Role of intracardiac echocardiography for guiding ablation of tricuspid valve arrhythmias

Mapping and Ablation of Premature Ventricular Complexes: State of the Art

Premature ventricular complexes (PVCs) are common arrhythmias in clinical practice. Although benign and asymptomatic in most cases, PVCs may result in disabling symptoms, left ventricular systolic dysfunction, or PVC-induced ventricular fibrillation. Catheter ablation has emerged as a first-line therapy in such cases, with high rates of efficacy and low risk of complications. Significant progress in mapping and ablation technology has been made in the past 2 decades, along with the development of a growing body of knowledge and accumulated experience regarding PVC sites of origin, anatomical relationships, electrocardiographic characterization, and mapping/ablation strategies. This paper provides an overview of the main indications for catheter ablation of PVCs, electrocardiographic features, PVC mapping techniques, and contemporary ablation approaches. The authors also review the most common sites of PVC origin and the main considerations and challenges with ablation in each location.

Mid-term outcome of catheter ablation of idiopathic non-outflow tract ventricular arrhythmias

BACKGROUND

Catheter ablation is recommended in patients with frequent and symptomatic ventricular arrhythmias (VAs) in an otherwise normal heart. Right or left outflow tract (OT) are the most common origins, and catheter ablation is highly effective with low complication rates. However, outcome of catheter ablation of VAs other than the OT (non-OTVAs) is limited. The aim of this single-center study was to assess the safety and mid-term outcome of catheter ablation for non-OTVAs.

METHOD AND RESULTS

From 2013 to 2018, 251 patients who underwent catheter ablation for idiopathic non-OTVAs were enrolled and grouped according to the origins including His-Purkinje system (HPS, n = 108), papillary muscle / moderator band (PM/MB, n = 47), tricuspid annulus (TA, n = 70), and mitral annulus (MA, n = 26), 244 (97.2%) had acute elimination of VAs. The time of VAs recurrence of the single procedure was 1.69 (0.12,9.72) months, with 66% occurring within the first 3 months. The recurrence rate was significantly higher in the PM/MB group than in the TA (p = 0.025) and MA groups (p = 0.023). The single procedure success rate in all patients was 70.1%, in which 66.7%, 59.6%, 80%, and 76.9% were achieved in the HPS, PM/MB, TA, and MA groups, respectively (p = 0.284). After multiple procedures, the total success rate was 76.5% at the follow-up of 4.38 ± 2.42 years. The rate was significantly lower in the PM/MB group than in the TA group (p = 0.035). In subgroup analysis, no significant difference was observed in the recurrence rate of single procedure in patients with different VA origins within the PM/MB (log-rank test, p = 0.546).

CONCLUSION

Despite a certain percentage of recurrences observed in the mid-term follow-up, catheter ablation remained feasible and effective for idiopathic non-OTVAs.

Intracardiac MR imaging (ICMRI) guiding-sheath with amplified expandable-tip imaging and MR-tracking for navigation and arrythmia ablation monitoring: Swine testing at 1.5 and 3T

PURPOSE

Develop a deflectable intracardiac MR imaging (ICMRI) guiding-sheath to accelerate imaging during MR-guided electrophysiological (EP) interventions for radiofrequency (500 kHz) ablation (RFA) of arrythmia. Requirements include imaging at three to five times surface-coil SNR in cardiac chambers, vascular insertion, steerable-active-navigation into cardiac chambers, operation with ablation catheters, and safe levels of MR-induced heating.

METHODS

ICMRI's 6 mm outer-diameter (OD) metallic-braided shaft had a 2.6 mm OD internal lumen for ablation-catheter insertion. Miniature-Baluns (MBaluns) on ICMRI's 1 m shaft reduced body-coil-induced heating. Distal section was a folded "star"-shaped imaging-coil mounted on an expandable frame, with an integrated miniature low-noise-amplifier overcoming cable losses. A handle-activated movable-shaft expanded imaging-coil to 35 mm OD for imaging within cardiac-chambers. Four MR-tracking micro-coils enabled navigation and motion-compensation, assuming a tetrahedron-shape when expanded. A second handle-lever enabled distal-tip deflection. ICMRI with a protruding deflectable EP catheter were used for MR-tracked navigation and RFA using a dedicated 3D-slicer user-interface. ICMRI was tested at 3T and 1.5T in swine to evaluate (a) heating, (b) cardiac-chamber access, (c) imaging field-of-view and SNR, and (d) intraprocedural RFA lesion monitoring.

RESULTS

The 3T and 1.5T imaging SNR demonstrated >400% SNR boost over a 4 × 4 × 4 cm3 FOV in the heart, relative to body and spine arrays. ICMRI with MBaluns met ASTM/IEC heating limits during navigation. Tip-deflection allowed navigating ICMRI and EP catheter into atria and ventricles. Acute-lesion long-inversion-time-T1-weighted 3D-imaging (TWILITE) ablation-monitoring using ICMRI required 5:30 min, half the time needed with surface arrays alone.

CONCLUSION

ICMRI assisted EP-catheter navigation to difficult targets and accelerated RFA monitoring.

