Atrial involvement in arrhythmogenic right ventricular cardiomyopathy patients referred for ventricular arrhythmias ablation

Reduced plakoglobin increases the risk of sodium current defects and atrial conduction abnormalities in response to androgenic anabolic steroid abuse

Androgenic anabolic steroids (AAS) are commonly abused by young men. Male sex and increased AAS levels are associated with earlier and more severe manifestation of common cardiac conditions, such as atrial fibrillation, and rare ones, such as arrhythmogenic right ventricular cardiomyopathy (ARVC). Clinical observations suggest a potential atrial involvement in ARVC. Arrhythmogenic right ventricular cardiomyopathy is caused by desmosomal gene defects, including reduced plakoglobin expression. Here, we analysed clinical records from 146 ARVC patients to identify that ARVC is more common in males than females. Patients with ARVC also had an increased incidence of atrial arrhythmias and P wave changes. To study desmosomal vulnerability and the effects of AAS on the atria, young adult male mice, heterozygously deficient for plakoglobin (Plako+/-), and wild type (WT) littermates were chronically exposed to 5α-dihydrotestosterone (DHT) or placebo. The DHT increased atrial expression of pro-hypertrophic, fibrotic and inflammatory transcripts. In mice with reduced plakoglobin, DHT exaggerated P wave abnormalities, atrial conduction slowing, sodium current depletion, action potential amplitude reduction and the fall in action potential depolarization rate. Super-resolution microscopy revealed a decrease in NaV1.5 membrane clustering in Plako+/- atrial cardiomyocytes after DHT exposure. In summary, AAS combined with plakoglobin deficiency cause pathological atrial electrical remodelling in young male hearts. Male sex is likely to increase the risk of atrial arrhythmia, particularly in those with desmosomal gene variants. This risk is likely to be exaggerated further by AAS use. KEY POINTS: Androgenic male sex hormones, such as testosterone, might increase the risk of atrial fibrillation in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), which is often caused by desmosomal gene defects (e.g. reduced plakoglobin expression). In this study, we observed a significantly higher proportion of males who had ARVC compared with females, and atrial arrhythmias and P wave changes represented a common observation in advanced ARVC stages. In mice with reduced plakoglobin expression, chronic administration of 5α-dihydrotestosterone led to P wave abnormalities, atrial conduction slowing, sodium current depletion and a decrease in membrane-localized NaV1.5 clusters. 5α-Dihydrotestosterone, therefore, represents a stimulus aggravating the pro-arrhythmic phenotype in carriers of desmosomal mutations and can affect atrial electrical function.

Risk of atrial arrhythmias in patients with ventricular tachycardia in arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

In arrhythmogenic right ventricular cardiomyopathy (ARVC), risk of atrial arrhythmias (AAs) persists after ventricular tachycardia (VT) ablation.

OBJECTIVE

The purpose of this study was to determine the type, prevalence, outcome, and risk correlates of AA in ARVC in patients undergoing VT ablation.

METHODS

Prospectively collected procedural and clinical data on ARVC patients undergoing VT ablation were analyzed. Risk score for typical atrial flutter was determined from univariate logistic regression analysis.

RESULTS

Of 119 consecutive patients with ARVC and VT ablation, 40 (34%) had AA: atrial fibrillation (AF) in 31, typical isthmus-dependent atrial flutter (AFL) in 27, and atrial tachycardia/atypical flutter (AT) in 10. Seventeen patients (43%) with AA experienced inappropriate defibrillator therapy, with 15 patients experiencing shocks. Ablation was performed for typical AFL in 21 (53%), AT in 5 (13%), and pulmonary vein isolation for AF in 4 (10%) patients and prevented AA in 78% and all AFL during additional mean follow-up of 65 months. Risk score for typical flutter included age >40 years (1 point), ≥moderate right ventricular dysfunction (2 points), ≥moderate tricuspid regurgitation (2 points), ≥moderate right atrial dilation (2 points), and right ventricular volume >250 cc (3points), with score >4 identifying 50% prevalence of typical flutter.

CONCLUSION

AAs are common in patients with ARVC and VT, can result in inappropriate implantable cardioverter-defibrillator shocks, and typically are controlled with atrial ablation. A risk score can be used to identify patients at high risk for typical AFL who may be considered for isthmus ablation at the time of VT ablation.

