Cardio-oncology is a new field of interest in cardiology focusing on the detection and treatment of cardiovascular diseases, such as arrhythmias, myocarditis, and heart failure, as side-effects of chemotherapy and radiotherapy. The association between chemotherapeutic agents and arrhythmias has previously been established. Atrial tachyarrhythmias, particularly atrial fibrillation, are most common, but ventricular arrhythmias, including those related to treatment-induced QT prolongation, and bradyarrhythmias can also occur. However, the association between chemotherapeutic agents and atrioventricular re-entrant tachycardia (AVRT)/atrioventricular node re-entrant tachycardia (AVNRT) remains poorly understood. Here, we report a patient with new-onset AVRT/AVNRT and lung cancer who underwent chemotherapy. We considered that chemotherapy or cancer itself may have been a trigger for the initiation of paroxysmal AVRT/AVNRT, and that radiofrequency catheter ablation was effective in treating this type of tachycardia. Here, possible mechanisms and potential genes (mostly ion channels) involved in AVRT/AVNRT are summarized and the mechanisms underlying the possible regulatory patterns of cancer cells and chemotherapy on ion channels are reviewed. Finally, we considered that ion channel abnormalities may link cancer or chemotherapy to the onset of AVRT/AVNRT. The aim of the present study was to highlight the association between chemotherapeutic agents and AVRT/AVNRT and to provide new insights for future research. Understanding the intermediate mechanisms between chemotherapeutic agents and AVRT/AVNRT may be beneficial in preventing chemotherapy-evoked AVRT/AVNRT (and/or other arrhythmias) in future.

UNASSIGNED: Sudden cardiac arrest is associated with high morbidity and mortality. Despite having a disproportionate burden of sudden cardiac death (SCD), rates of primary and secondary prevention of SCD with implantable cardioverter-defibrillator (ICD) therapy are lower among eligible racially minoritized patients. This review highlights the racial and ethnic disparities in ICD utilization, associated barriers to ICD care, and proposed interventions to improve equitable ICD uptake.
UNASSIGNED: Racially minoritized populations are disproportionately eligible for ICD therapy but are less likely to see cardiac specialists, be counseled on ICD therapy, and ultimately undergo ICD implantation, fueling disparate outcomes. Racial disparities in ICD utilization are multifactorial, with contributions at the patient, provider, health system, and structural/societal level.
UNASSIGNED: Racial and ethnic disparities have been demonstrated in preventing SCD with ICD use. Proposed strategies to mitigate these disparities must prioritize care delivery and access to care for racially minoritized patients, increase the diversification of clinical and implementation trial participants and the healthcare workforce, and center reparative justice frameworks to rectify a long history of racial injustice.

ECG changes in pneumothorax have gained recognition as important indicators of cardiopulmonary interactions. This narrative review examines the existing literature to provide insights into the various ECG abnormalities observed in patients with pneumothorax, their underlying mechanisms, and clinical implications. The review highlights the commonly reported changes, including alterations in the electrical axis, ST segment deviations, T-wave abnormalities, and arrhythmias. The rightward shift of the electrical axis is attributed to cardiac displacement caused by increased intrathoracic pressure. ST segment deviations may reflect the influence of altered intrathoracic pressure on myocardial oxygen supply and demand. T-wave abnormalities may result from altered myocardial repolarization and hypoxemia. Arrhythmias, although varying in incidence and type, have been associated with pneumothorax. The clinical implications of these ECG changes are discussed, emphasizing their role in diagnosis, risk stratification, treatment optimization, and prognostication. Additionally, future research directions are outlined, including prospective studies, mechanistic investigations, and the integration of artificial intelligence. Enhancing our understanding of ECG changes in pneumothorax can lead to improved patient care, better management strategies, and the development of evidence-based guidelines. The objective of this review is to demonstrate the presence of various ECG abnormalities in patients with pneumothorax.

Arrhythmias frequently accompany heart failure and left ventricular dysfunction. Tachycardias, atrial fibrillation, and premature ventricular contractions can induce a reversible form of dilated cardiomyopathy (CM) known as arrhythmia-induced CM (AiCM). The intriguing question is why certain individuals are more susceptible to AiCM, despite similar arrhythmia burdens. The primary challenge is determining the extent of arrhythmias\' contribution to left ventricular systolic dysfunction. AiCM should be considered in patients with a mean heart rate of >100 beats/min, atrial fibrillation, or a PVC burden of >10%. Confirmation of AiCM occurs when CM reverses upon eliminating the responsible arrhythmia. Therapy choice depends on the specific arrhythmia, patient comorbidities, and preferences. After left ventricular function is restored, ongoing follow-up is essential if an abnormal myocardial substrate persists. Accurate diagnosis and treatment of AiCM have the potential to enhance patients\' quality of life, improve clinical outcomes, and reduce hospital admissions and overall health care costs.

