Arrhythmogenic right ventricular cardiomyopathy: From pathophysiology to diagnosis and advances in management

Our understanding of arrhythmogenic right ventricular cardiomyopathy (ARVC) has advanced considerably over the past 30- 40 years. This is an inherited cardiomyopathy with complicated genetic inheritance and variable penetrance. Desmosomal dysfunction underlies most cases, and appreciating this pathophysiology has contributed to patient management, particularly with respect to exercise restriction to reduce disease progression. The diagnosis is made according to a series of Task Force Criteria, and subsequent management is guided by expert consensus in the absence of comparative data. ARVC is associated with sudden cardiac death (SCD), particularly in young athletic individuals who unknowingly harbour the condition. Risk stratification is important to guide implantable cardioverter- defibrillator use and reduce SCD. Residual gaps in our understanding, particularly surrounding incomplete penetrance, the underlying pathophysiology and risk stratification, are being targeted by collaborative efforts, large registries, prospective studies and translational research

Novel electrocardiographic criteria for the diagnosis of arrhythmogenic right ventricular cardiomyopathy

Aims: In order to improve the electrocardiographic (ECG) diagnosis of arrhythmogenic right ventricular cardiomyopathy (ARVC), we evaluated novel quantitative parameters of the QRS complex and the value of bipolar chest leads (CF leads) computed from the standard 12 leads. Methods and results: We analysed digital 12-lead ECGs in 44 patients with ARVC, 276 healthy subjects including 44 age and sex-matched with the patients and 36 genotyped members of ARVC families. The length and area of the terminal S wave in V1 to V3 were measured automatically using a common for all 12 leads QRS end. T wave negativity was assessed in V1 to V6 and in the bipolar CF leads computed from the standard 12 leads. The length and area of the terminal S wave were significantly shorter, whereas the S wave duration was significantly longer in ARVC patients compared with matched controls. Among members of ARVC families, those with mutations (n = 15) had shorter QRS length in V2 and V3 and smaller QRS area in lead V2 compared with those without mutations (n = 20). In ARVC patients, the CF leads were diagnostically superior to the standard unipolar precordial leads. Terminal S wave duration in V1 >48 ms or major T wave negativity in CF leads separated ARVC patients from matched controls with 90% sensitivity and 86% specificity. Conclusion: The terminal S wave length and area in the right precordial leads are diagnostically useful and suitable for automatic analysis in ARVC. The CF leads are diagnostically superior to the unipolar precordial leads

Effectiveness of physiotherapy and costs in patients with clinical signs of shoulder impingement syndrome: One-year follow-up of a randomized controlled trial

Objectives: To investigate the effect of manual physiotherapy and exercises compared with exercises alone in patients with shoulder impingement syndrome one year after inclusion. Design: Randomized controlled trial. Subjects: Patients with shoulder impingement of more than 4 weeks. Methods: The intervention group received individualized manual physiotherapy plus individualized exercises; the control group received individualized exercises only. Both groups had 10 treatments over 5 weeks; afterwards all patients continued their exercises for another 7 weeks at home. Primary outcomes were the Shoulder Pain and Disability Index and Patients' Global Impression of Change. The Generic Patient-Specific Scale was used as secondary outcome. Costs were recorded in a log-book. Results: Ninety patients were included in the study and 87 could be analyzed at 1-year follow-up. Both groups showed significant improvements in all outcome measures, but no difference was detected between the groups. Only costs differed significantly in favour of the control group (p=0.03) after 5 weeks. Conclusion: Individualized exercises resulted in lower costs than manual physiotherapy and showed a significant effect on pain and functioning within the whole group after one year. Exercises should therefore be considered as a basic treatment. Due to the progressive improvement that occurred during the follow-up period with individualized exercises further treatments should be delayed for 3 to 4 months

Low Prevalence of Risk Markers in Cases of Sudden Death Due to Brugada Syndrome Relevance to Risk Stratification in Brugada Syndrome

