A novel treatment strategy for therapy refractory ventricular arrhythmias in the setting of arrhythmogenic right ventricular dysplasia

Heart Failure in Patients with Arrhythmogenic Cardiomyopathy

Arrhythmogenic cardiomyopathy (ACM) is a rare inherited cardiomyopathy characterized as fibro-fatty replacement, and a common cause for sudden cardiac death in young athletes. Development of heart failure (HF) has been an under-recognized complication of ACM for a long time. The current clinical management guidelines for HF in ACM progression have nowadays been updated. Thus, a comprehensive review for this great achievement in our understanding of HF in ACM is necessary. In this review, we aim to describe the research progress on epidemiology, clinical characteristics, risk stratification and therapeutics of HF in ACM.

Termination of Atrial Fibrillation With Epicardial Cooling in the Oblique Sinus

OBJECTIVES

This study aimed to determine if epicardial cooling could repeatedly terminate induced atrial fibrillation (AF) in a canine heart.

BACKGROUND

Rapid termination of AF could control symptoms and prevent atrial remodeling; however, defibrillation by internal electrical cardioversion is not tolerable to most patients. Cooling of the epicardium slows atrial conduction and may provide a less painful method to quickly terminate AF.

METHODS

AF was induced with atrial myocardial epinephrine injections and rapid atrial pacing in an open-chest canine. Attempts at termination were performed with a small metal device that was either cooled to 5°C or kept at body temperature (control module). The device was placed on the epicardial surface in the oblique sinus. The time from device contact to termination of AF was recorded.

RESULTS

In 5 different canine studies, there were 57 attempts at AF termination with either a 5°C module (34 attempts) or a control module (23 attempts). The median (interquartile range [IQR]) time to AF termination was 24 s (IQR: 15 to 35 s) for the 5°C therapy and 100 s (IQR: 47 to 240 s) for the body temperature treatments (p < 0.001). In the control group, there were 8 AF episodes that continued up to 4 min. Subsequent application of the 5°C cooling module terminated AF in all cases.

CONCLUSIONS

Epicardial cooling in the oblique sinus is effective for repeated termination of AF in a canine heart. If reproduced in human studies, epicardial cooling with an implantable device may provide a method for management of patients with AF.

Right ventricular dysplasia: management and treatment in light of current evidence

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a rare cardiovascular disease that predisposes to ventricular arrhythmias potentially leading to sudden cardiac death (SCD). ARVC varies considerably with multiple clinical presentations, ranging from no symptoms to cardiac arrhythmias to SCD. ARVC prevalence is not well known, but the estimated prevalence in the general population is 1:5000. Diagnosis of ARVC can be made by using the Revised European Society of Cardiology criteria for ARVC that includes ventricular structural and functional changes, ECG abnormalities, arrhythmias, family and genetic factors. The management of ARVC is focused on prevention of lethal events such as SCD. Implantable cardioverter defibrillator placement is the only proven mortality benefit in treatment of ARVC. Other treatment strategies include medications such as beta blockers and antiarrhythmics, radiofrequency ablation, surgery, cardiac transplantation, and lifestyle changes. All these interventions help in symptomatic treatment but none of them have proved to decrease mortality rates. ARVC is a progressive disease that leads to SCD if not treated appropriately. Management of these diseases has been a challenge for physicians. With the advent of technology and many new drugs/devices under clinical investigation, this might change in the future. However, while advances in technologies have helped elucidate many aspects of these diseases, many mysteries still remain of this unique disease. With continued research, we can expect more cost-effective and patient-friendly drug therapies and ablation techniques to be developed in the near future.

Treatment of Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia: An International Task Force Consensus Statement

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The Emerging Role of Epicardial Ablation

Sosa and colleagues first described a percutaneous approach (via the subxiphoid area) to access the pericardial space in 1996. Epicardial mapping and ablation is increasingly used for the treatment of supraventricular and ventricular arrhythmias and represents an adjunctive approach for challenging arrhythmias to improve procedural success rates. Epicardial ablation should be considered not only after the failure of an endocardial ablation but often as a first-line approach. Complications may occur during percutaneous access and epicardial ablation, and these might be reduced or avoided by improved operator skills and experience. New tools to access the epicardial space are being evaluated.

