Implantable cardioverter defibrillator use in arrhythmogenic right ventricular cardiomyopathy in North America and Europe

BACKGROUND AND AIMS

Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to identify cross-continental differences in utilization of primary prevention ICDs and survival free from sustained ventricular arrhythmia (VA) in ARVC.

METHODS

This was a retrospective analysis of ARVC patients without prior VA enrolled in clinical registries from 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe and were further stratified by baseline predicted VA risk into low- (<10%/5 years), intermediate- (10%-25%/5 years), and high-risk (>25%/5 years) groups. Differences in ICD implantation and survival free from sustained VA events (including appropriate ICD therapy) were assessed.

RESULTS

One thousand ninety-eight patients were followed for a median of 5.1 years; 554 (50.5%) received a primary prevention ICD, and 286 (26.0%) experienced a first VA event. After adjusting for baseline risk factors, North Americans were more than three times as likely to receive ICDs {hazard ratio (HR) 3.1 [95% confidence interval (CI) 2.5, 3.8]} but had only mildly increased risk for incident sustained VA [HR 1.4 (95% CI 1.1, 1.8)]. North Americans without ICDs were at higher risk for incident sustained VA [HR 2.1 (95% CI 1.3, 3.4)] than Europeans.

CONCLUSIONS

North American ARVC patients were substantially more likely than Europeans to receive primary prevention ICDs across all arrhythmic risk strata. A lower rate of ICD implantation in Europe was not associated with a higher rate of VA events in those without ICDs.

Epidemiology of arrhythmogenic ventricular cardiomyopathy in China

BACKGROUND

Arrhythmogenic ventricular cardiomyopathy (AVC) is a common cause of ventricular arrhythmias and mortality, but limited data are available from large Asian cohorts. Our aim was to explore the current status of AVC and second, we examined the prevalence of ventricular tachycardia (VT), heart failure (HF) and mortality in patients with AVC in the Chinese population.

HYPOTHESIS

At present, some studies have reported that the incidence of AVC is on the rise, which may be due to the increasing number of diagnostic methods for AVC. However, there is no epidemiological data on AVC in the Chinese population, so we speculate that the incidence of AVC in the Chinese population is increasing.

METHODS AND RESULTS

We studied 15 888 adults from the Beijing Municipal Health Commission Information Center (BMHCIC) registry database in China from January 2010 to December 2020, and calculated the average annual percentage change (AAPC). Second, we determined the incidence of VT, HF and mortality in patients with AVC. Of the 10 318 men and 5570 women who were screened by cardiac magnetic resonance or examined by myocardial biopsy, there were a total of 256 newly diagnosed AVC patients (mean [SD]: 37.54[17.10]; 39.45% female). The incidence of AVC increased from 7.60 (3.12-12.06) in 2010 to 19.62 (11.51-27.75) per 1000 person-years in 2020. Males had higher incidence of AVC than females. The AAPC for the rising incidence of AVC was 8.9 %. Males had similar VT prevalence (70.32% vs. 62.38%, p = 0.19) and mortality (1.94% vs. 1.98%, p = 0.98) but lower HF prevalence (42.58% vs. 60.40%, p = 0.006), when compared to females. Radiofrequency ablation (RFA) was more likely to be performed in males (p = 0.006).

CONCLUSIONS

The rising trend in AVC incidence was evident, with two-fold increase by 2020. Males with AVC had similar VT prevalence and mortality rate, but HF prevalence were lower than females, perhaps impacted by RFA use.

Individualized Family Screening for Arrhythmogenic Right Ventricular Cardiomyopathy

BACKGROUND

Clinical guidelines recommend regular screening for arrhythmogenic right ventricular cardiomyopathy (ARVC) to monitor at-risk relatives, resulting in a significant burden on clinical resources. Prioritizing relatives on their probability of developing definite ARVC may provide more efficient patient care.

OBJECTIVES

The aim of this study was to determine the predictors and probability of ARVC development over time among at-risk relatives.

METHODS

A total of 136 relatives (46% men, median age 25.5 years [IQR: 15.8-44.4 years]) from the Netherlands Arrhythmogenic Cardiomyopathy Registry without definite ARVC by 2010 task force criteria were included. Phenotype was ascertained using electrocardiography, Holter monitoring, and cardiac imaging. Subjects were divided into groups with "possible ARVC" (only genetic or familial predisposition) and "borderline ARVC" (1 minor task force criterion plus genetic or familial predisposition). Cox regression was performed to determine predictors and multistate modeling to assess the probability of ARVC development. Results were replicated in an unrelated Italian cohort (57% men, median age 37.0 years [IQR: 25.4-50.4 years]).

RESULTS

At baseline, 93 subjects (68%) had possible ARVC, and 43 (32%) had borderline ARVC. Follow-up was available for 123 relatives (90%). After 8.1 years (IQR: 4.2-11.4 years), 41 (33%) had developed definite ARVC. Independent of baseline phenotype, symptomatic subjects (P = 0.014) and those 20 to 30 years of age (P = 0.002) had a higher hazard of developing definite ARVC. Furthermore, patients with borderline ARVC had a higher probability of developing definite ARVC compared with those with possible ARVC (1-year probability 13% vs 0.6%, 3-year probability 35% vs 5%; P < 0.01). External replication showed comparable results (P > 0.05).

CONCLUSIONS

Symptomatic relatives, those 20 to 30 years of age, and those with borderline ARVC have a higher probability of developing definite ARVC. These patients may benefit from more frequent follow-up, while others may be monitored less often.

Prevalence and Disease Expression of Pathogenic and Likely Pathogenic Variants Associated With Inherited Cardiomyopathies in the General Population

BACKGROUND

Pathogenic and likely pathogenic variants associated with arrhythmogenic right ventricular cardiomyopathy (ARVC), dilated cardiomyopathy (DCM), and hypertrophic cardiomyopathy (HCM) are recommended to be reported as secondary findings in genome sequencing studies. This provides opportunities for early diagnosis, but also fuels uncertainty in variant carriers (G+), since disease penetrance is incomplete. We assessed the prevalence and disease expression of G+ in the general population.

METHODS

We identified pathogenic and likely pathogenic variants associated with ARVC, DCM and/or HCM in 200 643 UK Biobank individuals, who underwent whole exome sequencing. We calculated the prevalence of G+ and analyzed the frequency of cardiomyopathy/heart failure diagnosis. In undiagnosed individuals, we analyzed early signs of disease expression using available electrocardiography and cardiac magnetic resonance imaging data.