ObjectivesThe objective of this study was to determine the prevalence of conventional risk factors in sudden arrhythmic death syndrome (SADS) probands with Brugada syndrome (BrS).BackgroundPatients with BrS and previous aborted sudden cardiac death (SCD) are at high risk of recurrent events. Other universally accepted clinical features associated with higher risk include unheralded syncope and the presence of a spontaneous type 1 electrocardiogram (ECG).MethodsWe analyzed reported symptoms and reviewed ECGs from SADS probands with familial diagnoses of BrS, established by cardiological evaluation, including ECG, 2-dimensional echocardiography, Holter monitoring, exercise tolerance testing, and ajmaline provocation. These cases underwent familial evaluation between 2003 and 2010.ResultsA total of 49 consecutive families with a confirmed SADS death and a diagnosis of BrS were evaluated, comprising assessment of 202 family members in total. One family had 2 members with SADS, resulting in a total of 50 probands included. Mean age of death of probands was 29.1 ± 10.6 years, with 41 males (82%) (p < 0.05). Antemortem ECGs were available for 5 SADS probands, 1 of which demonstrated a spontaneous type 1 pattern. In 45 probands, symptoms before death were reported reliably by family members. Of these, 9 (20%) had experienced at least 1 syncopal episode before the fatal event. Importantly, 68% of probands would not have fulfilled any current criteria for consideration of implantable cardioverter-defibrillator.ConclusionsThe “low-risk” asymptomatic BrS group comprises the majority of SCD in this cohort. Current risk stratification would appear to be inadequate, and new markers of risk are vital

Late gadolinium enhancement in Brugada syndrome: A marker for subtle underlying cardiomyopathy?

BACKGROUND: There is increasing evidence that the Brugada ECG pattern is a marker of subtle structural heart disease. OBJECTIVE: We characterised Brugada syndrome (BrS) patients using cardiovascular magnetic resonance (CMR) with late gadolinium enhancement (LGE). METHODS: BrS was diagnosed according to international guidelines. 26% BrS patients carried SCN5A mutations. CMR data from 78 BrS patients were compared with 78 healthy controls (44±15 vs 42±14 years; p=0.434 and 64% vs 64% male; p=1.000). RESULTS: Right ventricular (RV) ejection fraction was slightly lower (61±8% vs 64±5%; p=0.004) and RV end-systolic volume slightly greater (31±10mL/m(2) vs 28±6mL/m(2); p=0.038) in BrS compared with controls. These values remained within the normal range. LGE was demonstrated in 8% BrS patients (left ventricular (LV) midwall LGE in 5%) but not in controls (p=0.028). In BrS patients with midwall LGE there were no other features of cardiomyopathy at the time of CMR but genetic testing and follow-up has revealed a desmoplakin mutation in one patient and evolution of T-wave inversion throughout all precordial ECG leads in another. Neither patient fulfils diagnostic criteria for arrhythmogenic right ventricular cardiomyopathy. CONCLUSION: Some BrS patients have LV midwall LGE consistent with an underlying cardiomyopathic process. Even cases without LGE show greater RV volumes and reduced RV function. These findings lend further support to the presence of subtle structural abnormalities in BrS. The BrS pattern with LGE may serve as early markers for evolution of a cardiomyopathic phenotype over time. CMR is a potentially useful adjunct investigation in the clinical evaluation of BrS

ECG Wavelet Analysis for the Detection of Gene Mutations in Patients with Brugada Syndrome

