Usefulness of precordial T-wave inversion to distinguish arrhythmogenic right ventricular cardiomyopathy from idiopathic ventricular tachycardia arising from the right ventricular outflow tract

Humanized Dsp ACM Mouse Model Displays Stress-Induced Cardiac Electrical and Structural Phenotypes

Arrhythmogenic cardiomyopathy (ACM) is an inherited disorder characterized by fibro-fatty infiltration with an increased propensity for ventricular arrhythmias and sudden death. Genetic variants in desmosomal genes are associated with ACM. Incomplete penetrance is a common feature in ACM families, complicating the understanding of how external stressors contribute towards disease development. To analyze the dual role of genetics and external stressors on ACM progression, we developed one of the first mouse models of ACM that recapitulates a human variant by introducing the murine equivalent of the human R451G variant into endogenous desmoplakin (DspR451G/+). Mice homozygous for this variant displayed embryonic lethality. While DspR451G/+ mice were viable with reduced expression of DSP, no presentable arrhythmogenic or structural phenotypes were identified at baseline. However, increased afterload resulted in reduced cardiac performance, increased chamber dilation, and accelerated progression to heart failure. In addition, following catecholaminergic challenge, DspR451G/+ mice displayed frequent and prolonged arrhythmic events. Finally, aberrant localization of connexin-43 was noted in the DspR451G/+ mice at baseline, becoming more apparent following cardiac stress via pressure overload. In summary, cardiovascular stress is a key trigger for unmasking both electrical and structural phenotypes in one of the first humanized ACM mouse models.

Arrhythmogenic Right Ventricular Cardiomyopathy and Differential Diagnosis with Diseases Mimicking Its Phenotypes

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited heart muscle disease, which is characterized by fibro-fatty replacement of predominantly the right ventricle (RV). The disease can result in ventricular tachyarrhythmias and sudden cardiac death. Our understanding of the pathophysiology and clinical expressivity of ARVC has been continuously evolving. The diagnosis can be challenging due to its variable expressivity, incomplete penetrance and the lack of specific diagnostic criteria. Idiopathic RV outflow tract tachycardia, Brugada Syndrome, athlete’s heart, dilated cardiomyopathy, myocarditis, cardiac sarcoidosis, congenital aneurysms and diverticula may mimic clinical phenotypes of ARVC. This review aims to provide an update on the differential diagnosis of ARVC.

Diagnosing arrhythmogenic right ventricular cardiomyopathy by 2010 Task Force Criteria: clinical performance and simplified practical implementation

Aims

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is diagnosed by a complex set of clinical tests as per 2010 Task Force Criteria (TFC). Avoiding misdiagnosis is crucial to prevent sudden cardiac death as well as unnecessary implantable cardioverter-defibrillator implantations. This study aims to validate the overall performance of the TFC in a real-world cohort of patients referred for ARVC evaluation.

Methods and results

We included patients consecutively referred to our centres for ARVC evaluation. Patients were diagnosed by consensus of three independent clinical experts. Using this as a reference standard, diagnostic performance was measured for each individual criterion as well as the overall TFC classification. Of 407 evaluated patients (age 38 ± 17 years, 51% male), the expert panel diagnosed 66 (16%) with ARVC. The clinically observed TFC was false negative in 7/66 (11%) patients and false positive in 10/69 (14%) patients. Idiopathic outflow tract ventricular tachycardia was the most common alternative diagnosis. While the TFC performed well overall (sensitivity and specificity 92%), signal-averaged electrocardiogram (SAECG, P = 0.43), and several family history criteria (P ≥ 0.17) failed to discriminate. Eliminating these criteria reduced false positives without increasing false negatives (net reclassification improvement 4.3%, P = 0.019). Furthermore, all ARVC patients met at least one electrocardiogram (ECG) or arrhythmia criterion (sensitivity 100%).

Conclusion

The TFC perform well but are complex and can lead to misdiagnosis. Simplification by eliminating SAECG and several family history criteria improves diagnostic accuracy. Arrhythmogenic right ventricular cardiomyopathy can be ruled out using ECG and arrhythmia criteria alone, hence these tests may serve as a first-line screening strategy among at-risk individuals.

