Determinants of Ventricular Arrhythmias in Mitral Valve Prolapse

BACKGROUND

Mitral valve prolapse (MVP) may be associated with ventricular arrhythmias (VA) even in the absence of significant valvular regurgitation. Curling, mitral annulus disjunction (MAD) and myocardial fibrosis (late gadolinium enhancement [LGE]) may account for arrhythmogenesis.

OBJECTIVES

This study investigated the determinants of VA in patients with MVP without significant regurgitation.

METHODS

This study included 108 patients with MVP (66 female; median age: 48 years) without valve regurgitation. All patients underwent 12-lead electrocardiography, 12-lead 24-hour electrocardiographic Holter monitoring, exercise stress test, and cardiac magnetic resonance. Patients were divided into 2 groups (arrhythmic and no-arrhythmic MVP), according to the presence of VA with a right bundle branch block pattern.

RESULTS

The 62 patients (57%) with arrhythmic MVP showed: 1) higher MAD (median length: 6.0 vs 3.2 mm; P = 0.017); 2) higher prevalence of curling (79% vs 52%; P = 0.012); and 3) higher prevalence of left ventricular LGE (79% vs 52%; P = 0.012). Mediation analysis showed that curling had both a direct (P = 0.03) and indirect effect mediated by LGE (P = 0.04) on VA, whereas the association between MAD and VA was completely mediated by LGE. Patients with severe VA showed more pronounced morphofunctional alterations, in terms of MAD (7.0 vs 4.6 mm; P = 0.004) and presence and severity of curling (respectively, 91% vs 64%; P = 0.010; and 4 vs 3 mm; P = 0.004), compared to those without severe VA.

CONCLUSIONS

In patients with MVP the occurrence of VA with right bundle branch block morphology is the expression of more severe morphologic, mechanical, and tissue alterations. Curling has both a direct and an indirect effect on VA.

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.

Thinning of compact layer and systolic dysfunction in isolated left ventricular non-compaction: A cardiac magnetic resonance study

BACKGROUND

The Petersen' index reflects an excess of myocardial trabeculation which is not a specific morpho-functional feature of left ventricular non-compaction (LVNC) cardiomyopathy, but a "phenotypic trait" even observed in association with other myocardial diseases and over-loading conditions. The present study was designed to evaluate the relation between a critical thinning of compact layer and the development of systolic dysfunction and LVNC cardiomyopathy.

METHODS

We compared CMR morpho-functional features and measurements of LV wall thickness using a 17 segment model of a cohort of patients fulfilling the Petersen criterion for LVNC with LV systolic dysfunction versus those of a cohort of age- and sex-matched controls with LVNC and preserved LV systolic function. All the study patients had an "isolated" LVNC defined as positive Petersen criterion in the absence of other diseases such as hypertrophic and dilated cardiomyopathy, valvular heart disease, or congenital heart disease and over-loading conditions.

RESULTS

he study population included 33 patients with "isolated" LVNC: 11 consecutive index patients with a reduced LV ejection fraction (LVNCrEF) and 22 controls with a preserved LVEF (LVNCpEF). The compact myocardial layer was thinner in patients with LVNCrEF than in those with LVNCpEF patients, both in mid-ventricular and apical LV segments. On linear regression analysis, there was a linear correlation between median thickness of mid-ventricular free wall segments and left ventricular ejection fraction (r = 0.51, p = 0.005). On the ROC curves analysis, ≥2 segments with a compact myocardial layer <5 mm in the free wall mid-ventricular segments showed the best accuracy for reduced LVEF (100% sensitivity and 60% specificity; AUC 0.81, p < 0.01). The negative predictive value for LV systolic dysfunction of <2 free wall mid ventricular segments <5 mm was 100%. On quantitative analysis, the mass of papillary muscles was lower in patients with LVNCrEF [1.2 (0.8-1.4) versus 1.6 (1.1-1.8) g/mq; p = 0.08].

CONCLUSIONS

A thinned compact layer of mid-ventricular segments of the LV free wall was associated with a reduced systolic function and "isolated" LVNC cardiomyopathy.

Atrial electrofunctional predictors of incident atrial fibrillation in cardiac amyloidosis

BACKGROUND

Atrial fibrillation (AF) is common in patients with cardiac amyloidosis (CA) and is a significant risk factor for heart failure hospitalization and thromboembolic events.

OBJECTIVE

This study was designed to investigate the atrial electrofunctional predictors of incident AF in CA.

METHODS

A multicenter, observational study was conducted in 4 CA referral centers including sinus rhythm patients with light-chain (AL) and transthyretin (ATTR) CA undergoing electrocardiography and cardiac magnetic resonance imaging. The primary end point was new-onset AF occurrence.

RESULTS

Overall, 96 patients (AL-CA, n = 40; ATTR-CA, n = 56) were enrolled. During an 18-month median follow-up (Q1-Q3, 7-29 months), 30 patients (29%) had incident AF. Compared with those without AF, patients with AF were older (79 vs 73 years; P = .001). They more frequently had ATTR (87% vs 45%; P < .001); electrocardiographic interatrial block (IAB), either partial (47% vs 21%; P = .011) or advanced (17% vs 3%; P = .017); and lower left atrial ejection fraction (LAEF; 29% vs 41%; P = .004). Age (hazard ratio [HR], 1.059; 95% CI, 1.002-1.118; P = .042), any type of IAB (HR, 2.211; 95% CI, 1.03-4.75; P = .041), and LAEF (HR, 0.967; 95% CI, 0.936-0.998; P = .044) emerged as independent predictors of incident AF. Patients exhibiting any type of IAB, LAEF <40%, and age >78 years showed a cumulative incidence for AF of 40% at 12 months. This risk was significantly higher than that carried by 1 (8.5%) or none (7.6%) of these 3 risk factors.

CONCLUSION

In patients with CA, older age, IAB on 12-lead electrocardiography, and reduced LAEF on cardiac magnetic resonance imaging are significant and independent predictors of incident AF. A closer screening for AF is advisable in CA patients carrying these features.

Interpolated junctional extrasystoles mimicking complex polymorphic ventricular arrhythmias in a healthy young athlete: a case report

Background

In young competitive athletes, ventricular arrhythmias could be a reason for concern as they may represent the sign of a serious underlying cardiac condition. On the other hand, atrial or conduction system premature beats are usually benign. However, when the properties of the His-Purkinje system lead to conduction aberrancies, there is a risk of misinterpreting benign arrhythmias as potentially at risk ventricular ectopic beats.

