The RV1-V3 transition ratio: A novel electrocardiographic criterion for the differentiation of right versus left outflow tract premature ventricular complexes.

BACKGROUND: Several electrocardiographic (ECG) indices have been proposed to predict the origin of premature ventricular complexes (PVCs) with precordial transition in lead V3. However, the accuracy of these algorithms is limited. OBJECTIVES: We sought to evaluate a new ECG criterion differentiating the origin of outflow tract with precordial transition in lead V3. METHODS: We included in our study patients exhibiting outflow tract PVCs with precordial transition in lead V3 referred for ablation. We analyzed a novel new ECG criterion, RV1-V3 transition ratio, for distinguishing right from left idiopathic outflow tract PVCs with precordial transition in lead V3. The RV1-V3 transition ratio was defined as (RV1+RV2+RV3) PVC / (RV1+RV2+RV3) SR (sinus rhythm). RESULTS: We included 58 patients in our study. The ratio was lower for right ventricular outflow tract origins than left ventricular outflow tract (LVOT) origins (median [interquartile range], 0.6953 [0.4818-1.0724] vs 1.5219 [1.1582-2.4313], P < .001). Receiver operating characteristic analysis revealed an area under the curve of 0.856 for the ratio, and a cut-off value of ≥0.9 predicting LVOT origin with 94% sensitivity and 73% specificity. This ratio was superior to any previously proposed ECG criterion for differentiating right from left outflow tract PVCs. CONCLUSION: The RV1-V3 transition ratio is a simple and accurate novel ECG criterion for distinguishing right from left idiopathic outflow tract PVCs with precordial transition in lead V3.

Atrial substrate characterization in patients with atrial fibrillation and hypertrophic cardiomyopathy: Evidence for an extensive fibrotic disease.

INTRODUCTION: Data regarding the left atrial (LA) electroanatomical substrate in patients with hypertrophic cardiomyopathy (HCM) and atrial fibrillation (AF) are missing. In this electroanatomical mapping (EAM) study, we evaluated the extent of LA fibrosis and its impact on catheter ablation outcomes in patients with HCM and AF. MATERIALS AND METHODS: High-density LA EAM was performed during AF in 28 consecutive patients with obstructive HCM and AF (42.9% displayed paroxysmal AF and 57.1% persistent AF). Propensity score (PS) matching analysis was performed to reduce the impact of potential confounding factors. PS were derived to match patients at a 1:1 ratio. Patients were matched according to age, sex and LA diameter. After PS, 28 non-HCM patients with AF were selected, and served as controls. Two different cut-off values of bipolar signal amplitude were investigated for fibrosis characterization (≤0.25 mV and ≤ 0.4 mV). HCM patients underwent pulmonary vein antral isolation (PVAI) and roof line, while non-HCM patients PVAI only. RESULTS: After the 3-month blanking period, 10 HCM patients (35.7%) displayed atrial arrhythmia recurrence. HCM patients with arrhythmia recurrence showed significantly greater low voltage areas defined as either bipolar voltage ≤0.25 mV (22.5 ± 10% vs. 5.5 ± 6.4%, p = 0.001) or ≤ 0.4 mV (32 ± 13.9% vs. 5.9 ± 5.1%, p < 0.001). The presence of low voltage areas ≤0.4 mV greater than 14.1% of the total LA area also predicted arrhythmia recurrence with excellent sensitivity (100%) and specificity (100%). Univariate analysis revealed that the extent of LA fibrosis was the only predictor of AF recurrence. After PS matching with non-HCM patients, patients with HCM exhibited wider fibrotic regions ≤0.25 mV compared to non-HCM patients (p = 0.016). CONCLUSIONS: High-density EAM reveals extensive LA fibrotic disease in patients with HCM, an event with certain implications in catheter ablation outcomes.

Safety of catheter ablation of atrial fibrillation without pre- or peri-procedural imaging for the detection of left atrial thrombus in the era of uninterrupted anticoagulation.

