing a significant increase from 2014 to 2020 (APC: 4.33; 95% CI: 3.53 to 5.56). Men had consistently higher AAMRs than women (4.7 vs. 2.2). Furthermore, we found that AAMRs were highest among Non-Hispanic (NH) Black or African Americans and lowest in NH Asian or Pacific Islanders (4 vs. 1.9). Nonmetropolitan areas had higher AAMRs than metropolitan areas (3.6 vs. 3.2).

CONCLUSIONS

Our analysis showed a significant decrease in mortality from paroxysmal tachycardia since 1999, although there has been a slight increase in recent years. However, disparities remain, with higher AAMRs among men, NH Black or African Americans, and residents of non-metropolitan areas. These findings call for immediate public health actions to curb the rising trends and reduce potential disparities.

Immunometabolism in the Aging Heart

Structural, functional, and molecular-level changes in the aging heart are influenced by a dynamic interplay between immune signaling and cellular metabolism that is referred to as immunometabolism. This review explores the crosstalk between cellular metabolic pathways including glycolysis, oxidative phosphorylation, fatty acid metabolism, and the immune processes that govern cardiac aging. With a rapidly aging population that coincides with increased cardiovascular risk and cancer incidence rates, understanding the immunometabolic underpinnings of cardiac aging provides a foundation for identifying therapeutic targets to mitigate cardiac dysfunction. Aging alters the immune environment of the heart by concomitantly driving the changes in immune cell metabolism, mitochondrial dysfunction, and redox signaling. Shifts in these metabolic pathways exacerbate inflammation and impair tissue repair, creating a vicious cycle that accelerates cardiac functional decline. Treatment with cancer therapy further complicates this landscape, as aging-associated immunometabolic disruptions augment the susceptibility to cardiotoxicity. The current review highlights therapeutic strategies that target the immunometabolic axis to alleviate cardiac aging pathologies. Interventions include modulating metabolic intermediates, improving mitochondrial function, and leveraging immune signaling pathways to restore cardiac health. Advances in immunometabolism thus hold significant potential for translating preclinical findings into therapies that improve the quality of life for the aging population and underscore the need for approaches that address the immunometabolic mechanisms of cardiac aging, providing a framework for future research.

Predictors of Mortality in Out-of-hospital Cardiac Arrest (OHCA) Patients: A Retrospective Cross-sectional Study from the Sultanate of Oman

Background

Out-of-hospital cardiac arrest (OHCA) is a significant global health challenge with high incidence and low survival rates; this study aimed to predict mortality in these patients.

Methods

This 5-year retrospective chart review, conducted at the emergency departments (EDs) of two tertiary hospitals, systematically categorized, coded, and analyzed variables to assess mortality risk in OHCA patients.

Results

Of the 822 (36.5%) patients who met the inclusion criteria, the mean age was 60.2 years (SD ± 17.6), with 65.7% being male. Cardiopulmonary resuscitation (CPR) was attempted on 586 patients, with 178 (30.4%) achieving return of spontaneous circulation (ROSC) in the ED. Significant risk factors for mortality included hypertension (p = 0.01), diabetes mellitus (p = 0.05), respiratory illnesses (p = 0.04), and having three or more comorbidities (p = 0.01). Manifestations in previous ED visits (<180 days), such as cardiac complaints (p = 0.05) and dyspnea due to fluid overload (p = 0.02), were significant. Among the cohort, 76.4% visited the ED (<180 days) and had a mortality rate of 95.7%, compared to 78.4% for those who did not visit. Asystole and pulseless electrical activity (PEA) were significant factors for the nonachievement of ROSC (p < 0.001 vs p = 0.032) and mortality (p < 0.001 vs p = 0.03). Overall, 49 patients (8.4%) survived to hospital discharge.

Conclusion

Elderly males with hypertension, diabetes, respiratory ailments, and multiple comorbidities constituted a significant risk group. Factors such as prior episodes of chest pain and fluid overload were associated with higher mortality. Patients with asystole and PEA had low survival rates.

How to cite this article

Al-Habsi T, Al-Mandhari A, Hazra D, Al-Badri M, Al Harthi K, Al-Obaidani T, et al. Predictors of Mortality in Out-of-hospital Cardiac Arrest (OHCA) Patients: A Retrospective Cross-sectional Study from the Sultanate of Oman. Indian J Crit Care Med 2024;28(11):1056-1062.

The association between interoception and olfactory affective responses

Odors are known to affect an individual's emotions and physiological states. Recent research has revealed that olfaction is linked to the mental representation of internal sensations, known as interoception. However, little research has examined how interoception relates to emotional responses to odors. This research aimed to fill this gap in the literature. We conducted two studies with a total of 548 Japanese women (n = 500 and n = 48 in Studies 1 and 2, respectively). Study 1 used an online survey to assess the relationship between self-reported interoceptive traits and the intensity of positive emotions in response to daily odors. Study 2 examined how self-reported interoceptive traits modulated the arousal ratings of odors presented in the laboratory and the concordance between these perceived arousal ratings and odor-evoked physiological responses. Study 1 confirmed that self-reported interoceptive traits were significant predictors of positive emotional intensity of odors. In Study 2, individuals with high interoceptive measure scores showed concordance between their perceived emotional arousal and the physiological responses associated with that emotion, whereas individuals with low scores did not. These findings suggest that how people perceive their internal sensations contributes to shaping their olfactory affective experiences, thereby broadening the scope of interoception research and aromachology. The practical implications of these findings for the development of commercial fragrances are discussed.

Donepezil and Memantine-Induced Second-Degree Atrioventricular Block: A Case Report

Donepezil and memantine are second-generation antipsychotics widely used in the management of mild to moderate Alzheimer's disease. These drugs are highly selective for the central nervous system, targeting different neural pathways to mitigate cognitive decline. Donepezil is a reversible and specific acetylcholinesterase inhibitor, while memantine is an NMDA receptor antagonist which modulates glutamatergic activity. Although these medications are safe, they are associated with adverse effects, and cardiovascular complications are rare. The reported cardiac adverse drug reactions include bradycardia, atrioventricular block, and prolonged QT interval. We are reporting a case of an 81-year-old male patient with schizophrenia, Alzheimer's disease and bilateral sensorineural deafness receiving oral donepezil and memantine presented with second-degree atrioventricular block. The patient's atrioventricular block recovered completely in 2 to 3 weeks after the discontinuation of donepezil-memantine and with a short course of sympathomimetic drugs.

Sex-associated differences in cardiac ageing: Clinical aspects and molecular mechanisms

Despite the extensive clinical and scientific advances in prevention, diagnostics and treatment, cardiovascular diseases (CVD) remain the leading cause of morbidity and mortality worldwide for people aged 65 and over. Of all ageing-related diseases, CVD are responsible for almost one-third of deaths in the elderly, being above all cancers combined. Age is an independent and unavoidable risk factor contributing to the impairment of heart and blood vessels. As the average age of the population in industrialized countries has doubled in the last century, and almost a fifth of the world's population is predicted to be over 65 in the next decade, we can assume that the burden of CVD will fall primarily on the elderly. Evidence from basic and clinical science has shown that sex significantly influences the onset and severity of CVD. In women, CVD usually develop later than in men and with atypical symptomatology. After menopause, however, the incidence and severity of CVD increase in women, reaching equality in both sexes. Although intrinsic sexual dimorphism in cardiovascular ageing may contribute to the sex differences in CVD progression, the molecular mechanisms associated with cardiovascular ageing and their clinical value are not known in detail. In this review, we discuss the scientific knowledge available, focusing on structural, hormonal, genetic/epigenetic and inflammatory pathways, seeking to transfer these findings to the cardiovascular clinic in terms of prevention, diagnosis, prognosis and management of these pathologies and proposing possible validation of target specifics.