RESULTS

We found a prevalence of 1:578, 1:251, and 1:149 for pathogenic and likely pathogenic variants associated with ARVC, DCM and HCM respectively. Compared with controls, cardiovascular mortality was higher in DCM G+ (odds ratio 1.67 [95% CI 1.04; 2.59], P=0.030), but similar in ARVC and HCM G+ (P≥0.100). Cardiomyopathy or heart failure diagnosis were more frequent in DCM G+ (odds ratio 3.66 [95% CI 2.24; 5.81], P=4.9×10^-7) and HCM G+ (odds ratio 3.03 [95% CI 1.98; 4.56], P=5.8×10^-7), but comparable in ARVC G+ (P=0.172). In contrast, ARVC G+ had more ventricular arrhythmias (P=3.3×10^-4). In undiagnosed individuals, left ventricular ejection fraction was reduced in DCM G+ (P=0.009).

CONCLUSIONS

In the general population, pathogenic and likely pathogenic variants associated with ARVC, DCM, or HCM are not uncommon. Although G+ have increased mortality and morbidity, disease penetrance in these carriers from the general population remains low (1.2-3.1%). Follow-up decisions in case of incidental findings should not be based solely on a variant, but on multiple factors, including family history and disease expression.

Population Prevalence of Premature Truncating Variants in Plakophilin-2 and Association With Arrhythmogenic Right Ventricular Cardiomyopathy: A UK Biobank Analysis

BACKGROUND

Truncating variants in the desmosomal gene PKP2 (PKP2tv) cause arrhythmogenic right ventricular cardiomyopathy (ARVC) yet display varied penetrance and expressivity.

METHODS

We identified individuals with PKP2tv from the UK Biobank (UKB) and determined the prevalence of an ARVC phenotype and other cardiovascular traits based on clinical and procedural data. The PKP2tv minor allelic frequency in the UKB was compared with a second cohort of probands with a clinical diagnosis of ARVC (ARVC cohort), with a figure of 1:5000 assumed for disease prevalence. In silico predictors of variant pathogenicity (combined annotation-dependent depletion and Splice AI [Illumina, Inc.]) were assessed.

RESULTS

PKP2tv were identified in 193/200 643 (0.10%) UKB participants, with 47 unique PKP2tv. Features consistent with ARVC were present in 3 (1.6%), leaving 190 with PKP2tv without manifest disease (UKB cohort; minor allelic frequency 4.73×10-4). The ARVC cohort included 487 ARVC probands with 144 distinct PKP2tv, with 25 PKP2tv common to both cohorts. The odds ratio for ARVC for the 25 common PKP2tv was 0.047 (95% CI, 0.001-0.268; P=2.43×10-6), and only favored ARVC (odds ratio >1) for a single variant, p.Arg79*. In silico variant analysis did not differentiate PKP2tv between the 2 cohorts. Atrial fibrillation was over-represented in the UKB cohort in those with PKP2tv (7.9% versus 4.3%; odds ratio, 2.11; P=0.005).

CONCLUSIONS

PKP2tv are prevalent in the population and associated with ARVC in only a small minority, necessitating a more detailed understanding of how PKP2tv cause ARVC in combination with associated genetic and environmental risk factors.

Prevalence and clinical correlates of exercise-induced ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy

Exercise has a deleterious effect on the phenotypic expression of arrhythmogenic right ventricular cardiomyopathy (ARVC) and increases the risk of sudden death. The aim of the study was to determine the prevalence and correlates of exercise-induced arrhythmias during exercise tolerance test (ETT) in patients with ARVC. Between 2010 and 2019, 30 (47% males, mean age 42 ± 12 years) consecutive patients with a definite diagnosis of ARVC underwent a full genotypic and phenotypic characterization at our center. Exercise-induced arrhythmic response (EIAR) was defined by the development of complex or repetitive ventricular arrhythmias after stage 2 of exercise. A heart rate ≥ 85% of predicted was achieved by 23 (77%) patients. In 16 (53%) cases, a desmosomal pathogenic variant was found [most commonly PKP2 (n = 7) and DSP (n = 3)]. In 12 (40%) cases, an EIAR was observed. In 2 (6%) patients, ETT was interrupted due to the onset of ventricular tachycardia (sustained with a LBBB/inferior axis pattern in one case, and non-sustained LBBB/superior axis pattern in the other). Mean body surface area (BSA)-indexed left ventricular (LV) end-diastolic volumes (EDV) were higher in the EIAR group (92 ± 12 ml/m² vs 80 ± 7 ml/m², p = 0.002), as well as right ventricular EDV/BSA (110 ± 18 ml/m² vs 91 ± 27 ml/m², p = 0.04). Subepicardial/mid-wall LV late gadolinium enhancement (LGE) was more common in the EIAR group (67% vs 22%, p = 0.01). ARVC patients commonly exhibit exercise-induced ventricular arrhythmias. Patients with more significant RV remodeling and LV involvement (based on the presence of LV dilatation and LGE) appear more susceptible to exercise-induced arrhythmias.

Left ventricular fibro-fatty replacement in arrhythmogenic right ventricular dysplasia/cardiomyopathy: prevalence, patterns, and association with arrhythmias

BACKGROUND

Left ventricular (LV) fibrofatty infiltration in arrhythmogenic right ventricular (RV) dysplasia/cardiomyopathy (ARVD/C) has been reported, however, detailed cardiovascular magnetic resonance (CMR) characteristics and association with outcomes are uncertain. We aim to describe LV findings on CMR in ARVD/C patients and their relationship with arrhythmic outcomes.

METHODS

CMR of 73 subjects with ARVD/C according to the 2010 Task Force Criteria (TFC) were analyzed for LV involvement, defined as ≥ 1 of the following features: LV wall motion abnormality, LV late gadolinium enhancement (LGE), LV fat infiltration, or LV ejection fraction (LVEF) < 50%. Ventricular volumes and function, regional wall motion abnormalities, and the presence of ventricular fat or fibrosis were recorded. Findings on CMR were correlated with arrhythmic outcomes.

RESULTS

Of the 73 subjects, 50.7% had CMR evidence for LV involvement. Proband status and advanced RV dysfunction were independently associated with LV abnormalities. The most common pattern of LV involvement was focal fatty infiltration in the sub-epicardium of the apicolateral LV with a "bite-like" pattern. LGE in the LV was found in the same distribution and most often had a linear appearance. LV involvement was more common with non-PKP2 genetic mutation variants, regardless of proband status. Only RV structural disease on CMR (HR 3.47, 95% CI 1.13-10.70) and prior arrhythmia (HR 2.85, 95% CI 1.33-6.10) were independently associated with arrhythmic events.

CONCLUSION

Among patients with 2010 TFC for ARVD/C, CMR evidence for LV abnormalities are seen in half of patients and typically manifest as fibrofatty infiltration in the subepicardium of the apicolateral wall and are not associated with arrhythmic outcomes.

Prevalence of atrial arrhythmia in patients with arrhythmogenic right ventricular cardiomyopathy: a systematic review and meta-analysis

BACKGROUND/OBJECTIVES

Little is known about atrial involvement in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). Recent studies have suggested that atrial arrhythmia, including atrial fibrillation, atrial flutter (AFL), and atrial tachycardia, was common among these patients although the reported prevalence varied considerably across the studies. The current systematic review and meta-analysis was conducted with the aim of comprehensively investigating the prevalence of overall atrial arrhythmia and each atrial arrhythmia subtype in the setting of ARVC by identifying all relevant studies and combining their results together.

