Should ECG criteria for Low QRS voltage (LQRSV) be specific for Sex?

INTRODUCTION

Low QRS peak-to-nadir voltage (LQRSV) is associated with arrhythmogenic right ventricular cardiomyopathy (ARVC) and other cardiomyopathies. Recent studies have proposed criteria for LQRSV when screening athletes for cardiovascular disease. These criteria have not yet been evaluated in a large population of healthy young athletes.

METHODS

The target population was 10,728 (42.5% female, 57.5% male, mean age 18.1 ± 4.3 years) athletes who participated in mass ECG screenings between 2014 and 2021 at multiple sites across the United States including grade schools (11%), high schools (32%), colleges (50%), and professional athletic teams (6%) with digitally recorded ECGs and a standardized protocol. Since by design, complete follow up for outcomes and the results of testing were not available. Including only ECGs from initial evaluation among athletes 14-35 years of age and excluding those with right bundle branch block, left bundle branch block, Wolf-Parkinson-White pattern, reversed leads and 3 clinically diagnosed cardiomyopathies at Stanford, 8,679 (58% males, 42% females) remained eligible for analysis. QRS voltage was analyzed for each ECG lead and LQRSV criteria were applied and stratified by sex.

RESULTS

QRS voltage was lower in all leads in female athletes compared to male athletes. Using traditional limb lead criteria or precordial lead criteria, the prevalence of LQRSV was significantly lower in males than females (P < .001). Strikingly, LQRSV using the Sokolow-Lyon Index was present in 1.9% of males and 9.8% of females (P < .001). Applying first percentile for LQRS amplitude criteria provided possible values for screening young athletes for LQRSV.

CONCLUSIONS

LQRSV is more common among female athletes than male athletes using established criteria. Using first percentile sex-specific cut points should be considered in future analyses. Proposed novel LQRSV criteria in young athletes should be specific for males and females.

Phenotypic Expression and Clinical Outcomes in Patients With Arrhythmogenic Cardiomyopathies

BACKGROUND

In recent years, it has become evident that arrhythmogenic cardiomyopathy (ACM) displays a wide spectrum of ventricular involvement. Furthermore, the influence of various clinical phenotypes on the prognosis of the disease is currently being assessed.

OBJECTIVES

The purpose of this study was to evaluate the impact of phenotypic expression in ACM on patient outcomes.

METHODS

We conducted an analysis of 446 patients diagnosed with ACM. These patients were categorized into 3 groups based on their phenotype: arrhythmogenic right ventricular cardiomyopathy (ARVC) (right-dominant ACM), arrhythmogenic left ventricular cardiomyopathy (ALVC) (left-dominant ACM), and biventricular arrhythmogenic cardiomyopathy (BIV). We compared clinical, instrumental, and genetic findings among these groups and also evaluated their outcomes RESULTS: Overall, 44% of patients were diagnosed with ARVC, 23% with ALVC, and 33% with BIV forms. Subjects showing with ARVC and BIV phenotype had a significantly higher incidence of life-threatening ventricular arrhythmias compared with ALVC (P < 0.001). On the other hand, heart failure, heart transplantation, and death caused by cardiac causes were more frequent in individuals with BIV forms compared to those with ALVC and ARVC (P < 0.001). Finally, patients with an ALVC phenotype had a higher incidence of hot phases compared with those with ARVC and BIV forms (P = 0.013).

CONCLUSIONS

The comparison of ACM phenotypes demonstrated that patients with right ventricular involvement, such as ARVC and BIV forms, exhibit a higher incidence of life-threatening ventricular arrhythmias. Conversely, ACM forms characterized by left ventricular involvement, such as ALVC and BIV, show a higher incidence of heart failure, heart transplantation, and hot phases.