Cardiogeriatrics: the current state of the art

It is estimated that by 2050, 17% of the world's population will be greater than 85 years old, which, combined with cardiovascular disease (CVD) being the leading cause of death and disability, sets an unprecedented burden on our health and care systems. This perfect storm will be accompanied by a rise in the prevalence of CVD due to increased survival of patients with pre-existing CVD and the incidence of CVD that is associated with the process of ageing. In this review, we will focus on the diagnosis and management of common CVD conditions in old age, namely: heart failure (HF), coronary artery disease (CAD), atrial fibrillation (AF) and valvular heart disease (VHD). Despite limited evidence, clinical guidelines are increasingly considering the complexity of management of these conditions in the older person, which often coexist, for example, AF and HF or CAD and VHD. Furthermore, they, in turn, need specific consideration in the context of comorbidities, polypharmacy, frailty and impaired cognition found in this age group. Hence, the emerging role of the geriatric cardiologist is therefore vital in performing comprehensive geriatric assessment, attending multidisciplinary team meetings and ultimately considering the patient and the sum of their diseases in their totality. There have been recent advances in CVD management but how we apply these to deliver integrated care to the elderly population is key. This review article aims to bring together emerging studies and guidelines on assessment and management of CVD in the elderly, summarising latest definitions, diagnostics, therapeutics and future challenges.

Impact of age on hospital outcomes after catheter ablation for ventricular tachycardia

Background

The real-world data on the safety profile of ventricular tachycardia (VT) ablation among elderly patients is not well-established. This study aimed to evaluate the procedural outcomes among those aged 18-64 years versus those aged ≥65 years who underwent catheter ablation of VT.

Method

Using the Nationwide Readmissions Database, our study included patients aged ≥18 years who underwent VT catheter ablation between 2017 and 2020. We divided the patients into non-elderly (18-64 years old) and elderly age groups (≥65 years old). We then analyzed the in-hospital procedural outcome and 30-day readmission between these two groups.

Results

Our study included 2075 (49.1%) non-elderly patients and 2153 (50.9%) elderly patients who underwent VT ablation. Post-procedurally, elderly patients had significantly higher rates of prolonged index hospitalization (≥7 days; 35.5% vs. 29.3%, p < .01), non-home discharge (13.4% vs. 6.0%, p < .01), 30-day readmission (17.0% vs. 11.4%, p < .01), and early mortality (5.5% vs. 2.4%, p < .01). There was no significant difference in the procedural complications between two groups, namely vascular complications, hemopericardium/cardiac tamponade, cerebrovascular accident (CVA), major bleeding requiring blood transfusion, and systemic embolization. Through multivariable analysis, the elderly group was associated with higher odds of early mortality (OR: 7.50; CI 1.86-30.31, p = .01), non-home discharge (OR: 2.41; CI: 1.93-3.00, p < .01) and 30-day readmission (OR: 1.58; CI 1.32-1.89, p < .01).

Conclusion

Elderly patients have worse in-hospital outcome, early mortality, non-home discharge, and 30-day readmission following catheter ablation for VT. There was no significant difference between elderly and non-elderly groups in the procedural complications.

Deletion of Interleukin-1β Converting Enzyme Alters Mouse Cardiac Structure and Function

Interleukin-1β converting enzyme (ICE, caspase-1) is a thiol protease that cleaves the pro-inflammatory cytokine precursors of IL-1β and IL-18 into active forms. Given the association between caspase-1 and cardiovascular pathology, we analyzed the hearts of ICE knockout (ICE KO) mice to test the hypothesis that caspase-1 plays a significant role in cardiac morphology and function. We characterized the histological and functional changes in the hearts of ICE KO mice compared to the Wild type. The cardiomyocytes from the neonatal ICE KO mice showed an impaired response to oxidative stress. Subsequently, the hearts from the ICE KO mice were hypertrophied, with a significant increase in the left ventricular and septal wall thickness and a greater LV mass/body weight ratio. The ICE KO mice hearts exhibited irregular myofibril arrangements and disruption of the cristae in the mitochondrial structure. Proapoptotic proteins that were significantly increased in the hearts of ICE KO versus the Wild type included pErk, pJNK, p53, Fas, Bax, and caspase 3. Further, the antiapoptotic proteins Bag-1 and Bcl-2 are activated in ICE KO hearts. Functionally, there was an increase in the left ventricular epicardial diameter and volume in ICE KO. In conclusion, our findings support the important role of caspase-1 in maintaining cardiac health; specifically, a significant decrease in caspase-1 is detrimental to the cardiovascular system.

Continual learning framework for a multicenter study with an application to electrocardiogram

Deep learning has been increasingly utilized in the medical field and achieved many goals. Since the size of data dominates the performance of deep learning, several medical institutions are conducting joint research to obtain as much data as possible. However, sharing data is usually prohibited owing to the risk of privacy invasion. Federated learning is a reasonable idea to train distributed multicenter data without direct access; however, a central server to merge and distribute models is needed, which is expensive and hardly approved due to various legal regulations. This paper proposes a continual learning framework for a multicenter study, which does not require a central server and can prevent catastrophic forgetting of previously trained knowledge. The proposed framework contains the continual learning method selection process, assuming that a single method is not omnipotent for all involved datasets in a real-world setting and that there could be a proper method to be selected for specific data. We utilized the fake data based on a generative adversarial network to evaluate methods prospectively, not ex post facto. We used four independent electrocardiogram datasets for a multicenter study and trained the arrhythmia detection model. Our proposed framework was evaluated against supervised and federated learning methods, as well as finetuning approaches that do not include any regulation to preserve previous knowledge. Even without a central server and access to the past data, our framework achieved stable performance (AUROC 0.897) across all involved datasets, achieving comparable performance to federated learning (AUROC 0.901).

Prevalence of Medication Associated with QTc Prolongation Used Among Critically Ill Patients

Background

Acquired prolonged corrected QT (QTc) interval can lead to life-threatening Torsade de Pointes (TdP) arrhythmia. Multiple risk factors including medications, comorbidities, and electrolyte imbalances contribute significantly to acquired manifestations of the QTc prolongation. Critically ill patients are particularly more vulnerable to TdP due to complex medical conditions, aging, and polypharmacy.

Objective

This study aimed to assess the prevalence of TdP-associated medication prescribing, identify risk factors for QTc prolongation and TdP, and determine primary predictors of high TdP medication usage in critically ill patients in Jordan.

