Israel Medical Association Journal

Background: The incidence, characteristics, and clinical significance of catheter-induced mechanical suppression (trauma) of ventricular arrhythmias originating in the outflow tract (OT) area have not been thoroughly evaluated.

Objectives: To determine these variables among our patient cohort.

Methods: All consecutive patients with right ventricular OT (RVOT) and left ventricular OT (LVOT) arrhythmias ablated at two medical centers from 1998 to 2014 were included. Patients were observed for catheter-induced trauma during ablation procedures. Procedural characteristics, as well as response to catheter-induced trauma and long term follow-up, were recorded.

Results: During 288 ablations of OT arrhythmias in 273 patients (RVOT n=238, LVOT n=50), we identified 8 RVOT cases (3.3%) and 1 LVOT (2%) case with catheter-induced trauma. Four cases of trauma were managed by immediate radiofrequency ablation (RFA), three were ablated after arrhythmia recurrence within a few minutes, and two were ablated after > 30 minutes without arrhythmia recurrence. Patients with catheter-induced trauma had higher rates of repeat ablations compared to patients without: 3/9 (33%) vs. 12/264 (0.45%), P = 0.009. The three patients with arrhythmia recurrence were managed differently during the first ablation procedure (immediate RFA, RFA following early recurrence, and delayed RFA). During the repeat procedure of these three patients, no catheter trauma occurred in two, and in one no arrhythmia was observed.

Conclusions: Significant catheter-induced trauma occurred in 3.1% of OT arrhythmias ablations, both at the RVOT and LVOT. Arrhythmia suppression may last > 30 minutes and may interfere with procedural success. The optimal mode of management following trauma is undetermined.

Background: Limited information exists about detailed clinical characteristics and management of the small subset of Brugada syndrome (BrS) patients who had an arrhythmic event (AE).

Objectives: To conduct the first nationwide survey focused on BrS patients with documented AE.

Methods: Israeli electrophysiology units participated if they had treated BrS patients who had cardiac arrest (CA) (lethal/aborted; group 1) or experienced appropriate therapy for tachyarrhythmias after prophylactic implantable cardioverter defibrillator (ICD) implantation (group 2).

Results: The cohort comprised 31 patients: 25 in group 1, 6 in group 2. Group 1: 96% male, mean CA age 38 years (range 13–84). Nine patients (36%) presented with arrhythmic storm and three had a lethal outcome; 17 (68%) had spontaneous type 1 Brugada electrocardiography (ECG). An electrophysiology study (EPS) was performed on 11 patients with inducible ventricular fibrillation (VF) in 10, which was prevented by quinidine in 9/10 patients. During follow-up (143 ± 119 months) eight patients experienced appropriate shocks, none while on quinidine. Group 2: all male, age 30–53 years; 4/6 patients had familial history of sudden death age < 50 years. Five patients had spontaneous type 1 Brugada ECG and four were asymptomatic at ICD implantation. EPS was performed in four patients with inducible VF in three. During long-term follow-up, five patients received ≥ 1 appropriate shocks, one had ATP for sustained VT (none taking quinidine). No AE recurred in patients subsequently treated with quinidine.

Conclusions: CA from BrS is apparently a rare occurrence on a national scale and no AE occurred in any patient treated with quinidine.

Background: Multiform fascicular tachycardia (FT) was recently described as a ventricular tachycardia (VT) that has a reentrant mechanism using multiple fascicular branches and produces alternate fascicular VT forms. Ablating the respective fascicle may cause a change in the reentrant circuit resulting in a change in morphology. Ablation of the septal fascicle is crucial for successful treatment.

Objectives: To describe four cases of FT in which ablation induced a change in QRS morphologies and aggravated clinical course.

Methods: Four out of 57 consecutive FT cases at three institutions were retrospectively analyzed and found to involve multiform FT. These cases underwent electrophysiological study, fascicular potential mapping, and electroanatomical mapping. All patients initially had FT with right bundle branch block (RBBB) and superior axis morphology.

Results: Radiofrequency catheter ablation (RFCA) targeting the distal left posterior fascicle (LPF) resulted in a second VT with an RBBB-inferior axis morphology that sometimes became faster and/or incessant and/or verapamil-refractory in characteristics. RFCA in the upper septum abolished the second VT with no complications and uneventful long-term follow-up.

Conclusions: The change in FT morphology during ablation may be associated with a change in clinical course when shifting from one route to another and may aggravate symptoms. Targeting of the proximal conduction system (such as bifurcation, LPF, left anterior fascicle, high septal/auxiliary pathway) may serve to solve this problem.

Background: Left ventricular outflow tract (LVOT) arrhythmias are increasingly recognized. Data regarding the distribution of the sites of origin (SOO) of the arrhythmias are sparse.

Objectives: To describe the clinical characteristics of patients with LVOT arrhythmias and the distribution of their SOO. 

Methods: All 42 consecutive patients with LVOT arrhythmias who underwent radiofrequency (RF) ablation during the period 2000–2014 were included. SOO identification was based on mapping activation, pace mapping and a 3D mapping system in eight patients. 

Results: The study group comprised 28 males (66.7%) and 14 females, the mean age was 55 ±15.4 years. Most patients (76%) were symptomatic. All suffered from high grade ventricular arrhythmias. Left ventricular (LV) dysfunction (ejection fraction ≤ 50%) was observed in 15 patients (35.7%), of whom 14 (93.3%) were males. The left coronary cusp (LCC) was the most common arrhythmia SOO (64.3%). Other locations were the right coronary cusp (RCC), the junction of the RCC-LCC commissure, aortic-mitral continuity, endocardial-LVOT, and a coronary sinus branch. Acute successful ablation was achieved in 29 patients (69%) and transient arrhythmia abolition in 40 (95.2%). There was a trend for a higher success rate using cooled tip ablation catheters as compared to standard catheters. The ablation procedure significantly improved LV function in all patients with tachycardiomyopathy. 

Conclusions: LVOT arrhythmias mostly originate from the LCC and are associated with LV dysfunction in 36% of patients. Knowledge regarding the prevalence of the anatomic origin of the LVOT arrhythmias may help achieve successful ablation. The use of cooled tip ablation catheters might have beneficial effects on the success rate of the procedure.