[Arrhythmogenic right ventricular cardiomyopathy associated with arrhythmia-induced cardiomyopathy: A case report]

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a kind of inherited cardio-myopathy, which is characterized by fibro-fatty replacement of right ventricular myocardium, leading to ventricular arrhythmia. However, rapid atrial arrhythmias are also common, including atrial fibrillation, atrial flutter and atrial tachycardia. Long term rapid atrial arrhythmia can lead to further deterioration of cardiac function. This case is a 51-year-old male. He was admitted to Department of Cardiology, Peking University Third Hospital with palpitation and fatigue after exercise. Electrocardiogram showed incessant atrial tachycardia. Echocardiography revealed dilation of all his four chambers, especially the right ventricle, with the left ventricular ejection fraction of 40% and the right ventricular hypokinesis. Cardiac magnetic resonance imaging found that the right ventricle was significantly enlarged, and the right ventricular aneurysm had formed; the right ventricular ejection fraction was as low as 8%, and the left ventricular ejection fraction was 35%. The patients met the diagnostic criteria of ARVC, and both left and right ventricles were involved. His physical activities were restricted, and metoprolol, digoxin, spironolactone and ramipril were given. Rivaroxaban was also given because atrial tachycardia could cause left atrial thrombosis and embolism. His atrial tachycardia converted spontaneously to normal sinus rhythm after these treatments. Since the patient had severe right ventricular dysfunction, frequent premature ventricular beats and non-sustained ventricular tachycardia on Holter monitoring, indicating a high risk of sudden death, implantable cardioverter defibrillator (ICD) was implanted. After discharge from hospital, physical activity restriction and the above medicines were continued. As rapid atrial arrhythmia could lead to inappropriate ICD shocks, amiodarone was added to prevent the recurrence of atrial tachycardia, and also control ventricular arrhythmia. After 6 months, echocardiography was repeated and showed that the left ventricle diameter was reduced significantly, and the left ventricular ejection fraction increased to 60%, while the size of right ventricle and right atrium decreased slightly. According to the clinical manifestations and outcomes, he was diagnosed with ARVC associated with arrhythmia induced cardiomyopathy. According to the results of his cardiac magnetic resonance imaging, the patient had left ventricular involvement caused by ARVC, and the persistent atrial tachycardia led to left ventricular systolic dysfunction.

Cardiomyopathies in China: A 2018-2019 state-of-the-art review

Cardiomyopathies are diseases of the cardiac muscle and are often characterized by ventricular dilation, hypertrophy, and cardiac arrhythmia. Patients with cardiomyopathies often experience sudden death and cardiac failure and require cardiac transplantation during the course of disease progression. Early diagnosis, differential diagnosis, and genetic consultation depend on imaging techniques, genetic testing, and new emerging diagnostic tools such as serum biomarkers. The molecular genetics of cardiomyopathies has been widely studied recently. The discovery of mechanisms underlying heterogeneity and overlapping of the phenotypes of cardiomyopathies has revealed the existence of disease modifiers, and this has led to the emergence of novel disease-modifying therapy. This 2018-2019 state-of-the-art review outlines the pathogenesis, diagnosis, and treatment of cardiomyopathies in China.

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.

Effect of Pregnancy in Arrhythmogenic Right Ventricular Cardiomyopathy

Less is known about pregnancy in women with arrhythmogenic right ventricular cardiomyopathy (ARVC). From April 1995 to May 2018, 157 women with ARVC were retrospectively enrolled. Data on pregnancy and cardiac outcomes were analyzed. There were 224 pregnancies in 120 patients including 30 (13.4%) spontaneous and 2 (0.9%) medical abortions, 12 cardiac adverse events were recorded including new onset frequent premature ventricular contractions (PVC) in 3 (2.5%) patients, previous PVC numbers increased more than 100% in 5 (4.2%), syncope in 2 (1.7%), sustained ventricular tachycardia and heart failure required hospitalization each in one patient (0.8%). Women with cardiac events showed lower left ventricular ejection fraction (LVEF) (50.3 ± 2.7 vs 60.0 ± 7.3; p = 0.004). No significant change in cardiac structure and function was found at 1 year follow-up postpartum. At a median follow-up of 8 (1 to 32) years, 36 (22.9%) women died. Earlier symptom onset age (hazard ratio 1.046; 95% confidence interval 1.017 to 1.075; p = 0.002) and decreased LVEF (hazard ratio 1.127; 95% confidence interval 1.001 to 1.154; p = 0.041) increased the risk of all-cause mortality, pregnancy had no negative influence on survival. In all the 192 offsprings (mean age 26.3 ± 13.5 years), 2 died of sudden death, no definite ARVC was found. Pregnancy seemed to be acceptable in ARVC, decreased LVEF increased the risk of pregnancy and was associated with poorer long-term survival.