Methods

We conducted a retrospective cross-sectional analysis of electronic medical records for patients from King Abdullah University Hospital who were admitted to Intensive Care Unit (ICU) between (July 2012-July 2022). We collected data on patients' demographics, clinical characteristics, comorbidities, laboratory results, and prescribed medications. Medications were categorized into three TdP risk levels according to CredibleMeds® assessment tool. Data were analyzed using descriptive statistics and a binary logistic regression model.

Results

Of the 13,300 patients (58.2% male, median age 62 years). Prescribing prevalence for medications with known TdP risk was 19%, possible risk (24.7%), conditional risk (21.6%), and confirmed conditional risk (8.3%). Common comorbidities included hypertension (40.9%), diabetes (33.3%), and cancer (15.4%). Drugs with known TdP risk included citalopram, amiodarone, clarithromycin, and ciprofloxacin. A binary regression model revealed that as age increased, the odds of TdP associated medication prescribing decreased (OR = 0.989, p < 0.001), while patients on more than five medications had higher odds (OR = 4.281, p < 0.001).

Conclusion

The study identified a notable prevalence of prescribing for medications with QTc prolongation/TdP risk in critically ill patients. Healthcare providers in the ICU should exercise caution to minimize the inadvertent prescription of TdP associated medications especially among older patients and those with polypharmacy.

Role of Genetic Variation in Transcriptional Regulatory Elements in Heart Rhythm

Genetic predisposition to cardiac arrhythmias has been a field of intense investigation. Research initially focused on rare hereditary arrhythmias, but over the last two decades, the role of genetic variation (single nucleotide polymorphisms) in heart rate, rhythm, and arrhythmias has been taken into consideration as well. In particular, genome-wide association studies have identified hundreds of genomic loci associated with quantitative electrocardiographic traits, atrial fibrillation, and less common arrhythmias such as Brugada syndrome. A significant number of associated variants have been found to systematically localize in non-coding regulatory elements that control the tissue-specific and temporal transcription of genes encoding transcription factors, ion channels, and other proteins. However, the identification of causal variants and the mechanism underlying their impact on phenotype has proven difficult due to the complex tissue-specific, time-resolved, condition-dependent, and combinatorial function of regulatory elements, as well as their modest conservation across different model species. In this review, we discuss research efforts aimed at identifying and characterizing-trait-associated variant regulatory elements and the molecular mechanisms underlying their impact on heart rate or rhythm.

p38γ/δ activation alters cardiac electrical activity and predisposes to ventricular arrhythmia

Ventricular fibrillation (VF) is a leading immediate cause of sudden cardiac death. There is a strong association between aging and VF, although the mechanisms are unclear, limiting the availability of targeted therapeutic interventions. Here we found that the stress kinases p38γ and p38δ are activated in the ventricles of old mice and mice with genetic or drug-induced arrhythmogenic conditions. We discovered that, upon activation, p38γ and p38δ cooperatively increase the susceptibility to stress-induced VF. Mechanistically, our data indicate that activated p38γ and p38δ phosphorylate ryanodine receptor 2 (RyR2) disrupt Kv4.3 channel localization, promoting sarcoplasmic reticulum calcium leak, Ito current reduction and action potential duration prolongation. In turn, this led to aberrant intracellular calcium handling, premature ventricular complexes and enhanced susceptibility to VF. Blocking this pathway protected genetically modified animals from VF development and reduced the VF duration in aged animals. These results indicate that p38γ and p38δ are a potential therapeutic target for sustained VF prevention.

SGLT2 Inhibitors in Aging-Related Cardiovascular Disease: A Review of Potential Mechanisms

Population aging combined with higher susceptibility to cardiovascular diseases in older adults is increasing the incidence of conditions such as atherosclerosis, myocardial infarction, heart failure, myocardial hypertrophy, myocardial fibrosis, arrhythmia, and hypertension. sodium-glucose cotransporter 2 inhibitors (SGLT2i) were originally developed as a novel oral drug for patients with type 2 diabetes mellitus. Unexpectedly, recent studies have shown that, beyond their effect on hyperglycemia, SGLT2i also have a variety of beneficial effects on cardiovascular disease. Experimental models of cardiovascular disease have shown that SGLT2i ameliorate the process of aging-related cardiovascular disease by inhibiting inflammation, reducing oxidative stress, and reversing endothelial dysfunction. In this review, we discuss the role of SGLT2i in aging-related cardiovascular disease and propose the use of SGLT2i to prevent and treat these conditions in older adults.

Pancreatic T2* Magnetic Resonance Imaging for Prediction of Cardiac Arrhythmias in Transfusion-Dependent Thalassemia

We assessed the value of pancreatic T2* magnetic resonance imaging (MRI) for predicting cardiac events from a large prospective database of transfusion-dependent thalassemia (TDT) patients. We considered 813 TDT patients (36.47 ± 10.71 years, 54.6% females) enrolled in the Extension-Myocardial Iron Overload in Thalassemia Network. MRI was used to measure hepatic, pancreatic, and cardiac iron overload (IO), to assess biventricular function and atrial dimensions, and to detect replacement myocardial fibrosis. The mean follow-up was 50.51 ± 19.75 months. Cardiac complications were recorded in 21 (2.6%) patients: one with heart failure (HF) and 20 with arrhythmias. The single patient who developed HF had, at the baseline MRI, a reduced pancreas T2*. Out of the 20 recorded arrhythmias, 17 were supraventricular. Pancreatic T2* values were a significant predictor of future arrhythmia-related events (hazard ratio = 0.89; p = 0.015). Pancreas T2* remained significantly associated with future arrhythmias after adjusting for any other univariate predictor (age and male sex, diabetes, history of previous arrhythmias, or left atrial area index). According to the receiver-operating characteristic curve analysis for arrhythmias, a pancreas T2* < 6.73 ms was the optimal cut-off value. In TDT, pancreatic iron levels had significant prognostic power for arrhythmias. Regular monitoring and the development of targeted interventions to manage pancreatic IO may help improve patient outcomes.

Presence of Permanent Pacemakers: Implications for Elderly Patients Presenting with Traumatic Injuries

Background

The presence of permanent pacemakers (PPM) is common among the elderly population. Trauma literature has shown that the inability to augment cardiac output by at least 30% after injury portends a higher mortality. The presence of a PPM may be a surrogate marker to identify patients who are unable to increase cardiac output. We aimed to evaluate the association between the presence of PPM and clinical outcomes in elderly patients presenting with traumatic injuries.

Methods

A total of 4505 patients aged ≥65 years admitted with acute trauma from 2009 to 2019 at our Level I Trauma center were evaluated and stratified into two groups using propensity matching on age, sex, injury severity score (ISS), and year of admission based on the presence of PPM. Logistic regression was performed to analyze the impact of the presence of PPM on mortality, surgical intensive care unit (SICU) admission, operative intervention, and length of stay. Prevalence of cardiovascular comorbidities was compared using χ2 analysis.

Results

Data from 208 patients with PPM and 208 propensity-matched controls were evaluated. Charlson Comorbidity Index, mechanism of injury, intensive care unit admission, and rate of operative intervention were comparable in the two groups. PPM patients had more coronary artery disease (p=0.04), heart failure with reduced ejection fraction (p=0.003), atrial fibrillation (AF, p<0.0001), and antithrombotic use (p<0.0001). We found no association between mortality amongst the groups after controlling for influencing variables (OR=2.1 (0.97 to 4.74), p=0.061). Patient characteristics associated with survival included female sex (p=0.009), lower ISS (p<0.0001), lower revised trauma score (p<0.0001), and lower SICU admission (p=0.001).

