Worldwide Experience With an Irrigated Needle Catheter for Ablation of Refractory Ventricular Arrhythmias: Final Report.

BACKGROUND: We previously reported feasibility of irrigated needle ablation (INA) with a retractable 27-G end-hole needle catheter to treat nonendocardial ventricular arrhythmia substrate, an important cause of ablation failure. OBJECTIVES: The purpose of this study was to report outcomes and complications in our entire INA-treated population. METHODS: Patients with recurrent sustained monomorphic ventricular tachycardia (VT) or high-density premature ventricular contractions (PVCs) despite radiofrequency ablation were prospectively enrolled at 4 centers. Endpoints included a 70% decrease in VT frequency or PVC burden decrease to <5,000/24 h at 6 months. RESULTS: INA was performed in 111 patients (median: 2 failed prior ablations, 71% nonischemic heart disease, and left ventricular ejection fraction 36% ± 14%). INA acutely abolished targeted PVCs in 33 of 37 patients (89%), and PVCs were reduced to <5,000/day in 29 patients (78%). During 6-month follow-up, freedom from hospitalization was observed in 50 of 72 patients with VT (69%), and improvement or abolition of VT occurred in 47%. All patients received multiple INA applications, with more in the VT group than in the PVC group (median: 12 [IQR: 7-19] vs 7 [5-15]; P < 0.01). After INA, additional endocardial standard radiofrequency ablation was required in 23% of patients. Adverse events included 4 pericardial effusions (3.5%), 3 cases of (anticipated) atrioventricular block (2.6%), and 3 heart failure exacerbations (2.6%). During 6-month follow-up, 5 deaths occurred; none were procedure-related. CONCLUSIONS: INA achieves improved arrhythmia control in 78% of patients with PVCs and avoids hospitalization in 69% of patients with VT refractory to standard ablation at 6-month follow-up. Procedural risks are acceptable. (Intramural Needle Ablation for Ablation of Recurrent Ventricular Tachycardia, NCT01791543; Intramural Needle Ablation for the Treatment of Refractory Ventricular Arrhythmias, NCT03204981).

Pulmonary Vein Stenosis After Catheter Ablation of Atrial Fibrillation Using a Cryoballoon, Hot Balloon, or Laser Balloon.

BACKGROUND: Pulmonary vein stenosis (PVS) after PV isolation (PVI) for atrial fibrillation (AF) is a severe complication that requires angioplasty. This study aimed to compare the reduction of the cross-sectional PV area (PVA) and the incidence of PVS after cryoballoon (CB)-PVI, hot balloon (HB)-PVI, or laser balloon (LB)-PVI.Methods and Results: A total of 320 patients who underwent an initial catheter ablation procedure for AF using a CB, HB, or LB in 2 hospitals were included. They underwent contrast-enhanced multidetector CT before and 3 months after the procedure. In all 4 PVs, the reduction in PVA was more significant in the LB group than in the CB or HB groups, respectively. Moderate (50-75%) and severe (>75%) PVS were observed in 5.3% and 0.5% of the PVs, respectively. Although moderate PVS was more frequently observed in the LB group than in the CB or HB groups (8.2%, 3.8%, and 5.0%; P=0.03), the incidence of severe PVS was similar in the LB, CB, and HB groups (0.3%, 0.5%, and 1.0%; P=0.46). Symptomatic PVS requiring intervention occurred in 1 (0.3%) patient. CONCLUSIONS: Although the reduction in cross-sectional PVA and the incidence of moderate PVS after LB-PVI was more significant than after CB-PVI or HB-PVI, it rarely led to severe PVS. Symptomatic PVS requiring intervention was rare after the balloon ablation of AF.

Using the pre-freezing technique results in a wider area of antral isolation during cryoballoon pulmonary vein isolation in patients with atrial fibrillation.

