We describe the case of a 38-year-old male with a long history of paroxysmal supraventricular tachycardia (PSVT) who was found to have typical slow–fast atrioventricular nodal reentrant tachycardia (AVNRT) and nodoventricular reentrant tachycardia (NVRT). During an electrophysiology study, a wide complex tachycardia with left bundle branch block (LBBB) morphology with V2 transition was induced, exhibiting ventriculo-atrial (VA) dissociation and characteristics suggesting an AV node–ventricle reentrant circuit. Careful mapping and pacing maneuvers supported the diagnosis of a nodoventricular reentrant tachycardia (NVRT) with insertion site in the LV septum by using high density mapping coexisting with typical AVNRT. The patient was successfully treated with radiofrequency ablation at the slow pathway region, eliminating both arrhythmias. This case highlights the evidence of unusual NV pathway with LV insertion and importance of differentiating AVNRT with aberrancy or concomitant ventricular tachycardia (VT) from an accessory pathway-mediated reentrant tachycardia.

Objective Ventricular arrhythmias originating from the upper ventricular septum have been described, but the involvement of the His-Purkinje System (HPS) remains underexplored. This study aims to characterize ventricular arrhythmias arising from the upper ventricular septum with HPS involvement and assess the role of catheter ablation in this patient population. Methods We retrospectively analyzed cases of VT ablation performed at Taipei Veterans General Hospital between 2018 and 2024. The study included patients with structural heart disease presenting with clinical polymorphic VT or VF and diseased HPS. Results Nine patients (78% male) with VT involving the HPS region were analyzed. The mean LVEF was 45.3 ± 10.5%, and the LVIDD was 53.5 ± 10.2 mm. Structural heart disease was ischemic in 5 patients (55%), dilated non-ischemic cardiomyopathy in 3 (33%), and valvular cardiomyopathy in 1 (11%). All patients had documented VF or unstable VT on ECG or device recordings. VT was inducible in all cases, with an average of 2.67 ± 1.15 VT morphologies per patient. Strategic Multielectrode Positioning (StaMP) mapping, late ventricular activation (LAVA) modification, and pace mapping for stable morphologies were applied. All arrhythmogenic areas were adjacent to diseased HPS. These strategies achieved non-inducibility of VT/VF in all patients. Post-ablation, conduction system injury occurred in all patients, manifesting as prolonged QRS duration or pacing dependency. One patient experienced recurrence, successfully managed with a repeat procedure. Conclusion Catheter ablation is a feasible treatment for unstable VT and VF in patients with structural heart disease. Achieving non-inducibility often necessitates ablation of the LV septum and opposing RV septum, albeit at the risk of conduction system injury and pacing dependency. These findings provide insights into ablation strategies for managing this complex patient population.

Tachycardia-induced cardiomyopathy could present with acute heart failure, and an electrophysiology study with ablation was proven effective treatment in these circumstances. However, an invasive emergency procedure could always carry an increasing risk of complication, which could be devastating in a failing heart. We reported a case with incessant refractory supraventricular tachycardia and the ablation therapy complicated by ventricular fibrillation. Despite such a mishap, we managed to eliminate the accessory pathway as the cause of the tachycardia, and the patient was successfully treated with percutaneous cardiopulmonary support.

Introduction: Ventricular arrhythmia (VA) from the left ventricular summit (LVS) is a common origin of VA, which resulting LV dysfunction in some patients. However, the predictors of LV cardiomyopathy were not well-elucidated. The present study sought to investigate the risk factor of LV cardiomyopathy and the outcome in patients with LVS VA Methods: Between 2013 and 2018, a total of 139 patients (60.7% men; mean age 53.2 ± 13.9 years-old) underwent catheter ablation for LVS VA from two centers. Detailed patient demographics, electrocardiograms, electrophysiological characteristics, and clinical outcomes were extracted for analysis. LV cardiomyopathy was defined as LV ejection fraction (LVEF) <50%. Results: Acute procedural success was achieved in 92.8 % of patients. There were 40 patients (28.8%) with LV cardiomyopathy, and the mean LVEF improved from 37.5 ± 9.3% to 48.5 ± 10.2% after ablation ( p < 0.001). After multivariate analysis, the independent predictors of LV dysfunction were wider QRS duration of the VA (odds ratio [OR]1.02; 95% confidence interval [CI]: 1.00-1.04; p = 0.046) and the absolute earliest activation time discrepancy (AEAD) between epicardium and endocardium (OR 1.05; 95% confidence interval CI: 1.00-1.09; p = 0.048). After ablation, the LV function was completely recovered in 20 patients (50%). The predictors for irreclaimable LV function included wider PVC QRS duration (OR 1.09; 95% CI: 1.02-1.17; p = 0.012) and poorer LVEF (OR 0.85; 95% CI: 0.74-0.97; p = 0.020). Conclusion: In patients with VA from LVS, PVC QRS duration and AEAD predicted the deteriorating LV systolic function. Catheter ablation could reverse the LV remodeling. Narrower QRS duration and better LVEF predicted a better recovery of LV function after ablation.

Catheter ablation for tachyarrhythmia via superior approach has been used in patients without possible inferior vena cava access such as in cases of venous occlusion or complex anomaly. Difficulty in catheter manipulation, instability, number of required vascular access, and radiation exposure of operator had been described in the procedure. Application of three-dimensional (3-D) mapping system in catheter ablation via superior approach could navigate the guiding catheter and provide more precise ablation. We reported four cases receiving catheter ablation due to atrioventricular nodal reentry tachycardia, atrial fibrillation and right ventricular arrhythmia via superior approach facilitated by 3-D mapping system with fewer vascular access and catheters.