Conclusion

Our study shows no association between mortality among patients with PPM admitted for treatment of trauma. Presence of a PPM may be an indicator of cardiovascular disease, but this does not translate into increased risk in the modern era of trauma management in our patient population.

Level of evidence

Level III.

What to consider for ECG in mice-with special emphasis on telemetry

Genetically or surgically altered mice are commonly used as models of human cardiovascular diseases. Electrocardiography (ECG) is the gold standard to assess cardiac electrophysiology as well as to identify cardiac phenotypes and responses to pharmacological and surgical interventions. A variety of methods are used for mouse ECG acquisition under diverse conditions, making it difficult to compare different results. Non-invasive techniques allow only short-term data acquisition and are prone to stress or anesthesia related changes in cardiac activity. Telemetry offers continuous long-term acquisition of ECG data in conscious freely moving mice in their home cage environment. Additionally, it allows acquiring data 24/7 during different activities, can be combined with different challenges and most telemetry systems collect additional physiological parameters simultaneously. However, telemetry transmitters require surgical implantation, the equipment for data acquisition is relatively expensive and analysis of the vast number of ECG data is challenging and time-consuming. This review highlights the limits of non-invasive methods with respect to telemetry. In particular, primary screening using non-invasive methods can give a first hint; however, subtle cardiac phenotypes might be masked or compensated due to anesthesia and stress during these procedures. In addition, we detail the key differences between the mouse and human ECG. It is crucial to consider these differences when analyzing ECG data in order to properly translate the insights gained from murine models to human conditions.

Chronic D-Galactose Administration Induces Natural Aging Characteristics, in Rat's Brain and Heart

We aimed to investigate the effect of chronic D-galactose exposure on the mimicking of natural aging processes based upon the hallmarks of aging. Seven-week-old male Wistar rats (n = 12) were randomly assigned to receive either normal saline solution as a vehicle (n = 6) or 150mg/kg/day of D-galactose subcutaneously for 28 weeks. Seventeen-month-old rats (n = 6) were also included as the chronologically aged controls. At the end of week 28 of the experiment (when the rats reach 35 weeks old and 24 months old), all rats were sacrificed for brain and heart collection. Our results showed that chronic D-galactose exposure mimicked natural aging characteristics of the brain and the heart in terms of deregulated nutrient sensing, mitochondrial dysfunction, cellular senescence, stem cell exhaustion, altered intercellular communication, and functional impairment. All of which highlight the potential of D-galactose as a substance for inducing brain and cardiac aging in animal experiments. DATA AVAILABILITY: The data that support the findings of this study are available from the corresponding author upon reasonable request.

Elderly Patients and Management in Intensive Care Units (ICU): Clinical Challenges

There is a growing population of older adults requiring admission to the intensive care unit (ICU). This population outpaces the ability of clinicians with geriatric training to assist in their management. Specific training and education for intensivists in the care of older patients is valuable to help understand and inform clinical care, as physiologic changes of aging affect each organ system. This review highlights some of these aging processes and discusses clinical implications in the vulnerable older population. Other considerations when caring for these older patients in the ICU include functional outcomes and morbidity, as opposed to merely a focus on mortality. An overall holistic approach incorporating physiology of aging, applying current evidence, and including the patient and their family in care should be used when caring for older adults in the ICU.

Cardiac System during the Aging Process

The aging process is accompanied by a continuous decline of the cardiac system, disrupting the homeostatic regulation of cells, organs, and systems. Aging increases the prevalence of cardiovascular diseases, thus heart failure and mortality. Understanding the cardiac aging process is of pivotal importance once it allows us to design strategies to prevent age-related cardiac events and increasing the quality of live in the elderly. In this review we provide an overview of the cardiac aging process focus on the following topics: cardiac structural and functional modifications; cellular mechanisms of cardiac dysfunction in the aging; genetics and epigenetics in the development of cardiac diseases; and aging heart and response to the exercise.

The Aging Heart: A Molecular and Clinical Challenge

Aging is associated with an increasing burden of morbidity, especially for cardiovascular diseases (CVDs). General cardiovascular risk factors, ischemic heart diseases, heart failure, arrhythmias, and cardiomyopathies present a significant prevalence in older people, and are characterized by peculiar clinical manifestations that have distinct features compared with the same conditions in a younger population. Remarkably, the aging heart phenotype in both healthy individuals and patients with CVD reflects modifications at the cellular level. An improvement in the knowledge of the physiological and pathological molecular mechanisms underlying cardiac aging could improve clinical management of older patients and offer new therapeutic targets.

Temporal trends of arrhythmias at delivery hospitalizations in the United States: Analysis from the National Inpatient Sample, 2009-2019

BACKGROUND

Cardiac arrhythmias are associated with increased maternal morbidity. There are limited data on trends of arrhythmias among women hospitalized for delivery.

MATERIALS AND METHODS

We used the National Inpatient Sample (NIS) database to identify delivery hospitalizations for individuals aged 18-49 years between 2009 to 2019 and utilized coding data from the 9th and 10th editions of the International Classification of Diseases to identify supraventricular tachycardias (SVT), atrial fibrillation (AF), atrial flutter, ventricular tachycardia (VT), and ventricular fibrillation (VF). Arrhythmia trends were analyzed by age, race-ethnicity, hospital setting, and hospital geographic regions. Multivariable logistic regression was used to evaluate the association of demographic, clinical, and socioeconomic characteristics with arrhythmias.

RESULTS

Among 41,576,442 delivery hospitalizations, the most common arrhythmia was SVT (53%), followed by AF (31%) and VT (13%). The prevalence of arrhythmia among delivery hospitalizations increased between 2009 and 2019. Age > 35 years and Black race were associated with a higher arrhythmia burden. Factors associated with an increased risk of arrhythmias included valvular disease (OR: 12.77; 95% C1:1.98-13.61), heart failure (OR:7.13; 95% CI: 6.49-7.83), prior myocardial infarction (OR: 5.41, 95% CI: 4.01-7.30), peripheral vascular disease (OR: 3.19, 95% CI: 2.51-4.06), hypertension (OR: 2.18; 95% CI: 2.07-2.28), and obesity (OR 1.69; 95% CI: 1.63-1.76). Delivery hospitalizations complicated by arrhythmias compared with those with no arrhythmias had a higher proportion of all-cause in-hospital mortality (0.95% vs. 0.01%), cardiogenic shock (0.48% vs. 0.00%), preeclampsia (6.96% vs. 3.58%), and preterm labor (2.95% vs. 2.41%) (all p < 0.0001).

CONCLUSION

Pregnant individuals with age > 35 years, obesity, hypertension, valvular heart disease, or severe pulmonary disease are more likely to have an arrhythmia history or an arrhythmia during a delivery hospitalization. Delivery hospitalizations with a history of arrhythmia are more likely to be complicated by all-cause in-hospital mortality, cardiovascular, and adverse pregnancy outcomes (APOs). These data highlight the increased risk associated with pregnancies among individuals with arrhythmias.