Case summary

We described the case of a healthy young athlete with asymptomatic interpolated junctional ectopic beats interpreted as polymorphic ventricular tachycardia during pre-participation screening.

Discussion

Strange and rare electrocardiogram pictures may be observed during sport pre-participation screening. The small atrioventricular (AV) junction is made up of many specialized fibres with different conduction properties. Junctional arrhythmias can have a normal anterograde conduction or can be conducted with aberrancy. Rarely, they can be interpolated and cause PR prolongation or bundle branch block by increasing the refractory period of the AV node and/or the conduction system. When aberrancy occurs, they can be mistaken for 'atypical' ventricular arrhythmias. Prognosis of these events remains uncertain.

Prevalence and clinical significance of low QRS voltages in healthy individuals, athletes and patients with cardiomyopathy: implications for sports preparticipation cardiovascular screening

Low QRS voltages (LQRSV), defined as a QRS amplitude from peak to nadir <0.5 mV in all limb leads, are an emerging diagnostic finding on the electrocardiogram (ECG). In healthy individuals and athletes, LQRSV are rare (2.2-4% of elite athletes, 0.5% of recreational athletes and 0.3% of sedentary individuals). LQRSV athletes commonly show ventricular arrhythmias (VAs) on exercise, and up to 40% of those with LQRSV and VAs have late gadolinium (LGE) on cardiac magnetic resonance (CMR). The prevalence of LQRSV in arrhythmogenic cardiomyopathy (ACM) ranges 17-40%, predicts left ventricular (LV) involvement, and is correlated with more extensive LGE replacement on CMR. In hypertrophic cardiomyopathy (HCM), LQRSV ranges 0.7% to 11%. LQRSV-HCM patients have more segments with LGE, despite relatively smaller LV mass, suggesting a more advanced clinical stage and a worse prognosis. In dilated cardiomyopathy (DCM), LQRSV range 6%-7%, but may be higher (36%) in certain genetic forms of DCM. On a follow-up, LQRSV are independently associated with incident cardiac events, such as sudden death, sustained ventricular arrhythmia, or appropriate internal cardioverter defibrillator discharge. In cardiac amyloid (CA), LQRSV range from 34% to 66% and demonstrate a negative prognostic value, with worse clinical outcomes regardless of underlying biologic, genetic, and clinical variables. In conclusion, LQRSV deserve careful consideration for exclusion of arrhythmogenic substrates in healthy individuals, athletes, and patients. While additional research is needed, it is reasonable that LQRSV should trigger clinical investigation to exclude underlying diseases at risk of life-threatening arrhythmias.

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.

Incidence, risk assessment and prevention of sudden cardiac death in cardiomyopathies

Cardiomyopathies are a significant contributor to cardiovascular morbidity and mortality, mainly due to the development of heart failure and increased risk of sudden cardiac death (SCD). Despite improvement in survival with contemporary treatment, SCD remains an important cause of mortality in cardiomyopathies. It occurs at a rate ranging between 0.15% and 0.7% per year (depending on the cardiomyopathy), which significantly surpasses SCD incidence in the age- and sex-matched general population. The risk of SCD is affected by multiple factors including the aetiology, genetic basis, age, sex, physical exertion, the extent of myocardial disease severity, conduction system abnormalities, and electrical instability, as measured by various metrics. Over the past decades, the knowledge on the mechanisms and risk factors for SCD has substantially improved, allowing for a better-informed risk stratification. However, unresolved issues still challenge the guidance of SCD prevention in patients with cardiomyopathies. In this review, we aim to provide an in-depth discussion of the contemporary concepts pertinent to understanding the burden, risk assessment and prevention of SCD in cardiomyopathies (dilated, non-dilated left ventricular, hypertrophic, arrhythmogenic right ventricular, and restrictive). The review first focuses on SCD incidence in cardiomyopathies and then summarizes established and emerging risk factors for life-threatening arrhythmias/SCD. Finally, it discusses validated approaches to the risk assessment and evidence-based measures for SCD prevention in cardiomyopathies, pointing to the gaps in evidence and areas of uncertainties that merit future clarification.

Efficacy and Safety of Isoprenaline during Unstable Third-Degree Atrioventricular Block

Unstable and symptomatic complete atrioventricular block represents a potentially fatal condition that requires prompt therapy while waiting for definitive pacemaker implantation. Although transcutaneous pacing is included in acute management, it could be a difficult approach due to its painfulness and the occasional failure of mechanical capture. Drug therapy is a feasible choice, and current guidelines encompass the use of atropine, dopamine, or epinephrine. Isoprenaline has never been investigated in this setting, and no specific indication of its use has been provided despite its potentially more favorable pharmacological profile. The study population included a consecutive series of patients who presented to the emergency department because of unstable third-degree atrioventricular block and were treated with either isoprenaline or dopamine infusion while waiting for definitive pacemaker implantation. Asymptomatic patients or those with reversible causes of complete atrioventricular block were excluded. The clinical response to the drug was deemed poor if, despite achieving a full drug dose, patients remained symptomatic and/or with hemodynamic instability, ventricular rate and rhythm did not improve or worsened, including if ventricular arrhythmias or asystolic pauses and/or irrepressible nausea/vomiting occurred. Isoprenaline infusion has proved to be safe and tolerated with no arrhythmia induction or hypotensive issues. Isoprenaline has also proven to be more satisfactory in achieving an effective clinical response in 84% of patients rather than dopamine (31%, p < 0.001), reducing the need for temporary artificial pacing. Our data point out the efficacy and safety of isoprenaline infusion and its greater tolerability over dopamine in the acute management of unstable third-degree AV block while waiting for definitive pacemaker implantation.

Interpretation and management of premature ventricular beats in athletes: An expert opinion document of the Italian Society of Sports Cardiology (SICSPORT)

Premature ventricular beats (PVBs) are recorded in a sizeable proportion of athletes during pre-participation screening, especially if the evaluation includes both resting and exercise ECG. While in the majority of cases no underlying heart disease is present, in others PVBs may be the sign of a condition at risk of sudden cardiac death, including cardiomyopathies, congenital, coronary artery, heart valves and ion channels diseases. In this expert opinion document of the Italian Society of Sports Cardiology, we propose a multiparametric interpretation approach to PVBs in athletes and a stepwise diagnostic algorithm. The clinical work-up should include the assessment of the probable site of origin based on the ECG pattern of the ectopic QRS and of the arrhythmia behavior (including the number of different PVB morphologies, complexity, response to exercise and reproducibility), as well as first-line tests such as echocardiography. Based on this initial evaluation, most athletes can be reassured of the benign nature of PVBs and cleared for competition under periodical follow-up. However, when the clinical suspicion is high, further investigations with non-invasive (e.g. cardiac magnetic resonance, cardiac computed tomography, genetic testing) and, in very selected cases, invasive (e.g. endocardial voltage mapping and endomyocardial biopsy) tests should be carried out to rule out a high-risk condition. Importantly, such advanced tests should be performed in centers with a consolidated experience not only in the technique, but also in evaluation of athletes.

