Two siblings presented with cardiomyopathy, hypertension, arrhythmia, and fibrosis of the left atrium. Each had a homozygous null variant in
CORIN
, the gene encoding atrial natriuretic peptide ...(ANP)–converting enzyme. A plasma sample obtained from one of the siblings had no detectable levels of corin or N-terminal pro-ANP but had elevated levels of B-type natriuretic peptide (BNP) and one of the two protein markers of fibrosis that we tested. These and other findings support the hypothesis that BNP cannot fully compensate for a lack of activation of the ANP pathway and that corin is critical to normal ANP activity, left atrial function, and cardiovascular homeostasis.
Findings from a study involving two siblings homozygous for a null variant in
CORIN
have implications for understanding the extent to which the BNP and ANP pathways overlap.
Information on young patients with Brugada syndrome (BrS) and arrhythmic events (AEs) is limited.
The purpose of this study was to describe their characteristics and management as well as risk ...factors for AE recurrence.
A total of 57 patients (age ≤20 years), all with BrS and AEs, were divided into pediatric (age ≤12 years; n = 26) and adolescents (age 13 to 20 years; n = 31).
Patients’ median age at time of first AE was 14 years, with a majority of males (74%), Caucasians (70%), and probands (79%) who presented as aborted cardiac arrest (84%). A significant proportion of patients (28%) exhibited fever-related AE. Family history of sudden cardiac death (SCD), prior syncope, spontaneous type 1 Brugada electrocardiogram (ECG), inducible ventricular fibrillation at electrophysiological study, and SCN5A mutations were present in 26%, 49%, 65%, 28%, and 58% of patients, respectively. The pediatric group differed from the adolescents, with a greater proportion of females, Caucasians, fever-related AEs, and spontaneous type-1 ECG. During follow-up, 68% of pediatric and 64% of adolescents had recurrent AE, with median time of 9.9 and 27.0 months, respectively. Approximately one-third of recurrent AEs occurred on quinidine therapy, and among the pediatric group, 60% of recurrent AEs were fever-related. Risk factors for recurrent AE included sinus node dysfunction, atrial arrhythmias, intraventricular conduction delay, or large S-wave on ECG lead I in the pediatric group and the presence of SCN5A mutation among adolescents.
Young BrS patients with AE represent a very arrhythmogenic group. Current management after first arrhythmia episode is associated with high recurrence rate. Alternative therapies, besides defibrillator implantation, should be considered.
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Background
Cardiovascular and arrhythmic events have been reported in hospitalized COVID-19 patients. However, arrhythmia manifestations and treatment strategies used in these patients have not been ...well-described. We sought to better understand the cardiac arrhythmic manifestations and treatment strategies in hospitalized COVID-19 patients through a worldwide cross-sectional survey.
Methods
The Heart Rhythm Society (HRS) sent an online survey (via SurveyMonkey) to electrophysiology (EP) professionals (physicians, scientists, and allied professionals) across the globe. The survey was active from March 27 to April 13, 2020.
Results
A total of 1197 respondents completed the survey with 50% of respondents from outside the USA, representing 76 countries and 6 continents. Of respondents, 905 (76%) reported having COVID-19-positive patients in their hospital. Atrial fibrillation was the most commonly reported tachyarrhythmia whereas severe sinus bradycardia and complete heart block were the most common bradyarrhythmias. Ventricular tachycardia/ventricular fibrillation arrest and pulseless electrical activity were reported by 4.8% and 5.6% of respondents, respectively. There were 140 of 631 (22.2%) respondents who reported using anticoagulation therapy in all COVID-19-positive patients who did not otherwise have an indication. One hundred fifty-five of 498 (31%) reported regular use of hydroxychloroquine/chloroquine (HCQ) + azithromycin (AZM); concomitant use of AZM was more common in the USA. Sixty of 489 respondents (12.3%) reported having to discontinue therapy with HCQ + AZM due to significant QTc prolongation and 20 (4.1%) reported cases of Torsade de Pointes in patients on HCQ/chloroquine and AZM. Amiodarone was the most common antiarrhythmic drug used for ventricular arrhythmia management.
Conclusions
In this global survey of > 1100 EP professionals regarding hospitalized COVID-19 patients, a variety of arrhythmic manifestations were observed, ranging from benign to potentially life-threatening. Observed adverse events related to use of HCQ + AZM included prolonged QTc requiring drug discontinuation as well as Torsade de Pointes. Large prospective studies to better define arrhythmic manifestations as well as the safety of treatment strategies in COVID-19 patients are warranted.
