Diego Penela

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.

Hypothermia in acute coronary syndrome: brain salvage versus stent thrombosis?

To the Editor: Mild hypothermia therapy (HT), defined as body temperature between 33°C and 34°C, is associated with improvement in neurological outcome after cardiac arrest. HT reduces cerebral metabolism of glucose and oxygen consumption with ensuing neuroprotection. In 2002, randomized clinical

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.

Sinus rhythm detection of conducting channels and ventricular tachycardia isthmus in arrhythmogenic right ventricular cardiomyopathy.

BACKGROUND The identification of conducting channels (CCs) based on its relative high voltage or the presence of electrograms with delayed components has been proposed for substrate-guided scar-related ventricular tachycardia (VT) ablation. The relationship of these channels with the VT isthmuses remains unclear. OBJECTIVE To assess the link between CCs identified during sinus rhythm (SR) and VT isthmuses in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC). METHODS Twenty-two consecutive patients with ARVC undergoing substrate-guided VT ablation (scar dechanneling technique) were analyzed. High-density endocardial and epicardial electroanatomic maps were obtained during SR. Standard bipolar cutoff values (0.5-1.5 and <0.5 mV) were used to define border zone and dense scar. The CCs were identified by voltage threshold adjustment (voltage channels) or by tagging the electrograms with delayed components that are sequentially activated (late potential channels). RESULTS A total of 87 CCs were identified; 65 (74.7%) of them on the epicardial surface. Twenty-four (27.6%) CCs were voltage channels, and compared with late potential CCs, these had a higher bipolar voltage (0.96 [0.48-1.29] mV vs 0.39 [0.26-0.50] mV; P < .001] and required more radiofrequency applications (5 [4-7] vs 3 [2-5]; P = .048]. Eighteen (90%) of 20 identified VT isthmuses were located on the epicardium. Only 8 (40%) VT isthmuses were related to a voltage CC. The remaining 12 (60%) VT isthmuses were linked to a late potential CC. CONCLUSION Late potential CCs more frequently act as the VT substrate in ARVC and therefore should also be considered to guide SR substrate-guided ablation.

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.

Fusion‐Optimized Intervals (FOI): A New Method to Achieve the Narrowest QRS for Optimization of the AV and VV Intervals in Patients Undergoing Cardiac Resynchronization Therapy

Optimization of atrioventricular (AV) and interventricular (VV) intervals may improve cardiac resynchronization therapy (CRT) response but is a complex task. Fusion with intrinsic conduction may increase the benefit of CRT. The aim was to describe fusion‐optimized intervals (FOI), a new method of optimizing CRT based on QRS duration.

Impact of earliest activation site location in the septal right ventricular outflow tract for identification of left vs right outflow tract origin of idiopathic ventricular arrhythmias

BACKGROUND The earliest activation site (EAS) location in the septal right ventricular outflow tract (RVOT) could be an additional mapping data predictor of left ventricular outflow tract (LVOT) vs RVOT origin of idiopathic ventricular arrhythmias (VAs). OBJECTIVE The purpose of this study was to assess the impact of EAS location in predicting LVOT vs RVOT origin. METHODS Macroscopic and histologic study was performed in 12 postmortem hearts. Electroanatomic maps (EAMs) from 37 patients with outflow tract (OT) VA with the EAS in the septal RVOT were analyzed. Pulmonary valve (PV) was defined by voltage scanning after validation of voltage thresholds by image integration. EAM measurements were correlated with those of macroscopic/histologic study. RESULTS A cutoff value of 1.9 mV discriminated between subvalvular and supravalvular positions (90% sensitivity, 96% specificity). EAS ≥1 cm below PV excluded RVOT site of origin (SOO). According to anatomic findings (distance PV-left coronary cusp = 5 ± 3 vs PV-right coronary cusp = 11 ± 5 mm), EAS-PV distance was significantly shorter in VAs arising from left coronary cusp than from the other LVOT locations (4.2 ± 5.4 mm vs 9.2 ± 7 mm; P = .034). The 10-ms isochronal longitudinal/perpendicular diameter ratio was higher in the RVOT vs the LVOT SOO group (1.97 ± 1.2 vs 0.79 ± 0.49; P = .001). An algorithm based on EAS-PV distance and the 10-ms isochronal longitudinal/perpendicular diameter ratio predicted LVOT SOO with 91% sensitivity and 100% specificity. CONCLUSION An algorithm based on the EAS-PV distance and the 10-ms isochronal longitudinal/perpendicular diameter ratio accurately predicts LVOT vs RVOT SOO in outflow tract VAs with EAS in the septal RVOT.