State-of-the-art document on optimal contemporary management of cardiomyopathies

Cardiomyopathies represent significant contributors to cardiovascular morbidity and mortality. Over the past decades, a progress has occurred in characterization of the genetic background and major pathophysiological mechanisms, which has been incorporated into a more nuanced diagnostic approach and risk stratification. Furthermore, medications targeting core disease processes and/or their downstream adverse effects have been introduced for several cardiomyopathies. Combined with standard care and prevention of sudden cardiac death, these novel and emerging targeted therapies offer a possibility of improving the outcomes in several cardiomyopathies. Therefore, the aim of this document is to summarize practical approaches to the treatment of cardiomyopathies, which includes the evidence-based novel therapeutic concepts and established principles of care, tailored to the individual patient aetiology and clinical presentation of the cardiomyopathy. The scope of the document encompasses contemporary treatment of dilated, hypertrophic, restrictive and arrhythmogenic cardiomyopathy. It was based on an expert consensus reached at the Heart Failure Association online Workshop, held on 18 March 2021.

Chest pain in cardiac amyloidosis: occurrence, causes and prognostic significance

BACKGROUND

Chest pain is experienced by patients with cardiac amyloidosis (CA), but a systematic investigation of its frequency, underlying etiologies and clinical significance is lacking.

METHODS

Clinical, echocardiographic, laboratory characteristics, available coronary arteries imaging and endomyocardial biopsy (EMB) findings of 174 patients with CA (n = 104 with transthyretin, ATTR; n = 70 with light chains, AL) were analyzed.

RESULTS

Chest pain was reported in 66 (38%) CA patients. Compared to those without, patients with chest pain had more frequently a history of coronary artery disease (CAD) (27% vs 15%, p = 0.048) and heart failure (HF) symptoms (62% vs 43%, p = 0.015), higher high sensitivity troponin I (hs-cTnI, 101 vs 65 ng/L, p = 0.032) and higher brain natriuretic peptide (597 vs 407 ng/L, p = 0.024). Among CA patients with chest pain undergoing coronary arteries imaging (n = 37), obstructive CAD was detected in 14 (38%), 13 of whom with ATTR-CA. Of these 37 patients, EMB was available in 10 and vascular/perivascular amyloid deposition was detected in 4/5 (80%) of AL-CA patients and 1/5 ATTR-CA. Among patients with suspected acute coronary syndrome (n = 22), obstructive CAD was detected in 9/17 (53%) ATTR-CA and 0/5 AL-CA; hs-cTnI levels were similar between those with and without obstructive CAD. During a follow-up of 17 (8-34) months, chest pain was a significant predictor of HF hospitalization (HR1.86, 95% CI 1.02-3.39, p = 0.042), even after adjustment for CA subtype and CAD.

CONCLUSION

Chest pain is a common symptom in patients with CA, reflects a more advanced cardiac impairment and predicts future HF hospitalization. The etiology of chest pain seems to differ, with obstructive CAD more frequent in ATTR-CA whilst amyloid vascular/perivascular involvement more common in AL-CA.

Is Congenital Muscular Mitral-Aortic Discontinuity Another Feature of Obstructive Hypertrophic Cardiomyopathy? A Pathology Validation Study

Hypertrophic cardiomyopathy (HCM) is an inherited myocardial disease at risk of sudden cardiac death and heart failure, even requiring heart transplantation. A "muscular mitral-aortic discontinuity" has been reported during surgery in the obstructive form. We aimed to validate these findings through pathological analysis of HCM heart specimens from the cardiovascular pathology tissue registry. Hearts with septal asymmetric HCM from sudden cardiac death, other causes of death, or heart transplantation were included. Sex-matched and age-matched patients without HCM served as controls. Gross and histologic analysis of the mitral valve (MV) apparatus and the mitral-aortic continuity were performed. Thirty HCM hearts (median age, 29.5 years; 15 men) and 30 controls (median age, 30.5 years; 15 men) were studied. In HCM hearts, a septal bulging was present in 80%, an endocardial fibrous plaque in 63%, a thickening of the anterior MV leaflet in 56.7%, and an anomalous insertion of papillary muscle in 10%. All cases but 1 (97%) revealed a myocardial layer overlapping the mitral-aortic fibrous continuity on the posterior side, corresponding to the left atrial myocardium. A negative correlation between the length of this myocardial layer and the age and the anterior MV leaflet length was found. The length did not differ between HCM and controls. Pathologic study of obstructive HCM hearts does not confirm the existence of a "muscular mitral-aortic discontinuity". An extension of left atrial myocardium, overlapping posteriorly the intervalvular fibrosa, is rather visible, and its length decreases with age, possibly as a consequence of left atrial remodeling. Our study highlights the fundamental role of thorough gross examination and the value of organ retention for further analysis in order to validate new surgical and imaging findings.

Evolving spectrum of arrhythmogenic cardiomyopathy: Implications for Sports Cardiology

Arrhythmogenic cardiomyopathy (ACM) is a genetic heart muscle disease, structurally characterized by progressive fibro-fatty replacement of the normal myocardium and clinically by ventricular arrhythmias (VAs). Predominantly thanks to the use of cardiac magnetic resonance, we have learnt that the spectrum of the disease encompasses not only the classical right ventricular phenotype, but also biventricular and left dominant variants. Sport activity contributes to the phenotypic expression and progression of ACM and may trigger life-threatening VAs and sudden cardiac death (SCD). We conducted a review of the literature about ACM and its implications in Sport Cardiology and summarized the main findings in this topic. Early identification of affected athletes through preparticipation screening (PPS) is fundamental but, while classical right-ventricular or biventricular phenotypes are usually suspected because of electrocardiogram (ECG) and echocardiographic abnormalities, variants with predominant left ventricular involvement are often characterized by normal ECG and unremarkable echocardiography. Usually the only manifestations of such variants are exercise-induced VAs and for this reason exercise testing may empower the diagnostic yield of the PPS. Patients with ACM are not eligible to competitive sports activity, but low-to-moderate intensity physical activity under medical supervision is possible in most cases.

