Roger Borràs

Integration of 3D Electroanatomic Maps and Magnetic Resonance Scar Characterization Into the Navigation System to Guide Ventricular Tachycardia Ablation

Background— Scar heterogeneity identified with contrast-enhanced cardiac magnetic resonance (CE-CMR) has been related to its arrhythmogenic potential by using different algorithms. The purpose of the study was to identify the algorithm that best fits with the electroanatomic voltage maps (EAM) to guide ventricular tachycardia (VT) ablation. Methods and Results— Three-dimensional scar reconstructions from preprocedural CE-CMR study at 3T were obtained and compared with EAMs of 10 ischemic patients submitted for a VT ablation. Three-dimensional scar reconstructions were created for the core (3D-CORE) and border zone (3D-BZ), applying cutoff values of 50%, 60%, and 70% of the maximum pixel signal intensity to discriminate between core and BZ. The left ventricular cavity from CE-CMR (3D-LV) was merged with the EAM, and the 3D-CORE and 3D-BZ were compared with the corresponding EAM areas defined with standard cutoff voltage values. The best match was obtained when a cutoff value of 60% of the maximum pixel signal intensity was used, both for core (r 2=0.827; P<0.001) and BZ (r 2=0.511; P=0.020), identifying 69% of conducting channels (CC) observed in the EAM. Matching improved when only the subendocardial half of the wall was segmented (CORE: r 2=0.808; P<0.001 and BZ: r 2=0.485; P=0.025), identifying 81% of CC. When comparing the location of each bipolar voltage intracardiac electrogram with respect to the 3D CE-CMR–derived structures, a Cohen &kgr; coefficient of 0.70 was obtained. Conclusions— Scar characterization by means of high resolution CE-CMR resembles that of EAM and can be integrated into the CARTO system to guide VT ablation.

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.

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.

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.

Emerging risk factors and the dose-response relationship between physical activity and lone atrial fibrillation: a prospective case-control study.

Abstract Aims The role of high-intensity exercise and other emerging risk factors in lone atrial fibrillation (Ln-AF) epidemiology is still under debate. The aim of this study was to analyse the contribution of each of the emerging risk factors and the impact of physical activity dose in patients with Ln-AF. Methods and results Patients with Ln-AF and age- and sex-matched healthy controls were included in a 2:1 prospective case–control study. We obtained clinical and anthropometric data transthoracic echocardiography, lifetime physical activity questionnaire, 24-h ambulatory blood pressure monitoring, Berlin questionnaire score, and, in patients at high risk for obstructive sleep apnoea (OSA) syndrome, a polysomnography. A total of 115 cases and 57 controls were enrolled. Conditional logistic regression analysis associated height [odds ratio (OR) 1.06 [1.01–1.11]], waist circumference (OR 1.06 [1.02–1.11]), OSA (OR 5.04 [1.44–17.45]), and 2000 or more hours of cumulative high-intensity endurance training to a higher AF risk. Our data indicated a U-shaped association between the extent of high-intensity training and AF risk. The risk of AF increased with an accumulated lifetime endurance sport activity ≥2000 h compared with sedentary individuals (OR 3.88 [1.55–9.73]). Nevertheless, a history of <2000 h of high-intensity training protected against AF when compared with sedentary individuals (OR 0.38 [0.12–0.98]). Conclusion A history of ≥2000 h of vigorous endurance training, tall stature, abdominal obesity, and OSA are frequently encountered as risk factors in patients with Ln-AF. Fewer than 2000 total hours of high-intensity endurance training associates with reduced Ln-AF risk.

Left atrial size and function by three-dimensional echocardiography to predict arrhythmia recurrence after first and repeated ablation of atrial fibrillation

AIMS Left atrial (LA) size has been related to the success of radiofrequency catheter ablation (RFCA) for atrial fibrillation (AF). However, potential predictors after a repeated procedure are unknown. We evaluate predictive factors related to successful AF ablation after a first and a repeated RFCA. METHODS AND RESULTS A total of 154 patients with AF were treated with RFCA. LA size and function were assessed with three-dimensional echocardiography (3D Echo) before RFCA. The effectiveness of RFCA was evaluated after 6 months. Recurrence of the arrhythmia was defined as any documented (clinically or by 24-h Holter recording) atrial tachyarrhythmia lasting >30 s after 12 weeks following RFCA. Of 154 patients, 103 (67%) underwent a first ablation (Group 1) and 51 (33%) a repeated RFCA (Group 2). At follow-up, arrhythmias were eliminated in 56 of 103 (54%) patients after a first RFCA and in 20 of 51 (40%) after a repeated ablation. In Group I, hypertension and LA expansion index derived from 3D Echo were independent predictors of arrhythmia elimination. In Group 2, only age predicted persistence of sinus rhythm; and only in younger patients (≤54 year old), though 3D LA maximal volumes were significantly smaller in those without when compared with those with AF recurrences. CONCLUSION A combination of the analysis of LA function with 3D Echo and clinical data predicts elimination of AF after a first ablation procedure for AF, beyond LA size. Among patients undergoing a repeated procedure, age and 3D echocardiographic LA maximum volume in younger patients predict the success of RFCA.

EAARN score, a predictive score for mortality in patients receiving cardiac resynchronization therapy based on pre‐implantation risk factors

The beneficial effects of CRT in patients with advanced heart failure, wide QRS, and low LVEF have been clearly established. Nevertheless, mortality remains high in some patients. The aims of our study were to identify the predictors of mortality in patients treated with CRT and to design a risk score for mortality.