Bosentan in heart transplantation candidates with severe pulmonary hypertension: efficacy, safety and outcome after transplantation

Increased pulmonary vascular resistance (PVR) is associated with increased right ventricular failure and mortality after heart transplantation.

Safety, long-term outcomes and predictors of recurrence after first-line combined endoepicardial ventricular tachycardia substrate ablation in arrhythmogenic cardiomyopathy. Impact of arrhythmic substrate distribution pattern. A prospective multicentre study

Background First-line endoepicardial ventricular tachycardia (VT) ablation has been proposed for patients with arrhythmogenic cardiomyopathy (AC). This study reports procedural safety, outcomes, and predictors of recurrence. Methods and Results Forty-one consecutive patients [12 with left ventricle (LV) involvement, 7 left-dominant] underwent first-line endoepicardial VT substrate ablation. Standard bipolar and unipolar thresholds were used to define low-voltage areas (LVA). Arrhythmogenic substrate area (ASA) was defined as the area containing electrograms with delayed components. Implantable cardioverter defibrillator interrogations were evaluated for VT recurrence. Epicardial LVA was larger in all cases (102.5 ± 78.6 vs. 19.3 ± 24.4 cm2; P< 0.001). Consistent with an epicardium-to-endocardium arrhythmogenic substrate progression pattern, epicardial ASA (epi-ASA) was negatively correlated with bipolar endocardial LVA (r = -0.368; P= 0.035) and with endocardial bipolar/unipolar-LVA (Bi/Uni-LVA) ratio (r= -0.38; P= 0.037). A Bi/Uni-LVA ratio >0.23 predicted an epi-ASA ≤10 cm2 (100% sensitivity, 84% specificity). Patients showing an epi-ASA < 10 cm2 required less epicardial (8.4 ± 5.8 vs. 25.3 ± 16; P= 0.045) and more endocardial (16.5 ± 8.6 vs. 7.5 ± 8.2; P= 0.047) radiofrequency applications. One patient with epi-ASA < 10 cm2 died of cardiac tamponade after epicardial puncture. Acute success (no VT inducibility after procedure) was achieved in 36 patients (90%). After 32.2 ± 21.8 months, 11 (26.8%) patients had VT recurrences. Left-dominant AC was associated with an increased risk of recurrence (HR = 3.41 [1.1-11.2], P= 0.044; log-rank P= 0.021). Conclusion First-line endoepicardial VT substrate ablation achieves good long-term results in AC. Left-dominant AC is associated with an increased risk of recurrence. The Bi/Uni-LVA ratio identifies patients with limited epicardial arrhythmogenic substrate in whom the indication of epicardial approach should be more cautiously assessed.

Substrate modification or ventricular tachycardia induction, mapping, and ablation as the first step? A randomized study

BACKGROUND The role and optimal sequence of ventricular tachycardia (VT) induction, mapping, and ablation when combined with substrate modification is unclear. OBJECTIVE The purpose of this study was to test the benefits of starting the scar-related VT ablation procedure with substrate modification vs the standard protocol of VT induction, mapping, and ablation as the first step. METHODS Forty-eight consecutive patients with structural heart disease and clinical VTs were randomized to simplified substrate ablation procedure with scar dechanneling as the first step (group 1, n = 24) or standard procedure with VT induction, mapping, and ablation followed by scar dechanneling (group 2, n = 24). Procedure and fluoroscopy times, the need for external cardioversion, acute results, and VT recurrence during follow-up were compared between groups. RESULTS Thirty-seven patients had ischemic cardiomyopathy, 10 nonischemic cardiomyopathy, and 1 arrhythmogenic cardiomyopathy. Before substrate ablation, 32 VTs were induced and targeted for ablation in 23 patients of group 2. Procedure time (209 ± 70 minutes vs 262 ± 63 minutes; P = .009), fluoroscopy time (14 ± 6 minutes vs 21± 9 minutes; P = .005), and electrical cardioversion (25% vs 54%; P = .039) were lower in group 1. After substrate ablation, 16 patients (66%) of group 1 and 12 patients (50%) of group 2 were noninducible (P = .242). End-procedure success (after residual inducible VT ablation) was achieved in 87.5% and 70.8% of patients, respectively (P = .155). There were no differences in VT recurrence rate between groups during a mean follow-up of 22 ± 14 months (log rank, P = .557). CONCLUSION VT induction and mapping before substrate ablation prolongs the procedure, radiation exposure, and the need for electrical cardioversion without improving acute results and long-term ablation outcomes.