Catheter ablation of premature ventricular complexes associated with false tendons: A case report

BACKGROUND False tendon is a common intraventricular anatomical variation. It refers to a fibroid or fibromuscular structure that exists in the ventricle besides the normal connection of papillary muscle and mitral or tricuspid valve. A large number of clinical studies have suggested that there is a significant correlation between false tendons and premature ventricular complexes. However, few studies have verified this correlation during radiofrequency catheter ablation of premature ventricular complexes.CASE SUMMARY A 45-year-old male was admitted to receive radiofrequency ablation for symptomatic premature ventricular complexes. A three-dimensional model of the left ventricle was established by intracardiac echocardiography using the CartoSound^TM mapping system. In addition to the left anterior papillary muscle,the posterior papillary muscle was mapped. False tendons were found at the base of the interventricular septum, and the other end was connected to the left ventricular free wall near the apex. An irrigated touch force catheter was advanced into the left ventricle via the retrograde approach. The earliest activation site was marked at the interventricular septum attachment of the false tendons and was successfully ablated.CONCLUSION This case verified that false tendons can cause premature ventricular complexes and may be cured by radiofrequency ablation guided by intracardiac echocardiography with the Carto Sound TM system.

A Case of Premature Ventricular Complexes from the Proximal Left Bundle Branch Successfully Ablated from the Right Coronary Cusp

Background:Premature ventricular complexes(PVCs)from the proximal left bundle branch(LBB)can be ablated in the left ventricular outflow tract but can easily damage normal conduction bundles.Here,we report a case of successful ablation of PVCs from the proximal LBB within the right coronary cusp(RCC).Case presentation:Our patient was a 70-year-old woman with PVCs from the proximal LBB that were successfully ablated via the RCC through radiofrequency catheter ablation with a 3D mapping system;she had a complication of incomplete right bundle branch block(RBBB)and remained asymptomatic during follow-up.Conclusion:The RCC provides an alternative approach for ablating PVCs originating from the proximal LBB,ow-ing to the close relationship between the RCC and proximal LBB.

Evaluation of global and regional left ventricular systolic function in patients with frequent isolated premature ventricular complexes from the right ventricular outflow tract

Background Frequent premature ventricular complexes from the right ventricular outflow tract （RVOT-PVCs） are associated with left ventricular dysfunction.This study adopted two-dimensional speckle tracking imaging to evaluate global and regional left ventricular myocardial function in patients with frequent RVOT-PVCs.Methods This study included 30 patients with frequent RVOT-PVCs and 30 healthy subjects.Aortic systolic velocity-time integral （AoVTI） and myocardium strain in circumferential （CS）,radial （RS） and longitudinal （LS） directions were evaluated by conventional echocardiography and speckle tracking imaging.All values of patients with RVOT-PVCs were recorded during sinus （PVC-S） and PVC beats （PVC-V）.Results Significant differences were demonstrated in global CS,RS and LS between the control subjects and the PVC-V （CS：（17.46±2.48）% vs.（11.52±3.28）%,RS：（48.26±10.20）% vs.（20.92±9.78）%,LS：（19.89±2.62）% vs.（11.79±3.66）%,P 〈0.01）,and in segmental RS and LS of nearly all the left ventricular segments.Statistical differences in segmental CS between the PVC-V and the control subjects were only observed in anterior,anteroseptal and septal segments （only seen in anteroseptal and septal segments at apex）.Furthermore,V/S AoVTI （AoVTI during the PVC beat divided by AoVTI during the sinus beat,then multiplied by 100%） correlated with coupling interval （r=0.67,P 〈0.001） and global strain （CS：r=0.48,P=0.007; RS：r=0.65,P 〈0.001; LS：r=0.65,P 〈0.001）.Conclusions Frequent RVOT-PVCs can induce global and regional left ventricular systolic dysfunction.The reduction of hemodynamic parameters relates to the coupling interval and the global systolic function.

Impact of catheter-tissue contact force on lesion size during right ventricular outflow tract ablation in a swine model

Background:The catheter-tissue contact force(CF)is one of the significant determinants of lesion size and thus has a considerable impact on the effectiveness of ablation procedures.This study aimed to evaluate the impact of CF on the lesion size during right ventricular outflow tract(RVOT)ablation in a swine model.Methods:Twelve Guangxi Bama miniature male pigs weighing 40 to 50 kg were studied.After general anesthesia,a ThermoCool SmartTouch contact-sensing ablation catheter was introduced to the RVOT via the femoral vein under the guidance of the CARTO 3 system.The local ventricular voltage amplitude and impedance were measured using different CF levels.We randomly divided the animals into the following four groups according to the different CF levels:group A(3–9 g);group B(10–19 g);group C(20–29 g);and group D(30–39 g).Radiofrequency ablations were performed at three points in the free wall and septum of the RVOT in power control mode at 30 W for 30 s while maintaining the saline irrigation rate at 17 mL/min.At the end of the procedures,the maximum depth,surface diameter,and lesion volume were measured and recorded.A linear regression analysis was performed to determine the relationship between continuous variables.Results:A total of 72 ablation lesions were created in the RVOT of the 12 Bama pigs.The maximum depth,surface diameter,and volume of the lesions measured were well correlated with the CF(free wall:b=0.105,b=0.162,b=3.355,respectively,P<0.001;septum:b=0.093,b=0.150,b=3.712,respectively,P<0.001).The regional ventricular bipolar voltage amplitude,unipolar voltage amplitude,and impedance were weakly positively associated with the CF(b=0.065,b=0.125,and b=1.054,respectively,P<0.001).There was a significant difference in the incidence of steam pops among groups A,B,C,and D(free wall:F=7.3,P=0.032;septum:F=10.5,P=0.009);and steam pops occurred only when the CF exceeded 20 g.Trans-mural lesions were observed when the CF exceeded 10 g in the free wall,while the lesions in the septum were non-trans-mural even though the CF reached 30 g.Conclusions:CF seems to be a leading predictive factor for the size of formed lesions in RVOT ablation.Maintaining the CF value between 3 and 10 g may be reasonable and effective for creating the necessary lesion size and reducing the risk of complications,such as steam pops and perforations.