Intracardiac echocardiography as an adjunctive tool for accessory pathway ablation in Ebstein anomaly

BACKGROUND

Accessory pathway (AP)-related arrhythmias are frequent in patients with Ebstein anomaly (EA), and arrhythmia recurrence after catheter ablation remains high despite current technological developments.

METHODS

Case series report of patients with EA who were taken to an accessory pathway ablation procedure and where clinical, procedure, and follow-up data are described. In all cases, mapping of the true tricuspid annulus guided by intracardiac ultrasound was used.

RESULTS

Six patients with EA underwent an ablation procedure using ICE to delineate the true tricuspid annulus. The duration of the procedure was 253.33 ± 60.92 min, with an acute success of 100%. After a mean follow-up of 16.16 ± 7.7 months, no recurrences of tachycardia were documented, and all patients were free of antiarrhythmic medications.

CONCLUSION

Intraprocedural ICE helps to delineate the true tricuspid annulus that contains the APs, facilitating mapping and ablation. We hypothesize that the systematic use of ICE in this scenario improves ablation efficacy while reducing complications, but this must be verified in prospective studies.

Intracardiac Echocardiography to Guide Catheter Ablation of Idiopathic Ventricular Arrythmias

Catheter ablation is the most effective treatment option for idiopathic ventricular arrhythmias. Intracardiac echocardiography (ICE) has been increasingly used during ablation procedures, allowing real-time visualization of cardiac anatomy, and improving our understanding of the relationships between different cardiac structures. In this article we review the adjuvant role of ICE to guide mapping and ablation of ventricular arrhythmias in the structurally normal heart.

Clinical outcomes of percutaneous debulking of tricuspid valve endocarditis in intravenous drug users

OBJECTIVES

A retrospective case series of a percutaneous approach to debulk tricuspid valve endocarditis (TVE) using an 8 French mechanical aspiration system in patients with a history of intravenous drug use (IVDU) was reported. IVDU associated TVE is increasing in the United States and is associated with high mortality despite early surgical debridement. Patients with advanced disease, shock, and respiratory failure may not be candidates for surgical debridement or replacement. These patients have recurrent events despite medical therapy METHODS: About 25 patients with IVDU associated TVE with persistent bacteremia confirmed by repeat blood cultures after 72 hr of sensitivity directed antibiotics and presence of pulmonary emboli confirmed by computed tomographic (CT) scan, who had undergone percutaneous aspiration were included. Patients were all deemed high risk for surgical debridement by a CT surgeon and evaluated by an infectious disease consultant. Procedures were performed under moderate sedation with intracardiac echo and a steerable guide with a CAT8 Penumbra aspiration catheter.

RESULTS

There were no intraprocedural deaths or complications. About 36% had septic shock on presentation. Survival of index hospitalization was 88%. Repeat blood cultures showed no growth on all surviving patients. Readmission rate was 4% (n = 1) at 1 month. About 40% (n = 2) patients with septic shock survived at 1 month compared with 100% survival (n = 20) in those without shock. Presence of septic shock was associated with reduced survival at 1 month (p < .01).

CONCLUSION

Percutaneous mechanical aspiration with an 8 Fr system is a feasible, minimally invasive alternative to surgical debulking. Mortality remains high in those presenting with septic shock. Further studies are needed to evaluate long-term outcomes.

Image Integration Using Intracardiac Echography and Three-dimensional Reconstruction for Mapping and Ablation of Atrial and Ventricular Arrhythmias

This article reviews the basis for image integration of intracardiac echocardiography (ICE) with three-dimensional electroanatomic mapping systems and preprocedural cardiac imaging modalities to enhance anatomic understanding and improve guidance for atrial and ventricular ablation procedures. It discusses the technical aspects of ICE-based integration and the clinical evidence for its use. In addition, it presents the current technical limitations and future directions for this technology. This article also includes figures and videos of clinical representative arrhythmia cases where the use of ICE is key to a safe and successful outcome.

Pulmonary Cusp Positioning of a Right Ventricular Outflow Tract Ventricular Tachycardia in a Pediatric Patient Identified Using Intracardiac Echocardiography

Ventricular premature beats originating from the right ventricular outflow tract can have myocardial extensions to the pulmonary valve and pulmonary artery. Treatment may consist of catheter ablation combined with the use of three-dimensional mapping to determine the exact location of ectopy. The location of ectopy relative to the pulmonary valve may be hard to ascertain. Intracardiac echocardiography (ICE) is a noninvasive approach by which one can determine the relationship of the pulmonary valve relative to the ablation catheter prior to ablation. ICE has achieved increasing popularity during the ablation of other arrhythmias such as tricuspid valve arrhythmias and has been shown to be helpful in guiding catheter placement prior to ablation. The additional information gained from deploying ICE may ensure more precise ablation, prevent theoretical damage to the pulmonary valve, and alleviate the need for a repeat procedure. Here, we present a case involving the use of ICE during a pediatric patient’s second ablation procedure to precisely determine the location of ectopy of nonsustained ventricular tachycardia originating from the distal pulmonary valve.