Proposed diagnostic criteria for arrhythmogenic cardiomyopathy: European Task Force consensus report

Arrhythmogenic cardiomyopathy (ACM) is a heart muscle disease characterized by prominent "non-ischemic" myocardial scarring predisposing to ventricular electrical instability. Diagnostic criteria for the original phenotype, arrhythmogenic right ventricular cardiomyopathy (ARVC), were first proposed in 1994 and revised in 2010 by an international Task Force (TF). A 2019 International Expert report appraised these previous criteria, finding good accuracy for diagnosis of ARVC but a lack of sensitivity for identification of the expanding phenotypic disease spectrum, which includes left-sided variants, i.e., biventricular (ABVC) and arrhythmogenic left ventricular cardiomyopathy (ALVC). The ARVC phenotype together with these left-sided variants are now more appropriately named ACM. The lack of diagnostic criteria for the left ventricular (LV) phenotype has resulted in clinical under-recognition of ACM patients over the 4 decades since the disease discovery. In 2020, the "Padua criteria" were proposed for both right- and left-sided ACM phenotypes. The presently proposed criteria represent a refinement of the 2020 Padua criteria and have been developed by an expert European TF to improve the diagnosis of ACM with upgraded and internationally recognized criteria. The growing recognition of the diagnostic role of CMR has led to the incorporation of myocardial tissue characterization findings for detection of myocardial scar using the late‑gadolinium enhancement (LGE) technique to more fully characterize right, biventricular and left disease variants, whether genetic or acquired (phenocopies), and to exclude other "non-scarring" myocardial disease. The "ring-like' pattern of myocardial LGE/scar is now a recognized diagnostic hallmark of ALVC. Additional diagnostic criteria regarding LV depolarization and repolarization ECG abnormalities and ventricular arrhythmias of LV origin are also provided. These proposed upgrading of diagnostic criteria represents a working framework to improve management of ACM patients.

Characterizing Decision-Making Surrounding Exercise in ARVC: Analysis of Decisional Conflict, Decisional Regret, and Shared Decision-Making

BACKGROUND

Limiting high-intensity exercise is recommended for patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) due to its association with penetrance, arrhythmias, and structural progression. Guidelines recommend shared decision-making (SDM) for exercise level, but there is little evidence regarding its impact. Therefore, we sought to evaluate the extent and implications of SDM for exercise, decisional conflict, and decisional regret in patients with ARVC and at-risk relatives.

METHODS

Adults diagnosed with ARVC or with positive genetic testing enrolled in the Johns Hopkins ARVC Registry were invited to complete a questionnaire that included exercise history and current exercise, SDM (SDM-Q-9), decisional conflict, and decisional regret.

RESULTS

The response rate was 64.8%. Two-thirds of participants (68.0%, n=121) reported clinically significant decisional conflict regarding exercise at diagnosis/genetic testing (DCS [decisional conflict scale]≥25), and half (55.1%, n=98) in the past year. Prevalence of decisional regret was also high with 55.3% (n=99) reporting moderate to severe decisional regret (DRS [decisional regret scale]≥25). The extent of SDM was highly variable ranging from no (0) to perfect (100) SDM (mean, 59.6±25.0). Those diagnosed in adolescence (≤age 21) reported significantly more SDM (P=0.013). Importantly, SDM was associated with less decisional conflict (ß=-0.66, R2=0.567, P<0.01) and decisional regret (ß=-0.37, R2=0.180, P<0.001) and no difference in vigorous intensity aerobic exercise in the 6 months after diagnosis/genetic testing or the past year (P=0.56; P=0.34, respectively).

CONCLUSIONS

SDM is associated with lower decisional conflict and decisional regret; and no difference in postdiagnosis exercise. Our data thus support SDM as the preferred model for exercise discussions for ARVC.

Phenotyping heart failure by genetics and associated conditions

Heart failure is a highly heterogeneous disease, and genetic testing may allow phenotypic distinctions that are incremental to those obtainable from imaging. Advances in genetic testing have allowed for the identification of deleterious variants in patients with specific heart failure phenotypes (dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, and hypertrophic cardiomyopathy), and many of these have specific treatment implications. The diagnostic yield of genetic testing in heart failure is modest, and many rare variants are associated with incomplete penetrance and variable expressivity. Environmental factors and co-morbidities have a large role in the heterogeneity of the heart failure phenotype. Future endeavours should concentrate on the cumulative impact of genetic polymorphisms in the development of heart failure.