Arrhythmogenic right ventricular cardiomyopathy in patients with biallelic JUP-associated skin fragility

Arrhythmogenic right ventricular cardiomyopathy (ARVC), with skin manifestations, has been associated with mutations in JUP encoding plakoglobin. Genotype–phenotype correlations regarding the penetrance of cardiac involvement, and age of onset have not been well established. We examined a cohort of 362 families with skin fragility to screen for genetic mutations with next-generation sequencing-based methods. In two unrelated families, a previously unreported biallelic mutation, JUP: c.201delC; p.Ser68Alafs^*92, was disclosed. The consequences of this mutation were determined by expression profiling both at tissue and ultrastructural levels, and the patients were evaluated by cardiac and cutaneous work-up. Whole-transcriptome sequencing by RNA-Seq revealed JUP as the most down-regulated gene among 21 skin fragility-associated genes. Immunofluorescence showed the lack of plakoglobin in the epidermis. Two probands, 2.5 and 22-year-old, with the same homozygous mutation, allowed us to study the cross-sectional progression of cardiac involvements in relation to age. The older patient had anterior T wave inversions, prolonged terminal activation duration (TAD), and RV enlargement by echocardiogram, and together with JUP mutation met definite ARVC diagnosis. The younger patient had no evidence of cardiac disease, but met possible ARVC diagnosis with one major criterion (the JUP mutation). In conclusion, we identified the same biallelic homozygous JUP mutation in two unrelated families with skin fragility, but cardiac findings highlighted age-dependent penetrance of ARVC. Thus, young, phenotypically normal patients with biallelic JUP mutations should be monitored for development of ARVC.

A novel noninvasive surface ECG analysis using interlead QRS dispersion in arrhythmogenic right ventricular cardiomyopathy

Background

This study investigated the feasibility of using the precordial surface ECG lead interlead QRS dispersion (IQRSD) in the identification of abnormal ventricular substrate in arrhythmogenic right ventricular cardiomyopathy (ARVC).

Methods

Seventy-one consecutive patients were enrolled and reclassified into 4 groups: definite ARVC with epicardial ablation (Group 1), ARVC with ventricular tachycardia (VT, Group 2), idiopathic right ventricular outflow tract VT without ARVC (Group 3), and controls without VT (Group 4). IQRSD was quantified by the angular difference between the reconstruction vectors obtained from the QRS-loop decomposition, based on a principal component analysis (PCA). Electroanatomic mapping and simulated ECGs were used to investigate the relationship between QRS dispersion and abnormal substrate.

Results

The percentage of the QRS loop area in the Group 1–2 was smaller than the controls (P = 0.01). The IQRSD between V1-V2 could differentiate all VTs from control (P<0.01). Group 1–2 had a greater IQRSD than the Group 3–4 (V4-V5,P = 0.001), and Group 1 had a greater IQRSD than Group 3–4 (V6-Lead I, P<0.001). Both real and simulated data had a positive correlation between the maximal IQRSD (γ = 0.62) and the extent of corresponding abnormal substrate (γ = 0.71, both P<0.001).

Conclusions

The IQRSD of the surface ECG precordial leads successfully differentiated ARVC from controls, and could be used as a noninvasive marker to identify the abnormal substrate and the status of ARVC patients who can benefit from epicardial ablation.

Electrocardiographic (ECG) clues to differentiate idiopathic right ventricular outflow tract tachycardia (RVOTT) from arrhythmogenic right ventricular cardiomyopathy (ARVC)

INTRODUCTION

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a genetic cardiomyopathy that most commonly affects young adults. The most commonly observed reason of death in patients suffering from ARVC/D is sudden cardiac death (SCD). On the other hand, idiopathic right ventricular outflow tract tachycardia (RVOT VT) usually has a benign course. Both of the entities may have ventricular tachycardia (VT) with left bundle branch block (LBBB) pattern and inferior axis. We tried to propose new discriminating electrocardiographic indices for differentiation of foretold entities.

MATERIAL AND METHOD

This was a retrospective study. We reviewed records of patients admitted between 2003 and 2012 with the diagnosis of either ARVC/D or RVOT VT that presented with VT (LBBB morphology).

