Electrocardiographic Features, Electrophysiological Mapping And Radiofrequency Ablation And Genetic Characteristics Of Ventricular Premature Ventricular Contraction In The Right Ventricle Non - Effluent

Section I:Electrocardiogram Characteristics of Right Ventricular Premature Contraction Arising from the Non-outflow TractObject:Most idiopathic ventricular arrhythmia originate from the right ventricular outflow tract. Data on premature ventricular contraction (PVC) from the other site of right ventricle are limited. This study aimed to analyze the electrocardiogram characteristics of PVC originating from the free wall or septal wall of right ventricular body.Methods:A total of thirty-six patients (25 male,35.7±18.2 years) who underwent ablation for premature ventricular contraction arising from the body of right ventricle were retrospectively studied. The endocardial mapping and catheter ablation were performed in all patients under the guidance of Ensite-Navx system. The PVCs was divided into free wall group and septum group by the ablation target and the electrocardiogram characteristics were analyzed.Results:Among the 36 patients,11 (31%) originated from the septum and 25 (69%) from the free wall. All PVCs had a left bundle branch block pattern. A QS pattern in lead V1 was observed more often in PVCs arising from the septum than those from the free wall. R-wave transition occurred beyond lead V3 more often in PVCs arising from the free wall than those from the septum (P<0.01). QRS duration were longer in PVCs arising from the free wall than those from the septum(P<0.001). Notching of the QRS complex was observed more often in PVCs arising from the free wall than those from the septum (P<0.01). The sensitivity and specificity of QS pattern in lead V1 in predicting septal origin was 100% and 96.2%, respectively. The positive predictive value was 90.9%, negative predictive value was 100%. The area under curve of QRS duration in differentiating origin of PVC was 0.898. With the cut-off value 150 ms, the sensitivity and specificity in predicting origin of PVC was 88% and 81.8%, respectively. The positive predictive value was 91.7%, negative predictive value was 75%.Conclusions:Idiopathic PVCs from the right ventricle body has distinctive electrocardiogram characteristics. We can distinguish the original site of PVC from the electrocardiogram. A QS pattern in lead V1 could best predict the septal origin.Section Ⅱ:Electrophysiological Characteristics and Radiofrequency Catheter Ablation of Right Ventricular Premature Contraction not Arising from the Outflow TractObject:Data on electrophysiological characteristics and radiofrequency catheter ablation of right ventricular premature contraction not arising from the outflow tract are limited. This study aimed to analyze the electrophysiological characteristics and radiofrequency catheter ablation of premature ventricular contraction (PVC) originating from the body of right ventricle with normal cardiac structure.Methods:A total of thirty-six patients (25 male.35.7± 18.2 years) who underwent ablation for PVC arising from the body of right ventricle were studied. Right ventricle geometry model was built by Ensite NavX system. Activation mapping, pacemapping and voltage mapping were performed to confirm the origin of PVC. The earliest activity of PVC and the low voltage zone were ablation by RF. The PVCs was divided into free wall group and septum group by the origin.Results:Among the 36 patients,11 (31%) originated from the septum and 25 (69%) from the free wall. RF catheter ablation eliminated 9 (82%) of the PVCs arising from the septum except two parahisian PVCs which targets were too close to atrioventricular node. There was low voltage zone in 11(44%) patients whose PVCs arising from free wall of right ventricle and regional ablation was performed. RF catheter ablation eliminated 22(88%) of the PVCs arising from the free wall except three case whose PVCs were supposed to originate from epicardium because no pace mapping was matched in endocardium. No complications were observed in all the patients.Conclusions:Most PVCs arising from the right ventricle body can be eliminated by radiofrequency catheter ablation. It is helpful to locate and ablate the exact target of PVC by three-dimensional electroanatomic system.Section III:Screening of Arrhythmogenic Right Ventricular Cardiomyopathy Pathogenic Genes in Right Ventricular Premature Contraction not Arising from the Outflow TractObjective:The low-voltage zone and thermally induced ventricular tachycardia were usually found during the mapping of right ventricular premature contraction arising from the basal-lateral part of the tricuspid annulus. These electrophysiological characteristics were similar to arrhythmogenic right ventricular cardiomyopathy (ARVC). The basal-lateral part of the tricuspid annulus was also the most common location of ARVC ventricular tachycardia. This study was aimed to screening ARVC-causing genes in these patients and find out whether they are in the early stage ofARVC.Methods:A total of 17 patients whose premature ventricular contracts were confirmed arising from the basal-lateral part of the tricuspid annulus by electrophysiological study and 300 age, gender and ethnicity-matched healthy controls were genetically tested for 9 previously reported ARVC-causing genes, including plakophilin-2(PKP2), desmoplakin (DSP), desmoglein-2 (DSG2), desmocollin-2 (DSC2), and plakoglobin (JUP), transforming growth factor beta-3 (TGFfβ3), transmembrane protein 43 (TMEM43), desmin (DES) and Lamin A/C (LMNA), with multiplexing targeted resequencing. Clinical characteristics and electrophysiological characteristics were compared between the two groups of mutation carriers and non-carriers.Results:Three mutations were identified in 18%(3/17) of the patients, among which, two were missense mutation and one was splice mutation. All the mutation were located in desmosomal protein genes, including PKP2,DSP and DSG2. No mutation was found in non-desmosomal genes. Genotype-phenotype analysis showed that no difference was found in the clinical characteristics and electrophysiological characteristics between mutation carriers and non-carriers.Conclusions:The ARVC-causing genes can be found in patients whose premature ventricular contracts were arising from the basal-lateral part of the tricuspid annulus. No difference was found in the clinical characteristics and electrophysiological characteristics between mutation carriers and non-carriers.