Trend in Age at the Initial Pacemaker Implantation in Patients With Bradyarrhythmia - A 50-Year Analysis (1970-2019) in Japan

BACKGROUND

This study investigated whether the age of patients undergoing pacemaker implantation is increasing.

METHODS AND RESULTS

This study retrospectively reviewed the consecutive cases of 3,582 patients who underwent an initial pacemaker implantation at our hospitals because of symptomatic bradyarrhythmias between 1970 and 2019. The exclusion criteria were: patients with AV block due to cardiac surgery or AV junction ablation, and patients aged <20 years. The patients were divided into 5×10-year groups: those treated in the 1970s (1970-1979), 1980s (1980-1989), 1990s (1990-1999), 2000s (2000-2009), and 2010s (2010-2019). A total of 3,395 patients satisfied the study criteria. The average age at which the patients underwent a first pacemaker implantation increased across the 10-year periods: 63.7±13.2 years in the 1970s, 66.2±12.6 years (1980s), 69.1±12.4 years (1990s), 72.0±11.1 years (2000s), and 75.8±10.0 years (2010s) and advanced significantly in the 1990s, 2000s, and 2010s compared to the 1970s (all P<0.001). The ratio of patients aged ≥80 and ≥90 years increased from 10.6% and 0% in the 1970 s to 38.2% (P<0.001) and 5.2% (P= 0.017) in the 2010s, respectively.

CONCLUSIONS

The average age at initial pacemaker implantation increased by 12.1 years over the last 50 years in Japan. In particular, the ratios of ≥80 and ≥90 years as the patients age increased significantly.

In-hospital outcomes of TAVR patients with a bundle branch block: Insights from the National Inpatient Sample 2011-2018

INTRODUCTION

Data on the outcomes following transcatheter aortic valve replacement (TAVR) in patients with a bundle branch block (BBB) remains limited.

METHODS

We studied the outcomes of TAVR patients with a BBB from the National Inpatient Sample (NIS) database between 2011 and 2018 using ICD-9-CM and ICD-10-CM codes.

RESULTS

Between 2011 and 2018, 194,237 patients underwent TAVR, where 1.7% (n = 3,232) had a right BBB (RBBB) and 13.7% (n = 26,689) had a left BBB (LBBB). Patients with a RBBB and LBBB had a higher rate of new permanent pacemaker (PPM) implantation (31.5% - RBBB, 15.7% LBBB vs. 10.2% - no BBB). RBBB was associated with a significantly longer median length of stay (5 days) and total hospitalization cost ($53,669) compared with LBBB (3 days and $47,552) and no BBB (3 days and $47,171). Trend analysis revealed lower rates of PPM implantation and reduced lengths of stay and costs across all comparison groups.

CONCLUSION

In conclusion, patients undergoing TAVR with a BBB are associated with higher new rates of PPM implantation. RBBB is the strongest independent predictor for new PPM implantation following TAVR. Rates of new PPM implantation in TAVR patients with and without a BBB have improved over time including reductions in length of stay and hospital costs. Further study is needed to reduce the risks of PPM implantation in TAVR patients.

Aging-associated susceptibility to stress-induced ventricular arrhythmogenesis is attenuated by tetrodotoxin

Aging is associated with increased prevalence of life-threatening ventricular arrhythmias, but mechanisms underlying higher susceptibility to arrhythmogenesis and means to prevent such arrhythmias under stress are not fully defined. We aimed to define differences in aging-associated susceptibility to ventricular fibrillation (VF) induction between young and aged hearts. VF induction was attempted in isolated perfused hearts of young (6-month) and aged (24-month-old) male Fischer-344 rats by rapid pacing before and following isoproterenol (1 μM) or global ischemia and reperfusion (I/R) injury with or without pretreatment with low-dose tetrodotoxin, a late sodium current blocker. At baseline, VF could not be induced; however, the susceptibility to inducible VF after isoproterenol and spontaneous VF following I/R was 6-fold and 3-fold higher, respectively, in old hearts (P < 0.05). Old animals had longer epicardial monophasic action potential at 90% repolarization (APD₉₀; P < 0.05) and displayed a loss of isoproterenol-induced shortening of APD₉₀ present in the young. In isolated ventricular cardiomyocytes from older but not younger animals, 4-aminopyridine prolonged APD and induced early afterdepolarizations (EADs) and triggered activity with isoproterenol. Low-dose tetrodotoxin (0.5 μM) significantly shortened APD without altering action potential upstroke and prevented 4-aminopyridine-mediated APD prolongation, EADs, and triggered activity. Tetrodotoxin pretreatment prevented VF induction by pacing in isoproterenol-challenged hearts. Vulnerability to VF following I/R or catecholamine challenge is significantly increased in old hearts that display reduced repolarization reserve and increased propensity to EADs, triggered activity, and ventricular arrhythmogenesis that can be suppressed by low-dose tetrodotoxin, suggesting a role of slow sodium current in promoting arrhythmogenesis with aging.

Heterogeneities in Ventricular Conduction Following Treatment with Heptanol: A Multi-Electrode Array Study in Langendorff-Perfused Mouse Hearts

Background: Previous studies have associated slowed ventricular conduction with the arrhythmogenesis mediated by the gap junction and sodium channel inhibitor heptanol in mouse hearts. However, they did not study the propagation patterns that might contribute to the arrhythmic substrate. This study used a multi-electrode array mapping technique to further investigate different conduction abnormalities in Langendorff-perfused mouse hearts exposed to 0.1 or 2 mM heptanol. Methods: Recordings were made from the left ventricular epicardium using multi-electrode arrays in spontaneously beating hearts during right ventricular 8 Hz pacing or S1S2 pacing. Results: In spontaneously beating hearts, heptanol at 0.1 and 2 mM significantly reduced the heart rate from 314 ± 25 to 189 ± 24 and 157 ± 7 bpm, respectively (ANOVA, p < 0.05 and p < 0.001). During regular 8 Hz pacing, the mean LATs were increased by 0.1 and 2 mM heptanol from 7.1 ± 2.2 ms to 19.9 ± 5.0 ms (p < 0.05) and 18.4 ± 5.7 ms (p < 0.05). The standard deviation of the mean LATs was increased from 2.5 ± 0.8 ms to 10.3 ± 4.0 ms and 8.0 ± 2.5 ms (p < 0.05), and the median of phase differences was increased from 1.7 ± 1.1 ms to 13.9 ± 7.8 ms and 12.1 ± 5.0 ms by 0.1 and 2 mM heptanol (p < 0.05). P5 took a value of 0.2 ± 0.1 ms and was not significantly altered by heptanol at 0.1 or 2 mM (1.1 ± 0.9 ms and 0.9 ± 0.5 ms, p > 0.05). P50 was increased from 7.3 ± 2.7 ms to 24.0 ± 12.0 ms by 0.1 mM heptanol and then to 22.5 ± 7.5 ms by 2 mM heptanol (p < 0.05). P95 was increased from 1.7 ± 1.1 ms to 13.9 ± 7.8 ms by 0.1 mM heptanol and to 12.1 ± 5.0 ms by 2 mM heptanol (p < 0.05). These changes led to increases in the absolute inhomogeneity in conduction (P5−95) from 7.1 ± 2.6 ms to 31.4 ± 11.3 ms, 2 mM: 21.6 ± 7.2 ms, respectively (p < 0.05). The inhomogeneity index (P5−95/P50) was significantly reduced from 3.7 ± 1.2 to 3.1 ± 0.8 by 0.1 mM and then to 3.3 ± 0.9 by 2 mM heptanol (p < 0.05). Conclusion: Increased activation latencies, reduced CVs, and the increased inhomogeneity index of conduction were associated with both spontaneous and induced ventricular arrhythmias.