Low QRS voltages and left ventricular hypertrophy: a risky association

AIMS

Low QRS voltages (LQRSV) are an unexpected finding in left ventricular hypertrophy, i.e. hypertrophic cardiomyopathy (HCM) or athlete's heart.

METHODS AND RESULTS

Prevalence and clinical correlates of LQRSV were investigated in 197 consecutive HCM patients, aged 58 ± 13 years and comparatively in 771 Olympic athletes, aged 23 ± 4. Clinical characterization included family/personal history, symptoms, New York Heart Association (NYHA) functional class, electrocardiographic pattern, ventricular arrhythmias, and cardiac magnetic resonance (CMR). Twenty-two (11%) of HCM and 18 (2.3%) of athletes presented LQRSV. At initial evaluation, in HCM, LQRSV showed no differences vs. non-LQRSV for functional class (90% vs. 91%, in Classes I and II; P = 0.983), symptoms (27% vs. 18%; P = 0.478), and ventricular arrhythmias (40% vs. 39%; P = 857) but showed larger extent of late gadolinium enhancement (LGE) at CMR (4.1 ± 1.5 vs. 1.5 ± 0.7 affected segments; P < 0.001). In athletes, LQRSV was associated with larger prevalence of inverted T-waves (22% vs. 9%; P < 0.001) and ventricular arrhythmias (28% vs. 8%; P = 0.005). In one LQRSV athlete, arrhythmogenic cardiomyopathy was identified. Over 4.5 ± 2.6-year follow-up, presence of LQRSV in HCM was associated with larger incidence of functional deterioration (31% vs. 14%; P = 0.038), stroke (22% vs. 6%; P = 0.008), and implantable cardioverter defibrillator (ICD) implant (27% vs. 10%; P = 0.015). No clinical events occurred in LQRSV athletes without initial evidence of cardiac disease.

CONCLUSION

LQRSV are relatively common (11%) in HCM and have clinical relevance, being predictive over a medium term for a worsening functional class, incidence of stroke, and ICD implant. Instead, LQRSV are rare (2.3%) in athletes but may occasionally be a marker that raises suspicion for underlying cardiac disease at risk.

Ventricular arrhythmias recorded on 12-lead ambulatory electrocardiogram monitoring in healthy volunteer athletes and controls: what is common and what is not

AIMS

Premature ventricular beats (PVBs) in athletes are often benign, but sometimes they may be a sign of an underlying disease. We evaluated the prevalence, burden, and morphology of PVBs in healthy voluntary athletes and controls with the main purpose of defining if certain PVB patterns are 'common' and 'training related' and, as such, are more likely benign.

METHODS AND RESULTS

We studied 433 healthy competitive athletes [median age 27 (18-43) years, 74% males] and 261 age- and sex-matched sedentary subjects who volunteered to undergo 12-lead 24 h ambulatory electrocardiogram (ECG) monitoring (24H ECG), with a training session in athletes. Ventricular arrhythmias (VAs) were evaluated in terms of their number, complexity [i.e. couplet, triplet, or non-sustained ventricular tachycardia (NSVT)], exercise inducibility, and morphology. Eighty-six percent of athletes and controls exhibited a total of ≤10 PVBs/24 h, and >90% did not show any couplets, triplets, or runs of NSVT > 3 beats. An higher number of PVBs correlated with increasing age (P < 0.01) but not with sex and level of training. The most frequent morphologies among the 36 athletes with >50 PVBs were the infundibular (44%) and fascicular (22%) ones. In a comparison between athletes and sedentary individuals, and male and female athletes, no statistically significant differences were found in PVBs morphologies.

CONCLUSION

The prevalence and complexity of VAs at 24H ECG did not differ between athletes and sedentary controls and were not related to the type and amount of sport or sex. Age was the only variable associated with an increased PVB burden. Thus, no PVB pattern in the athlete can be considered 'common' or 'training related'.

Cardiac Magnetic Resonance-Detected Acute Myocardial Edema as Predictor of Favourable Prognosis: A Comprehensive Review

Acute myocardial edema (AME) is increased water content in the myocardium and represents the first and transient pathophysiological response to an acute myocardial injury. In-vivo and non-invasive evaluation is feasible with cardiac magnetic resonance (CMR), which is a powerful imaging technique capable of tissue characterization. In the clinical setting, early demonstration of AME has a recognized diagnostic value for acute coronary syndromes and acute myocarditis, although its prognostic value is not well established. This article provides a comprehensive narrative review on the clinical meaning of AME in heart diseases. In particular, the available evidence of a possible favourable prognostic value in several clinical scenarios is addressed.

Electrocardiographic characteristics of right-bundle-branch-block premature ventricular complexes predicting absence of left ventricular scar in athletes with apparently structural normal heart

AIMS

Left ventricular scar is an arrhythmic substrate that may be missed by echocardiography and diagnosed only by cardiac magnetic resonance (CMR), which is a time-consuming and expensive imaging modality. Premature ventricular complexes (PVCs) with a right-bundle-branch-block (RBBB) pattern are independent predictors of late gadolinium enhancement (LGE) but their positive predictive value is low. We studied which electrocardiographic features of PVCs with an RBBB pattern are associated with a higher probability of the absence of an underlying LGE.

METHODS

The study included 121 athletes (36 ± 16 years; 48.8% men) with monomorphic PVCs with an RBBB configuration and normal standard clinical investigations who underwent CMR. LGE was identified in 35 patients (29%), predominantly in those with PVCs with a superior/intermediate axis (SA-IntA) compared to inferior axis (IA) (38% vs. 10%, P = 0.002). Among patients with SA-IntA morphology, the contemporary presence of qR pattern in lead aVR and V1 was exclusively found in patients without LGE at CMR (51.0% vs. 0%, P < 0.0001). Among patients with IA, the absence of LGE correlated to a narrow ectopic QRS (145 ± 16 vs. 184 ± 27 msec, P < 0.001).

CONCLUSIONS

Among athletes with apparently idiopathic PVCs with a RBBB configuration, the presence of a concealed LGE at CMR was documented in 29% of cases, mostly in those with a SA-IntA. In our experience, the contemporary presence of qR pattern in lead aVR and V1 in PVCs with RBBB/SA-IntA morphology or, on the other hand, a relatively narrow QRS in PVCs with an IA, predicted absence of LGE.