METHODS

A comprehensive literature review was conducted by searching for published articles indexed in MEDLINE and EMBASE databases from inception through to 22 September 2019 to identify cohort studies of patients with ARVC that described the prevalence of atrial arrhythmia among the participants. The pooled prevalence across studies was calculated using a random-effect, generic inverse variance method of DerSimonian and Laird with a double arcsine transformation.

RESULTS

A total of 16 cohort studies with 1986 patients with ARVC were included in this meta-analysis. The pooled prevalence of overall atrial arrhythmia among patients with ARVC was 17.9% [95% confidence interval (CI), 13.0-24.0%; I 88%], the pooled prevalence of atrial fibrillation of 12.9% (95% CI, 9.6-17.0%; I 78%), the pooled prevalence of AFL of 5.9% (95% CI, 3.7-9.2%; I 70%), and the pooled prevalence of atrial tachycardia of 7.1% (95% CI, 3.7-13.0%; I 49%).

CONCLUSION

Atrial arrhythmia is common among patients with ARVC with the pooled prevalence of approximately 18%, which is substantially higher than the reported prevalence of atrial arrhythmia in the general population.

[RIGHT VENTRICULAR ARRHYTMOGENIC CARDIOMYOPATHY – HAVE WE AVOIDED A FAMILY TRAGEDY BY APPLYING CONTEMPORARY DIAGNOSTIC AND TREATMENT APPROACH?]

Arrhytmogenic right ventricular cardiomyopathy (ARVC) is an inherited cardiomyopathy characterized by fibrofatty replacement, dominantly in the right, but often also in the left ventricle. It is a significant cause of sudden death in children and adolescents. A thorough family history and contemporary diagnostic and treatment approach are prerequisites for the prevention of the sudden death syndrome. The diagnosis is more often established in adults than in children. Patients: We present a family with four members affected and diagnosed with ARVC already in childhood/adolescence. The average age of symptom presentation was 12 years (10–14 years). The importance of family tree isemphasized and contemporary diagnostic and treatment methods, with the aim of sudden death prevention, are described. Conclusions: Family history is essential for the early ARVC diagnosis. There is a need for revision of current diagnostic criteria in pediatric population. In the future progression of fibrous tissue proportion in relation to age and the stage of the disease should be taken in account. Furthermore, the repolarisation abnormality is inappropriate as a criterion in children less than 14 years old, so in that age group less of present diagnostic criteria can be applied. A combination of modern implantable cardioverter defibrillator and radiofrequency ablation assures an excellent life quality in our patients. However, the longterm prognosis for our patients, because of a progressive course of the disease, remains uncertain.

Management of arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a genetically determined heart muscle disorder, predisposing to sudden cardiac death (SCD), particularly in young patients and athletes. Pathological features include loss of myocytes and fibrofatty replacement of right ventricular myocardium; a biventricular involvement is often observed. The diagnosis of ARVC (prevalence 1:5.000 in the general population) does not rely on a single gold standard test but is achieved using a scoring system, proposed in 2010 by an International Task Force, which encompasses familial and genetic factors, ECG abnormalities, arrhythmias, and structural/functional ventricular alterations. The main goal of treatment is the prevention of SCD. Implantable cardioverter defibrillator (ICD) is the only proven "lifesaving" therapy; however, it is associated with a significant morbidity due to device-related complications and inappropriate ICD interventions. Other treatment options such as life style changes, antiarrhythmic drugs, beta-blockers and catheter ablation may reduce the arrhythmic burden and alleviate symptoms, without evident impact on prevention of SCD. Selection of patient candidates to ICD implantation is the most challenging issue in the clinical management of ARVC. This article reviews the current perspective on management of ARVC, focusing on clinical manifestations, diagnostic criteria, risk stratification and therapeutic strategies of affected patients.

Adipositas cordis sudden death: a series of 79 patients

BACKGROUND

The principal aim of this study was to investigate the clinical, epidemiological and pathologic features for a series of 79 cases of adipositas cordis sudden death.

METHODS

We analyzed clinical and autopsy pathological features of 79 patients (43 females and 36 males) with adipositas cordis who died suddenly between 1975 and 2010. Data were extracted from China National Knowledge Infrastructure and Wan Fang Database.

RESULTS

The average age of the 79 cases was 36.6 ± 1.4 years old ranging from 13 to 68, and 82.3% of them were between 20 to 50 years old. Sudden death was the first symptom in 62 (78.5%) of the cases, only 17 (21.5%) had a history of chest distress or dyspnea. More than 4/5 (87.3%) of the cases had no any past medical history. At autopsy, the subjects' heart weight was mild or moderately increased, and a large amount of fatty tissues but not fibrous or fibro fatty was accumulated underneath the epicardium and infiltrated toward the right ventricle walls, and even infiltrated to all layers of the cardiac walls. Regional epidemiological data showed that about 80% of cases were living north and only 20% were living south of the Yangzi River, but not any familial heredity.

CONCLUSION

Adipositas cordis sudden death is a very severe disease, it occurs mostly in youth and middle-aged and sudden death is often the first symptom. There is a significant regional difference, but not any genetic correlation. The pathogenesis of adipositas cordis sudden death should to be further explored.

Analysis of statistical biases in studies used to formulate guidelines: the case of arrhythmogenic right ventricular cardiomyopathy (ARVC) the case of ARVC

RATIONALE AND OBJECTIVES

To analyze the statistical biases in the studies used to derive cardiac magnetic resonance-based major and minor criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC).

MATERIALS AND METHODS

ARVC is a rare disorder of the heart that can lead to sudden death in young adults. Cardiac magnetic resonance imaging (CMR) plays a role in the diagnosis by contributing to the criteria set by experts. The original criteria emphasized qualitative analysis of CMR. The criteria were modified in 2010 to provide quantitative cutoffs.

RESULTS

We apply the Quality Assessment of Diagnostic Accuracy Studies (QUADAS-2) tool for systematic review of diagnostic accuracy to the studies cited in the guidelines written in 1994 and revised in 2010. We use the signaling questions in QUADAS-2 to identify different types of statistical bias.

CONCLUSIONS

The studies have understandable biases that affect the sensitivity and specificity of CMR in the diagnosis of ARVC, as well as the truth of the disease state. There is potential to overdiagnose ARVC particularly in low prevalence populations.

Effect of the 2010 task force criteria on reclassification of cardiovascular magnetic resonance criteria for arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

We sought to evaluate the effect of application of the revised 2010 Task Force Criteria (TFC) on the prevalence of major and minor Cardiovascular Magnetic Resonance (CMR) criteria for Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) versus application of the original 1994 TFC. We also assessed the utility of MRI to identify alternative diagnoses for patients referred for ARVC evaluation.

