Pathological Arrhythmias Research Articles

Pulse-wave analysis during routine blood pressure measurement shows potential to distinguish between sinus and nonsinus rhythm.

To investigate whether pulse-wave analysis (PWA) performed by trained evaluators facilitates detection of nonsinus rhythm. Same-day, high-definition oscillometry pulse-wave data and ECG results of 155 animals (144 dogs and 11 cats) were analyzed. In this cross-sectional study, we enrolled 18 participants from various backgrounds, all of whom received PWA training. The ability to distinguish between sinus and nonsinus rhythms was assessed using receiver operating characteristic curve analysis. The pulse-wave datasets were divided into 5 ECG categories. Agreement between ECG diagnoses and PWA-based arrhythmia detection was evaluated using Cohen κ values, and the correlation between the academic year of veterinary students and their κ values was assessed. All cardiology researchers demonstrated satisfactory accuracy in distinguishing pathological rhythms using PWA (area under the curve, 0.704 to 0.761), with the highest accuracy in detecting atrial fibrillation (area under the curve, 0.811 to 0.845). Fair agreement with ECG categorization was achieved by all 3 cardiology researchers, 2 of 5 general practitioners, and 3 of 10 veterinary undergraduates. The veterinary undergraduates' years of study were correlated with their diagnostic performance (Spearman ρ = 0.658; P = .019). PWA during routine noninvasive blood pressure measurement showed significant potential for the detection of pathological arrhythmias, notably atrial fibrillation. This approach yielded improved effectiveness when it was used by veterinarians with cardiology experience. Thus, introducing hands-on training courses, particularly those focused on cardiology and interactive workshops, may enable frontline veterinarians to promptly identify arrhythmias using PWA, facilitating timely ECG examinations or referrals.

Electrocardiographic Predictors of Atrial Fibrillation

Atrial fibrillation (AF) is the most common pathological arrhythmia, and its complications lead to significant morbidity and mortality. However, patients with AF can often go undetected, especially if they are asymptomatic or have a low burden of paroxysms. Identification of those at high risk of AF development may help refine screening and management strategies. PubMed and Embase databases were systematically searched for studies looking at electrocardiographic predictors of AF from inception to August 2021. A total of 115 studies were reported which examined a combination of atrial and ventricular parameters that could be electrocardiographic predictors of AF. Atrial predictors include conduction parameters, such as the PR interval, p-wave index and dispersion, and partial interatrial or advanced interatrial block, or morphological parameters, such as p-wave axis, amplitude and terminal force. Ventricular predictors include abnormalities in QRS amplitude, morphology or duration, QT interval duration, r-wave progression and ST segment, i.e., t-wave abnormalities. There has been significant interest in electrocardiographic prediction of AF, especially in populations at high risk of atrial AF, such as those with an embolic stroke of undetermined source. This review highlights the breadth of possible predictive parameters, and possible pathological bases for the predictive role of each parameter are proposed.

Presence of Pathological Arrhythmia in Patients Admitted to the Emergency Room for Cardiac Arrhythmia

