José María Tolosana

Combined Endocardial and Epicardial Catheter Ablation in Arrhythmogenic Right Ventricular Dysplasia Incorporating Scar Dechanneling Technique

Background— Ventricular tachycardia (VT) ablation in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) has a low success rate. A more extensive epicardial (Epi) arrhythmogenic substrate could explain the low efficacy. We report the results of combined endocardial (Endo) and Epi VT ablation and conducting channel (CC) elimination. Methods and Results— Eleven consecutive patients with ARVD/C were included in the study. A high-density 3D Endo (321±93 sites mapped) and Epi (302±158 sites mapped) electroanatomical voltage map was obtained during sinus rhythm to define scar areas (<1.5 mV) and CCs inside the scars, between scars, or between the tricuspid annulus and a scar. The end point of the ablation procedure was the elimination of all identified CCs (scar dechanneling) and the abolition of all inducible VTs. The mean procedure and fluoroscopy time were 177±63 minutes and 20±8 minutes, respectively. Epi scar area was larger in all cases (26±18 versus 94±45 cm2, P<0.01). The combined Endo and Epi VT ablation eliminated all clinical and induced VTs, and the addition of scar dechanneling resulted in noninducibility in all cases. Seven patients continued on sotalol. During a median follow-up of 11 months (6–24 months), only 1 (9%) patient had a VT recurrence. There was a single major bleeding event that did not preclude a successful procedure. Conclusions— Combined Endo and Epi mapping reveals a wider Epi VT substrate in patients with ARVD/C with clinical VTs. As a first-line therapy, combined Endo and Epi VT ablation incorporating scar dechanneling achieves a very good short- and midterm success rate.

Preparation for pacemaker or implantable cardiac defibrillator implants in patients with high risk of thrombo-embolic events: oral anticoagulation or bridging with intravenous heparin? A prospective randomized trial.

Aims Current guidelines recommend stopping oral anticoagulation (OAC) and starting heparin infusion before implanting/replacing a pacemaker/implantable cardioverter-defibrillator (ICD) in patients with high risk for thrombo-embolic events. The aim of this study was to demonstrate that the maintenance of OAC during device implantation/replacement is as safe as bridging to intravenous heparin and shortens in-hospital stay. Methods and results A cohort of 101 consecutive patients with high risk for embolic events and indication for implant/replacement of a pacemaker/ICD were randomized to two anticoagulant strategies: bridging from OAC to heparin infusion (n = 51) vs. maintenance of OAC to reach an INR = 2 ± 0.3 at the day of the procedure (n = 50). Haemorrhagic and thrombo-embolic complications were evaluated at discharge, 15 and 45 days after the procedure. A total of 4/51 patients (7.8%) from heparin group and 4/50 (8.0%) from the OAC group developed pocket haematoma following the implant (P = 1.00). One haematoma in each group required evacuation (1.9 vs. 2%, P = 1.00). No other haemorrhagic events or embolic complications developed during the follow-up. Duration of the hospital stay was longer in the heparin group [median of 5 (4–7) vs. 2 (1–4) days; P < 0.001]. Conclusion Implant of devices maintaining OAC is as safe as bridging to heparin infusion and allows a significant reduction of in-hospital stay.

A mutation in the sodium channel is responsible for the association of long QT syndrome and familial atrial fibrillation

BACKGROUND Type 3 long-QT syndrome (LQT-3) is caused by gain-of-function mutations in the SCN5A encoding the cardiac sodium channel. Familial atrial fibrillation (AF), previously considered a potassium channelopathy, has recently been related to sodium genetic variants, both in isolated forms and in patients with underlying heart disease. OBJECTIVE The purpose of this study was to describe the first family associating LQT-3 and AF due to a gain-of-function mutation in SCN5A and assess the usefulness of the sodium blocker flecainide in individuals with both phenotypes. METHODS Complete family screening was performed after identifying a proband showing paroxysmal AF and a long QT interval suggestive of LQT-3. Secondary causes of AF were ruled out in all individuals. Flecainide was used in two patients for LQT-3 diagnosis and therapeutic treatment of AF. Genetic screening was performed by direct sequencing of the exons and exon-intron boundaries of SCN5A. RESULTS We identified a three-generation family (eight members), all of them showing long QT intervals. Paroxysmal AF initiated between 20 and 35 years of age in all three adults. The flecainide test led to shortening of the QTc interval. Flecainide was also effective in acutely restoring sinus rhythm. A Y1795C mutation was identified in all members. CONCLUSION This is the first report showing an association of familial AF and LQT-3 due to a mutation in SCN5A. This finding provides further evidence of the role of SCN5A in AF. We also confirm the usefulness of flecainide in this particular complex phenotype, both as a diagnostic tool for LQT-3 and as an acute treatment for AF.