METHODS

968 consecutive patients referred to our institution for CMR with clinical suspicion of ARVC from 1995 to 2010, were evaluated for the presence of major and minor CMR criteria per the 1994 and 2010 ARVC TFC. CMR criteria included right ventricle (RV) dilatation, reduced RV ejection fraction, RV aneurysm, or regional RV wall motion abnormalities. When quantitative measures of RV size and function were not available, and in whom abnormal size or function was reported, a repeat quantitative analysis by 2 qualified CMR physicians in consensus.

RESULTS

Of 968 patients, 220 (22.7%) fulfilled either a major or a minor 1994 TFC, and 25 (2.6%) fulfilled any of the 2010 TFC criterion. Among patients meeting any 1994 criteria, only 25 (11.4%) met at least one 2010 criterion. All patients who fulfilled a 2010 criteria also satisfied at least one 1994 criterion. Per the 2010 TFC, 21 (2.2%) patients met major criteria and 4 (0.4%) patients fulfilled at least one minor criterion. Eight patients meeting 1994 minor criteria were reclassified as satisfying 2010 major criteria, while 4 patients fulfilling 1994 major criteria were reclassified to only minor or no criteria under the 2010 TFC.Eighty-nine (9.2%) patients had alternative cardiac diagnoses, including 43 (4.4%) with clinically significant potential ARVC mimics. These included cardiac sarcoidosis, RV volume overload conditions, and other cardiomyopathies.

CONCLUSIONS

Application of the 2010 TFC resulted in reduction of total patients meeting any diagnostic CMR criteria for ARVC from 22.7% to 2.6% versus the 1994 TFC. CMR identified alternative cardiac diagnoses in 9.2% of patients, and 4.4% of the diagnoses were potential mimics of ARVC.

Stop-gain mutations in PKP2 are associated with a later age of onset of arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a cardiac disease characterized by the presence of fibrofatty replacement of the right ventricular myocardium, which may cause ventricular arrhythmias and sudden cardiac death. Pathogenic mutations in several genes encoding mainly desmosomal proteins have been reported. Our aim is to perform genotype-phenotype correlations to establish the diagnostic value of genetics and to assess the role of mutation type in age-related penetrance in ARVC.

METHODS AND RESULTS

Thirty unrelated Spanish patients underwent a complete clinical evaluation. They all were screened for PKP2, DSG2, DSC2, DSP, JUP and TMEM43 genes. A total of 70 relatives of four families were also studied. The 30 patients fulfilled definite disease diagnostic criteria. Genetic analysis revealed a pathogenic mutation in 19 patients (13 in PKP2, 3 in DSG2, 2 in DSP, and 1 in DSC2). Nine of these mutations created a truncated protein due to the generation of a stop codon. Familial assessment revealed 28 genetic carriers among family members. Stop-gain mutations were associated to a later age of onset of ARVC, without differences in the severity of the pathology.

CONCLUSIONS

Familial genetic analysis helps to identify the cause responsible for the pathology. In discrepancy with previous studies, the presence of a truncating protein does not confer a worse severity. This information could suggest that truncating proteins may be compensated by the normal allele and that missense mutations may act as poison peptides.

Usefulness of inducible ventricular tachycardia to predict long-term adverse outcomes in arrhythmogenic right ventricular cardiomyopathy

The role of the electrophysiologic (EP) study for risk stratification in patients with arrhythmogenic right ventricular cardiomyopathy is controversial. We investigated the role of inducible sustained monomorphic ventricular tachycardia (SMVT) for the prediction of an adverse outcome (AO), defined as the occurrence of cardiac death, heart transplantation, sudden cardiac death, ventricular fibrillation, ventricular tachycardia with hemodynamic compromise or syncope. Of 62 patients who fulfilled the 2010 Arrhythmogenic Right Ventricular Cardiomyopathy Task Force criteria and underwent an EP study, 30 (48%) experienced an adverse outcome during a median follow-up of 9.8 years. SMVT was inducible in 34 patients (55%), 22 (65%) of whom had an adverse outcome. In contrast, in 28 patients without inducible SMVT, 8 (29%) had an adverse outcome. Kaplan-Meier analysis showed an event-free survival benefit for patients without inducible SMVT (log-rank p = 0.008) with a cumulative survival free of an adverse outcome of 72% (95% confidence interval [CI] 56% to 92%) in the group without inducible SMVT compared to 26% (95% CI 14% to 50%) in the other group after 10 years. The inducibility of SMVT during the EP study (hazard ratio [HR] 2.99, 95% CI 1.23 to 7.27), nonadherence (HR 2.74, 95% CI 1.3 to 5.77), and heart failure New York Heart Association functional class II and III (HR 2.25, 95% CI 1.04 to 4.87) were associated with an adverse outcome on univariate Cox regression analysis. The inducibility of SMVT (HR 2.52, 95% CI 1.03 to 6.16, p = 0.043) and nonadherence (HR 2.34, 95% CI 1.1 to 4.99, p = 0.028) remained as significant predictors on multivariate analysis. This long-term observational data suggest that SMVT inducibility during EP study might predict an adverse outcome in patients with arrhythmogenic right ventricular cardiomyopathy, advocating a role for EP study in risk stratification.

The right heart in athletes. Evidence for exercise-induced arrhythmogenic right ventricular cardiomyopathy

Although 'athlete's heart' usually constitutes a balanced dilation and hypertrophy of all four chambers, there is increasing evidence that intense endurance activity may particularly tax the right ventricle (RV), both acutely and chronically. We review the evidence that the high wall stress of the RV during intense sports may explain observed B-type natriuretic peptide (BNP) elevations immediately after a race, may lead to cellular disruption and leaking of cardiac enzymes, and may even result in transient RV dilatation and dysfunction. Over time, this could lead to chronic remodelling and a pro-arrhythmic state resembling arrhythmogenic RV cardiomyopathy (ARVC) in some cases. ARVC in high-endurance athletes most often develops in the absence of underlying desmosomal abnormalities, probably only as a result of excessive RV wall stress during exercise. Therefore, we have labelled this syndrome 'exercise-induced ARVC'. Sports cardiologists should be aware that excessive sports activity can lead to cardiac sports injuries in some individuals, just like orthopaedic specialists are familiar with musculoskeletal sports injuries. This does not negate the fact that moderate exercise has positive cardiovascular effects and should be encouraged.