Carvajal Syndrome- A Variant of Naxos Disease: A Case Report

Carvajal syndrome is a rare variant of Naxos disease, a recessive mutation of the desmoplakin gene characterized by presence of woolly hair, palmoplantar keratoderma and dilated cardiomyopathy, mainly left ventricular involvement. The main clinical complication is progressive heart disease which may lead to heart failure and sudden cardiac death in childhood and adolescence. Cardiomyopathy is diagnosed by Task Force Criteria. The goal of treatment is to prevent sudden cardiac death by lifestyle modification and regular clinical monitoring with pharmacotherapy. We report a nine years female who had skin and hair abnormality and was admitted with features of heart failure. She was clinically diagnosed as Carvajal syndrome, an under-recognized cardio cutaneous manifestation in children. Clinicians should be aware, if any child present with keratoderma of palm and soles with woolly hair since birth should evaluate for cardiomyopathy. Genetic tests should be done whenever available, for confirming the diagnosis and counseling.

Right Ventricular Endocardial Mapping and a Potential Arrhythmogenic Substrate in Cardiac Amyloidosis-Role of ICD

Patients with cardiac amyloidosis (CA) have an increased risk of sudden cardiac death. (SCD). However, the role of an implantable cardioverter-defibrillator in the primary prevention of SCD in this group of patients is still controversial. We present a case with CA with recurrent syncope and non-sustained ventricular tachycardia. In order to further stratify the risk of SCD, an electrophysiological study with endocardial electroanatomic voltage mapping was performed prior to the ICD placement.

Oxidized low-density lipoproteins as a novel risk factor and therapeutic target for ACM

Arrhythmogenic cardiomyopathy (ACM) is an inherited heart disease involving arrhythmia in young adults accompanied by structural changes at later stages. In this issue of EMBO Molecular Medicine, Sommariva et al (2021) identified a positive correlation between circulating levels of oxidized low-density lipoproteins (oxLDL) and ACM disease penetrance, which contributes to fibro-fatty cardiac remodeling via the oxLDL/CD36/PPARγ axis. These data identify oxidized low-density lipoproteins as a risk factor for ACM and uncover a novel therapeutic intervention option to block disease pathogenesis.

Establishment of induced pluripotent stem cell lines from a family of an ARVC patient receiving heart transplantation in infant age carrying compound heterozygous mutations in DSP gene

The mutations of desmoplakin (DSP) lead to arrhythmia right ventricular cardiomyopathy (ARVC) which is a kind of progressive cardiomyopathy characterized by arrhythmia, heart failure and sudden cardiac death. The human induced pluripotent stem (iPS) cell line HUBUi001-A was generated from a patient carrying the compound DSP heterozygous mutations (c.104G > T p.G35V; c.5617C > T p.R1873C), which were inherited from his parents (HUBUi002-A, HUBUi003- A), who presented a normal phenotype. We have derived the iPSC cell lines through peripheral blood mononuclear (PBMCs) cell reprogramming technology. Pluripotency and differentiation capacity have been confirmed by RT-PCR, immunocytochemistry and teratoma experiment. These cell lines can help us understand the pathogenic mechanism and screening potential therapeutic options.