BACKGROUND: The need for pre- or peri-procedural imaging to rule out the presence of left atrial thrombus in patients undergoing catheter ablation of atrial fibrillation (AF) is unclear in the era of uninterrupted direct oral anticoagulant (DOAC) regimen. We sought to examine the safety of catheter ablation in appropriately selected patients with paroxysmal AF without performing screening for left atrial thrombus. PATIENTS AND METHODS: Consecutive patients planned for radiofrequency AF catheter ablation between January 2016 and June 2020 were enrolled, and prospectively studied. All subjects were receiving uninterrupted anticoagulation with DOACs for at least 4 weeks before the procedure. All subjects were in sinus rhythm the day of the procedure. The primary outcome of the study was ischemic stroke or transient ischemic attack (TIA) during at 30 days. RESULTS: A total of 451 patients (age 59.7 ± 10.2 years, 289 males) with paroxysmal AF were included in the study. The mean CHA2DS2-VASc score was 1.4 ± 1.2. The mean left ventricular ejection fraction and left atrial diameter were 60 ± 5% and 39.3 ± 4 mm, respectively. Regarding the anticoagulation regimen, apixaban was used in 197 (43.6%) patients, rivaroxaban in 148 (32.8%) patients, and dabigatran in 106 (23.5%) patients. None of the patients developed clinical ischemic stroke or TIA during the 30-day post-discharged period. CONCLUSIONS: Catheter ablation can be safely performed in low-risk patients with paroxysmal AF without imaging for the detection of left atrial thrombus in the era of uninterrupted DOAC anticoagulation.

Electrophysiologic study and catheter ablation of a supraventricular tachycardia in a patient with inferior vena cava congenital anomaly.

Electrophysiologic procedures are performed widely nowdays, for the successful treatment of several cardiac arrhythmias. In this case report, we describe a rare congenital anomaly of the inferior vena cava, as an incidental finding during a scheduled electrophysiologic procedure for a supraventricular tachycardia ablation. The patient is a 32 year old male with an unremarkable medical history, suffering from sustained episodes of paroxysmal tachycardia. The electrophysiological maneuvers confirmed the presence of atrioventricular nodal reentry tachycardia, followed by a successful slow pathway ablation. We provide imaging details and guidance on the successful catheter positioning. In cases like this, the prognosis is excellent, while the follow up of our patient was unremarkable.

High-density mapping of de novo focal atrial tachycardias using a new software: Protected low-voltage areas by zones of conduction delay.

BACKGROUND: The pathophysiological mechanism of focal atrial tachycardias (AT) remains obscure. METHODS: Fifteen patients (6 males, age 45 ± 18) with focal AT underwent high-density activation mapping using a new software called extended early-meets-late (EEML). RESULTS: Irrespective of the arrhythmia mechanism, low bipolar voltage fractionated signals (0.14 ± 0.10 mV) were seen at the earliest activation site. The mean low-voltage area (LVA) at the earliest activation site was 3.2 ± 1.0 cm2. EEML mapping revealed zones of conduction delay at the borders of LVAs. CONCLUSIONS: LVAs protected by zones of slow conduction appears to play an important role in the initiation and maintenance of focal ATs.

Fasciculoventricular bypass tracts: Electrocardiographic and electrophysiologic features.

Fasciculoventricular accessory pathways are rare variants of preexcitation. The differential diagnosis of fasciculoventricular accessory pathways from other preexcitation variants can be challenging. Based on two cases, we discuss the specific electrocardiographic and electrophysiologic features of fasciculoventricular bypass tracts.

The aortic cusps are the predominant successful ablation site of idiopathic outflow-tract ventricular arrhythmias.

BACKGROUND: Data regarding the successful ablation site of idiopathic outflow tract (OT) ventricular arrhythmias (VAs) in the modern era of mapping and ablation are limited. METHODS AND RESULTS: Over a 4-year period, a total of 309 patients underwent detailed activation mapping of OT VAs including the right ventricular outflow tract (RVOT), the left ventricular outflow tract (LVOT) and the aortic cusps (AC), and the coronary venous system. 244 cases were successfully ablated at the index procedure (78.9%). The successful ablation site was more frequently located at the LVOT/ACs (51.6%) followed by RVOT (36.2%). In particular, the ACs was the predominant successful ablation site of idiopathic OT VAs (46.7%). An epicardial site of origin was predictor of ablation failure (p < 0.05). CONCLUSIONS: The ACs is the predominant successful ablation site of idiopathic OT VAs. TAKE-HOME MESSAGE: The aortic cusps are the predominant successful ablation site of idiopathic idiopathic outflow tract ventricular arrhythmias.