Scarring/arrhythmogenic cardiomyopathy

The designation of 'arrhythmogenic cardiomyopathy' reflects the evolving concept of a heart muscle disease affecting not only the right ventricle (ARVC) but also the left ventricle (LV), with phenotypic variants characterized by a biventricular (BIV) or predominant LV involvement (ALVC). Herein, we use the term 'scarring/arrhythmogenic cardiomyopathy (S/ACM)' to emphasize that the disease phenotype is distinctively characterized by loss of ventricular myocardium due to myocyte death with subsequent fibrous or fibro-fatty scar tissue replacement. The myocardial scarring predisposes to potentially lethal ventricular arrhythmias and underlies the impairment of systolic ventricular function. S/ACM is an 'umbrella term' which includes a variety of conditions, either genetic or acquired (mostly post-inflammatory), sharing the typical 'scarring' phenotypic features of the disease. Differential diagnoses include 'non-scarring' heart diseases leading to either RV dilatation from left-to-right shunt or LV dilatation/dysfunction from a dilated cardiomyopathy. The development of 2020 upgraded criteria ('Padua criteria') for diagnosis of S/ACM reflected the evolving clinical experience with the expanding spectrum of S/ACM phenotypes and the advances in cardiac magnetic resonance (CMR) imaging. The Padua criteria aimed to improve the diagnosis of S/ACM by incorporation of CMR myocardial tissue characterization findings. Risk stratification of S/ACM patients is mostly based on arrhythmic burden and ventricular dysfunction severity, although other ECG or imaging parameters may have a role. Medical therapy is crucial for treatment of ventricular arrhythmias and heart failure. Implantable cardioverter defibrillator (ICD) is the only proven life-saving treatment, despite its significant morbidity because of device-related complications and inappropriate shocks. Selection of patients who can benefit the most from ICD therapy is one of the most challenging issues in clinical practice.

Third-generation subcutaneous implantable cardioverter defibrillator and intermuscular two-incision implantation technique in patients with Arrhythmogenic cardiomyopathy: 3-year follow-up

BACKGROUND

Long-term data on the potential advantages of combining the third-generation subcutaneous implantable cardioverter defibrillator (S-ICD) with modern software upgrade including the "SMART Pass", modern programming strategies and the intermuscular (IM) two-incision implantation technique in arrhythmogenic cardiomyopathy (ACM) with different phenotypic variants are lacking. In this study we evaluated the long-term outcome of patients with ACM who underwent third-generation S-ICD (Emblem, Boston Scientific) and IM two-incision technique.

METHODS

The study population included 23 consecutive patients [70% male, median age 31 (24-46) years] diagnosed with ACM with different phenotypic variants who received third-generation S-ICD implantation with the IM two-incision technique.

RESULTS

During a median follow-up of 45.5 months [16-65], 4 patients (17.4%) received a at least one inappropriate shock (IS), with median annual event rate of 4.5%. Extra-cardiac oversensing (myopotential) during effort represented the only cause of IS. No IS due to T-wave oversensing (TWOS) were recorded. Only one patient (4.3%) experienced device-related complication consisting of premature cell battery depletion requiring device replacement. No device explantation because of need for anti-tachycardia pacing or ineffective therapy occurred. There was no significant difference between patients who did and did not experienced IS with regard to baseline clinical, ECG and technical characteristics. Five patients (21.7%) received appropriate shock on ventricular arrythmias.

CONCLUSIONS

According to our finding, although the third-generation S-ICD implanted with the IM two-incision technique appears to be associated with a low risk of complications and IS due to cardiac oversensing, the risk of IS due to myopotential mainly during effort should be considered.

Value of screening for the risk of sudden cardiac death in young competitive athletes

AIMS

This study aimed to report the long-term findings of the Italian programme of cardiovascular preparticipation screening (PPS) in young, competitive athletes.

METHODS AND RESULTS

The study assessed the diagnostic yield for diseases at risk of sudden cardiac death (SCD), the costs of serial evaluations, and the long-term outcomes of PPS in a large population of Italian children (age range, 7-18 years). The PPS was repeated annually and included medical history, physical examination, resting electrocardiogram, and stress testing; additional tests were reserved for athletes with abnormal findings. Over an 11-year study period, 22 324 consecutive children [62% males; mean age, 12 (interquartile range, 10-14) years at first screening] underwent a total of 65 397 annual evaluations (median 2.9/child). Cardiovascular diseases at risk of SCD were identified in 69 children (0.3%) and included congenital heart diseases (n = 17), channelopathies (n = 14), cardiomyopathies (n = 15), non-ischaemic left ventricular scar with ventricular arrhythmias (n = 18), and others (n = 5). At-risk cardiovascular diseases were identified over the entire age range and more frequently in children ≥12 years old (n = 63, 91%) and on repeat evaluation (n = 44, 64%). The estimated cost per diagnosis was 73 312€. During a follow-up of 7.5 ± 3.7 years, one child with normal PPS findings experienced an episode of resuscitated cardiac arrest during sports activity (event rate of 0.6/100.000 athletes/year).

CONCLUSION

The PPS programme led to the identification of cardiovascular diseases at risk of SCD over the whole study age range of children and more often on repeat evaluations. Among screened children, the incidence of sport-related cardiac arrest during long-term follow-up was low.

Electrocardiographic features and rhythm disorders in cardiac amyloidosis

Cardiac amyloidosis (CA) is an infiltrative cardiomyopathy caused by extracellular deposition of amyloid fibrils, mainly derived from transthyretin, either wild-type or hereditary variants, or immunoglobulin light chains misfolding. It is characterized by an increased left ventricular (LV) mass and diastolic dysfunction, which can lead to heart failure with preserved ejection fraction and/or conduction disturbances. The diagnosis is based on invasive pathology demonstration of amyloid deposits, or non-invasive criteria using advanced cardiovascular imaging techniques. Nevertheless, 12-lead electrocardiogram (ECG) remains of crucial importance in the assessment of patients with CA, since they can manifest peculiar features such as low QRS voltages, in discordance with the LV hypertrophy, but also pseudo-infarction patterns, sinus node dysfunction, atrioventricular blocks, premature supraventricular and ventricular beats, which support the presence of a myocardial disease. Great awareness of these common ECG characteristics of CA is needed to increase diagnostic performance and improve patient's outcome. In the present review, we discuss the current role of the ECG in the diagnosis and management of CA, focusing on the most common ECG abnormalities and rhythm disorders.