Duty to warn and genetic disease

In this clinical column, we discuss the ambiguous distinction between genetic research and clinical genetics, particularly for Mendelian diseases with high recurrence risk, high morbidity and/or mortality and the possible amelioration of such diseases by screening or treatment. We use arrhythmogenic right ventricular cardiomyopathy as an example of a lethal Mendelian disorder, which prompted the discussion contained in this column. Working with such diseases may mean that genetic researchers have some responsibility for both immediate research subjects and their extended families, as they obtain molecular genetic information. For some diseases, therefore, a willingness to accept genetic research results should be an inclusion criterion, and it may be considered unethical for research ethics boards to approve genetic studies unless measures to ensure clinical follow-up have been established. We recommend managing the tensions between genetic research and clinical practice by using disease-based genetic registers, organized within a clinical genetic service.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia in Iraq

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a disorder that involves replacement of the right ventricular myocardium with fibro-fatty tissue. Ventricular tachycardia is a main presenting feature. There are no known reports of this disease from the Arab countries in the Middle East. This is the first report of 34 patients from Iraq.

METHODS

Thirty four patients with ARVC/D diagnosed from January 2003 to May 2007 according to the International Task Force criteria were included in this study.

RESULTS

All patients presented with ventricular tachycardia of left bundle branch block morphology. The following findings were seen on the 12-lead electrocardiography during sinus rhythm: T wave inversion V1-V3 or beyond in 80%, epsilon wave in 28%, and parietal block in 48%. Right ventricular enlargement by echocardiography was seen in 69%. Twenty two per cent had a family history of sudden cardiac death. All patients were treated with implanted cardioverter-defibrillators.

CONCLUSIONS

ARVC/D is a disease seen in Iraq. It requires a high diagnostic suspicion with verification using the international task force criteria.

[Prevalence of Epsilon wave in patients with arrhythmogenic right ventricular cardiomyopathy]

OBJECTIVE

To investigate the prevalence of Epsilon wave in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC).

METHODS

The epsilon wave was detected in 32 patients [24 men, mean age (42.3 +/- 13.3) years] with ARVC using three different electrocardiography (ECG) recording methods: standard twelve leads ECG (S-ECG), right precordial leads ECG (R-ECG) and Fontaine bipolar precordial leads ECG (F-ECG). The Epsilon wave was defined as wiggler, small spike wave and smooth potential between the end of the QRS complex and the beginning of the ST segment.

RESULTS

Epsilon wave was detected in 37.5%, 37.5% and 50.0% patients with ARVC by S-ECG, R-ECG and F-ECG respectively. The detection rates derived from the three recording methods were similar (P > 0.05). The Epsilon wave was only detectable by S-ECG in one case, by R-ECG in three cases, and by F-ECG in five cases. The detection rate of Epsilon wave was 50.0% by combined use of S-ECG and R-ECG (SR-ECG), 56.3% by combined use of S-ECG and F-ECG (SF-ECG), and 65.6% by combined use of the three recording methods (SRF-ECG). The detection rate was significantly higher by SF-ECG (56.3%) and SRF-ECG (65.6%) than by S-ECG alone (37.5%, all P < 0.05). Most Epsilon waves detected by the S-ECG, R-ECG and F-ECG were small spiked waves.

CONCLUSION

Combined use of S-ECG, F-ECG and R-ECG could increase the detection rate of Epsilon wave in patients with ARVC.

Arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy is a rare inherited heart-muscle disease that is a cause of sudden death in young people and athletes. Causative mutations in genes encoding desmosomal proteins have been identified and the disease is nowadays regarded as a genetically determined myocardial dystrophy. The left ventricle is so frequently involved as to support the adoption of the broad term arrhythmogenic cardiomyopathy. Clinical diagnosis can be achieved by demonstrating function and structure changes of the right ventricle, electrocardiogram depolarisation and repolarisation abnormalities, ventricular arrhythmias, and fibrofatty replacement through endomyocardial biopsy. Although specific, the standardised diagnostic criteria lack sensitivity for early disease and their primary application remains in establishing the diagnosis in probands. However, the main clinical targets are early detection of concealed forms and risk stratification for preventive strategies, which include physical exercise restriction, antiarrhythmic drugs, and implantable cardioverter-defibrillator therapy. Cascade genetic screening of family members of gene-positive probands allows the identification of asymptomatic carriers who would require lifelong follow-up due to the age-related penetrance.

Arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy is a cardiac disorder manifested by the replacement of the ventricular myocardium by fibro fatty tissue and has been known to cause sudden cardiac death in young adults. In 30% to 50% of cases, the disease has familial links, which can have implications for the patients and families involved. Achieving a diagnosis can be taxing on all involved, and for the patient, it can mean having to go through a battery of tests. Once diagnosis has been confirmed, treatment for the disease includes implantation of an implantable defibrillator and/or pharmacotherapy to control the ventricular tachyarrhythmias.

Clinical and genetic characterization of families with arrhythmogenic right ventricular dysplasia/cardiomyopathy provides novel insights into patterns of disease expression

BACKGROUND

According to clinical-pathological correlation studies, the natural history of arrhythmogenic right ventricular dysplasia/cardiomyopathy is purported to progress from localized to global right ventricular dysfunction, followed by left ventricular (LV) involvement and biventricular pump failure. The inevitable focus on sudden death victims and transplant recipients may, however, have created a skewed perspective of a genetic disease. We hypothesized that unbiased representation of the spectrum of disease expression in arrhythmogenic right ventricular dysplasia/cardiomyopathy would require in vivo assessment of families in a genetically heterogeneous population.

METHODS AND RESULTS

A cohort of 200 probands and relatives satisfying task force or modified diagnostic criteria for arrhythmogenic right ventricular dysplasia/cardiomyopathy underwent comprehensive clinical evaluation. Desmosomal mutations were identified in 39 individuals from 20 different families. Indices of structural severity correlated with advancing age and were increased in long-term endurance athletes. Fulfillment of modified criteria indicated phenotypically mild disease, whereas asymptomatic status did not. In >80%, ECG, rhythm monitoring, and/or gadolinium-enhanced cardiovascular magnetic resonance were suggestive of LV involvement, the extent of which often was marked among individuals with chain-termination mutations and/or desmoplakin disease. Three patterns of disease expression were identified: (1) classic, with isolated right ventricular disease or LV involvement in association with significant right ventricular impairment; (2) left dominant, with early and prominent LV manifestations and relatively mild right-sided disease; and (3) biventricular, characterized by parallel involvement of both ventricles.

CONCLUSIONS

LV involvement in arrhythmogenic right ventricular dysplasia/cardiomyopathy may precede the onset of significant right ventricular dysfunction. Recognition of disease variants with early and/or predominant LV involvement supports adoption of the broader term arrhythmogenic cardiomyopathy.

The value of different electrocardiographic depolarization criteria in the diagnosis of arrhythmogenic right ventricular dysplasia/cardiomyopathy

BACKGROUND

The use of electrocardiographic (ECG) depolarization and repolarization criteria plays a large role in the diagnosis of arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C). Different ECG algorithms should be analyzed in making the diagnosis of ARVD/C with the use of normal and modified recording techniques.