RESULT

A total of fifty nine patients (30 RVOT VT and 29 ARVC/D) were enrolled. In ARVC/D group, men were dominant while the reverse was true of RVOT VT. Palpitation was more common in the RVOT VT group (90% vs. 66.7%), but aborted SCD and sustained VT were more common in ARVC/D group. The new ECG criteria proposed by us mean QRS duration in V1-V3, QRS difference in right and left precordial leads, S wave upstroke duration, JT interval dispersion, QRS and JT interval of right to left precordial leads were all significantly longer in ARVC/D when compared to RVOT VT patients (p < 0.001).

CONCLUSION

The proposed ECG criteria can be used for non-invasive diagnosis of ARVC/D and incorporation in the future updates of ARVC/D task force criteria.

Usefulness of T(peak) -T(end) interval to distinguish arrhythmogenic right ventricular cardiomyopathy from idiopathic right ventricular outflow tract tachycardia

BACKGROUND

The two predominant etiologies of right ventricular tachycardia (VT) are arrhythmogenic right ventricular cardiomyopathy (ARVC) and idiopathic VT arising from the right ventricular outflow tract (RVOT). Discrimination between these two entities is critical, as their prognoses and therapeutic options differ. The Tpeak -Tend (Tpe) interval reflects the transmural repolarization dispersion and its prolongation is associated with high mortality.

METHODS

We compared the sinus rhythm electrocardiogram (ECG) of 43 patients (24 male, 43 ± 16 years) with VT originating from right ventricle. Five patients under antiarrhythmic drug therapy were excluded. Tpe interval was measured in each precordial leads and compared among patients with ARVC and RVOT-VT.

RESULTS

Twenty-five patients (16 male, 42 ± 16 years) met the Task Force criteria for the diagnosis of ARVC, and 13 patients (seven male, 45 ± 14 years) had idiopathic RVOT tachycardia. Patients with ARVC had significantly prolonged Tpe intervals in all precordial leads compared to patients with idiopathic RVOT VT (137.1 ± 32.6 ms vs 93.8 ± 16.9 ms; P < 0.001 in V1, 133.2 ± 35.5 ms vs 104.7 ± 16.9 ms; P = 0.01 in V2, 125.7 ± 31.5 ms vs 99.1 ± 19.6 ms; P = 0.09 in V3, 121.9 ± 26.5 ms vs 92.3 ± 19.7 ms; P = 0.001 in V4, 123.1 ± 26.5 ms vs 99.5 ± 20:1 ms; P = 0.04 in V5 and 126.9 ± 32.2 ms vs 89 ± 11.3 ms; P < 0.001 in V6, respectively). For the diagnosis of ARVC, Tpe cut-off value of 97 ms in V1 had 84% sensitivity and 62% specificity (area under curve = 0.880).

CONCLUSION

In patients with VT of RV origin, the prolonged Tpe interval in sinus rhythm electrocardiogram supports the diagnosis of ARVC.

The electrocardiographic manifestations of arrhythmogenic right ventricular dysplasia

The ECG is abnormal in most patients with arrhythmogenic right ventricular dysplasia (ARVD). Right ventricular parietal block, reduced QRS amplitude, epsilon wave, T wave inversion in V1-3 and ventricular tachycardia in the morphology of left bundle branch block are the characteristic changes that reflect the underlying genetic predetermined pathology and pathoelectrophysiology. Recognizing the characteristic ECG changes in ARVD will be of help in making a correct diagnosis of this rare disease.

An electrocardiographic scoring system for distinguishing right ventricular outflow tract arrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy from idiopathic ventricular tachycardia

BACKGROUND

Ventricular arrhythmias in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) and idiopathic ventricular tachycardia (VT) can share a left bundle branch block/inferior axis morphology. We previously reported electrocardiogram characteristics during outflow tract ventricular arrhythmias that helped distinguish VT related to ARVD/C from idiopathic VT.

OBJECTIVE

To prospectively validate these criteria.