[Key Points of the 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope]

The article presents key points of published in March 2017, Guideline for the Evaluation and Management of Patients With Syncope (A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines, and the Heart Rhythm Society). This document contains summary and analysis of evidence base and accumulated experience in this field and reflect further development of the problem of the management of adult and pediatric patients with suspected syncope. Traditionally, the basis of diagnostic algorithm of these patients has been primary examination, and in the present guideline one can find strengthening of the importance of anamnestic criteria, and supplementation of ECG criteria of arrhythmic syncope. At the same time, the diagnostic value of provocative tests has been revised, and the class of indications for these tests has been lowered. According to the guideline, along with diagnosis of the cause of fainting, risk stratifcation of short- and long-term adverse outcomes has a key value. The guideline summarizes latest achievements in the treatment of fainting in sarcoidosis, arrhythmogenic right ventricular dysplasia, primary arrhythmic heart diseases, orthostatic hypotension, and reflex-mediated syncope. Despite orientation on specifc properties of medical care in the USA, the guideline can be useful to practical physicians in choice of the best strategy of diagnosis and treatment of syncope in each individual case.

[Epicardial VT ablation : In whom, when, how and why?]

Ventricular tachycardia (VT) is a leading cause of cardiovascular death and remains the main cause of sudden cardiac death. Implanted cardiac defibrillators (ICD) improve survival but the recurrent ICD therapies, mostly ICD shocks, are associated with an increased mortality and deleterious psychological effects. In this regard and based on the results of multicenter studies, the current European guidelines recommend early referral for catheter ablation. The ablation strategy (isolated endocardial approach or combined epi-/endocardial) depends mostly on the underlying myocardial disease. Thus, almost all patients with right ventricular dysplasia and Chagas disease, the majority of those with dilative cardiomyopathy, and some patients with ischemic cardiomyopathy (mostly posterior wall infarction or large transmural anterior wall infarction) have an epicardial scar as the underlying substrate for recurrent VT episodes. Thus, in this group of patients, isolated endocardial VT ablation may be associated with an increased VT recurrence and therefore an epicardial approach is also needed. Cardiac imaging (cardio-CT/MRI with late enhancement[MRI LE]) can reliably identify the distribution and characteristics of the myocardial scar and may be helpful in planning the ablation strategy. When performed in highly specialized centers, epicardial catheter ablation of VT leads to a significant reduction of recurrent VT episodes compared to the endocardial VT ablation alone and with lower complication rates.

Relationship between arrhythmogenic right ventricular dysplasia and exercise

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is rare cardiomyopathy associated with life-threatening arrhythmias and increased risk of sudden cardiac death. In addition to mutations in desmosomal genes, environmental factors such as exercise have been implicated in the pathogenesis of the disease. Recent studies have shown that exercise may be associated with adverse outcomes in ARVD/C patients. Based on current evidence, ARVD/C patients are recommended to limit exercise irrespective of their mutation status. In addition, some studies have suggested the presence of an entirely acquired form of the disease caused by exercise that has been dubbed exercise-induced ARVD/C.

Death due to Arrhythmogenic Right Ventricular Dysplasia: A case report

Arrhythmogenic right ventricular dysplasia (ARVD) is both a myocardial disease that predominantly affects the right ventricle (RV) and one of the major causes of sudden death in the young and athletes. A 28-year-old man with no signicant medical history, applied to an emergency department with feeling very ill. After his initial examinations, electrocardiography (ECG) showed ventricular extra systoles and he was recommended for admission to a cardiology polyclinic. The next day, his condition worsened and he was dead on arrival at the hospital. A histological examination of heart samples, which were obtained from the RV and LV, revealed the massive replacement of myocardium by fibrous and mature adipose tissue in the RV. In this case, there were no symptoms, family and medical history and its clinical presentation was as an unexpected sudden death.

KEYWORDS

Arrhythmogenic right ventricular dysplasia, sudden cardiac death, autopsy.