Aim: The presence of a patient with indications brought on by cardiac arrhythmia is a regular condition that brings them to the emergency room. Nonetheless, up to this point, the incidence of abnormal heart rhythm among children who have been triaged for cardiac arrhythmia in our emergency department is unclear. Methods : The design of this study was prospective observational study design. This study was conducted in Pakistan Institute of Medical Sciences and the duration of this study was from January 2021 to April 2021. 345 patients in the emergency department (ED) or after admission, a workup consisting of echocardiography was conducted at discretion of treating physician. The examinations remained carried out by cardiology residents or associates who had previous experience with echocardiography. To use the individuals' initial electrocardiogram (ECG) following admission, patients were categorized as either having a "pathological heart rhythm" or having a "norm recurrent sinus rhythm." This was done so that additional investigation could be performed. Individuals whose heart rates fall inside the current range often do not exhibit any symptomatology of bradycardia or tachycardia that need medical care, which led to the definition of norm frequent SR as SR occurring at a heart rate of between 50 and 100 beats per minute. Every single heart rhythm that was dissimilar from the form of frequent SR was considered to be a pathological heart rhythm Results: Individuals who had been triaged and referred to multidisciplinary emergency department of Pakistan Institute Of Medical Sciences (PIMS), Islamabad for cardiac arrhythmia treatment during the previous year remained involved in the current retrospective cohort research. After that, the therapeutic approach, admission frequency, and diagnoses at discharge were examined, as well as the heart rhythm as shown on the 12-lead ECG. Out of a maximum of 37,850 individuals, there were a maximum of 552 who were referred to a specialist for cardiac arrhythmia. On the first ECG, 43.6% of those individuals had a pathological heart rhythm, with 65.8% of them having atrial fibrillation, 17.6% had atrial flutter, and 18.6% having other heart rhythm abnormalities. Approximately 83% of patients walked in with emergency severity index III problems, which means that numerous resources are required but vitals are not urgent. Patients with a pathological electrocardiogram have always been taken to the hospital at a rate of 62 percent, while only 64 percent of patients with a sinus rhythm had been admitted. Additionally, 35.8 percent of the patients with a pathological electrocardiogram undertook invasive investigations, compared to 15.7 percent of the patients in the sinus rhythm cohort. The diagnosis of cardiac arrhythmia had already been present in 46.5% of patients due to their past interactions with medical professionals. Practical Implication: This study was to figure out the patients who had a pathological heart rhythm, as well as the actual preponderance of this condition among these patient populations, and to assess additional medical treatment, successive hospitalization, and the primary diagnostic test made upon discharge Conclusion: It was determined that cardiac arrhythmia was present in a total of 2.9% of the individuals who presented themselves to our multidisciplinary emergency department. The hospital admission rate was fairly high, coming up at 48.6%, although the patients who presented themselves to the emergency room in our sample were seldom in a life-threatening state. Because such a significant number of people in our sample had a previous history of cardiac arrhythmia, improved outpatient care among those individuals is required in order to cut down on trips to the emergency department also save costs. Keywords: Cardiac Arrhythmia, Pakistan Institute Of Medical Sciences, Emergency Room.

Long‐term monitoring with an implantable loop recorder detects multiple episodes of paroxysmal atrial fibrillation after electrical cardioversion in a Warmblood horse

SummaryAtrial fibrillation (AF) is a pathological arrhythmia affecting performance horses and is termed paroxysmal (pAF) when self‐terminating to sinus rhythm. Little is known about pAF as its sporadic nature makes it difficult to diagnose. Therefore, continuous electrocardiographic monitoring devices, such as implantable loop recorders (ILR), are necessary to detect the time of onset and episode duration. This case report presents the detection of pAF in a 9‐year‐old Warmblood horse after successful transvenous electrical cardioversion (TVEC). An ILR continuously monitored the heart rhythm over 28 months and detected 12 episodes of pAF of which two episodes were associated with reduced performance, while others occurred asymptomatically at rest. The estimated episode duration ranged from 6 min to 46.5 h. The antiarrhythmic drug sotalol (2 mg/kg bwt BID PO) was given prior to TVEC and then for 4 weeks. As episodes continued to occur, sotalol was prescribed for another 4 weeks, 6 months after TVEC. Continuous monitoring after TVEC allows for detection of AF recurrence and identification of AF burden, approximate time of onset and possible identification of trigger events. Early diagnosis and antiarrhythmic treatment may prevent a progression to persistent AF.

A Prospective Evaluation of Arrhythmias in a Large Tertiary Neonatal Intensive Care Unit.