UNASSIGNED: Unlike tachyarrhythmias, which are common in pregnancy, there is a paucity of data regarding maternal bradycardias. Our objective was to describe the characteristics, associated conditions, and prognosis of women who develop bradycardia post-partum.
UNASSIGNED: We conducted a retrospective chart review of patients referred to the Obstetrical Medicine service at British Columbia Women\'s Hospital from January 2012 to May 2020 for post-partum maternal bradycardia.
UNASSIGNED: Twenty-four patients with post-partum bradycardia were included (age 34.2  ±  4.8 years; heart rate 40.4  ±  8.1 beats per minute; blood pressure 131/72 mm Hg). Sinus bradycardia (79.2%) was the most common rhythm. Dyspnea (29.4%) and chest pain (23.5%) were common symptoms. Mean time to resolution of bradycardia was 3.6  ±  3.8 days. Associated conditions potentially explaining the bradycardia were preeclampsia (54.1%), underlying (16.7%), medications (8.3%), and neuraxial anesthesia (8.3%).
UNASSIGNED: Maternal bradycardia is an uncommon condition complicating the post-partum period, that is generally self-limiting, with the majority only require clinical observation.

Smartwatches represent one of the most widely adopted technological innovations among wearable devices. Their evolution has equipped them with an increasing array of features, including the capability to record an electrocardiogram. This functionality allows users to detect potential arrhythmias, enabling prompt intervention or monitoring of existing arrhythmias, such as atrial fibrillation. In our research, we aimed to compile case reports, case series, and cohort studies from the Web of Science, PubMed, Scopus, and Embase databases published until 1 August 2023. The search employed keywords such as \"Smart Watch\", \"Apple Watch\", \"Samsung Gear\", \"Samsung Galaxy Watch\", \"Google Pixel Watch\", \"Fitbit\", \"Huawei Watch\", \"Withings\", \"Garmin\", \"Atrial Fibrillation\", \"Supraventricular Tachycardia\", \"Cardiac Arrhythmia\", \"Ventricular Tachycardia\", \"Atrioventricular Nodal Reentrant Tachycardia\", \"Atrioventricular Reentrant Tachycardia\", \"Heart Block\", \"Atrial Flutter\", \"Ectopic Atrial Tachycardia\", and \"Bradyarrhythmia.\" We obtained a total of 758 results, from which we selected 57 articles, including 33 case reports and case series, as well as 24 cohort studies. Most of the scientific works focused on atrial fibrillation, which is often detected using Apple Watches. Nevertheless, we also included articles investigating arrhythmias with the potential for circulatory collapse without immediate intervention. This systematic literature review provides a comprehensive overview of the current state of research on arrhythmia detection using smartwatches. Through further research, it may be possible to develop a care protocol that integrates arrhythmias recorded by smartwatches, allowing for timely access to appropriate medical care for patients. Additionally, continuous monitoring of existing arrhythmias using smartwatches could facilitate the assessment of the effectiveness of prescribed therapies.

UNASSIGNED: Common cardiac arrhythmias seen in patients with leptospirosis are usually atrial fibrillation or first-degree atrioventricular block, with bradyarrhythmia being rare in this group. It is essential to prioritize the examination of the patient\'s medical background, clinical symptoms, and comprehensive physical evaluation in order to promptly identify and address the patient\'s condition.
UNASSIGNED: Leptospirosis, a zoonotic disease that is widespread worldwide, has a significant impact on tropical areas and can affect various organs throughout the infection. During the initial stage, symptoms are typically non-specific. Although cases of all three cardiac layers being affected have been reported, issues with the conduction system are especially significant in the early phase of the disease. The most frequent discoveries in these patients are atrial fibrillation or first-degree atrioventricular block, with bradyarrhythmia being rare. We describe a 37-year-old male farmer who initially sought medical attention for general symptoms that had been deteriorating despite receiving outpatient treatment for 3 days for a presumed diagnosis of influenza. During his initial assessment, he exhibited sinus bradycardia, anemia, leukocytosis, elevated levels of direct and total bilirubin, and abnormal liver function test results. Through thorough history-taking, physical examination, and laboratory analyses, a diagnosis of leptospirosis was conclusively established for him. Focusing on the patient\'s medical history, clinical manifestations, and thorough physical assessment is crucial for promptly diagnosing and treating patients. This becomes particularly significant for individuals who exhibit atypical symptoms, exemplified by our patient presenting with nonspecific indications and cardiac issues manifested as bradycardia.