The "pre-freezing" technique was a method in which a fully inflated balloon after the start of freezing was pressed against the pulmonary vein (PV) during cryoballoon ablation and has been applied especially in large-size PVs. Of 556 patients who underwent cryoballoon ablation for atrial fibrillation (AF), the pre-freezing technique was applied to 48 patients. The resulting 2:1 propensity score-matched data set included 120 patients. Using the pre-freezing technique, all left-superior PVs, all left-inferior PVs, and 95% of right-superior PVs were successfully isolated. In most right-inferior PVs, complete sealing using the pre-freezing technique was challenging, and this technique was not applied. Procedure time was similar between the two groups. In the pre-freezing group, the percentage of the left atrial posterior wall isolated was larger (47.6 ± 10.3 vs. 42.8 ± 15.7%, P = 0.006), and the postoperative reduction of diaphragmatic compound motor action potentials tended to occur less frequently (2.5 vs. 12.5%, P = 0.07), and the reduction of the cross-sectional LSPV area was smaller (17.5 ± 12.2 vs. 27.2 ± 19.8%, P = 0.03) than the conventional group. The AF-free rate of the two groups was similar between the two groups (P = 0.15). The pre-freezing technique was a simple method that can isolate a wider surface area during cryoballoon PV isolation. While the postoperative AF recurrence was comparable, the postoperative reduction in the cross-sectional PV area was less than that of the conventional method, which may reduce the risk of PV stenosis.

A 15-year follow-up study of radiofrequency catheter ablation for atrial fibrillation in patients with tachycardia-bradycardia syndrome.

INTRODUCTION: Catheter ablation for atrial fibrillation (AF) in patients with tachycardia-bradycardia syndrome (TBS) can be a major therapeutic option to replace permanent pacemaker implantation (PMI). However, the very long-term outcome of more than 15 years in these patients has not been elucidated. METHODS: From 2002 to 2008, 25 consecutive TBS patients (62 ± 7.9 years old, 68% male) with both AF and symptomatic sinus pauses (>3.0 s) were performed radiofrequency AF ablation. These patients were followed for 15 ± 2.7 years. RESULTS: The median longest sinus pause before the ablation procedure was 6.0 s (4.4-8.0). Following 1.6± 0.8 ablation procedures, 18 (72%) patients remained free from AF. Three (12%) patients died due to noncardiovascular causes, and seven (28%) patients underwent PMI due to symptomatic sinus pause after recurrent AF in five patients and progression of sinus node dysfunction in two patients. The median duration from the first AF ablation to PMI was 6.3 years (range: 9 days to 11.0 years). Five and two patients required PMI more than 5 and 10 years after the first ablation procedure, respectively. CONCLUSION: AF ablation prevented PMI in 72% of TBS patients for a 15-year follow-up. However, in consideration of the long duration of PMI, a continuous careful long-term follow-up was warranted.

Effect of air removal with extracorporeal balloon inflation on incidence of asymptomatic cerebral embolism during cryoballoon ablation of atrial fibrillation: A prospective randomized study.

Background: It was previously reported, based on a retrospective study, that preliminary removal of air bubbles in heparinized saline water with extracorporeal balloon inflation reduced the incidence of asymptomatic cerebral embolism (ACE). The present study aims to compare the incidence of ACE between a conventional and pre-inflation method during cryoballoon ablation in a prospective randomized controlled study. Methods: A total of 98 atrial fibrillation patients were enrolled and randomized into conventional and pre-inflation groups. Patients in the pre-inflation group received balloon massaging with preliminary extracorporeal balloon inflation in saline water before the cryoballoon was inserted into the body. Results: The baseline characteristics were similar between the two groups. Post-procedural 3-Tesla MRI revealed CE in 27.6% of patients. Symptomatic CE only occurred in two patients in the pre-inflation group. One patient had transient dysarthria and mild muscle weakness in one hand; the other patient complained of transient left upper limb weakness, left lower limb paresthesia and dysarthria. The incidence of ACE detected by cerebral MRI did not differ between the two groups to a statistically significant extent (conventional vs. pre-inflation; 22.9% vs. 29.2%; P = 0.49). In the multivariable analysis, eGFR was independently associated with the presence of ACE (odds ratio 0.95; 95% confidence interval 0.907-0.995; P = 0.03). Conclusion: In this prospective randomized study, the preliminary removal of air bubbles in heparinized saline water with extracorporeal balloon inflation had no impact on the incidence of ACE.

Intramural Needle Ablation for Refractory Premature Ventricular Contractions.