Arrhythmias in the neonatal period are common and can be classified as bradyarhythmias and tachyarrhythmias and as benign or non-benign. Neonatal arrhythmias are further differentiated between those with abnormalities in generation (non-sinus) and those with abnormalities in propagation. Because the neonatal myocardium is immature and operates at the peak of the Starling curve, significant changes in heart rate can result in a decline in cardiac output and compromise end-organ perfusion. This is especially true for premature neonates, those critically ill, or those with concomitant congenital heart disease. While sustained arrhythmias are frequently witnessed and recorded in tertiary neonatal intensive care units (NICU) very little data exist on the observance of non-sustained brady- or tachyarrhythmias in this cohort. No prospective study has been performed on all neonates admitted to a large tertiary NICU throughout their entire stay. The purpose of this study was to prospectively evaluate the prevalence and type of arrhythmias in a large NICU population from admission to discharge. All neonates admitted to the NICU at Inova Children's Hospital at Inova Fairfax Medical Campus between January 1, 2021 and April 1, 2021 were prospectively evaluated from admission to hospital discharge via continuous bedside monitoring reviewed every 24h. Concerning telemetry strips were reviewed by two team members as well as the senior electrophysiologist. Two-hundred and one neonates (mean gestational age = 344/7weeks) were enrolled in the study. Admission length ranged from 1 to 195days (total of 5624 patient days, median 16days). Overall, 68% (N = 137) of admissions had one or more arrhythmias, the most common of which was sinus tachycardia (65%, N = 130), followed by sinus bradycardia (30%, N = 60). Clinically relevant arrhythmias were diagnosed in 6.5% of neonates. During the study period there were four deaths, none of which were directly attributable to a primary arrhythmia. Approximately 68% of neonates exhibited at least one arrhythmia. Although the vast majority of these arrhythmias were benign, clinically relevant arrhythmias were observed in 6.5%. Patients admitted to the NICU appear to have a relatively high burden of benign arrhythmias, but a relatively low burden of pathologic arrhythmias.

Prevalence of pathological arrhythmia in patients triaged to “cardiac arrhythmia” in the emergency department: a preliminary study

BackgroundSymptoms caused by cardiac arrhythmia are common problems that lead to presentation to the emergency department. However, the prevalence of pathological heart rhythm in patients triaged for cardiac arrhythmia in the emergency department remains up to now unknown.Methods and resultsIn this retrospective study, patients triaged for cardiac arrhythmia admitted to the interdisciplinary emergency department of the Ludwig-Maximilians University Hospital in Munich within 1 year were included. Subsequently, cardiac rhythm in the 12-lead electrocardiogram, clinical presentation, admission rate, and diagnosis at discharge was analyzed. A total of 558 out of 39,798 patients were triaged for cardiac arrhythmia. Of these 42.3% of patients showed a pathological heart rhythm on the initial electrocardiogram (66.9% atrial fibrillation, 16.5% atrial flutter, 16.5% others). About 80% presented in emergency severity index III (many resources are needed without critical vitals) conditions. Sixty-two percent of the pathological electrocardiogram group and 60% of the sinus rhythm group of patients were admitted to the hospital, and 34.7% with pathological electrocardiogram underwent invasive investigations (16.8% in the sinus rhythm group). In 43.4% of patients, the diagnosis of cardiac arrhythmia was already known from previous medical contacts.ConclusionA total of 1.8% of patients who presented to our interdisciplinary emergency department were triaged for cardiac arrhythmia. With 49.5%, the hospital admission rate was quite high but the patients presented to the emergency department in our cohort were rarely in critical condition. As a high percentage of our cohort had a history of cardiac arrhythmia, better outpatient management is needed for these patients to reduce emergency department visits and save resources.

Utilizing smartphone-based electrocardiography and thoracic radiography to evaluate cardiac function and morphology in geriatric Sika deer (Cervus nippon).

To describe qualitative and quantitative cardiothoracic values in geriatric Sika deer (Cervus nippon) using digital radiography, 6-lead ECG (sECG), and smartphone-based ECG (aECG). 10 healthy geriatric Sika deer (9 females and 1 male). Deer were chemically immobilized, thoracic radiographs were obtained, and inhalant anesthesia was initiated. An sECG and aECG were simultaneously recorded for each animal using the same ECG specifications. Results were compared between devices. Radiographically, no deer had any cardiopulmonary abnormalities. Median (range) values for the most important cardiac measurements were 170 (153-193) mm for cardiac height, 135 (122-146) mm for cardiac width, 9 (8-9) for vertebral heart score, and 99 (69-124) mm for cardiosternal contact. All deer had a normal sinus rhythm with no pathological arrhythmias noted. A significant difference between sECG and aECG was identified for minimum heart rate (49 vs 51 beats/min, respectively), P wave duration (0.05 vs 0.03 seconds), P wave amplitude (0.28 vs 0.10 mV), PR interval (0.15 vs 0.12 seconds), and QT interval (0.39 vs 0.30 seconds). Thoracic radiographs were suitable to evaluate basic cardiothoracic morphology in Sika deer. The aECG was useful for assessing heart rate and rhythm but, compared with sECG, proved no substitute for evaluating duration and amplitude of ECG waveforms.