Purpose To develop an arrhythmia-insensitive rapid (AIR) cardiac T sub(1) mapping pulse sequence for quantification of diffuse fibrosis. Methods An arrhythmia-insensitive cardiac T sub(1) mapping ...pulse sequence was developed based on saturation recovery T sub(1) weighting, which is inherently insensitive to heart rate and rhythm, and two single-shot balanced steady-state free precession image acquisitions with centric k-space ordering, where T sub(1) calculation is inherently insensitive to T sub(2) effects. Its performance against conventional cardiac T sub(1) mapping based on inversion recovery (i.e., MOLLI) is compared. Phantom experiments (T sub(1) ranging from 535 to 2123 ms) were performed with heart rate and rhythm simulated at 60 and 120 beats per minute (bpm) and arrhythmia using an external triggering device. Ten human subjects and 17 large animals were scanned precontrast and 5, 10, and 15 min after contrast agent administration. Results Compared with the reference T sub(1) mapping, AIR yielded lower normalized root-mean-square error than MOLLI (8% vs. 3%, respectively, at 60 bpm, 28% vs. 3%, respectively, at 120 bpm, and 22% vs. 3%, respectively, at arrhythmia). In vivo studies showed that T sub(1) measurements made by MOLLI and AIR were strongly correlated (r = 0.99) but in poor agreement (mean difference = 161.8 ms, upper and lower 95% limits of agreements = 347.5 ms and -24.0 ms). Conclusion Our AIR pulse sequence may be clinically useful for assessment of diffuse myocardial fibrosis in patients. Magn Reson Med 70:1274-1282, 2013. copy 2012 Wiley Periodicals, Inc.
The electrocardiogram (ECG) is a standard test used to monitor the activity of the heart. Many cardiac abnormalities will be manifested in the ECG including arrhythmia which is a general term that ...refers to an abnormal heart rhythm. The basis of arrhythmia diagnosis is the identification of normal versus abnormal individual heart beats, and their correct classification into different diagnoses, based on ECG morphology. Heartbeats can be sub-divided into five categories namely non-ectopic, supraventricular ectopic, ventricular ectopic, fusion, and unknown beats. It is challenging and time-consuming to distinguish these heartbeats on ECG as these signals are typically corrupted by noise. We developed a 9-layer deep convolutional neural network (CNN) to automatically identify 5 different categories of heartbeats in ECG signals. Our experiment was conducted in original and noise attenuated sets of ECG signals derived from a publicly available database. This set was artificially augmented to even out the number of instances the 5 classes of heartbeats and filtered to remove high-frequency noise. The CNN was trained using the augmented data and achieved an accuracy of 94.03% and 93.47% in the diagnostic classification of heartbeats in original and noise free ECGs, respectively. When the CNN was trained with highly imbalanced data (original dataset), the accuracy of the CNN reduced to 89.07%% and 89.3% in noisy and noise-free ECGs. When properly trained, the proposed CNN model can serve as a tool for screening of ECG to quickly identify different types and frequency of arrhythmic heartbeats.
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•Convolutional neural network (CNN) is used to classify 5 ECG classes.•9-layer deep CNN is implemented.•Generated synthetic data to overcome imbalance problem.•Accuracy of 94.03% and 93.47% with and without noise removal respectively.
There has been a significant progress in our understanding of the molecular mechanisms by which calcium (Ca) ions mediate various types of cardiac arrhythmias. A growing list of inherited gene ...defects can cause potentially lethal cardiac arrhythmia syndromes, including catecholaminergic polymorphic ventricular tachycardia, congenital long QT syndrome, and hypertrophic cardiomyopathy. In addition, acquired deficits of multiple Ca-handling proteins can contribute to the pathogenesis of arrhythmias in patients with various types of heart disease. In this review article, we will first review the key role of Ca in normal cardiac function—in particular, excitation–contraction coupling and normal electric rhythms. The functional involvement of Ca in distinct arrhythmia mechanisms will be discussed, followed by various inherited arrhythmia syndromes caused by mutations in Ca-handling proteins. Finally, we will discuss how changes in the expression of regulation of Ca channels and transporters can cause acquired arrhythmias, and how these mechanisms might be targeted for therapeutic purposes.
Late sodium current (I
NaL
) is a small sustained inward current observed during the cardiac action potential plateau phase following decay of the early peak I
Na
. The endogenous I
NaL
is relatively ...small in normal hearts but exerts functionally significant effects on cardiomyocyte repolarization with potentially pro-arrhythmic effects in hearts with reduced repolarization reserve. Enhanced I
Na,L
occurs in long QT syndrome 3 (LQTS 3) patients, and under a number of pathological and pharmacological cardiovascular conditions, including bradycardia, myocardial ischemia, reperfusion injury, and heart failure. It may there play important roles in arrhythmogenesis and mechanical dysfunction. Experimental and clinical research suggests that I
NaL
inhibition may prevent and treat cardiac arrhythmias and improve ventricular pump function. Selective I
Na,L
inhibitors, exemplified by ranolazine, GS-967 and GS-458967 have little or no effect on peak sodium current and/or I
Kr
, and carry no or minimal pro-arrhythmic risk compared to those associated with administration of classical class I or III antiarrhythmic drugs, particularly in patients with ischemic heart disease. This increased understanding of I
NaL
may be encouraging to clinicians in use of I
NaL
inhibitors to treat cardiac arrhythmias and mechanical dysfunction directly associated with enhanced I
NaL
such as LQTS type 3, and myocardial ischemia. This review discusses the roles of endogenous and enhanced I
NaL
in arrhythmogenesis and mechanical dysfunction, and the basic and clinical research of I
NaL
inhibitors.
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