Abstract We applied wavelet transform (WT) Introduction The Brugada syndrome (BrS) is an inherited ion chanelopathy characterised by a typical electrocardiographic (ECG) pattern of J point and ST segment elevation in the right precordial leads and predisposition towards malignant ventricular arrhythmias Both depolarisation and repolarisation abnormalities contribute to the arrhythmia substrate and arrhythmia genesis in the BrS Wavelet analysis is a form of time-frequency transformation that has long been used in non-invasive electrocardiology for detection of characteristic ECG components, heart rate variability, analysis of ischaemic ST changes, ventricular repolarisation and others In this study, we hypothesised that continuous wavelet transform (WT) applied to the QRS and ST-T wave can help to identify carriers of SCN5A mutations among patients with the BrS. We analysed digital 15-lead ECGs previously recorded during positive diagnostic ajmaline test for BrS with simultaneous acquisition of the right precordial leads in both standard, as well as &quot;high&quot; electrode positions. Methods Study population and data acquisition The study population consisted of 26 patients (age 42.0±17.8 years, 13 men, 13 women, age 41.6±19.1 and 42.4±17.2, respectively, p=0.92 for men vs women) with suspected BrS who underwent diagnostic ajmaline test as part of their standard clinical management. All patients had either normal or non-diagnostic (i.e. not displaying type 1 Brugada ECG pattern) resting ECGs before the test. Details about this patient population have been partially described in previous publication

Anterior T-Wave Inversion in Young White Athletes and Nonathletes: Prevalance and Significance

BACKGROUND: Anterior T-wave inversion (ATWI) on electrocardiography (ECG) in young white adults raises the possibility of cardiomyopathy, specifically arrhythmogenic right ventricular cardiomyopathy (ARVC). Whereas the 2010 European consensus recommendations for ECG interpretation in young athletes state that ATWI beyond lead V1 warrants further investigation, the prevalence and significance of ATWI have never been reported in a large population of asymptomatic whites. OBJECTIVES: This study investigated the prevalence and significance of ATWI in a large cohort of young, white adults including athletes. METHODS: Individuals 16 to 35 years of age (n = 14,646), including 4,720 females (32%) and 2,958 athletes (20%), were evaluated by using a health questionnaire, physical examination, and 12-lead ECG. ATWI was defined as T-wave inversion in ≥2 contiguous anterior leads (V1 to V4). RESULTS: ATWI was detected in 338 individuals (2.3%) and was more common in women than in men (4.3% vs. 1.4%, respectively; p < 0.0001) and more common among athletes than in nonathletes (3.5% vs. 2.0%, respectively; p < 0.0001). T-wave inversion was predominantly confined to leads V1 to V2 (77%). Only 1.2% of women and 0.2% of men exhibited ATWI beyond V2. No one with ATWI fulfilled diagnostic criteria for ARVC after further evaluation. During a mean follow-up of 23.1 ± 12.2 months none of the individuals with ATWI experienced an adverse event. CONCLUSIONS: ATWI confined to leads V1 to V2 is a normal variant or physiological phenomenon in asymptomatic white individuals without a relevant family history. ATWI beyond V2 is rare, particularly in men, and may warrant investigation

The narrow-sense and common single nucleotide polymorphism heritability of early repolarization.

BACKGROUND: Early repolarization (ER) is a risk marker for sudden cardiac death. Higher risk is associated with horizontal/descending ST-segment ER in the inferior or inferolateral ECG leads. Studies in family cohorts have demonstrated substantial heritability for the ER pattern, but genome-wide association studies (GWAS) have failed to identify statistically significant and replicable genetic signals. METHODS AND RESULTS: We assessed the narrow-sense and common single nucleotide polymorphism (SNP) heritability of ER and ER subtypes using ECG data from 5829 individuals (TwinsUK, BRIGHT and GRAPHIC cohorts). ER prevalence was 8.3%. In 455 monozygous vs 808 dizygous twin pairs, concordances and twin correlations for ER subtypes (except horizontal/descending ST-segment ER) were higher and familial resemblance (except notched ER) was significant. Narrow-sense heritability estimates derived from 1263 female twin pairs using the structural equation program Mx ranged from 0.00-0.47 and common SNP heritability estimates derived from 4009 unrelated individuals of both sexes using Genome-wide Restricted Maximum Likelihood (GREML) ranged from 0.00-0.36, but none were statistically significant. CONCLUSION: From our data, ER shows limited genetic predisposition. There appears to be significant environmental influence and these modest narrow-sense and common SNP heritability estimates may explain why previous GWAS have been unsuccessful