Fundamentals of arrhythmogenic mechanisms and treatment strategies for equine atrial fibrillation

Atrial fibrillation (AF) is the most common pathological arrhythmia in horses. Although it is not usually a life-threatening condition on its own, it can cause poor performance and make the horse unsafe to ride. It is a complex multifactorial disease influenced by both genetic and environmental factors including exercise training, comorbidities or ageing. The interactions between all these factors in horses are still not completely understood and the pathophysiology of AF remains poorly defined. Exciting progress has been recently made in equine cardiac electrophysiology in terms of diagnosis and documentation methods such as cardiac mapping, implantable electrocardiogram (ECG) recording devices or computer-based ECG analysis that will hopefully improve our understanding of this disease. The available pharmaceutical and electrophysiological treatments have good efficacy and lead to a good prognosis for AF, but recurrence is a frequent issue that veterinarians have to face. This review aims to summarise our current understanding of equine cardiac electrophysiology and pathophysiology of equine AF while providing an overview of the mechanism of action for currently available treatments for equine AF.

Effect of a long-term high-energy diet on cardiovascular parameters in Shetland pony mares.

BackgroundChanges in cardiovascular parameters, including blood pressure (BP) and cardiac anatomical dimensions, are an inconsistent feature of the equine metabolic syndrome. The order in which these changes arise is unknown.ObjectivesDetermine the order in which EMS‐associated changes in cardiovascular parameters arise.AnimalsTwenty Shetland pony mares.MethodsHigh‐energy (HE) diet mares were fed 200% of net energy requirements for 1 (n = 3) or 2 (n = 7) consecutive diet‐years, with 17 weeks of hay‐only between years. Noninvasive BP measurements and echocardiograms were performed during both years. Resting 24‐hour ECGs and measurements of autonomic tone (splenic volume and packed cell volume [PCV]) were performed at the end of diet‐year 1. Results were compared to control mares receiving a maintenance diet for 1 (n = 7) or 2 (n = 3) consecutive years.ResultsIn year 1, HE mares had significantly higher values than control mares for mean relative left ventricular wall thickness (P = .001). After 2 diet‐years, mean systolic (P = .003), diastolic (P < .001) and mean arterial BP (P = .001), heart rate (HR; P < .001), and mean left ventricular wall thickness (P = .001) also were significantly increased in HE compared to control mares. No pathological arrhythmias or differences in splenic volume or PCV were detected.Conclusions and Clinical ImportanceIngesting a HE diet first induced minor changes in BP, and progressed to left‐sided cardiac hypertrophy in Shetland pony mares. These findings are of interest given the increasing incidence of obesity in horses.

Abstract P130: QTc Prolongation in Acute Medullary Infarction Maps to the Dorsal Vagal Nucleus

Objective: To determine the spatial relationship between acute medullary infarction and QTc prolongation. Background: Ischemic stroke has been associated with QTc-prolongation which increases the risk of cardiac arrhythmia and sudden cardiac death. In particular, pathological arrhythmia and unexpected sudden cardiac death has been described after acute medullary infarction (AMI). Nevertheless, it is not well understood why only as subset of patients with AMI develop significant cardiac arrhythmia. To gain insight into this issue, we sought to determine the possible anatomical structures relating to QTc-prolongation in patients. Methods: We retrospectively reviewed 1072 consecutive adult patients admitted for an acute ischemic stroke or a transient ischemic attack, who presented within 4.5 hours from the last known well time and had an admission ECG available. 724 patients had brain MRIs and among these, 13 (1.8 %) patients had an AMI and were included. For an unbiased lesion analyses, medullary infarcts were manually outlined on diffusion weighted MRI and manually co-registered with an anatomical atlas. Infarct lesions were then superimposed on each other as stratified by normal versus prolonged (men &gt; 430 ms, women &gt; 450 ms) QTc to determine the area of greatest degree of congruence. Results: 76.9 % of patients (10 out of 13, 9 men and 1 woman) had a prolonged QTc (476.9 ± 43.3 ms for men, 515 ms for women). There was no significant difference in electrolyte levels and preexisting comorbidities between subjects with normal and prolonged QTc. Among patients with QTc prolongation, the greatest degree of congruence of the infarct location was the dorsal vagal nucleus (DVN, 7 out of 10 patients). Conclusions: Our unbiased lesion segmentation approach identified the DVN a key anatomical substrate related to QTc-prolongation. Biological plausibility of our data and the presence of a causal link between the DVN and cardiac arrhythmia stems from the prior animal experimental data showing that selectively silencing the DVN via a pharmacogenetic approach caused QTc-prolongation in the rat. Further studies with more patients and high-resolution, volumetric MRI are needed to confirm our findings.