METHODS

In a cohort of 343 patients (210 men and 133 women; mean age, 46.0 +/- 13.7 years) meeting the Task Force of the Working Group on Myocardial and Pericardial Diseases of the European Society of Cardiology and the Scientific Council on Cardiomyopathies of the International Society and Federation of Cardiology diagnostic criteria for ARVD/C, the value of different ECG criteria (eg, localized right precordial QRS prolongation defined as QRS duration in (V1+V2+V3)/(V4+V5+V6) of 1.2 or higher, right precordial QRS prolongation with QRS in V1-3 of 110 milliseconds or higher, epsilon potentials in the right precordial leads, S-wave upstroke in V1-3 of 55 milliseconds or higher, and right precordial T-wave inversions) was analyzed with the use of a normal recording technique and a highly amplified and modified recording technique (n = 207) at a paper speed of 50 mm/s. Fifty-two phenotypically and genotypically unaffected individuals identified by systematic screening in 24 families (30 men; mean age, 42.4 +/- 8.3 years) were treated as control subjects.

RESULTS

In the normal as well as highly amplified and modified recording techniques, the incidence of localized right precordial QRS prolongation was 98% (100%), that of QRS in V1-3 of 110 milliseconds or higher was 75% (80%), that of prolonged right precordial S-wave upstroke was 84% (60%), that of epsilon potentials was 23% (77%), and that of right precordial T-wave inversions was 55%. Four of 6 patients without the phenomenon of localized right precordial QRS prolongation with the use of the normal recording technique had a prolonged S-wave upstroke of 55 milliseconds or higher. In the control group, localized right precordial QRS prolongation, QRS in V1-3 of 110 milliseconds or higher, and epsilon potentials could not be identified. An S-wave upstroke of 55 milliseconds or higher was present in 2 of 3 cases, and T-wave inversions were found in 3.

CONCLUSIONS

Electrocardiographic depolarization criteria for ARVD/C analyzed in this large cohort of patients meeting the International Society and Federation of Cardiology/European Society of Cardiology criteria presented with high sensitivity and specificity in comparison with those in the control group of phenotypically and genotypically unaffected individuals defined by systematic screening in 24 families with ARVD/C. The incidence of right precordial T-wave inversions was much lower, indicating that not only patients with overt right ventricular dilatation and dysfunction were included. Electrocardiographic algorithms, including localized right precordial QRS prolongation, prolonged S-wave upstroke, and epsilon potentials, with the use of the normal recording technique and the amplified and modified recording technique at a paper speed of 50 mm/s contribute significantly to the noninvasive diagnosis of ARVD/C.

Age- and Training-Dependent Development of Arrhythmogenic Right Ventricular Cardiomyopathy in Heterozygous Plakoglobin-Deficient Mice

Background— Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited disorder that causes sudden death and right ventricular heart failure in the young. Clinical data suggest that competitive sports may provoke ARVC in susceptible persons. Genetically, loss-of-function mutations in desmosomal proteins (plakophilin, desmoplakin, or plakoglobin) have been associated with ARVC. To test the hypothesis that reduced desmosomal protein expression causes ARVC, we studied the cardiac effects of heterozygous plakoglobin deficiency in mice.

Methods and Results— Ten-month-old heterozygous plakoglobin-deficient mice (plakoglobin +/− ) had increased right ventricular volume, reduced right ventricular function, and spontaneous ventricular ectopy (all P <0.05). Left ventricular size and function were not altered. Isolated, perfused plakoglobin +/− hearts had spontaneous ventricular tachycardia of right ventricular origin and prolonged right ventricular conduction times compared with wild-type hearts. Endurance training accelerated the development of right ventricular dysfunction and arrhythmias in plakoglobin +/− mice. Histology and electron microscopy did not identify right ventricular abnormalities in affected animals.

Conclusions— Heterozygous plakoglobin deficiency provokes ARVC. Manifestation of the phenotype is accelerated by endurance training. This suggests a functional role for plakoglobin and training in the development of ARVC.

Epidemiology of fat replacement of the right ventricular myocardium determined by multislice computed tomography using a logistic regression model

PURPOSE

We frequently observe fat replacement (FR) of the anterior wall of the right ventricular myocardium (RVM), but its epidemiological significance is not clear.

METHODS AND MATERIALS

49 consecutive subjects (28 males, 36-83 years old, median 67) underwent enhanced ECG-gated multislice CT (Light speed ultra 16, General Electrics, WI) and we retrospectively analyzed the presence of FR of RVM. A logistic model for predicting FR of RVM was constructed using age, sex, hypertension [HT], diabetes mellitus [DM], hyperlipidemia [HL] smoking, obesity (body mass index >25.0) and calcified and non-calcified plaques of coronary arteries (CA).

RESULTS

FR of RVM was detected in 21 subjects (12 males, 51-78 years old, median 67), 76% of whom had HT, 38% DM, 43% HL, 48% smoking history, 52% were obese, and 76% had calcified and 24% had non-calcified plaques of CA. Only obesity was significantly higher in FR (p<0.05). A logistic regression model showed, although there was a close association between obesity and an increased incidence of FR, it did not reach statistical significance (p=0.0515, relative risk 5.11).

CONCLUSIONS

Obesity is significantly more common in cases of FR, and despite a negative multivariable analysis, may influence FR in the RVM. FR in obesity may occur independently of clinically-significant arrhythmia, which is different from ARVC. Thus, even with FR, obesity must be considered as a diagnosis before ARVC.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy: screening, diagnosis, and treatment

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is a heart muscle disorder characterized pathologically by fatty or fibrofatty replacement and electrical instability of the right ventricular myocardium. Clinical manifestations include structural and functional malformations (fatty infiltration, dilatation, aneurysms) of the right ventricle, ECG abnormalities, and presentation with ventricular tachycardias with left bundle branch block pattern or sudden death. The disease often is familial with an autosomal inheritance. The typical hallmarks of ARVD/C are distributed in the so-called "triangle of dysplasia." The functional and morphologic characteristics are relevant to clinical imaging approaches such as contrast angiography, echocardiography, radionuclide angiography, ultrafast computed tomography, and cardiovascular magnetic resonance imaging. Evident forms of the disease are straightforward to diagnose based on a series of diagnostic criteria proposed by the International Task Force for Cardiomyopathy. However, the diagnosis of early and mild forms of the disease often is difficult. Treatment is directed toward preventing life-threatening ventricular arrhythmias in which radiofrequency ablation and implantable defibrillators play an increasing role. Despite new diagnostic and therapeutic approaches in ARVD/C, uncertainties about the etiology of the disease, the genetic basis, the appropriate diagnosis and therapy, and the clinical course of patients with ARVD/C have resulted in several registries to increase our knowledge of this intriguing disease.