Combined resection and radiofrequency ablation of rhabdomyoma in a child with sustained ventricular tachycardia

Cardiac rhabdomyoma is a benign tumor of the heart in childhood and can be associated with life-threatening arrhythmia. In this report, we present the case of a 2-year-old male with right ventricular rhabdomyoma, who was admitted with syncope that was associated with episodes of sustained ventricular tachycardia. The patient underwent combined surgical resection and radiofrequency ablation of the tumor. There was no recurrence of ventricular tachycardia after surgery.

Ablation of ventricular arrhythmias in arrhythmogenic right ventricular dysplasia/cardiomyopathy: arrhythmia-free survival after endo-epicardial substrate based mapping and ablation

BACKGROUND

In patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy, freedom from ventricular arrhythmias (VAs) after endocardial ablation is limited. We compared the long-term freedom from recurrent VAs by using endocardial-alone ablation versus endo-epicardial substrate-based ablation.

METHODS AND RESULTS

Forty-nine patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy undergoing ablation of ventricular tachycardia (VT) were divided into 2 groups: endocardial-alone ablation (group 1, n = 23) and endo-epicardial ablation (group 2, n = 26). All patients had an implantable cardioverter-defibrillator (ICD). Conventional and 3D mappings were used to determine the mechanism of induced VTs and to identify area of "scar" or "abnormal" myocardium. All critical sites responsible for VTs and points with "abnormal" potential were targeted for ablation from endocardium (group 1) or from both endocardium and epicardium (group 2). The procedural end point was noninducibility of sustained, monomorphic VT with isoproterenol. The presence of frequent premature ventricular contractions at the end of ablation was recorded. Patients were followed up by ECG, Holter, and ICD interrogation. After a follow-up of at least 3 years, freedom from VAs or ICD therapy was 52.2% (12/23) in group 1 and 84.6% (22/26) in group 2 (P = 0.029), with 21.7% (5/23) and 69.2% (18/26) patients off antiarrhythmic drugs (P < 0.001), respectively. Compared with patients with no premature ventricular contractions after ablation, patients with frequent premature ventricular contractions after ablation were more likely to have VA recurrence/ICD therapy [3/33 (9%) versus 12/16 (75%); log-rank P<0.001].

CONCLUSIONS

An endo-epicardial-based ablation strategy achieves higher long-term freedom from recurrent VAs off antiarrhythmic therapy in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy when compared with endocardial-alone ablation. The presence of ≥ 10 premature ventricular contractions per minute after ablation is associated with more VA recurrence.

Arrhythmogenic right ventricular cardiomyopathy/dysplasia: a not so rare "disease of the desmosome" with multiple clinical presentations

Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) is a rare but increasingly recognized form of a cardiomyopathy, involving primarily the right ventricle. Mutations in seven candidate genes coding for five desmosomal proteins (plakoglobin, plakophilin-2, desmoplakin, desmoglein-2, desmocollin-2), for the cardiac ryanodine receptor-2, for the transforming growth factor beta-3, and for the transmembrane protein 43, respectively, are pathogenetically important. A typical feature of the disease is the replacement of the right ventricular myocardium by fibrofatty infiltrates, leading to electrical instability including ventricular arrhythmias in the early stages, and reduced contractility and heart failure later on. The left ventricle may also be involved. Unfortunately, the disease is often diagnosed post mortem only, especially in young adults dying suddenly during exercise. Since the disease is inherited in up to 50% of cases, the screening of relatives is important. The implantable cardioverter defibrillator is an important therapeutic tool. Nevertheless, the mortality of the disease remains to be 2%-4% per year. Several clinical, electrocardiographic, and imaging parameters were identified as risk predictors for an adverse outcome. In this paper, we describe distinct clinical presentations of ARVC/D, review the genetic background of the disease, and discuss its diagnosis and treatment.