Anisotropic Cardiac Conduction.

Anisotropy is the property of directional dependence. In cardiac tissue, conduction velocity is anisotropic and its orientation is determined by myocyte direction. Cell shape and size, excitability, myocardial fibrosis, gap junction distribution and function are all considered to contribute to anisotropic conduction. In disease states, anisotropic conduction may be enhanced, and is implicated, in the genesis of pathological arrhythmias. The principal mechanism responsible for enhanced anisotropy in disease remains uncertain. Possible contributors include changes in cellular excitability, changes in gap junction distribution or function and cellular uncoupling through interstitial fibrosis. It has recently been demonstrated that myocyte orientation may be identified using diffusion tensor magnetic resonance imaging in explanted hearts, and multisite pacing protocols have been proposed to estimate myocyte orientation and anisotropic conduction in vivo. These tools have the potential to contribute to the understanding of the role of myocyte disarray and anisotropic conduction in arrhythmic states.

Arrhythmias in Pregnancy.

The prevalence of arrhythmias in pregnant women are rising, particularly among women with a history of structural heart disease or prior arrhythmia. The physiological changes of pregnancy increase the risk of both benign and pathologic arrhythmias, with atrial fibrillation representing the most common pathologic arrhythmia. While bradyarrhythmias rarely require treatment during pregnancy, pharmacotherapy is frequently required for tachyarrhythmias. Electrophysiological procedures including cardioversions, ablations, and device placement are occasionally required during pregnancy and can be performed safely with proper precautions. This chapter will discuss the diagnosis and management of a broad array of cardiac arrhythmias that may be encountered in pregnant women.

Validation of a portable ECG monitor for the diagnosis of arrhythmias in horses compared to a standard electrocardiograph

Electrocardiography (ECG) is a main diagnostic tool for diagnostics of rhythm disturbances. Since most pathological arrhythmias are only visible during movement and exercises the registration of exercising ECG becomes a mandatory diagnostic tool for monitoring of high-performance horses. Portable ECG monitor, developed together with specialists of National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute” is an electrocardiograph with telemetric data transmission system and four electrodes providing six-lead real-time ECG recordings at rest and during exercise. The objective of current study was validation of portable ECG monitor for diagnostics of arrhythmias in horses compared to a standard electrocardiograph. With this aim the ECG was performed by both devices simultaneously on animals with normal rhythm and rhythm disturbances. The ECG traces were therefore analyzed and compared. 14 horses of Ukrainian riding, Friesian, and Arabian breeds were divided in two groups: experimental one with arrhythmias, and control one with normal rhythm. ECG was performed by both devices simultaneously during rest, exercise, and post-exercise period. Electrocardiographic parameters were measured manually using on-screen calipers. Obtained data was analyzed using GraphPad Prism software by linear regression method for continuous parameters (HR, duration of QRS complex, PR, and QT intervals, and amplitude of P and S waves). For nominal parameters (rhythm, excitability, and conduction disorders) the analysis of sensitivity and specificity was performed. A total of 196 ECG records were analysed. Electrocardiographic intervals had high correlation: for HR and PR interval the correlation coefficient amounted to 0.98, for QRS complex and QT interval – to 0.97, for P and S waves – to 0.96. Among detected rhythm disturbances were physiological (second degree AV block first Mobitz type and SA block) and pathological arrhythmias (SVT and SVPCs). The sensitivity and specificity for rhythm, excitability, and conduction disorders of the portable ECG monitor compared to a standard electrocardiograph was 100 %. The portable ECG monitor allows to easily perform ECG registration during rest and exercises and to detect arrhythmias and other ECG abnormalities with accuracy, compared to a standard electrocardiograph.