METHODS

We created a risk score by using a derivation cohort. Two experienced electrophysiologists blinded to the diagnosis prospectively scored patients with VT/premature ventricular contractions (PVCs) with left bundle branch block/inferior axis pattern in a validation cohort of 37 ARVD/C tracings and 49 idiopathic VT tracings. All patients with ARVD/C had their diagnosis confirmed based on the revised task force criteria. Patients with idiopathic VT were selected based on structurally normal hearts with documented right ventricular outflow tract VT successfully treated with ablation. The scoring system provides 3 points for sinus rhythm anterior T-wave inversions in leads V1-V3 and during ventricular arrhythmia: 2 points for QRS duration in lead I≥120 ms, 2 points for QRS notching, and 1 point for precordial transition at lead V5 or later.

RESULTS

A score of 5 or greater was able to correctly distinguish ARVD/C from idiopathic VT 93% of the time, with a sensitivity of 84%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 91%.

CONCLUSIONS

We describe a simple scoring algorithm that uses 12-lead electrocardiogram characteristics to effectively distinguish right ventricular outflow tract arrhythmias originating from patients with ARVD/C versus patients with idiopathic VT.

Arrhythmogenic right ventricular cardiomyopathy 2012: diagnostic challenges and treatment

The most common presentation of arrhythmogenic right ventricular cardiomyopathy (ARVC) is palpitations or ventricular tachycardia (VT) of left bundle branch morphology in a young or middle-aged individual. The 12-lead electrocardiogram may be normal or have T-wave inversion beyond V(1) in an otherwise healthy person who is suspected of having ARVC. The most frequent imaging abnormalities are an enlarged right ventricle, decrease in right ventricular (RV) function, and localized wall motion abnormalities. Risk factors for implantable cardioverter defibrillator include a history of aborted sudden death, syncope, young age, decreased left ventricular function, and marked decrease in RV function. Recent results of treatment with epicardial ablation are encouraging.

Diagnostic and Therapeutic Dilemmas with Arrhythmic Right Ventricular Cardiomyopathy

The diagnosis of arrhythmic right ventricular cardiomyopathy (ARVC) can be difficult, particularly in patients who have early manifestations of the disease. Modification of the 1994 Diagnostic Test Task Force criteria has recently been published. The most frequent cause for misdiagnosis is incorrect interpretation of a cardiac imaging test, particularly magnetic resonance imaging. The results of genetic testing must be interpreted with caution. Genetic abnormalities may be absent in 50% of patients with ARVC and penetrance is variable.

Electrocardiographic comparison of ventricular arrhythmias in patients with arrhythmogenic right ventricular cardiomyopathy and right ventricular outflow tract tachycardia

OBJECTIVES

The purpose of this study was to evaluate whether electrocardiographic characteristics of ventricular arrhythmias distinguish patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) from those with right ventricular outflow tract tachycardia (RVOT-VT).

BACKGROUND

Ventricular arrhythmias in RVOT-VT and ARVD/C-VT patients can share a left bundle branch block/inferior axis morphology.

METHODS

We compared the electrocardiographic morphology of ventricular tachycardia or premature ventricular contractions with left bundle branch block/inferior axis pattern in 16 ARVD/C patients with that in 42 RVOT-VT patients.

RESULTS

ARVD/C patients had a significantly longer mean QRS duration in lead I (150 ± 31 ms vs. 123 ± 34 ms, p = 0.006), more often exhibited a precordial transition in lead V(6) (3 of 17 [18%] vs. 0 of 42 [0%] with RVOT-VT, p = 0.005), and more often had at least 1 lead with notching (11 of 17 [65%] vs. 9 of 42 [21%], p = 0.001). The most sensitive characteristics for the detection of ARVD/C were a QRS duration in lead I of ≥120 ms (88% sensitivity, 91% negative predictive value). QRS transition at V(6) was most specific at 100% (100% positive predictive value, 77% negative predictive value). The presence of notching on any QRS complex had 79% sensitivity and 65% specificity of (55% positive predictive value, 85% negative predictive value). In multivariate analysis, QRS duration in lead I of ≥120 ms (odds ratio [OR]: 20.4, p = 0.034), earliest onset QRS in lead V(1) (OR: 17.0, p = 0.022), QRS notching (OR: 7.7, p = 0.018), and a transition of V(5) or later (OR: 7.0, p = 0.030) each predicted the presence of ARVD/C.

CONCLUSIONS

Several electrocardiographic criteria can help distinguish right ventricular outflow tract arrhythmias originating from ARVD/C compared with RVOT-VT patients.