QRS Morphology Shift Following Catheter Ablation of Idiopathic Outflow Tract Ventricular Tachycardia.

A 42-year-old patient without structural heart disease was referred for catheter ablation of salvos of outflow tract ventricular tachycardia (VT). Activation mapping of the clinical VT (VT1) revealed the earliest ventricular activation site at the right ventricular outflow tract (RVOT). Catheter ablation at this site led to a slight QRS shift of the VT morphology (VT2). Activation mapping of VT2 established the site of origin at the commissure between the right (RCC) and left (LCC) coronary cusps. This case is indicative of the presence of myocardial fibers displaying preferential conduction properties from the RCC-LCC commissure to a breakout site at the RVOT.

Right ventricular outflow tract low-voltage areas identify the site of origin of idiopathic ventricular arrhythmias: A high-density mapping study.

INTRODUCTION: Electronatomical mapping allows direct and accurate visualization of myocardial abnormalities. This study investigated whether high-density endocardial bipolar voltage mapping of the right ventricular outflow tract (RVOT) during sinus rhythm may guide catheter ablation of idiopathic ventricular arrhythmias (VAs). METHODS AND RESULTS: Forty-four patients (18 males, mean age: 38.1 ± 13.8 years) with idiopathic RVOT VAs and negative cardiac magnetic resonance imaging underwent a stepwise mapping approach for the identification of the site of origin (SOO). High-density electronatomical mapping (1096.6 ± 322.3 points) was performed during sinus rhythm and identified at least two low bipolar voltage areas less than 1 mV (mean amplitude of 0.20 ± 0.10 mV) in 39 of 44 patients. The mean low-voltage surface area was 1.4 ± 0.8 cm2 . Group 1 consisted of 28 patients exhibiting low-voltage areas and high-arrhythmia burden during the procedure. Pace match to the clinical VAs was produced in one of these low-voltage areas. Activation mapping established the SOO at these sites in 27 of 28 cases. Group 2 comprised 11 patients exhibiting abnormal electroanatomical mapping, but very low-arrhythmia burden during the procedure. Pace mapping produced a near-perfect or perfect match to the clinical VAs in one of these areas in 9 of 11 patients which was marked as potential SOO and targeted for ablation. During the follow-up period, 25 of 28 patients from group 1 (89%) and 7 of 9 patients from group 2 (78%) were free from VAs. CONCLUSIONS: Small but detectable very low-voltage areas during mapping in sinus rhythm characterize the arrhythmogenic substrate of idiopathic RVOT VAs and may guide successful catheter ablation.

Percutaneous extraction of transvenous permanent pacemaker/defibrillator leads.

BACKGROUND: Widespread use of cardiovascular implantable electronic devices has inevitably increased the need for lead revision/replacement. We report our experience in percutaneous extraction of transvenous permanent pacemaker/defibrillator leads. METHODS: Thirty-six patients admitted to our centre from September 2005 through October 2012 for percutaneous lead extraction were included. Lead removal was attempted using Spectranetics traction-type system (Spectranetics Corp., Colorado, CO, USA) and VascoExtor countertraction-type system (Vascomed GmbH, Weil am Rhein, Germany). RESULTS: Lead extraction was attempted in 59 leads from 36 patients (27 men), mean ± SD age 61 ± 5 years, with permanent pacemaker (n = 25), defibrillator (n = 8), or cardiac resynchronisation therapy (n = 3) with a mean ± SD implant duration of 50 ± 23 months. The indications for lead removal included pocket infection (n = 23), endocarditis (n = 2), and ventricular (n = 10) and atrial lead dysfunction (n = 1). Traction device was used for 33 leads and countertraction device for 26 leads. Mean ± SD fluoroscopy time was 4 ± 2 minutes/lead for leads implanted <48 months (n = 38) and 7 ± 3 minutes/lead for leads implanted >48 months (n = 21), P = 0.03. Complete procedural success rate was 91.7% and clinical procedural success rate was 100%, while lead procedural success rate was 95%. CONCLUSIONS: In conclusion, percutaneous extraction of transvenous permanent pacemaker/defibrillator leads using dedicated removal tools is both feasible and safe.