Left Atrial Sphericity: A New Method to Assess Atrial Remodeling. Impact on the Outcome of Atrial Fibrillation Ablation

Atrial fibrillation (AF) ablation outcome is mainly determined by atrial remodeling that, nowadays, is only estimated through clinical presentation (persistent vs. paroxysmal) and left atrial (LA) dimension. The aim of the study was to stage the atrial remodeling process using the Left Atrial Sphericity (LASP) and determine whether this technique may help to predict AF ablation outcome.

Electrocardiographic Optimization of Interventricular Delay in Cardiac Resynchronization Therapy: A Simple Method to Optimize the Device

Introduction: Echocardiography is widely used to optimize CRT programming, but it is time‐consuming. This study aimed to correlate the optimal interventricular pacing (V‐V) interval obtained by echo with the optimal V‐V interval obtained by a simpler method based on the surface ECG.

Scar Dechanneling New Method for Scar-Related Left Ventricular Tachycardia Substrate Ablation

Background—Ventricular tachycardia (VT) substrate ablation usually requires extensive ablation. Scar dechanneling technique may limit the extent of ablation needed. Methods and Results—The study included 101 consecutive patients with left ventricular scar–related VT (75 ischemic patients; left ventricular ejection fraction, 36±13%). Procedural end point was the elimination of all identified conducting channels (CCs) by ablation at the CC entrance followed by abolition of residual inducible VTs. By itself, scar dechanneling rendered noninducibility in 54.5% of patients; ablation of residual inducible VT increased noninducibility to 78.2%. Patients needing only scar dechanneling had a shorter procedure (213±64 versus 244±71 minutes; P=0.027), fewer radiofrequency applications (19±11% versus 27±18%; P=0.01), and external cardioversion/defibrillation shocks (20% versus 65.2%; P<0.001). At 2 years, patients needing scar dechanneling alone had better event-free survival (80% versus 62%) and lower mortality (5% versus 11%). Incomplete CC-electrogram elimination was the only independent predictor (hazard ratio, 2.54 [1.06–6.10]) for the primary end point. Higher end point-free survival rates were observed in patients noninducible after scar dechanneling (log-rank P=0.013) and those with complete CC-electrogram elimination (log-rank P=0.013). The complications rate was 6.9%, with no deaths. Conclusions—Scar dechanneling alone results in low recurrence and mortality rates in more than half of patients despite the limited ablation extent required. Residual inducible VT ablation improves acute results, but patients who require it have worse outcomes. Recurrences are mainly related to incomplete CC-electrogram elimination.

Comparison of benefits and mortality in cardiac resynchronization therapy in patients with atrial fibrillation versus patients in sinus rhythm (Results of the Spanish Atrial Fibrillation and Resynchronization [SPARE] Study).

The efficacy of cardiac resynchronization therapy (CRT) in patients with atrial fibrillation (AF) and the need for atrioventricular junction ablation in these patients is controversial. The aim of the study was to analyze CRT results in patients with permanent AF. A total of 470 consecutive patients who underwent CRT in 6 centers were included in this study. Of these patients, 126 (27%) had permanent AF. Patients were evaluated at baseline and 12 months. No difference was found in the magnitude of improvement experienced by patients with AF compared with those in sinus rhythm (SR) with respect to quality of life, distance in 6-minute walking test, and left ventricular reverse remodeling. Despite the beneficial effects of CRT, death from refractory heart failure at 12 months was higher in patients with AF (17 of 126; 13.5%) than those in SR (14/344; 4.1%; p <0,001). Furthermore, permanent AF was an independent predictive factor for mortality from refractory heart failure (hazard ratio 5.4, 95% confidence interval 1.9 to 15.1). In conclusion, patients with AF treated with CRT who survived at the 12-month follow-up had the same functional improvement and remodeling as those in SR. However, AF was an independent risk factor for mortality from heart failure after CRT implantation.