Stress-induced premature senescence is associated with a prolonged QT interval and recapitulates features of cardiac aging

Rationale: Aging in the heart is a gradual process, involving continuous changes in cardiovascular cells, including cardiomyocytes (CMs), namely cellular senescence. These changes finally lead to adverse organ remodeling and resulting in heart failure. This study exploits CMs from human induced pluripotent stem cells (iCMs) as a tool to model and characterize mechanisms involved in aging. Methods and Results: Human somatic cells were reprogrammed into human induced pluripotent stem cells and subsequently differentiated in iCMs. A senescent-like phenotype (SenCMs) was induced by short exposure (3 hours) to doxorubicin (Dox) at the sub-lethal concentration of 0.2 µM. Dox treatment induced expression of cyclin-dependent kinase inhibitors p21 and p16, and increased positivity to senescence-associated beta-galactosidase when compared to untreated iCMs. SenCMs showed increased oxidative stress, alteration in mitochondrial morphology and depolarized mitochondrial membrane potential, which resulted in decreased ATP production. Functionally, when compared to iCMs, SenCMs showed, prolonged multicellular QTc and single cell APD, with increased APD variability and delayed afterdepolarizations (DADs) incidence, two well-known arrhythmogenic indexes. These effects were largely ascribable to augmented late sodium current (I_NaL) and reduced delayed rectifier potassium current (Ikr). Moreover sarcoplasmic reticulum (SR) Ca²⁺ content was reduced because of downregulated SERCA2 and increased RyR2-mediated Ca²⁺ leak. Electrical and intracellular Ca²⁺ alterations were mostly justified by increased CaMKII activity in SenCMs. Finally, SenCMs phenotype was furtherly confirmed by analyzing physiological aging in CMs isolated from old mice in comparison to young ones. Conclusions: Overall, we showed that SenCMs recapitulate the phenotype of aged primary CMs in terms of senescence markers, electrical and Ca²⁺ handling properties and metabolic features. Thus, Dox-induced SenCMs can be considered a novel in vitro platform to study aging mechanisms and to envision cardiac specific anti-aging approach in humans.

Assessment of age, gender, and anxiety on ECG waveform morphology in a large population of domestic dogs

Cardiovascular diseases are major causes of death in the western world and this incidence increases in the elderly population. With aging, there are physiologic changes to the cardiac structure secondary to adipose tissue deposition, calcification of valve leaflets and changes in the structure of the heart including atrial remodeling. Such changes can make the myocardium more susceptible to stress leading to a higher prevalence of cardiovascular diseases in the aging population. Studies in healthy humans have shown that these structural and molecular changes in the heart are manifested as changes on an electrocardiogram (ECG). Using animal models, similar ECG changes have been found in guinea pigs, rabbits, and mice. No veterinary study has specifically evaluated if comparable aging changes occur in canine species. In this cross-sectional retrospective study, 12,026 ECGs from apparently healthy dogs were obtained and evaluated. Age was observed to have both linear and non-linear associations with multiple ECG variables, including P wave amplitude and duration, R amplitude and QRS duration. This study confirmed that, like humans, there may be ECG changes secondary to normal physiological cardiac aging. Further studies are warranted to confirm and elaborate on these findings as canines may be a useful model for cardiac aging in humans.

Inhibitory G-protein-mediated modulation of slow delayed rectifier potassium channels contributes to increased susceptibility to arrhythmogenesis in aging heart

BACKGROUND

Slow delayed rectifier potassium current (I_Ks) is an important component of repolarization reserve during sympathetic nerve excitement. However, little is known about age-related functional changes of I_Ks and its involvement in age-dependent arrhythmogenesis.

OBJECTIVE

The purpose of this study was to investigate age-related alteration of the I_Ks response to β-adrenergic receptor (βAR) activation.

METHODS

Dunkin-Hartley guinea pigs were used. Whole-cell patch-clamp recording was used to record K⁺ currents. Optical mapping of membrane potential was performed in ex vivo heart.

RESULTS

There was no difference in I_Ks density in ventricular cardiomyocytes between young and old guinea pigs. However, in contrast to I_Ks potentiation in young hearts, isoproterenol (ISO) evoked an acute inhibition on I_Ks in a concentration-dependent manner in old guinea pig hearts. The β₂AR antagonist, but not β₁AR antagonist, reversed the inhibitory response. Preincubation of cardiomyocytes with the inhibitory G protein (Gi) inhibitor pertussis toxin (PTX) also reversed the inhibitory response. In HEK293 cells cotransfected with cloned I_Ks channel and β₂AR, ISO enhanced the current but reduced it when cells were cotransfected with Gi2, and PTX restored the ISO-induced excitatory response. Moreover, in aging cardiomyocytes, Gβγ inhibitor gallein, PLC inhibitor U73122, or protein kinase C inhibitor Bis-1 prevented the reduction of I_Ks by ISO. Furthermore, cardiac-specific Gi2 overexpression in young guinea pigs predisposed the heart to ventricular tachyarrhythmias. PTX pretreatment protected the hearts from ventricular arrhythmias.

CONCLUSION

βAR activation acutely induces an inhibitory I_Ks response in aging guinea pig hearts through β₂AR-Gi signaling, which contributes to increased susceptibility to arrhythmogenesis in aging hearts.

Sex Differences in Molecular Mechanisms of Cardiovascular Aging

Cardiovascular disease (CVD) is still the leading cause of illness and death in the Western world. Cardiovascular aging is a progressive modification occurring in cardiac and vascular morphology and physiology where increased endothelial dysfunction and arterial stiffness are observed, generally accompanied by increased systolic blood pressure and augmented pulse pressure. The effects of biological sex on cardiovascular pathophysiology have long been known. The incidence of hypertension is higher in men, and it increases in postmenopausal women. Premenopausal women are protected from CVD compared with age-matched men and this protective effect is lost with menopause, suggesting that sex-hormones influence blood pressure regulation. In parallel, the heart progressively remodels over the course of life and the pattern of cardiac remodeling also differs between the sexes. Lower autonomic tone, reduced baroreceptor response, and greater vascular function are observed in premenopausal women than men of similar age. However, postmenopausal women have stiffer arteries than their male counterparts. The biological mechanisms responsible for sex-related differences observed in cardiovascular aging are being unraveled over the last several decades. This review focuses on molecular mechanisms underlying the sex-differences of CVD in aging.

