ARVC is an autosomal hereditary cardiomyopathy. The age of onset is usually between 20 and 40 years old. The overall incidence is about 0.02%, and the incidence in Europe and the United States can reach 0.05% [2, 4]. The disease was originally thought to be a congenital defect of right ventricular myocardial dysplasia. After the discovery of a genetic defect in the cardiac desmosomes, ARVC was defined as a cardiomyopathy. Subsequently, ARVC was considerded as a type of cardiomyopathy by the American Heart Association [5]. Clinical manifestations include the early concealed stage, the electrical change stage, and the structural change stage. Palpitations, syncope, and even sudden cardiac death due to fatal arrhythmias and slowly progressive ventricular dysfunction are common. Pathological features are progressive loss of right ventricular.

myocardium and replacement by fibro-fatty tissue. The features of ECG and echocardiography are ventricular arrhythmia and structural abnormalities of the right ventricle respectively. ARVC is a progressive disease, the early cardiac structure changes are not obvious or localized in the right ventricle, and the left ventricle may be involved in the late stage. The most commonly involved sites are the anterior wall of the conus arteriosus, the apex of the right ventricle, and the subbasal side of the right ventricular tricuspid valve, forming the so-called “triangle of dysplasia” which is considered a hallmark of ARVC [6]. At present, most of the mutations are believed to be located in desmosomal coding genes, mainly PKP2 [1, 6].

The ECG of the patient in the case showed VT with a left bundle-branch block pattern. Right ventricular angiography showed the formation of right ventricular apical aneurysm, and weakened myocardial motion. Voltage matrix mapping confirmed obvious myocardial fibrosis in the right ventricular apical aneurysm. Our case met the three main diagnostic criteria, therefore, the diagnosis of ARVC was confirmed. Because the early structural changes of ARVC were not obvious or localized to the right ventricle, conventional echocardiography was difficult to detect the changes, and patients with early ARVC were easily missed. At present, cardiac MRI is also an important and effective technique for diagnosis of cardiomyopathy. Nevertheless, cardiac MRI is not a routine preoperative examination because of its time consuming and complicated examination process.

We performed right ventricular angiography combined with matrix mapping during the procedure, and the radiofrequency ablation achieved a satisfactory result by homogenization ablation in the case. Previous studies have shown that image integration combined with voltage mapping improved the success rate of radiofrequency ablation [7, 8]. However, cardiac MRI cannot observe synchronously during the operation, and it cannot be used for patients with implanted electrical devices incompatible with MRI. Cardiac MRI is not a routine examination for ARVC patients without obvious cardiac structural changes in the early stage. Therefore, right ventricular angiography combined with voltage mapping may be a better choice for those patients.

The clinical manifestations such as malignant arrhythmia and heart failure, are controlled by medicines and devices, which is a main treatment target of ARVC. Treatment strategies include class I, II, III antiarrhythmic drugs, ICD implantation, and catheter ablation [6, 9]. Unfortunately, there is no specific drug to control or eliminate arrhythmia, or to change the natural course of the disease, and no drug alone or in combination can completely prevent sudden death for ARVC patients. A study by Orgeron GM et al. showed that ICD implantation is a safe and effective measure to improve the natural history of ARVC and prevent sudden death [2]. However, ICD implantation cannot control the onset of malignant arrhythmias, and it may lead to unwanted results, such as pain, anxiety, restlessness when patients are treated by electrical shock during ventricular tachycardia storms repeatedly. Therefore, antiarrhythmic drugs should be used as adjuvant therapy for ARVC patients with frequent ICD discharges. Catheter ablation is currently the most effective method to reduce or even eliminate VT [4, 10]. Recent evidence-based medical results from the largest number of cases in Asia on ARVC catheter ablation showed that both transendocardial and transepicardial catheter ablation could reduce the burden of VT episodes in ARVC patients, and even achieved clinical cure for a long time, the effective rate was about 71% [11, 12]. The patient in our case got VT as the main clinical manifestation. The latest research showed, long-term VT-free survival had been achieved in over half of ARVC patients following ENDO-only-ablation, increasing to over 75% if VT noninducibility was achieved [11]. In our case, we also achieved a better clinical outcome with only epithelial ablation.

Echocardiography showed no obvious structural changes of the right ventricle. Intraoperative right ventricular angiography and voltage mapping confirmed that the cardiomyopathy was limited to the apex of the right ventricle. Considering that the origin of VT was highly consistent with the location of myocardial lesion, catheter ablation would probably eliminate the VT. In fact, VT was no longer induced after the homogenizational ablation of the diseased myocardium, and no VT occurred during postoperative follow-up. Although the patient had no clear family history, early ICD implantation was still recommended for him in consideration of the particularity of ARVC and ICD implantation indications, the patients refused it. Thus, regular follow-up was arranged for him.