Successful radiofrequency catheter ablation of ventricular tachycardia originating from underneath the mechanical prosthetic aortic valve

Clinical Significance of Ventricular Tachyarrhythmias in Patients Undergoing Valve Replacement: A Nationwide Population-Based Study

Background: The clinical significance and outcomes of ventricular tachyarrhythmias (VTa) in patients undergoing valve replacement have rarely been reported.

Objective: This study aimed to investigate the incidence and outcome of VTa after surgical valve replacement.

Methods: We conducted a population-based retrospective cohort study using data obtained from the Taiwan National Health Insurance Research Database. In total, 10,212 patients were selected after 1:1 propensity-score matching based on the type of prosthetic valve used (mechanical vs. bioprosthetic). Various outcomes during long-term follow-up were analyzed.

Results: After a median follow-up period of 59.6 months, the crude incidence rate of VTa after surgical valve replacement was 4.8/1,000 person-years, and the cumulative incidence of VTa persistently increased after surgery. Furthermore, the occurrences of VTa after valve replacement significantly increased the risk of cardiovascular (CV) death (P < 0.001, HR 1.67, 95% CI 1.41–1.96), stroke- (P < 0.001, HR 1.66, 95% CI 1.37–2.01), atrial fibrillation- (P < 0.001, HR 2.80, 95% CI 2.42–3.24), and congestive heart failure-related hospitalization (P < 0.001, HR 2.61, 95% CI 2.30–2.95). Among patients with VTa, all-cause mortality (P = 0.001, HR 0.49, 95% CI 0.32–0.75) and CV death (P = 0.047, HR 0.58, 95% CI 0.34–0.99) in those with implantable cardioverter-defibrillator (ICD) implantation were lower than those without.

Conclusion: The crude incidence rate of VTa after surgical valve replacement was 4.8/1,000 person-years, and the cumulative incidence of VTa persistently increased during follow-up. The presence of VTa after surgical valve replacement increases hospitalization and CV death, while ICD implantation reduced the mortality rate in these patients.

Percutaneous Interventricular Septal Access Guided by Subcostal Echocardiography and Fluoroscopy for Ventricular Tachycardia Ablation in a Patient with Aortic and Mitral Mechanical Valves

Mechanical prosthetic aortic and mitral valves preclude either a retrograde aortic or transseptal approach to the left ventricular (LV) endocardium. Several operators have reported on the application of nonconventional techniques for ventricular tachycardia (VT) ablation including transventricular septal puncture, epicardial approach, transmechanical valve approach, transcoronary venous approach, and transapical approach. Incorporating transventricular access to the LV under intracardiac echocardiography (ICE) guidance has been previously attempted in VT ablation procedures in patients with both aortic and mitral mechanical valves. However, while ICE is readily used in the United States, its use is less common in Europe, since the health insurance agencies largely do not cover the costs of ICE catheters. We therefore herein present a case of VT ablation in the LV using a transventricular approach in a patient who underwent mechanical double valve replacement performed under subcostal echocardiographic and fluoroscopic guidance.

Special considerations in mapping and ablation of focal ventricular arrhythmias originating from the left ventricular outflow tract in patients with a transcatheter aortic valve replacement

Transcatheter aortic valve replacements (TAVRs) have been increasingly performed in high-risk patients with severe aortic stenosis. Focal ventricular arrhythmias (VAs) originating from the left ventricular outflow tract (LVOT) can occur after a TAVR, and radiofrequency catheter ablation (RFCA) should be considered as a treatment option when those VAs are drug-refractory. There are specific challenges in the RFCA of LVOT VAs after a TAVR because the tubular structure of the TAVR device sits in the LVOT. However, if the anatomical background of the TAVR and LVOT VAs are well understood and the anatomical relationship between the TAVR device and LVOT is sufficiently evaluated, RFCA of LVOT VAs in patients with a TAVR should be safe and highly successful.

Electrophysiologic Substrate, Safety, Procedural Approaches, and Outcomes of Catheter Ablation for Ventricular Tachycardia in Patients After Aortic Valve Replacement

OBJECTIVES

This study sought to investigate the substrate, procedural strategies, safety, and outcomes of catheter ablation (CA) for ventricular tachycardia (VT) in patients with aortic valve replacement (AVR).

BACKGROUND

VT ablation in patients with AVR is challenging, particularly when mapping and ablation in the periaortic region are necessary.

METHODS

We identified consecutive patients with mechanical, bioprosthetic, and transcatheter AVR who underwent CA for VT refractory to antiarrhythmic drugs and analyzed VT substrate, approach to LV access, complications, and long-term outcomes.