Reproducibility of ventricular arrhythmias at exercise testing for prediction of non-ischaemic left ventricular scar in athletes

AIMS

The non-ischaemic left ventricular scar (NILVS) is an emerging substrate of ventricular arrhythmias (VA) in the athlete. We tested the diagnostic value of VA reproducibility at repeated exercise testing (ET).

METHODS AND RESULTS

We included consecutive athletes who underwent cardiac magnetic resonance (CMR) for evaluation of VA and two consecutive ET off-therapy within 12 months. Those with a positive family history of premature sudden death/cardiomyopathy, syncope/pre-syncope, ECG or echocardiography abnormalities, or low-risk VA (exercise-suppressed infundibular or fascicular VA) were excluded. The NILVS was defined as subepicardial/midmyocardial stria of late gadolinium enhancement involving >5% of the LV mass. Reproducibility was defined as the occurrence of VA with the same pattern and behaviour during repeated ET. Of 325 athletes who underwent CMR for evaluation of VA, 75 were included, and 30 showed NILVS involving three [2-4] LV segments. At first ET, athletes with NILVS showed a higher prevalence of exercise-induced VA (93% vs. 53%, P < 0.001), while other VA characteristics did not differ between groups. At repeated ET, reproducibility was observed in 97% of athletes with vs. 13% without NILVS (P < 0.001). The remaining 87% of athletes with normal CMR either did not show any VA at repeated ET (59%) or showed arrhythmias with different patterns, mostly infundibular. Reproducibility yielded a positive predictive value for NILVS of 83% and a negative predictive value of 98%.

CONCLUSION

VA reproducibility at repeated ET predicted an underlying NILVS in athletes with VA and otherwise normal clinical work-up. This finding may improve risk stratification and appropriate CMR referral of athletes with apparently idiopathic VA.

Intermuscular two-incision technique for implantation of the subcutaneous implantable cardioverter defibrillator: a 3-year follow-up

PURPOSE

The aim of the present study was to evaluate the outcome of patients underwent subcutaneous implantable cardioverter defibrillator (S-ICD) implantation with the intermuscular (IM) two-incision technique during 3-year follow-up.

METHODS

the study population consisted of 105 consecutive patients (79 male; median 50 [13-77] years) underwent S-ICD implantation with the IM two-incision technique. The composite primary end point of the study consisted of device-related complications and inappropriate shocks (IAS). Secondary end points included the individual components of the primary end point, death from any cause, appropriate therapy, major adverse cardiac events, hospitalization for heart failure, and heart transplantation.

RESULTS

According to the PRAETORIAN score, the risk of conversion failure was classified as low in 99 patients (94.3%), intermediate in 6 (5.7%).Ventricular fibrillation was successfully converted at ≤65 J in 97.4% of patients. During a median follow-up of 39 (16-53) months, 10 patients (9.5%) experienced device-related complications, and 9 (8.5%) patients reported IAS. Lead-associated complications were the most common (5 patients, 4.7%), including 2 cases of lead failure (1.9%). Pocket complications were reported in 2 patients (1.9%). Extra-cardiac oversensing (3.8%) represented the leading cause of IAS. No T-wave oversensing episodes were recorded. Twelve patients (11.4%) experienced appropriate shocks. Eight patients (7.6%) died during follow-up. IAS or device-related complications did not impact on mortality.

CONCLUSIONS

The overall device-related complications and IAS rates over 3 years of follow-up were 9.5% and 8.5%, respectively. According to our findings, the IM two-incision technique allows for optimal positioning of the device achieving a low PRAETORIAN score with a high conversion rate. IM two-incision technique allows low incidence of pocket complications, shifting the type of complications towards lead-related complications, which represent the most common complications. The IM two-incision technique would not seem to impact the occurrence of IAS. Management of complications are safe without impact on the outcome.

216 ARRHYTHMOGENIC CARDIOMYOPATHY: IS THERE EVIDENCE OF AN INFLAMMATORY MYOCARDIAL DISEASE?

Background and aim

Arrhythmogenic cardiomyopathy (ACM) is a heredo-familiar primary heart muscle disease, mainly due to mutations of desmosomal genes and characterized by progressive myocardial atrophy with fibro-fatty replacement, causing electrical instability at risk of sudden cardiac death (SCD). Since the first anatomopathological descriptions, the hypothesis that myocardial inflammation could have an important role in the onset and evolution of ACM has been advanced. With this work we aim to describe the prevalence of inflammatory cells in ACM and their characterization through histological and immunohistochemical (IHC) analysis in endomyocardial biopsy (EMB) and heart specimens coming from either SCD or heart transplantation (HTx).

Material and methods

We analysed EMB and whole heart specimens (from juvenile SCD registry – below 40 years of age at the time of death – and HTx) with a diagnosis of ACM, focusing on the presence of inflammatory infiltrates. For the whole hearts, in a subgroup of cases the inflammatory infiltrate was evaluated on 9 myocardial sections by applying a semi-quantitative score according to the number of sections involved (0 = none; 1 = 1 section involved; 2 = 2-5 sections; 3 = &gt;5 sections) and an IHC panel for myocarditis on 1 right ventricular and 1 left ventricular section (CD45, CD3, CD8, CD4, CD68, CD20, CD138 and vimentin- as a control for fibroblast).

Results

Among the 63 analysed EMB (41 M, mean age 45 years, range 18-71 years), 26 cases (41%) showed foci of inflammation with CD3+ &gt; 7/mm2. In all cases viral genome (DNA and RNA virus) was absent. A total of 106 heart specimens with a diagnosis of ACM were enrolled, including 73 juvenile SCD (49 M, mean age 26 years) and 33 HTx (18 M, mean age 45 years). Inflammation was reported in 95% of SCD an d 67% of HTx. The inflammatory infiltrate was focal or multifocal in all, except one case of juvenile SCD with diffuse myocarditis in the postero-lateral wall of the left ventricle. In the 24 reviewed cases, the inflammation was focal with a mean inflammatory score of 1.75 ±0.9 in the HTx group and 1.5±0.9 in the SD group (p = NS). By IHC we showed that: a) there is no significant difference in the inflammatory score between SD and HTx; b) the inflammation is mostly near-scarring (13 cases); c) inflammatory cells consist prevalently of cytotoxic T lymphocytes CD3+CD8+ (with CD4+&lt;CD8+ both in SD and HTx, p &lt; 0.05).