Use of myocardial scar characterization to predict ventricular arrhythmia in cardiac resynchronization therapy

AIMS There is insufficient evidence to implant a combined cardiac resynchronization therapy (CRT) device with defibrillation capabilities (CRT-D) in all CRT candidates. The aim of the study was to assess myocardial scar size and its heterogeneity as predictors of sudden cardiac death (SCD) in CRT candidates. METHODS AND RESULTS A cohort of 78 consecutive patients with dilated cardiomyopathy and class I indication for CRT-D were prospectively enrolled. Before CRT-D implantation, a contrast-enhanced cardiac magnetic resonance (ce-CMR) was performed. The core and border zone (BZ) of the myocardial scar were characterized and quantified with a customized post-processing software. The first appropriate implantable cardioverter defibrillator (ICD) therapy was considered as a surrogate of SCD. During a mean follow-up of 25 months (25-75th percentiles, 15-34), appropriate ICD therapy occurred in 11.5% of patients. In a multivariate Cox proportional hazards regression model for clinical and ce-CMR variables, the scar mass percentage [hazards ratio (HR) per 1% increase 1.1 (1.06-1.15), P < 0.01], the BZ mass [HR per 1 g increase 1.06 (1.04-1.09), P < 0.01], and the BZ percentage of the scar [HR per 1% increase 1.06 (1.02-1.11), P < 0.01], were the only independent predictors of appropriate ICD therapy. Receiver-operating characteristic curve analysis showed that a scar mass <16% and a BZ < 9.5 g had a negative predictive value of 100%. CONCLUSIONS The presence, size, and heterogeneity of myocardial scar independently predict appropriate ICD therapies in CRT candidates. The ce-CMR-based scar analysis might help identify a subgroup of patients at relatively low risk of SCD.

Neurohormonal, structural, and functional recovery pattern after premature ventricular complex ablation is independent of structural heart disease status in patients with depressed left ventricular ejection fraction: a prospective multicenter study.

OBJECTIVES This study aimed to assess the benefit after ablation of premature ventricular complexes (PVC) in patients with frequent PVC and left ventricular (LV) dysfunction, regardless of previous structural heart disease (SHD) diagnosis, PVC morphology, or estimated site of origin. BACKGROUND Ablation of PVC in patients with LV dysfunction is usually restricted to patients with suspected PVC-induced cardiomyopathy. METHODS Consecutive patients with frequent PVC and LV dysfunction accepted for ablation at 4 centers were prospectively included. Of the 80 patients included, 27 (34%) had a diagnosis of SHD. RESULTS Successful sustained ablation (SSA) was achieved in 53 (66%) patients, and LVEF improved in these patients from 33.7 ± 8% to 43.8 ± 9.4% and 45.8 ± 10.9% at 6 and 12 months, respectively (p < 0.05), without differences related to previous diagnosis of SHD (p = 0.69). BNP decreased from 109 [64 to 242] pg/ml to 60 [25 to 170] pg/ml, 50 [14 to 130] pg/ml, and 60 [19 to 81] pg/ml at 1, 6, and 12 months (p < 0.05). Patients in NYHA class I increased from 12 (23%) to 42 (79%) at 12 months (p < 0.05). A 13% baseline PVC burden had 100% sensitivity and 85% specificity to predict an absolute increase ≥ 5% in LVEF after SSA. Although 20 patients with >13% PVC and SSA had class I indication for cardioverter defibrillator implantation, these indications were absent at 6 months post-ablation. CONCLUSIONS Independently of the presence of SHD, the SSA of frequent PVC in patients with depressed LVEF induced a progressive clinical and functional improvement. Improvement in heart failure parameters was related to baseline PVC burden and persistence of ablation success.

Decreased likelihood of response to cardiac resynchronization in patients with severe heart failure

We hypothesized that a very advanced stage of dilated cardiomyopathy is associated with lower response to cardiac resynchronization therapy (CRT).