BACKGROUND: Frequent premature ventricular contractions (PVCs) are often amenable to catheter ablation. However, a deep intramural focus may lead to failure due to inability of standard ablation techniques to penetrate the focus. We sought to assess the efficacy and safety of infusion needle ablation (INA) for PVCs that are refractory to standard radiofrequency ablation. METHODS: Under 2 Food and Drug Administration approved protocols, INA was evaluated in patients with frequent PVCs that were refractory to standard ablation. Initial targets for ablation were selected by standard mapping techniques. INA was performed with a deflectable catheter equipped with an extendable/retractable needle at the tip that can be extended up to 12 mm into the myocardium and is capable of pacing and recording. After contrast injection for location assessment, radiofrequency ablation was performed with the needle tip using a temperature-controlled mode (maximum temperature 60 °C) with saline infusion from the needle. The primary end point was a decrease in PVC burden to <5000/24 hours at 6 months. The primary safety end point was incidence of procedure- or device-related serious adverse events. RESULTS: At 4 centers, 35 patients (age 55.3±16.9 years, 74.2% male) underwent INA. The baseline median PVC burden was 25.4% (interquartile range, 18.4%-33.9%) and mean left ventricular ejection fraction was 37.7±12.3%. Delivering 10.3±8.0 INA lesions/patient (91% had adjunctive standard radiofrequency ablation also) resulted in acute PVC elimination in 71.4%. After a mean follow-up of 156±109 days, the primary efficacy end point was met in 73.3%. The median PVC burden decreased to 0.8% (interquartile range, 0.1%-6.0%; P<0.001). The primary safety end point occurred in 14.3% consisting of 1 (2.9%) heart block, 1 (2.9%) femoral artery dissection, and 3 (8.6%) pericardial effusions (all treated percutaneously). CONCLUSIONS: INA is effective for the elimination of frequent PVCs that are refractory to conventional ablation and is associated with an acceptable safety profile. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT01791543 and NCT03204981.

Transition of the heart rate and atrial premature complex after cryoballoon vs. radiofrequency ablation for paroxysmal atrial fibrillation.

The temporal changes in ambulatory monitoring findings after cryoballoon (CB) ablation of atrial fibrillation (AF) have not been well elucidated. This study aims to compare the details of ambulatory monitoring after CB and radiofrequency catheter (RFC) ablation for AF. Of 724 consecutive AF patients who underwent initial ablation using a CB or RFC, 508 (254 pairs) were selected using propensity score matching. Ambulatory monitoring was performed at 1, 3, 6, 12, 24 and 36 months after the procedure. After 1, 3 and 6 months, the number of total heart beats (THBs) was larger in the CB group than in the RFC group. It gradually decreased and became significantly similar by 12 months after ablation. THBs significantly increased 1, 3, 6 and 12 months after ablation in both the RFC and CB groups and became statistically similar by 24 months after ablation. The atrial premature contraction burden was higher in the RFC group than in the CB group at 3 months after ablation. THB and APC burden after AF ablation were significantly different between the RF and CB groups. THBs returned to statistically similarity by 2 years after ablation in both groups.

Very long term outcome after linear versus electrogram guided ablation for persistent atrial fibrillation.

The optimal ablation strategy for persistent atrial fibrillation (PsAF) remains to be defined. We sought to compare very long-term outcomes between linear ablation and electrogram (EGM)-guided ablation for PsAF. In a retrospective analysis, long-term arrhythmia-free survival compared between two propensity-score matched cohorts, one with pulmonary vein isolation (PVI) and linear ablation including roof/mitral isthmus line (LINE-group, n = 52) and one with PVI and EGM-guided ablation (EGM-group; n = 52). Overall, 99% of patients underwent successful PVI. Complete block following linear ablation was achieved for 94% of roof lines and 81% of mitral lines (both lines blocked in 75%). AF termination by EGM-guided ablation was accomplished in 40% of patients. Non-PV foci were targeted in 7 (13%) in the LINE-group and 5 (10%) patients in the EGM-group (p = 0.76). During 100 ± 28 months of follow-up, linear ablation was associated with superior arrhythmia-free survival after the initial and last procedure (1.8 ± 0.9 procedures) compared with EGM-group (Logrank test: p = 0.0001 and p = 0.045, respectively). In multivariable analysis, longer AF duration and EGM-guided ablation remained as independent predictors of atrial arrhythmia recurrence. Linear ablation might be a more effective complementary technique to PVI than EGM-guided ablation for PsAF ablation.