Circadian clocks, internal mechanisms that generate 24-hour rhythms, play a crucial role in coordinating biological events with day-night cycles. In light-deprived environments such as caves, species, particularly isolated obligatory troglobites, may exhibit evolutionary adaptations in biological rhythms due to light exposure. To explore rhythm expression in these settings, we conducted a comprehensive literature review on invertebrate chronobiology in global subterranean ecosystems, analyzing 44 selected studies out of over 480 identified as of September 2023. These studies revealed significant taxonomic diversity, primarily among terrestrial species like Coleoptera, with research concentrated in the United States, Italy, France, Australia, and Brazil, and a notable gap in African records. Troglobite species displayed a higher incidence of aperiodic behavior, while troglophiles showed a robust association with rhythm expression. Locomotor activity was the most studied aspect (>60%). However, approximately 4% of studies lacked information on periodicity or rhythm asynchrony, and limited research under constant light conditions hindered definitive conclusions. This review underscores the need to expand chronobiological research globally, encompassing diverse geographical regions and taxa, to deepen our understanding of biological rhythms in subterranean species. Such insights are crucial for preserving the resilience of subsurface ecosystems facing threats like climate change and habitat loss.

Left ventricular noncompaction cardiomyopathy (LVNC) is a structural heart defect that has been associated with generation of arrhythmias in the population and is a cause of sudden cardiac death with severe systolic dysfunction and fatal arrhythmias. LVNC has gained increasing acknowledgment with increased prevalence. We conducted a systematic review of reported electrocardiogram (ECG) results for pediatric LVNC patients. EMBASE database query was performed, yielding 4531 articles related to LVNC between 1990 and December 2023. Patient age ranged from prenatal to 18 years of age. Qualitative analyses were performed to characterize individual arrhythmias, and summative interpretation of ECG evaluations was gathered for the entire cohort. Systematic review of 57 LVNC cases and ECG presentation revealed many waveform consistencies, including abnormal left ventricular, atrioventricular node, and interventricular septal patterns, and specifically a high incidence of Mobitz type II and Wolff-Parkinson-White waveforms. This review of ECG analysis reinforces the clinical and etiologic significance of pediatric LVNC. While LVNC in pediatric populations may not always present as acute clinical cases, further investigation into the electrophysiology of the disease supports the need for further evaluation and risk stratification for patients with suspected LVNC and/or ventricular arrhythmia.

BACKGROUND: Cholinesterase inhibitors (ChEIs) are regularly used in Alzheimer\'s disease. Of the three ChEIs approved for dementia, donepezil is among the most prescribed drugs in the United States with nearly 6 million prescriptions in 2020; however, it is classified as a \"known risk\" QT interval-prolonging medication (QTPmed). Given this claim is derived from observational data including single case reports, we aimed to evaluate high-quality literature on the frequency and nature of proarrhythmic major adverse cardiac events (MACE) associated with donepezil.
METHODS: We searched Medline, Embase, International Pharmaceutical Abstracts, and Cochrane Central from 1996 onwards for randomized controlled trials (RCTs) involving patients age ≥18 years comparing donepezil to placebo. The MACE composite included mortality, sudden cardiac death, non-fatal cardiac arrest, Torsades de pointes, ventricular tachyarrhythmia, seizure or syncope. Random-effects meta-analyses were performed with a treatment-arm continuity correction for single and double zero event studies.
RESULTS: Sixty RCTs (n = 12,463) were included. Twenty-five of 60 trials (n = 5886) investigated participants with Alzheimer\'s disease and 33 trials monitored electrocardiogram data. The mean follow-up duration was 31 weeks (SD = 36). Mortality was the most commonly reported MACE (252/331, 75.8% events), the remainder were syncope or seizures, with no arrhythmia events. There was no increased risk of MACE with exposure to donepezil compared to placebo (risk ratio [RR] 1.08, 95% CI 0.88-1.33, I2 = 0%) and this was consistent in the subgroup analysis of trials including participants with cardiovascular morbidities (RR 1.14, 95% CI 0.88-1.47). Subgroup analysis suggested a trend toward more events with donepezil with follow-up ≥52 weeks (RR: 1.32, 0.98-1.79).
CONCLUSIONS: This systematic review with meta-analysis found donepezil may not be arrhythmogenic. Donepezil was not associated with mortality, ventricular arrhythmias, seizure or syncope, although longer durations of therapy need more study. Further research to clarify actual clinical outcomes related to QTPmed is important to inform prescribing practices.