Naxos disease: cardiocutaneous syndrome due to cell adhesion defect

Naxos disease is a recessively inherited condition with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) and a cutaneous phenotype, characterised by peculiar woolly hair and palmoplantar keratoderma. The disease was first described in families originating from the Greek island of Naxos. Moreover, affected families have been identified in other Aegean islands, Turkey, Israel and Saudi Arabia. A syndrome with the same cutaneous phenotype and predominantly left ventricular involvement has been described in families from India and Ecuador (Carvajal syndrome). Woolly hair appears from birth, palmoplantar keratoderma develop during the first year of life and cardiomyopathy is clinically manifested by adolescence with 100% penetrance. Patients present with syncope, sustained ventricular tachycardia or sudden death. Symptoms of right heart failure appear during the end stages of the disease. In the Carvajal variant the cardiomyopathy is clinically manifested during childhood leading more frequently to heart failure. Mutations in the genes encoding the desmosomal proteins plakoglobin and desmoplakin have been identified as the cause of Naxos disease. Defects in the linking sites of these proteins can interrupt the contiguous chain of cell adhesion, particularly under conditions of increased mechanical stress or stretch, leading to cell death, progressive loss of myocardium and fibro-fatty replacement. Implantation of an automatic cardioverter defibrillator is indicated for prevention of sudden cardiac death. Antiarrhythmic drugs are used for preventing recurrences of episodes of sustained ventricular tachycardia and classical pharmacological treatment for congestive heart failure, while heart transplantation is considered at the end stages.

Arrhythmogenic right ventricular dysplasia: a United States experience

BACKGROUND

Arrhythmogenic right ventricular dysplasia (ARVD) is an inherited cardiomyopathy characterized by right ventricular dysfunction and ventricular arrhythmias. The purpose of our study was to describe the presentation, clinical features, survival, and natural history of ARVD in a large cohort of patients from the United States.

METHODS AND RESULTS

The patient population included 100 ARVD patients (51 male; median age at presentation, 26 [interquartile range {IQR}, 18 to 38; range, 2 to 70] years). A familial pattern was observed in 32 patients. The most common presenting symptoms were palpitations, syncope, and sudden cardiac death (SCD) in 27%, 26%, and 23% of patients, respectively. Among those who were diagnosed while living (n=69), the median time between first presentation and diagnosis was 1 (range, 0 to 37) year. During a median follow-up of 6 (IQR, 2 to 13; range, 0 to 37) years, implantable cardioverter/defibrillators (ICD) were implanted in 47 patients, 29 of whom received an appropriate ICD discharge, including 3 patients who received the ICD for primary prevention. At follow-up, 66 patients were alive, of whom 44 had an ICD in place, 5 developed signs of heart failure, 2 had a heart transplant, and 18 were on drug therapy. Thirty-four patients died either at presentation (n=23: 21 SCD, 2 noncardiac deaths) or during follow-up (n=11: 10 SCD, 1 of biventricular heart failure), of whom only 3 were diagnosed while living and 1 had an ICD implanted. On Kaplan-Meier analysis, the median survival in the entire population was 60 years.

CONCLUSIONS

ARVD patients present between the second and fifth decades of life either with symptoms of palpitations and syncope associated with ventricular tachycardia or with SCD. Diagnosis is often delayed. Once diagnosed and treated with an ICD, mortality is low. There is a wide variation in presentation and course of ARVD patients, which can likely be explained by the genetic heterogeneity of the disease.

Prevalence of right ventricular dysplasia-cardiomyopathy in a non-referral hospital

In a cardiological department of a non-referral hospital responsible for 80,000 inhabitants with 2500 in-hospital patients and 1500 out-hospital patients per year, the prevalence, symptoms and prognosis of arrhythmogenic right ventricular dysplasia-cardiomyopathy (ARVD/C) were examined retrospectively. From 1997 to 2002, ARVD/C was diagnosed in 35 females and 45 males (overall prevalence 1 in 1000 inhabitants) with a mean age of 45.6 years. Symptoms were chest pain (80%), palpitations (60%) and syncopes (30%), and clinical findings were repetitive ventricular premature beats (50%), supraventricular arrhythmias (30%), ventricular tachycardia (20%), aborted sudden death due to ventricular fibrillation (1%), right heart failure (4%), biventricular heart failure (1%) and high grade AV nodal block (4%). Endomyocardial biopsies were not performed. Aborted sudden death occurred in only one patient (0.3%) before the diagnosis was made, annual heart failure rate was 1%. No deaths appeared in a follow-up of 1-5 (mean 2.4) years with clinical assessment as the basis of diagnosis. The prevalence of ARVD/C is much higher and the prognosis better than expected from results of reference centers.

Prevalence of T-wave inversion beyond V1 in young normal individuals and usefulness for the diagnosis of arrhythmogenic right ventricular cardiomyopathy/dysplasia

T-wave inversion in precordial leads V1 to V3 is present in <3% of apparently healthy subjects who are 19 to 45 years of age but is present in 87% of patients who have arrhythmogenic right ventricular cardiomyopathy/dysplasia. T-wave inversion in lead V2 or V3 in a young or middle-aged patients who have no apparent heart disease but do have ventricular arrhythmias of left bundle branch morphology should raise the suspicion of arrhythmogenic right ventricular cardiomyopathy/dysplasia.

Natural history and risk stratification of arrhythmogenic right ventricular dysplasia/cardiomyopathy

BACKGROUND

Management of patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is complicated by the incomplete information on the natural history of the disease and by the lack of risk stratification for cardiovascular death. The aim of the study was the identification of risk factors related to long-term prognosis.

METHODS AND RESULTS

Data were collected from 130 patients (100 men; age at onset of symptoms, 31.8+/-14.4 years) from a tertiary center between 1977 and 2000 who fulfilled the international standardized diagnostic criteria for ARVD/C. Risk factors for cardiovascular death were determined by a logistic regression model. After a mean follow-up of 8.1+/-7.8 years, 24 deaths were recorded, with a mean age at death of 54+/-19 years (annual mortality rate, 2.3%). There were 21 deaths with a cardiovascular origin (progressive heart failure for 14 patients and sudden death for the remaining 7 patients). All patients who died had a history of ventricular tachycardia. Multivariate analysis showed that after adjustment for sex, history of syncope, chest pain, inaugural ventricular tachycardia, recurrence of ventricular tachycardia, and QRS dispersion, clinical signs of right ventricular failure and left ventricular dysfunction both remained independently associated with cardiovascular mortality. The combined presence of one of these risk factors and ventricular tachycardia identifies high-risk subjects for cardiovascular mortality, whereas patients without ventricular tachycardia displayed the best prognosis.

CONCLUSIONS

The information on the natural history of patients with ARVD allowed us to identify risks factors for cardiovascular mortality. An analysis of a large international registry is needed to refine these results.