DILTIAZEM VERSUS METOPROLOL FOR THE MANAGEMENT OF ATRIAL FIBRILLATION: A SYSTEMATIC REVIEW AND META-ANALYSIS

Atrial fibrillation (AF) is the most common pathological cardiac arrhythmia. AF is classified as Acute AF or Chronic AF. Heart rate control (RC) is the most common therapeutic approach for the management of both Acute AF and Chronic AF. Diltiazem and metoprolol are the most common agents used for RC

Treating atrial fibrillation in the 21st Century: part 1

Atrial fibrillation (AF) is the most common pathological cardiac arrhythmia in the horse. While it may be an incidental finding in some horses, it can be an important cause of poor exercise tolerance in the performance horse, especially those working at extremes of cardiac function. Although quinidine sulfate remains the most widely used treatment option for horses, alternatives, such as transvenous electrocardioversion, are growing in popularity. The decision-making process to establish the most appropriate treatment is based on a number of factors including chronicity, underlying disease, and cardiac size. The availability of transvenous electrocardioversion in the horse provides a valid alternative for the treatment of horses with atrial fibrillation.

Long non-coding RNA CCRR controls cardiac conduction via regulating intercellular coupling

Long non-coding RNAs (lncRNAs) have emerged as a new class of gene expression regulators playing key roles in many biological and pathophysiological processes. Here, we identify cardiac conduction regulatory RNA (CCRR) as an antiarrhythmic lncRNA. CCRR is downregulated in a mouse model of heart failure (HF) and in patients with HF, and this downregulation slows cardiac conduction and enhances arrhythmogenicity. Moreover, CCRR silencing induces arrhythmias in healthy mice. CCRR overexpression eliminates these detrimental alterations. HF or CCRR knockdown causes destruction of intercalated discs and gap junctions to slow longitudinal cardiac conduction. CCRR overexpression improves cardiac conduction by blocking endocytic trafficking of connexin43 (Cx43) to prevent its degradation via binding to Cx43-interacting protein CIP85, whereas CCRR silence does the opposite. We identified the functional domain of CCRR, which can reproduce the functional roles and pertinent molecular events of full-length CCRR. Our study suggests CCRR replacement a potential therapeutic approach for pathological arrhythmias.

CRISPR -Mediated Expression of the Fetal Scn5a Isoform in Adult Mice Causes Conduction Defects and Arrhythmias.

BackgroundThe sodium channel, Nav1.5, encoded by SCN5A, undergoes developmentally regulated splicing from inclusion of exon 6A in the fetal heart to exon 6B in adults. These mutually exclusive exons differ in 7 amino acids altering the electrophysiological properties of the Nav1.5 channel. In myotonic dystrophy type 1, SCN5A is mis‐spliced such that the fetal pattern of exon 6A inclusion is detected in adult hearts. Cardiac manifestations of myotonic dystrophy type 1 include conduction defects and arrhythmias and are the second‐leading cause of death.Methods and ResultsThis work aimed to determine the impact of SCN5A mis‐splicing on cardiac function. We used clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR‐associated protein 9 (Cas9) to delete Scn5a exon 6B in mice, thereby redirecting splicing toward exon 6A. These mice exhibit prolonged PR and QRS intervals, slowed conduction velocity, extended action potential duration, and are highly susceptible to arrhythmias.ConclusionsOur findings highlight a nonmutational pathological mechanism of arrhythmias and conduction defects as a result of mis‐splicing of the predominant cardiac sodium channel. Animals homozygous for the deleted exon express only the fetal isoform and have more‐severe phenotypes than heterozygotes that also express the adult isoform. This observation is directly relevant to myotonic dystrophy type 1, and possibly pathological arrhythmias, in which individuals differ with regard to the ratios of the isoforms expressed.

Clinical impact of a novel ambulatory rhythm monitor in children.