Conclusions

Our pathological data confirm that ACM is an inflammatory cardiomyopathy with a higher prevalence of inflammation in SCD cases. The inflammatory infiltrate is mainly composed of cytotoxic T lymphocytes with a variable presence of macrophages. These data, combined with the recent experimental studies demonstrating the role of immune mediators in the evolution of the disease, support the potential application of immunosuppressive therapy in ACM.

433 A PRO-ARRHYTHMIC DOUBLE HIT

A 42-year-old man went to the emergency room complaining about dyspnea and palpitations. He reported an episode of atrial fibrillation (AF) with symptoms of dizziness 8 years before. He had a family history of ischemic cardiopathy, his father has suffered from AF since a young age.Acute course: The ECG revealed AF at high ventricular frequency. The echocardiography demonstrated mild reduction of the left ventricular function (EF 45%) with diffuse hypokinesis, and mitral valve prolapse (MVP) with mild mitral regurgitation. The blood tests showed a troponin peak of 750 ng/L (n.v. 0–34 ng/L). The suspect was acute coronary syndrome. Thus, he was treated with dual antiplatet therapy and low doses of beta-blockers, and he underwent coronarography, which demonstrated no significant lesions. So, after a transesophageal echocardiography that excluded thrombosis, and a loading dose of amiodarone, a successful electrical cardioversion was performed. The discharge diagnosis was AF with mild left ventricular disfunction. Three months later: He came back to the emergency room because of suffering some days of progressive epigastric and retrosternal pain radiating to the shoulders. The ECG and the echocardiography were unchanged, the troponin-I values were 79 ng/L-74 ng/L. Therefore, he underwent cardiac magnetic resonance (CMR), which showed normal biventricular dimensions and function (LVEF 64%, LVEDV 80 ml/mq), MVP with mitral annular disjunction (MAD) and curling of the infero-lateral basal wall (Figure A). The native T1, T2 and ECV values were increased, and there was a wide left ventricular subepicardial late gadolinium enhancement (LGE). The conclusion was MVP and active myocarditis. Moreover, he underwent endomyocardial biopsy that revealed focal lymphocytic infiltration, PCRs for common cardiotropic viruses or bacteria were negative. Six months later: The basal ECG was characterized by low QRS voltages in limb leads (Figure B). The CMR revealed a wide left ventricular non-ischemic fibrosis with a ring-like pattern (Figure C). The 24-hours Holter ECG showed premature ventricular beats with a right bundle branch block/superior and inferior axis morphology (Figure D), in keeping with MVP. The next step was the genetic testing that resulted positive for a Filamin-C (FLNC) mutation associated with cardiomyopathy. The final diagnosis was “Hot-phase of Left Ventricular Arrhythmogenic Cardiomyopathy (ACM), MVP and paroxysmal AF”. Discussion: The ACM is a rare hereditary heart muscle disease, and the “hot phase” represents its uncommon clinical presentation. Mutations in FLNC gene could be involved in the pathogenesis of ACM. Moreover, there are few cases in literature about the correlation between FLNC mutations and MVP. FLNC mutation may be a cross-sectional substrate for both these pro-arrhythmic conditions.

291 BIVENTRICULAR ARRHYTMOGENIC CARDIOMYOPATHY: COULD ELECTROCARDIOGRAPHY SEE BEYOND THE CARDIAC MRI?

We described the case of a 34 year-old young athlete who was referred to our Department because of palpitations and fatigue, arising after hard effort but also present at rest. Family history was unremarkable for sudden cardiac death or cardiomyopathies. Electrocardiography (ECG) evidenced multifocal premature ventricular contractions (PVCs): left bundle branch block (LBBB) morphology and superior/inferior axis; right bundle branch block (RBBB) morphology and undetermined axis. Cardiac MRI showed extensive mid wall and subepicardial late gadolinium enhancement in the postero-lateral left ventricular wall. We decided to perform electroanatomic mapping (EAM) because we didn't explain the origin of the PVCs with LBBB configuration. During EAM we found an area extending from the right ventricular outflow tract to the subtricuspidal lateral inferior wall which it had not described by cardiac MRI. In the low voltage areas, the electrograms inscribed by the catheter's electrodes was fractionated with different waveforms, a finding that corresponds to a deficiency of healthy myocardial tissue. We performed an endomyocardial biopsy in the interventricular septum close to the ventricular out flow tract. The histological examination of the biopsy samples showed fibro-fatty replacement. Therefore genetic testing revealed a pathogenic desmoplakin mutation. According to “Padua Criteria”, we made a diagnosis of biventricular arrhythmogenic cardiomyopathy. We finally implanted a transvenous cardioverter defibrillator.

Conclusion

Diagnosis of arrhythmogenic cardiomyopathy (ACM) is complex and requires the combination of multiple clinical, histological and genetic parameters. This clinical case demonstrated that ECG represent an essential tool in diagnostic work-up of the disease, and electroanatomic mapping is useful in selected cases for the documentation of the diagnosis of arrhytmogenic cardiomyopathy.

197 INTERMUSCULAR TWO-INCISION TECHNIQUE FOR IMPLANTATION OF THE SUBCUTANEOUS IMPLANTABLE DEFIBRILLATOR: 3-YEAR FOLLOW-UP

Background

The aim of the present study was to evaluate the outcome of patients underwent subcutaneous implantable cardioverter defibrillator (S-ICD) implantation with the intermuscular (IM) two-incision technique during 3-year follow-up.

Methods

the study population consisted of 105 consecutive patients (79 male; median 50 [13-77] years) underwent S-ICD implantation with the IM two-incision technique.

Results

according to the PRAETORIAN score, the risk of conversion failure was classified as low in 99 patients (94.3%), intermediate in 6 (5.7%). Ventricular fibrillation was successfully converted at ≤65 J in 97.4% of patients. During a median follow-up of 39 (16-53) months, 10 patients (9.5%) experienced device-related complications and 9 (8.5%) patients reported shocks (IAS). Lead-associated complications were the most common (3.8%), including 2 cases of lead failure (1.9%). Pocket complications were reported in 2 patients (1.9%). Extra-cardiac oversensing (3.8%) represented the leading cause of IAS. No T-wave oversensing episodes were recorded. Twelve patients (11.4%) experienced appropriate shocks. Eight patients (7.6%) died during follow-up. IAS or device-related complications did not impact on mortality (HR 0.5;95%CI 0-4.3;P=0.5; HR 0.7;95%CI 0.1-6.0;P=0.8, respectively).