Dosing antipsychotics in special populations of patients with schizophrenia: severe psychotic agitation, first psychotic episode and elderly patients

Antipsychotic (AP) dosing is well established in nonelderly patients with acute exacerbations of schizophrenia, but not in special populations.This review describes the AP dosing procedures that have been used in clinical studies for acute psychotic agitation, a first episode of psychosis (FEP), and elderly patients. AP dosing data was extracted from the databases of drug regulatory authorities, and from clinical studies available in the medical literature. In acute psychotic agitation, intramuscular and oral APs are frequently prescribed in higher doses than those that saturate D2 receptors. Supersaturating doses of APs should be avoided due to an increased risk of adverse effects. In FEP, many studies showed efficacy of low doses of APs. Studies with risperidone and haloperidol suggested a dose reduction of approximately one third. Titration with a lower starting dose is recommended in elderly patients, due to possible decreases in pharmacokinetic clearance, and due to the risk of concomitant diseases and drug interactions. Exposure to some APs has been associated with QTc prolongation and arrhythmias, and a small but significant increase in the risk of stroke and mortality with APs has been seen, particularly in older people with dementia-related psychosis.

Melatonin to Rescue the Aged Heart: Antiarrhythmic and Antioxidant Benefits

Aging comes with gradual loss of functions that increase the vulnerability to disease, senescence, and death. The mechanisms underlying these processes are linked to a prolonged imbalance between damage and repair. Damaging mechanisms include oxidative stress, mitochondrial dysfunction, chronodisruption, inflammation, and telomere attrition, as well as genetic and epigenetic alterations. Several endogenous tissue repairing mechanisms also decrease. These alterations associated with aging affect the entire organism. The most devastating manifestations involve the cardiovascular system and may lead to lethal cardiac arrhythmias. Together with structural remodeling, electrophysiological and intercellular communication alterations during aging predispose to arrhythmic events. Despite the knowledge on repairing mechanisms in the cardiovascular system, effective antiaging strategies able to reduce the risk of arrhythmias are still missing. Melatonin is a promising therapeutic candidate due to its pleiotropic actions. This indoleamine regulates chronobiology and endocrine physiology. Of relevance, melatonin is an antiaging, antioxidant, antiapoptotic, antiarrhythmic, immunomodulatory, and antiproliferative molecule. This review focuses on the protective effects of melatonin on age-induced cardiac functional and structural alterations, potentially becoming a new fountain of youth for the heart.

Resuscitation of the Critically Ill Older Adult

In 30 years, adults 65 and older will represent 20% of the US population, with increased medical comorbidities leading to higher rates of critical illness and mortality. Despite significant acute illness, presenting symptoms and vital sign abnormalities may be subtle. Resuscitative guidelines are a helpful starting point but appropriate diagnostics, bedside ultrasound, and frequent reassessments are needed to avoid procrustean care that may worsen outcomes. Baseline functional status is as important as underlying comorbid conditions when prognosticating, and the patient's personal wishes should be sought early and throughout care with clear communication regarding prospects for immediate survival and overall recovery.

The Role of Oxidative Stress in Cardiovascular Aging and Cardiovascular Diseases

Aging can be seen as process characterized by accumulation of oxidative stress induced damage. Oxidative stress derives from different endogenous and exogenous processes, all of which ultimately lead to progressive loss in tissue and organ structure and functions. The oxidative stress theory of aging expresses itself in age-related diseases. Aging is in fact a primary risk factor for many diseases and in particular for cardiovascular diseases and its derived morbidity and mortality. Here we highlight the role of oxidative stress in age-related cardiovascular aging and diseases. We take into consideration the molecular mechanisms, the structural and functional alterations, and the diseases accompanied to the cardiovascular aging process.

Disparities in the characteristics and outcomes of patients hospitalized with acute decompensated heart failure admitted to internal medicine and cardiology departments: a single-centre, retrospective cohort study

Aims

Efforts are constantly made to decrease the rates of readmission after acute decompensated heart failure (ADHF). ADHF admissions to internal medicine departments (IMD) were previously associated with higher risk for readmission compared with those admitted to cardiology departments (CD). It is unknown if the earlier still applies after recent advancement in care over the last decade. This contemporary cohort compares characteristics and outcomes of ADHF patients admitted to IMD with those admitted to CD.

Methods and results

The data for this single‐centre, retrospective study utilized a cohort of 8332 ADHF patients admitted between 2007 and 2017. We compared patients' baseline characteristics and clinical and laboratory indices of patients admitted to CD and IMD with the outcome defined as 30 day readmission rate. In comparison with those admitted to CD, patients admitted to IMD (89.5% of patients) were older (79 [70–86] vs. 69 [60–78] years; P < 0.001) and had a higher incidence of co‐morbidities and a higher ejection fraction. Readmission rates at 30 days were significantly lower in patients admitted to CD (15.9% vs. 19.6%; P = 0.01). Conflicting results of three statistical models failed to associate between the admitting department and 30 day readmission (odds ratio for 30 day readmission in CD: forced and backward stepwise logistic regression 0.8, 95% confidence interval 0.65–0.97, P = 0.02; stabilized inverse probability weights model odds ratio 1.0, confidence interval 0.75–1.37, P = 0.96).

Conclusions

This contemporary analysis of ADHF patient cohort demonstrates significant differences in the characteristics and outcomes of patients admitted to IMD and CD. Thus, focusing strategies for readmission prevention in patients admitted to IMD may be beneficial.

Non-vitamin K antagonist oral anticoagulants for stroke prevention in atrial fibrillation: safety issues in the elderly

INTRODUCTION

Non-vitamin K antagonist oral anticoagulants (NOACs) are increasingly used for stroke prevention in patients with atrial fibrillation (AF). Since NOACs are predominantly used in the elderly with AF at high risk for stroke and bleeding and with comorbidities requiring polypharmacy, it is important to assess their safety and efficacy in this population.

AREAS COVERED

We review changes in pharmacokinetics and pharmacodynamics observed with senescence and the effect on NOACs and drug and food interactions. We also provide an update on challenges related to NOAC use in situations that increases the risk for bleeding or require temporary discontinuation and address practical issues in the elderly AF patients managed on NOACs. Clinical studies and trials with cardiovascular outcomes reported from January 1990 to August 2020 were identified through the Medline database using PubMed, Cochrane Library, and EMBASE database.

EXPERT OPINION

NOACs are highly effective in preventing stroke in AF patients with non-inferior or superior efficacy to warfarin, with reduced risk of major bleeding. However, in the older-elderly, evidence comes mainly from observational studies or extrapolation from studies in populations with minimal functional limitations or comorbidities. The high upfront cost and out-of-pocket expense for copayment or deductibles also limit the use of this effective therapy in a substantial number of patients. The cost reduction may further improve long-term use for NOACs in stroke prevention in elderly patients with AF.

Cardiac transmembrane ion channels and action potentials: cellular physiology and arrhythmogenic behavior

Cardiac arrhythmias are among the leading causes of mortality. They often arise from alterations in the electrophysiological properties of cardiac cells and their underlying ionic mechanisms. It is therefore critical to further unravel the pathophysiology of the ionic basis of human cardiac electrophysiology in health and disease. In the first part of this review, current knowledge on the differences in ion channel expression and properties of the ionic processes that determine the morphology and properties of cardiac action potentials and calcium dynamics from cardiomyocytes in different regions of the heart are described. Then the cellular mechanisms promoting arrhythmias in congenital or acquired conditions of ion channel function (electrical remodeling) are discussed. The focus is on human-relevant findings obtained with clinical, experimental, and computational studies, given that interspecies differences make the extrapolation from animal experiments to human clinical settings difficult. Deepening the understanding of the diverse pathophysiology of human cellular electrophysiology will help in developing novel and effective antiarrhythmic strategies for specific subpopulations and disease conditions.