Traditional ambulatory rhythm monitoring in children can have limitations, including cumbersome leads and limited monitoring duration. The ZioTM patch ambulatory monitor is a small, adhesive, single-channel rhythm monitor that can be worn up to 2 weeks. In this study, we present a retrospective cross-sectional analysis of the ZioTM monitor's impact in clinical practice. Patients aged 0-18 years were included in the study. A total of 373 studies were reviewed in 332 patients. In all, 28.4% had structural heart disease, and 16.9% had a prior surgical, catheterisation, or electrophysiology procedure. The most common indication for monitoring was tachypalpitations (41%); 93.5% of these patients had their symptoms captured during the study window. The median duration of monitoring was 5 days. Overall, 5.1% of ZioTM monitoring identified arrhythmias requiring new intervention or increased medical management; 4.0% identified arrhythmias requiring increased clinical surveillance. The remainder had either normal-variant rhythm or minor rhythm findings requiring no change in management. For patients with tachypalpitations and no structural heart disease, 13.2% had pathological arrhythmias, but 72.9% had normal-variant rhythm during symptoms, allowing discharge from cardiology care. Notably, for patients with findings requiring intervention or increased surveillance, 56% had findings first identified beyond 24 hours, and only 62% were patient-triggered findings. Seven studies (1.9%) were associated with complications or patient intolerance. The ZioTM is a well-tolerated device that may improve what traditional Holter and event monitoring would detect in paediatric cardiology patients. This study shows a positive clinical impact on the management of patients within a paediatric cardiology practice.

Catheter-associated venous air embolism in hospitalized horses: 32 cases.

BackgroundVenous air embolism is a potentially life‐threatening complication of IV catheter use in horses. Despite widespread anecdotal reports of their occurrence, few cases have been reported in the literature and the prognosis is currently unknown.Hypothesis/ObjectivesOur objective was to describe the surrounding circumstances, clinical signs, treatment, progression, and outcome of venous air embolism in hospitalized horses.AnimalsThirty‐two horses with acute onset of compatible clinical signs associated with IV catheter disconnection or damage.MethodsMulticenter retrospective study. Data extracted from clinical records included signalment, presenting complaint, catheter details, clinical signs, treatments, and outcome.ResultsMost cases resulted from extension set disconnection occurring within approximately 24 hours after catheter placement. In fewer horses, extension set damage was cited as a cause. Common clinical signs included tachycardia, tachypnea, recumbency, muscle fasciculations and agitation, with abnormal behavior including kicking and flank biting. Less commonly, pathological arrhythmias or more severe neurologic signs, including blindness and seizures, were noted. Progression was unpredictable, with some affected horses developing delayed‐onset neurologic signs. Mortality was 6/32 (19%), including 2 cases of sudden death and other horses euthanized because of persistent neurologic deficits. Negative outcomes were more common in horses with recorded blindness, sweating or recumbency, but blindness resolved in 5/8 affected horses.Conclusions and Clinical ImportanceThe prognosis for resolution of clinical signs after air embolism is fair, but permanent neurologic deficits or pathologic cardiac arrhythmias can arise. Unpredictable progression warrants close monitoring. Systematic clinic‐based surveillance could provide additional useful information to aid prevention.

Treatment of Subclinical Atrial Fibrillation: Does One Plus One Always Equal Two?

Atrial fibrillation (AF) is the most common pathological arrhythmia observed in clinical practice and it is associated with stroke, heart failure, and increased mortality. Multiple pivotal, randomized trials established the role of anticoagulation to reduce the risk of stroke among patients with AF with an elevated risk profile, as assessed by the CHADS2 or CHA2DS2-VASc scoring systems. As such, anticoagulation with warfarin or novel oral anticoagulants is a class I indication in the treatment of patients with AF by all major societies, even though these agents are consistently underutilized because of fear of hemorrhagic complications. Retrospective analyses of large, multicenter trials have more recently showed that stroke risk is somewhat higher with chronic in comparison with paroxysmal AF, but this difference is not sufficiently large to affect anticoagulation recommendations. The studies of anticoagulation use to prevent stroke, as well as most other treatments of AF are based on clinical documentation of the arrhythmia. Typically, this is driven by symptoms such as palpitations, syncope, dyspnea, or chest pain, but sometimes asymptomatic and incidentally discovered. The presence of arrhythmia-related symptoms does not appear to change the stroke risk, so anticoagulation recommendations are unaffected. Although pacemakers have been implanted for >50 …