Irrigated Needle Ablation Compared With Other Advanced Ablation Techniques for Failed Endocardial Ventricular Arrhythmia Ablation.

[Figure: see text].

Long-term course of phrenic nerve injury after cryoballoon ablation of atrial fibrillation.

While phrenic nerve palsy (PNP) due to cryoballoon pulmonary vein isolation (PVI) of atrial fibrillation (AF) was transient in most cases, no studies have reported the results of the long-term follow-up of PNP. This study aimed to summarize details and the results of long-term follow-up of PNP after cryoballoon ablation. A total of 511 consecutive AF patients who underwent cryoballoon ablation was included. During right-side PVI, the diaphragmatic compound motor action potential (CMAP) was reduced in 46 (9.0%) patients and PNP occurred in 29 (5.7%) patients (during right-superior PVI in 20 patients and right-inferior PVI in 9 patients). PNP occurred despite the absence of CMAP reduction in 0.6%. The PV anatomy, freezing parameters and the operator's proficiency were not predictors of PNP. While PNP during RSPVI persisted more than 4 years in 3 (0.6%) patients, all PNP occurred during RIPVI recovered until one year after the ablation. However, there was no significant difference in the recovery duration from PNP between PNP during RSPVI and RIPVI. PNP occurred during cryoballoon ablation in 5.7%. While most patients recovered from PNP within one year after the ablation, PNP during RSPVI persisted more than 4 years in 0.6% of patients.

Characteristics of myocardial tissue staining and lesion creation with an infusion-needle ablation catheter for the treatment of ventricular tachycardia in humans.

BACKGROUND: Intramural substrate causing ventricular tachycardia can be targeted by radiofrequency (RF) infusion-needle catheter ablation. OBJECTIVE: The purpose of the study was to assess fluid distribution within the myocardium after needle-ablation catheter infusion and its evidence to RF lesion creation. METHODS: In 25 patients (21 (84%) male; 67 ± 9 years; 8 (32%) with ischemic cardiomyopathy) intramural ablation of ventricular tachycardia was performed with a needle catheter. Fluoroscopic images of myocardial staining patterns produced by pre-RF saline/contrast infusion were analyzed. Lesion creation was defined as tissue inexcitability to high-output needle pacing. RESULTS: Data from 155 sites were eligible for analysis. Tissue staining was evident in 111 (72%) and absent in 44 (28%). The stain shapes were variable, with average dimensions of 20 ± 10 × 8 ± 4 mm with an area of 68 ± 58 mm2. Round/oval-shaped stains were most common (62 [56%]), while multisegmented (36 [32%]) and long flat (13 [12%]) configurations were less frequent. Evidence of staining was associated with evidence of lesion creation (92/111 (83%) vs 17/44 (39%); P ≤ .0001). Contrast staining around the needle was present in 50%, usually had blurred margins, and was associated with lesion creation. When staining extended well beyond the needle, the margins were often sharp, suggesting dissection through tissue planes, and lesion creation tended to be less effective. CONCLUSION: With infusion-needle ablation, preablation injection of contrast can help confirm an intramural position and predict lesion creation. Tissue diffusion patterns vary markedly, and studies to assess its relation to tissue architecture and ablation lesion geometry warrants further investigation. The findings also have implications for the injection of therapeutic agents into the regions of scar.

Anatomical and Procedural Factors of Severe Pulmonary Vein Stenosis After Cryoballoon Pulmonary Vein Ablation.