Matrix metalloproteinase 1 1 G/2 G gene polymorphism is associated with acquired atrioventricular block via linking a higher serum protein level

Limited studies are available regarding the pathophysiological mechanism of acquired atrioventricular block (AVB). Matrix metalloproteinases (MMPs) and angiotensin-converting enzyme (ACE) have been implicated in the pathogenesis of arrhythmia. However, the relationship between these molecules and acquired AVB is still unclear. One hundred and two patients with documented acquired AVB and 100 controls were studied. Gene polymorphisms of the MMP1 and ACE encoding genes were screened by the gene sequencing method or polymerase chain reaction-fragment length polymorphism assay, followed by an association study. The frequencies of the MMP1 −1607 2G2G genotype and MMP1 −1607 2 G allele were significantly higher in the AVB group than that in the controls (OR = 1.933, P = 0.027 and OR = 1.684, P = 0.012, respectively). Consistently, the level of serum MMP1 was significantly greater in acquired AVB patients than that in controls (6568.9 ± 5748.6 pg/ml vs. 4730.5 ± 3377.1 pg/ml, P = 0.019). In addition, the MMP1 2G2G genotype showed a higher MMP-1 serum level than the other genotypes (1G1G/1G2G) (7048.1 ± 5683.0 pg/ml vs. 5072.4 ± 4267.6 pg/ml, P = 0.042). MMP1 1 G/2 G gene polymorphism may contribute to determining the disease susceptibility of acquired AVB by linking the MMP serum protein level.

Efficient Detection of Ventricular Late Potentials on ECG Signals Based on Wavelet Denoising and SVM Classification

The analysis of cardiac signals is still regarded as attractive by both the academic community and industry because it helps physicians in detecting abnormalities and improving the diagnosis and therapy of diseases. Electrocardiographic signal processing for detecting irregularities related to the occurrence of low-amplitude waveforms inside the cardiac signal has a considerable workload as cardiac signals are heavily contaminated by noise and other artifacts. This paper presents an effective approach for the detection of ventricular late potential occurrences which are considered as markers of sudden cardiac death risk. Three stages characterize the implemented method which performs a beat-to-beat processing of high-resolution electrocardiograms (HR-ECG). Fifteen lead HR-ECG signals are filtered and denoised for the improvement of signal-to-noise ratio. Five features were then extracted and used as inputs of a classifier based on a machine learning approach. For the performance evaluation of the proposed method, a HR-ECG database consisting of real ventricular late potential (VLP)-negative and semi-simulated VLP-positive patterns was used. Experimental results show that the implemented system reaches satisfactory performance in terms of sensitivity, specificity accuracy, and positive predictivity; in fact, the respective values equal to 98.33%, 98.36%, 98.35%, and 98.52% were achieved.

Increasing age is associated with recurrent ventricular tachyarrhythmias and appropriate ICD therapies secondary to documented index ventricular tachyarrhythmias

BACKGROUND

Data regarding the prognostic impact of age in implantable cardioverter defibrillator (ICD) recipients is limited.

OBJECTIVE

The study sought to assess the impact of age on recurrences of ventricular tachyarrhythmias in ICD recipients.

METHODS

This "secondary prevention" study is based on a large retrospective registry including consecutive ICD recipients with documented ventricular tachyarrhythmias from 2002 to 2016. Patients < 75 years of age were compared to patients ≥ 75 years. The primary endpoint was first recurrence of ventricular tachyarrhythmias at 5 years. Secondary endpoints were ICD-related therapies, rehospitalization, and all-cause mortality at 5 years. Statistics comprised Kaplan-Meier survival curves, multivariable Cox regression analyses, and propensity-score matching.

RESULTS

A total of 592 consecutive ICD recipients with index ventricular tachyarrhythmias was included (< 75 years: 78%; ≥ 75 years 22%). Age ≥ 75 years was associated with the primary endpoint of first recurrence of ventricular tachyarrhythmias (49% vs. 43%, log-rank p = 0.015; HR 1.418; 95% CI 1.070-1.881; p = 0.015), and with the secondary endpoint of first appropriate ICD therapy (78% vs. 22%, log-rank p = 0.011) even within multivariable Cox regression analyses. After propensity-score matching, age ≥ 75 years was still associated with the primary endpoint of first recurrence of ventricular tachyarrhythmias (49% vs. 42%, log-rank p = 0.045; HR 1.482; 95% CI 1.007-2.182; p = 0.046).

CONCLUSION

Elderly ICD recipients aged ≥ 75 years are at increased risk of recurrent ventricular tachyarrhythmias, appropriate ICD therapies, and all-cause mortality at 5 years.

Trend and risk factors of recurrence and complications after arrhythmias radiofrequency catheter ablation: a nation-wide observational study in Taiwan

OBJECTIVES

This study determined the recurrence and complication rates after radiofrequency catheter ablation (RFCA) for those with paroxysmal supraventricular tachycardia (PSVT), Wolff-Parkinson-White syndrome (WPW), atrial flutter (AFL), atrial fibrillation (AF) and ventricular tachycardia (VT).

STUDY DESIGN AND SETTING

This retrospective study included RFCAs for 2001-2010 in the Taiwan National Health Insurance Research Database. Primary outcomes included perioperative complications (pericardial effusion and new-onset stroke), RFCA recurrence and long-term outcomes (high-grade atrioventricular block (AVB) and pacemaker implantation).

RESULTS

Of 19,475 patients who underwent RFCA, prevalence rates were 56.7% for PSVT, 13.5% for WPW, 9.5% for AFL, 5.1% for AF and 2.7% for VT. Prevalence rates increased in AF, AFL and VT over the study years. During an average follow-up period of 4.3 years (SD: 2.8 years), recurrence rates for PSVT, WPW, VT, AFL and AF were 2.0%, 4.9%, 5.7%, 5.8% and 16.1%, respectively. Compared with the PSVT group, the WPW and AF groups had significantly higher risk of pericardial effusion during admission (adjusted OR (aOR) 2.98, 95% CI (CI) 1.24 to 7.15; aOR 4.09, 95% CI 1.90 to 8.79, respectively); the AFL group had a higher risk of new-onset stroke during admission (aOR 4.07, 95% CI 1.39 to 11.91); the WPW group had a lower risk of high-grade AVB during follow-up (adjusted HR (aHR) 0.37, 95% CI 0.19 to 0.71) while the AFL group had a greater risk (aHR 1.74, 95% CI 1.17 to 2.60); and the AFL group had a higher risk of permanent pacemaker (aHR 2.14, 95% CI 1.27 to 3.62).

CONCLUSIONS

The RFCA rate increased rapidly during 2001-2010 for AF, AFL and VT. Recurrence was associated with congenital heart disease in PSVT and WPW, and with age in AF and AFL. AFL had a higher risk of permanent pacemaker implantation and new stroke. AF had a higher risk of life-threatening pericardial effusion.