Conclusions

according to our findings, the IM two-incision technique allows for optimal positioning of the device achieving a low PRAETORIAN score with a high conversion rate. IM two-incision technique allows low incidence of pocket complications, shifting the type of complications towards lead-related complications, which represent the most common complications. The IM two- incision technique would not seem to impact the occurrence of IAS. Management of complications are safe without impact on the outcome.

Pregnancy in Women with Arrhythmogenic Left Ventricular Cardiomyopathy

BACKGROUND

In the last few years, a phenotypic variant of arrhythmogenic cardiomyopathy (ACM) labeled arrhythmogenic left ventricular cardiomyopathy (ALVC) has been defined and researched. This type of cardiomyopathy is characterized by a predominant left ventricular (LV) involvement with no or minor right ventricular (RV) abnormalities. Data on the specific risk and management of pregnancy in women affected by ALVC are, thus far, not available. We have sought to characterize pregnancy course and outcomes in women affected by ALVC through the evaluation of a series of childbearing patients.

METHODS

A series of consecutive female ALVC patients were analyzed in a cross-sectional, retrospective study. Study protocol included 12-lead ECG assessments, 24-h Holter ECG evaluations, 2D-echocardiogram tests, cardiac magnetic resonance assessments, and genetic analysis. Furthermore, the long-term disease course of childbearing patients was compared with a group of nulliparous ALVC women.

RESULTS

A total of 35 patients (mean age 45 ± 9 years, 51% probands) were analyzed. Sixteen women (46%) reported a pregnancy, for a total of 27 singleton viable pregnancies (mean age at first childbirth 30 ± 9 years). Before pregnancy, all patients were in the NYHA class I and none of the patients reported a previous heart failure (HF) episode. No significant differences were found between childbearing and nulliparous women regarding ECG features, LV dimensions, function, and extent of late enhancement. Overall, 7 patients (20%, 4 belonging to the childbearing group) experienced a sustained ventricular tachycardia and 2 (6%)-one for each group-showed heart failure (HF) episodes. The analysis of arrhythmia-free survival patients did not show significant differences between childbearing and nulliparous women.

CONCLUSIONS

In a cohort of ALVC patients without previous episodes of HF, pregnancy was well tolerated, with no significant influence on disease progression and degree of electrical instability. Further studies on a larger cohort of women with different degrees of disease extent and genetic background are needed in order to achieve a more comprehensive knowledge regarding the outcome of pregnancy in ALVC patients.

May Strenuous Endurance Sports Activity Damage the Cardiovascular System of Healthy Athletes? A Narrative Review

The positive effects of physical activity are countless, not only on the cardiovascular system but on health in general. However, some studies suggest a U-shape relationship between exercise volume and effects on the cardiovascular system. On the basis of this perspective, moderate-dose exercise would be beneficial compared to a sedentary lifestyle, while very high-dose physical activity would paradoxically be detrimental. We reviewed the available evidence on the potential adverse effects of very intense, prolonged exercise on the cardiovascular system, both acute and chronic, in healthy athletes without pre-existing cardiovascular conditions. We found that endurance sports activities may cause reversible electrocardiographic changes, ventricular dysfunction, and troponin elevation with complete recovery within a few days. The theory that repeated bouts of acute stress on the heart may lead to chronic myocardial damage remains to be demonstrated. However, male veteran athletes with a long sports career show an increased prevalence of cardiovascular abnormalities such as electrical conduction delay, atrial fibrillation, myocardial fibrosis, and coronary calcifications compared to non-athletes. It must be underlined that the cause-effect relationship between such abnormalities and the exercise and, most importantly, the prognostic relevance of such findings remains to be established.

Reproducibility of exercise-induced premature ventricular beats predicts concealed non-ischemic left ventricular scar on cardiac magnetic resonance in athletes

Background

Non-ischemic left ventricular scar (NLVS) at cardiac magnetic resonance (CMR) is a common substrate of apparently idiopathic premature ventricular beats (PVBs) in athletes. PVBs morphology, complexity and exercise-behavior are known predictors of NLVS. It remains to be established whether reproducibility of PVBs at exercise testing correlates with CMR findings.

Purpose

We aimed to evaluate the possible role of PVBs reproducibility at repeated exercise testing in predicting the presence of an underlying NLVS in athletes who underwent CMR for apparently idiopathic ventricular arrhythmias.

Methods

We included all consecutive competitive athletes referred to our center for the evidence of PVBs during pre-participation screening, who underwent two maximal exercise testings within one month (the first at the time of pre-participation screening, the second at the time of outpatient evaluation at our sports cardiology clinic). Exclusion criteria were known heart disease, family history of cardiomyopathy or channelopathy, abnormal ECG and echocardiography. We also excluded athletes with “common/usually benign” PVBs (non-exercise-induced infundibular or fascicular PVBs) as well as those on ongoing antiarrhythmic therapy. Reproducibility was defined as the presence of PVBs with same morphology and exercise-behavior in two subsequent tests. LGE on CMR was quantified with 5-SD method, using a threshold of 5% to define the presence of pathological LVNS.

Results

A total of 64 apparently healthy competitive athletes (86% males, mean age of 33±14 years old) were included. On CMR, NLVS was identified in 26 (41%). PVBs reproducibility criteria was met in 32 athletes (50%). A statistically significant difference in PVBs reproducibility was found between patients with and without LVNS [26 (100%) versus 6 (16%), p&lt;0,001], irrespective of other factors such as age, sex, biventricular volumes and function (Figure 1). Among the 26 patients with NLVS, 18 (69%) showed PVBs with right-bundle branch block (R-BBB) with superior axis configuration, alone or associated with other morphologies. These arrhythmic patterns were confirmed by a second test in all cases. Among the 38 patients with normal CMR, the first exercise test showed R-BBB/superior axis PVBs, alone or associated with other morphologies, in 22 (57%); the second test confirmed such pattern in only 6 (16%), showing instead different morphologies in 8 (21%) and no PVBs in 24 (63%). Figure 2 represents an example of two cases included in the study.

Conclusion

In apparently healthy athletes who underwent CMR for “uncommon” PVBs, the presence of underlying LVNS was predicted by ventricular arrhythmia reproducibility. Specifically, reproducibility of PVBs with RBBB/superior axis morphology was highly predictive of a positive CMR. This finding may be very relevant for appropriate prescription of CMR in athletes with apparently idiopathic ventricular arrhythmias.

Funding Acknowledgement

Type of funding sources: None.