OBJECTIVES: This study examined the anatomical or procedural factors associated with severe pulmonary vein (PV) stenosis after cryoballoon PV isolation. BACKGROUND: PV stenosis is a complication associated with cryoballoon ablation. METHODS: The study included 170 consecutive patients with paroxysmal atrial fibrillation who underwent cryoballoon ablation. In addition to factors generally considered to be related to the occurrence of PV stenosis (PV size, cryoballoon application number and time, and minimum freezing temperature), we evaluated the following 4 factors: 1) depth of balloon position; 2) the PV angle (internal angle between each PV and horizontal line); 3) noncoaxial balloon placement (hemispherical occlusion); and 4) contact surface area between the cryoballoon and the PV wall (defined as the balloon contact ratio). RESULTS: Severe PV stenosis (≥75% area reduction) was observed in 9 (1.3%) PVs (6 left superior and 3 right superior PVs) in 9 patients. The PV size, cryoballoon application number and time, minimum freezing temperature, and the depth of cryoballoon position were not significantly associated with occurrence of severe PV stenosis, but the PV angle was significantly smaller in PVs with severe stenosis than it was in those without stenosis (25.6 ± 9.7° vs. 34.2 ± 6.4°; p < 0.001). Hemispherical occlusion was more frequently observed and balloon contact ratio was larger in PVs with severe stenosis (55.6% vs. 14.8%; p = 0.049) than in those without stenosis (0.70 ± 0.06 vs. 0.54 ± 0.08; p < 0.001). CONCLUSIONS: A horizontally connecting PV, noncoaxial placement of cryoballoon, and a larger contact surface area of the cryoballoon were predictors of the occurrence of severe PV stenosis after cryoballoon ablation.

Comparison of atrial arrhythmia recurrence after persistent atrial fibrillation ablation between patients with or without tachycardia-induced cardiomyopathy.

BACKGROUND: The presence of heart failure (HF) has been associated with poorer outcomes in patients undergoing catheter ablation (CA) for atrial fibrillation (AF). However, the effectiveness of CA amongst the subset of patients with tachycardia-induced cardiomyopathy (TIC) remains poorly defined. METHODS AND RESULTS: In a retrospective analysis we compared outcomes of first-time CA for persistent AF in a cohort of patients with previously diagnosed TIC (n = 45; age 58 ± 8 years; 91% male) to those with structurally normal hearts (non-TIC; n = 440; age 55 ± 9 years; 95% male). TIC was defined as an impaired ventricular function (left ventricular ejection function [LVEF] <50%), which was reversed after the treatment of HF. We compared atrial arrhythmias (AAs) recurrence after the CA in the TIC and non-TIC cohorts. In the TIC group, LVEF improved from 35.8% ± 8.1% to 57.5% ± 8.3% after treatment of HF. During 3.3 ± 1.5 years follow-up, AAs-free survival after CA was significantly higher in the TIC group as compared with the non-TIC group (69% vs 42%; P = .001), despite a comparable CA strategy between the two groups. In multivariable analysis, absence of HF with TIC, longer AF duration, and complex fractionated atrial electrogram ablation were independent predictors of arrhythmia recurrence (OR, 1.02; 95% CI, 1.01-1.03; P < .01; OR, 0.40; 95% CI, 0.20-0.79; P < .01 and OR, 2.29; 95%CI; 1.27-4.11; P < .01, respectively). In addition, the outcome after the last procedure was superior in the TIC cohort (89% vs 72%; P = .03) with fewer CA procedures as compared with the non-TIC cohort (1.3 ± 0.5 vs 1.5 ± 0.7; P = .01). CONCLUSIONS: Persistent patients with AF with TIC have a more favorable outcome after the CA as compared with those without.

Clinical significance of early recurrence of atrial fibrillation after cryoballoon vs. radiofrequency ablation-A propensity score matched analysis.