RESULTS

Overall, 29 patients (87% men, mean age 67.9 ± 9.8 years, left ventricular ejection fraction 39 ± 10%) with prior AVR (13 mechanical, 15 bioprosthetic, 1 transcatheter AVR) underwent 40 ablations from 2004 to 2016. Left-sided mapping/CA was performed in 27 patients (36 procedures). Access was retrograde aortic in 11 procedures (all bioprosthetic), transseptal in 24 (13 mechanical; 10 bioprosthetic; 1 transcatheter AVR), or transventricular septal in 1. Periaortic bipolar or unipolar scar was detected in all 24 patients in whom detailed periaortic mapping was performed. Clinical VT circuit(s) involved the periaortic region in 10 patients (34%), 2 (7%) had bundle branch re-entry VT, and 17 (59%) had substrate unrelated to AVR. There were 2 major complications (both related to vascular access). Only 2 patients (9.1%) had VT recurrence. Over median follow-up of 12.8 months, 11 patients died (none as a result of recurrent VT).

CONCLUSIONS

Whereas most patients undergoing CA for VT after AVR had VT from substrate unrelated to AVR, periaortic scar is universally present and bundle branch re-entry can be the VT mechanism. CA can be safely performed with excellent long-term VT elimination.

Ventricular arrhythmias originating from the aortomitral continuity: an uncommon variant of left ventricular outflow tract tachycardia

AIMS

Ventricular arrhythmias arising from the fibrous rings have been demonstrated, but knowledge about the aortomitral continuity (AMC) as a source of the arrhytmias is still limited. The objective is to describe the characteristics of ventricular arrhythmias originating from the AMC in patients without structural heart disease.

METHODS AND RESULTS

Ten patients with ventricular tachycardia (VT) and/or premature ventricular contractions, who had been successfully treated by catheter ablation at the AMC beneath the aortic valve, were enrolled. Clinical data and electrocardiographic characteristics were analysed. Three of the 10 patients had previously registered episodes of supraventricular tachycardia and had undergone catheter ablation of atrioventricular nodal reentrant tachycardia (AVNRT). In four patients with anterior AMC location, early R/S wave transition was found in the precordial leads, with equal R and S amplitudes in V2, rS in V1, and R in V3. In six patients whose VT arose from the middle part of the AMC, we demonstrated a special ('rebound') transition pattern, with which equal R and S amplitudes occurred in V2, and high R waves in V1 and V3. In the anterior AMC location, the S/R ratios in leads V1 and V2 were >1 and statistically significantly higher than those located in the middle (V1: 1.59 vs. 0.23, P< 0.001; V2: 1.52 vs. 0.41, P< 0.01).

CONCLUSIONS

We report a series of ventricular arrhythmias arising from the AMC with different R/S wave transition patterns in the precordial leads on the electrocardiogram. There may be a relationship between ventricular arrhythmias from AMC and AVNRT.

Transseptal versus transaortic approach for radiofrequency ablation in patients with cardioverter-defibrillator and electrical storm

PURPOSE

Radiofrequency current ablation (RFCA) of ventricular tachycardia (VT) is usually performed using a retrograde transaortic approach. We compared the mapping accuracy, procedural course, safety, and results of VT ablation using transseptal and transaortic route.

METHODS

Twenty-one consecutive patients with ischemic cardiomyopathy and history of electrical storm underwent RFCA with electro-anatomic mapping system. In six patients, ablation was performed with transseptal approach (transseptal group); in 15, retrograde approach to the left ventricle was used (retrograde group).

RESULTS

The endocardial surface of the left ventricle was similarly accessible in both methods. Less detailed maps of interventricular septum were constructed with the use of transseptal approach. The RFCA success rate was similar in the transseptal and retrograde groups (83 vs. 80%, p = NS). The median procedural time was 112 min in transseptal vs. 145 min in the retrograde group; radiation exposure was 200 vs. 67 mGy, respectively (both p < 0.05), and fluoroscopy time was 22 vs.16 min (p = NS). During the 3-month follow-up, VT recurrence occurred in one patient in the transseptal group and in three patients in the retrograde group (p = NS).

CONCLUSIONS

Transseptal approach is an accurate, safe, feasible, and effective method of RF ablation in patients with malignant, recurrent ventricular arrhythmias. However, limited access to the septal regions with the use of this method has to be remembered. Transseptal approach may be considered as an alternative to the transaortic route in patients with contraindication to the latter.