[Arrhythmogenic right ventricular cardiomyopathy]

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a primary myocardial disorder that is characterized by localized or diffuse atrophy of predominantly right ventricular myocardium with subsequent replacement by fatty and fibrous tissue. Arrhythmias of right ventricular origin are the main clinical manifestation. Affected patients present with ventricular premature beats and nonsustained or sustained ventricular tachycardia demonstrating a left bundle branch block pattern. However, since ventricular tachycardia may also degenerate into ventricular fibrillation, sudden death may be the first manifestation of ARVC.In recent years, ARVC has been more and more recognized as an important and frequent cause of ventricular tachyarrhythmias and sudden cardiac death, particularly in young patients and athletes, with apparently normal hearts. Evidence of the disease is found in 30-50% of family members. ARVC is a genetically heterogeneous disease. The diagnosis is based on electrocardiographic abnormalities and the identification of regional or global right ventricular dysfunction and fibrolipomatosis. Although several potentially causative genes have been identified, currently, genetic testing is not part of the routine diagnostic work-up.An implantable cardioverter-defibrillator is indicated in selected high-risk patients with ARVC (i. e., patients with life-threatening ventricular tachycardia or survivors of sudden cardiac death). The clinical course of the disease is often characterized by progression. In individual patients heart transplantation may become necessary.

Regulation of ryanodine receptors by FK506 binding proteins

Ryanodine receptors (RyRs) are the major sarcoplasmic reticulum calcium-release channels required for excitation-contraction coupling in skeletal and cardiac muscle. Mutations in RyRs have been linked to several human diseases. Mutations in the cardiac isoform of RyR2 are associated with catecholaminergic polymorphic ventricular arrhythmias (CPVT), and arrhythmogenic right ventricular dysplasia type 2 (ARVD2), whereas mutations in the skeletal muscle isoform (RyR1) are linked to malignant hyperthermia (MH) and central core disease (CCD). RyRs are modulated by several other proteins, including the FK506 binding proteins (FKBPs), FKBP12 and FKBP12.6. These immunophilins appear to stabilize a closed state of the channel and are important for cooperative interactions among the subunits of RyRs. This review discusses the regulation of RyRs by FKBPs and the possibility that defective modulation of RyR2 by FKBP12.6 could play a role in heart failure, CPVT, and ARVD2. Also discussed are the consequences of FKBP12 depletion to skeletal muscle and the possibility of FKBP12 involvement in certain forms of MH or CCD.

Arrhythmogenic left ventricular dysplasia' and sudden death

A 32-year-old man who died suddenly and unexpectedly was found at autopsy to have prominent fatty infiltration of his left ventricle with fibrous scarring, in the presence of normal coronary arteries. The right ventricle was minimally involved. A diagnosis of ventricular dysplasia largely limited to the left ventricle was made. Subsequent family screening identified a brother with clinical manifestations of ventricular dysplasia. This case provides further evidence for the association of left ventricular dysplasia with sudden death, and demonstrates that left ventricular involvement may also be inheritable. Whether predominantly left ventricular dysplasia is a manifestation of right ventricular dysplasia, or is a separate entity, is yet to be determined.

Arrhythmias in patients with mechanical ventricular dysfunction and myocardial stretch: role of mechano-electric feedback

Patients with dilated cardiomyopathy, ventricular volume or pressure overload, or dysynergistic ventricular contraction and relaxation are prone to develop severe ventricular arrhythmias. In these patients it has been suggested that the abnormal mechanics of contraction can disturb 'mechano-electric feedback', also known as 'contraction-excitation feedback', which is defined as the development of electrophysiological changes during or after changes in mechanical loading. This electrical instability, expressed by significant changes in ventricular repolarization and refractoriness and by the development of afterdepolarizations, has been variously reported in isolated tissues and isolated ventricles as well as in hearts in vivo. Furthermore, it is known that many patients with supraventricular tachycardia but otherwise structurally normal hearts can develop atrial fibrillation and that atrial arrhythmias frequently occur in the setting of acute or chronic increases in atrial size and pressure. It is possible that changes in atrial load directly alter the electrophysiological properties of the atrium by an analogue mechanism of contraction-excitation feedback. This paper reviews the literature concerning mechanoelectric feedback involvement in rhythm disorders, with the aim of investigating, through basic and clinical research, the clinical and therapeutic implications.