OBJECTIVES: One of the mechanisms of early recurrence of atrial fibrillation (ERAF) after AF ablation is considered to be the inflammatory reaction of the atrial tissue. The aim of this study is to compare the clinical significance of ERAF at each stage for true AF recurrence between cryoballoon (CB) and radiofrequency (RF) ablation. METHODS: Among 798 paroxysmal AF patients who underwent an initial ablation, 460 patients (CB, n = 230; RF, n = 230) were selected by propensity score matching. Very ERAF (VERAF), ERAF-1M, ERAF-3M and true AF recurrence were defined as AF recurrence at 0-2, 3-30, 31-90 days and more than 90 days after the procedure, respectively. RESULTS: The patient characteristics of the two groups were similar. ERAF was observed 21% and 27% in the CB and RF groups, respectively. In both the CB and RF group, VERAF, ERAF-1M and ERAF-3M were more frequently observed in patients with true AF recurrence than in those without. In a multivariable analysis, ERAF-1M and ERAF-3M were found to be independent predictors of true AF recurrence in both the CB (P = 0.04 and P<0.001, respectively) and RF groups (P = 0.02 and P = 0.001, respectively). However, while VERAF was associated with true AF recurrence after RF ablation (P = 0.03), it was not associated with true AF recurrence after CB ablation (P = 0.19). CONCLUSION: The relationship between ERAF and true AF recurrence differed between the RF and CB ablation groups. While VERAF was associated with true AF recurrence after RF ablation, it was not a predictor of true AF recurrence after CB ablation.

Infusion Needle Radiofrequency Ablation for Treatment of Refractory Ventricular Arrhythmias.

BACKGROUND: Catheter ablation is effective for eliminating most drug-refractory ventricular arrhythmias (VA). However, a major reason for procedural failure is arrhythmia originating deep within the myocardium where it is inaccessible to conventional endocardial or epicardial approaches. Affected patients have limited therapeutic options. OBJECTIVES: The objective of this study was to assess the safety and outcome of a novel radiofrequency ablation catheter that used an extendable/retractable 27-g needle capable of targeting deep arrhythmia (intramural) substrate. METHODS: Patients who failed at least one prior catheter ablation procedure for sustained ventricular tachycardia (VT) or nonsustained VA with associated left ventricular dysfunction were enrolled at 3 centers. The target was sustained monomorphic VT in 26 patients, including 8 with recent VT storm or VT requiring intravenous medication, and 5 with incessant VA associated with ventricular dysfunction. RESULTS: Needle ablation was performed in 31 patients (median of 2 failed prior ablation procedures; 71% nonischemic heart disease). After a median of 15 needle lesions/patient, ablation abolished at least 1 inducible VT in 19 of 26 VT patients (73%), and suppressed ambient arrhythmia in 4 of 5 nonsustained arrhythmia patients. At the 6-month follow-up, 48% of patients were free of recurrent arrhythmia and another 19% were improved. Procedure-related complications included a single pericardial effusion treated with percutaneous drainage and a left ventricular pacing lead dislodgement with no deaths. CONCLUSIONS: In patients with recurrent ventricular arrhythmias refractory to medications and conventional catheter ablation, intramural needle radiofrequency ablation offers significant arrhythmia control with an acceptable procedural risk.

Catheter ablation of polymorphic ventricular tachycardia/fibrillation in patients with and without structural heart disease.

BACKGROUND: Catheter ablation for polymorphic ventricular tachycardia and ventricular fibrillation (PMVT/VF) may target triggering premature ventricular contractions (PVCs). Targeting ventricular scar has also been suggested, but data are limited. OBJECTIVE: The purpose of this study was to characterize the electrophysiological findings and ablation outcomes for patients with PMVT/VF and structural heart disease (SHD) compared to those with idiopathic VF. METHODS: Data from 32 consecutive patients (13 idiopathic VF, 19 SHD) with recurrent PMVT/VF who underwent catheter ablation were reviewed. RESULTS: A low-voltage area of myocardial scar was present in 15 of 19 patients with SHD. Sustained monomorphic ventricular tachycardia (SMVT) associated with scar was inducible and targeted in 8, 3 of whom had previous SMVT episodes separate from PMVT/VF episodes and 5 had no history of SMVT. Triggering PVCs were identified in 11 patients and arose from an area of endocardial scar in 6. Only scar ablation was performed in 8 patients who did not have triggering PVCs. All idiopathic VF patients underwent PVC ablation only. During a median of 540 days, 74% of SHD patients and 77% of idiopathic VF patients were free of recurrence, including 75% of those with only PVC ablation, 86% of those with scar plus PVC ablation, and 63% of those with only scar ablation. CONCLUSION: Patients with recurrent PMVT/VF and SHD often have a low-voltage scar associated with PVCs or inducible SMVT, which may also be the substrate for PMVT/VF. When present, substrate ablation targeting scar is a reasonable option for treatment of PMVT/VF even if PVCs are absent.