Results of ajmaline testing in patients with arrhythmogenic right ventricular dysplasia–cardiomyopathy

An association between arrhythmogenic right ventricular dysplasia-cardiomyopathy (ARVD/C) and Brugada syndrome can be supposed according to several case reports. In order to examine a possible link between ARVD/C and Brugada syndrome, systematic ajmaline testing with 1 mg/kg body weight intravenously, was done in 55 patients (32 males, mean age 46.7+/-12.3 years) with ISFC/ESC criteria of ARVD/C. In nine patients ajmaline testing could demonstrate coved ST segment elevation of at least 2 mm in at least two right precordial leads. Three of these patients had recurrent syncopes. Electrophysiological study revealed non-sustained ventricular tachycardia with left bundle branch block configuration and inferior axis in only one case. Systematic ajmaline testing could demonstrate a definite link between ARVD/C and Brugada syndrome.

Familial form of arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Arrhythmogenic right ventricular dysplasia (ARVD) is characterised by fatty and fibrous infiltration of myocardial muscle. Clinical symptoms include dangerous cardiac arrhythmias and heart failure in the advanced form of the disease. ARVD is genetically determined in at least 50% of cases and is characterised by a marked variability of clinical presentation within one family.

AIM

To assess the prevalence of the familial form of ARVD in Poland, the mode of inheritance and the risk of sudden cardiac death as well as heart failure development in asymptomatic patients, in whom ARVD was detected during family screening.

METHODS

211 relatives of 40 patients with ARVD were examined. Thirty two families were identified in which at least two members had the disease. The analysed parameters included family history, physical examination, ECG, echocardiography and magnetic resonance.

RESULTS

Abnormalities of the right ventricle and/or cardiac arrhythmias suggesting ARVD were found in 71 subjects (mean age 32.4 years). In 28 cases ARVD was diagnosed. From this group, one patient had aborted sudden death. In the remaining 43 subjects a borderline form of the disease was detected. Of this group, one patient died suddenly. The degree of morphological changes in cardiac muscle correlated with patients' age.

CONCLUSIONS

1. The familial form of ARVD is frequent in Poland. 2. ARVD is inherited in an autosomal dominant mode. 3. Sudden cardiac death may be the first symptom of the disease, even in subjects with borderline ARVD. 4. ARVD is a progressive disease. Concomitant left ventricular involvement is not rare and probably represents a late stage of the disease.

Arrhythmogenic Right Ventricular Cardiomyopathy and Sudden Cardiac Death in Young Koreans

The aim of this study was to assess the frequency and clinical characteristics of arrhythmogenic right ventricular cardiomyopathy (ARVC) in young victims of sudden cardiac death (SCD). From January 1999 to December 2000, postmortem studies were conducted in 38 cases of SCD (age < or =35 (27+/-7) years old, 26 male) from the Taegu-Kyungpook region of southeastern Korea. Cases of sudden infant death syndrome were excluded. The causes of SCD were ARVC in 42%, acute myocardial infarction in 11%, myocarditis in 11%, pulmonary embolism in 8%, hypertrophic cardiomyopathy in 5%, aortic rupture in 3%, aortic stenosis in 3%, and unknown in 18%. The mean age of the 16 ARVC victims was 27+/-5 years and 10 were male. None were competitive athletes, or had been suspected of having cardiovascular disease before death. SCD was not related to vigorous physical or competitive activity and occurred during sleep in 7 cases, during work in 4, during bathing in 2, while driving, praying and eating in 1 case each. ARVC is an important cause of SCD in young people in this area of Korea.

Clinical profile and long-term follow-up of 37 families with arrhythmogenic right ventricular cardiomyopathy

OBJECTIVES

We sought to define the clinical picture and natural history of familial arrhythmogenic right ventricular cardiomyopathy (ARVC).

BACKGROUND

Arrhythmogenic right ventricular cardiomyopathy is a myocardial disease, often familial, clinically characterized by the impending risk of ventricular arrhythmias and sudden death.

METHODS

Thirty-seven ARVC families of northeast Italy were studied. Probands had a histologic diagnosis of ARVC, either at autopsy (19 families) or endomyocardial biopsy (18 families). Protocol of the investigation included basal electrocardiogram (ECG), 24-hour ECG, signal-averaged ECG, stress test and two-dimensional Doppler echocardiography. Invasive evaluation was performed when deemed necessary.

RESULTS

Of the 365 subjects, 151 (41%) were affected, 157 (43%) were unaffected, 17 (5%) were healthy carriers, and 40 (11%) were uncertain. Mean age at diagnosis was 31+/-13 years. By echocardiography, 64% had mild, 30% had moderate, and 6% had severe form. Forty percent had ventricular arrhythmias, 49 were treated with antiarrhythmic drugs, and two were treated with implantable cardioverter defibrillators. Sport activity was restricted in all. Of the 28 families who underwent linkage analysis, 6 mapped to chromosome 14q23-q24, 4 to 1q42-q43, and 4 to 2q32.1-q32.3. No linkage with known loci was found in four families and 10 had uninformative results. During a follow-up of 8.5+/-4.6 years, one patient died (0.08 patient/year mortality), and 15 developed an overt form of ARVC.

CONCLUSIONS

Arrhythmogenic right ventricular cardiomyopathy is a progressive disease appearing during adolescence and early adulthood. Systematic evaluation of family members leads to early identification of ARVC, characterized by a broad clinical spectrum with a favorable outcome. In the setting of positive family history, even minor ECG and echocardiographic abnormalities are diagnostic.

[Sudden death (VI). The Brugada syndrome and right myocardiopathies as a cause of sudden death. The differences and similarities]

In 1992 we described a new syndrome characterized by syncopal or sudden death episodes in patients with a structurally normal heart and a characteristic electrocardiogram 9 showing a pattern of right bundle branch block and ST segment elevation in right precordial leads V1 to V3. The disease is genetically determined with and autosomic dominant pattern of transmission. Until now three mutations and one polymorphism in the sodium cardiac channel gene have been identified in two families and one sporadic patient. As in many other genetically determined diseases, the disease is heterogeneous, caused by more than one gene. The syndrome has been identified in almost all countries in the world. Its incidence is difficult to evaluate, but it seems to be responsible for 4 to 10 sudden deaths per year per 10,000 inhabitants in areas like Laos or Thailand, and it represents the most frequent cause of death in young male adults in these countries. Up to 50% of all sudden deaths in patients with structurally normal heart are caused by the disease. The diagnosis can be easily made thanks to the characteristic electrocardiographic pattern. In some patients, the presence of concealed and intermittent forms might make the diagnosis more difficult. The electrocardiogram can be modulated by autonomic changes and administration of antiarrhythmic drugs. Beta-adrenergic stimulation normalizes the electrocardiogram, whereas ajmaline, flecainide or procainamide administration increase ST segment elevation. These drugs allow the unmasking of concealed or intermittent forms of the disease. Prognosis of patients with the syndrome is poor without an implantable defibrillator and antiarrhythmic drugs like amiodarone or betablockers do not protect against sudden death. The poor prognosis is similar in patients with a history of aborted sudden death or syncope and in asymptomatic patients in whom the abnormal electrocardiogram characteristic of the syndrome, was identified during a routine examination.