Left atrial deformation predicts success of first and second percutaneous atrial fibrillation ablation.

BACKGROUND Predictors of second radiofrequency catheter ablation (RFCA) success are not well known. Surgical ablation is accepted for failed first RFCA, but second RFCA has fewer complications. OBJECTIVE The purpose of this study was to evaluate left atrial (LA) size and function as potential predictors of second RFCA for atrial fibrillation (AF). METHODS Thirty-three healthy volunteers (group I) and 83 patients with symptomatic drug-refractory AF treated with a first RFCA (group II, n = 48) or a second RFCA (group III, n = 35 patients) were included. Echocardiography was performed in all patients in sinus rhythm before RFCA and in all volunteers. LA size and function were measured using longitudinal strain and strain rate during ventricular systole (LASs, LASRs) and during early diastole (LASRe) or late diastole (LASRa) with speckle tracking echocardiography. The effectiveness of RFCA on arrhythmia recurrence was evaluated at 6-month follow-up. RESULTS LASs, LASRs, and LASRa were significantly lower in group III patients compared to other groups (P < .001 for all). LA diameter or volumes did not predict success after RFCA. LASs was an independent predictor of arrhythmia suppression after a first RFCA and after a second RFCA, with the best cutoff at LASs >20% (sensitivity 86%, specificity 70%) and LASs >12% (sensitivity 84%, specificity 90%), respectively. CONCLUSION LA myocardial deformation imaging is a reliable tool for predicting success after a first and a second RFCA. These parameters could improve candidate selection, especially for a second RFCA.

Mapping Data Predictors of a Left Ventricular Outflow Tract Origin of Idiopathic Ventricular Tachycardia With V3 Transition and Septal Earliest Activation

Background—The proximity of the outflow tracts (OTs) frequently results in an overlap in surface electrocardiographic features of ventricular arrhythmias originating from this anatomic region, particularly when the transition occurs in lead V3. In addition, no reliable criteria to discriminate between a right ventricular OT (RVOT) and a left ventricular OT (LVOT) site of origin (SOO) are derived from intracardiac mapping. Methods and Results—A series of 15 patients underwent ablation because of OT ventricular arrhythmias having a V3 transition, and a septal earliest activation on the RVOT was included in the study. Electrocardiographic and mapping data were collected to analyze accuracy in predicting the RVOT versus the LVOT SOO of the ventricular arrhythmia. A 10-ms isochronal map area in the RVOT was smaller in the RVOT SOO group (1.2 [0.4–2.1] versus 3.4 [2.4–3.9] cm2, respectively; P=0.004) and had a shorter perpendicular diameter (13 [7–17] versus 28 [20–29] mm; P=0.001) and a higher longitudinal/perpendicular axis ratio (1.04 [0.95–1.11] versus 0.49 [0.44–0.57]; P=0.001). A 10-ms isochronal map area >2.3 cm2 predicted an LVOT origin with 85.7% sensitivity and 87.5% specificity, whereas a longitudinal/perpendicular axis ratio <0.8 predicted an LVOT origin with 100% sensitivity and 100% specificity. Electrocardiography-derived parameters showed lower values of sensitivity and specificity. The distal coronary sinus activation mapping did not permit distinction between RVOT and LVOT SOO. Conclusions—The 10-ms isochronal map area and the longitudinal/perpendicular axis ratio accurately predict the RVOT versus the LVOT SOO in patients with OT ventricular arrhythmias, a V3 transition, and a septal earliest activation.

Infarct transmurality as a criterion for first-line endo-epicardial substrate–guided ventricular tachycardia ablation in ischemic cardiomyopathy

BACKGROUND There is no consensus on the appropriate indications for the epicardial approach in substrate ablation of post-myocardial infarction (MI) ventricular tachycardia (VT). OBJECTIVE The purpose of this study was to investigate whether infarct transmurality (IT) could identify patients who would benefit from a combined first-line endo-epicardial approach. METHODS Before ablation, IT was assessed by contrast-enhanced cardiac magnetic resonance imaging (hyperenhancement ≥75% of the wall thickness in ≥1 segment), echocardiography (dyskinesia/akinesia + hyperrefringency + wall thinning), computed tomography (wall thinning), or scintigraphy (transmural necrosis). Prospectively from January 2011, an endocardial approach was used in patients with subendocardial MI (group 1) and a combined endo-epicardial approach in patients with transmural MI (group 2). Outcomes in both groups were compared with those in patients with transmural MI and only endocardial approach due to previous cardiac surgery or procedure performed before January 2011 (group 3). The primary end point was VT/ventricular fibrillation recurrence-free survival. RESULTS Ninety patients (92.2% men; mean age 67.4 ± 9.8 years) undergoing VT substrate ablation were included: group 1, n = 34; group 2, n = 24; group 3, n = 32. During a mean follow-up duration of 22.5 ± 13.7 months, 5 patients in group 1 (14.7%), 3 patients in group 2 (12.5%), and 13 patients in group 3 (40.6%) had VT recurrences (P = .011). Time to recurrence was the shortest in group 3 (log-rank, P = .018). The endocardial approach in patients with transmural MI was associated with an increased risk of recurrence (hazard ratio 4.01; 95% confidence interval 1.41-11.3; P = .009). CONCLUSION The endocardial approach in patients with transmural MI undergoing VT substrate ablation is associated with an increased risk of recurrence. IT may be a useful criterion for the selection of a first-line combined endo-epicardial approach.