Left Ventricular Entropy Is a Novel Predictor of Arrhythmic Events in Patients With Dilated Cardiomyopathy Receiving Defibrillators for Primary Prevention.

OBJECTIVES: The aim of this study was to assess the utility of left ventricular (LV) entropy, a novel measure of myocardial heterogeneity, for predicting cardiovascular events in patients with dilated cardiomyopathy (DCM). BACKGROUND: Current risk stratification for ventricular arrhythmia in patients with DCM is imprecise. LV entropy is a measure of myocardial heterogeneity derived from cardiac magnetic resonance imaging that assesses the probability distribution of pixel signal intensities in the LV myocardium. METHODS: A registry-based cohort of primary prevention implantable cardioverter-defibrillator patients with DCM had their LV entropy, late gadolinium enhancement (LGE) presence, and LGE mass measured on cardiac magnetic resonance imaging. Patients were followed from implantable cardioverter-defibrillator placement for arrhythmic events (appropriate implantable cardioverter-defibrillator therapy, ventricular arrhythmia, or sudden cardiac death), end-stage heart failure events (cardiac death, transplantation, or ventricular assist device placement), and all-cause mortality. RESULTS: One hundred thirty patients (mean age 55 years, 83% men, LV ejection fraction 29%, mean LV entropy 5.58 ± 0.72, LGE present in 57%) were followed for a median of 3.2 years. Eighteen (14.0%) experienced arrhythmic events, 17 (13.1%) experienced end-stage heart failure events, and 7 (5.4%) died. LV entropy provided substantial improvement of predictive ability when added to a model containing clinical variables and LGE mass (hazard ratio: 3.5; 95% confidence interval: 1.42 to 8.82; p = 0.007; net reclassification index = 0.345, p = 0.04). For end-stage heart failure events, LV entropy did not improve the model containing clinical variables and LGE mass (hazard ratio: 2.03; 95% confidence interval: 0.78 to 5.28; p = 0.14). Automated LV entropy measurement has excellent intraobserver (mean difference 0.04) and interobserver (mean difference 0.03) agreement. CONCLUSIONS: Automated LV entropy measurement is a novel marker for risk stratification toward ventricular arrhythmia in patients with DCM.

Complications and Anticoagulation Strategies for Percutaneous Epicardial Ablation Procedures.

BACKGROUND: Percutaneous pericardial access for catheter ablation is associated with a bleeding risk. We sought to elucidate the relation of hemorrhagic and thromboembolic events associated with epicardial procedures to anticoagulation strategy. METHODS: Anticoagulation strategy before and during pericardial access for 355 patients (57±14 years old) who had ventricular arrhythmia mapping and ablation were reviewed. Oral anticoagulants were stopped perioperatively and heparin administered before the procedure. Pericardial bleeding >80 mL was considered significant. The patients were divided into 3 groups per the anticoagulation strategy. Group 1: no heparin was administered before pericardial access, group 2: heparin was administered and reversed before pericardial access, and group 3: heparin was administered and not reversed. RESULTS: Significant pericardial bleeding occurred in 46 cases (13%) and did not differ among the groups ( P=0.720). Unintentional cardiac puncture and left ventricular ejection fraction ≤35% were independently associated with pericardial bleeding (odds ratio, 16.4; 95% CI, 7.35-36.40; P<0.001 and odds ratio, 2.28; 95% CI, 1.02-5.10; P=0.044). Of 38 procedures with unintentional cardiac puncture, there was no difference in pericardial bleeding for different anticoagulation strategies. Thromboembolic events occurred in 5 patients; 1 coronary embolism, 1 stroke, 2 deep vein thrombosis with 1 fatal pulmonary embolism, and 1 thrombus on a temporary ventricular assist device. CONCLUSIONS: Bleeding is the major risk related to pericardial access and seems to be more related to unintentional cardiac puncture than to the anticoagulation strategy. Thrombotic complications are infrequent but potentially severe. The major focus for improving safety should be on the prevention of unintentional cardiac puncture.