Ventricular arrhythmias in athletes: Role of a comprehensive diagnostic workup.

BACKGROUND: Ventricular arrhythmias (VAs) represent a critical issue with regard to sports eligibility assessment in athletes. The ideal diagnostic evaluation of competitive and leisure-time athletes with complex VAs has not been clearly defined. OBJECTIVE: The purpose of this study was to assess the clinical implications of invasive electrophysiological assessments and endomyocardial biopsy (EMB) among athletes with VAs. METHODS: We evaluated 227 consecutive athletes who presented to our institutions after being disqualified from participating in sports because of VAs. After noninvasive tests, electrophysiological study (EPS), electroanatomic mapping (EAM), and EAM- or cardiac magnetic resonance imaging-guided EMB was performed, following a prespecified protocol. Sports eligibility status was redefined at 6-month follow-up. RESULTS: From our sample, 188 athletes (82.8%) underwent EAM and EPS, and 42 (15.2%) underwent EMB. A diagnosis of heart disease could be formulated in 30% of the study population (67/227; 95% confidence interval [CI] 0.24-0.36) after noninvasive tests; in 37% (83/227; 95% CI 31%-43%) after EPS and EAM; and in 45% (102/227; 95% CI 39%-51%) after EMB. In the subset of athletes undergoing EMB, invasive diagnostic workup allowed diagnostic reclassification of half of the athletes (n = 21 [50%]). Reclassification was particularly common among subjects without definitive findings after noninvasive evaluation (n = 23; 87% reclassified). History of syncope, abnormal echocardiogram, presence of late gadolinium enhancement, and abnormal EAM were linked to sports ineligibility at 6-month follow-up. CONCLUSION: A comprehensive invasive workup provided additional diagnostic elements and could improve the sports eligibility assessment of athletes presenting with VAs. The extensive invasive evaluation presented could be especially helpful when noninvasive tests show unclear findings.

Worldwide Survey of COVID-19-Associated Arrhythmias.

[Figure: see text].

Characteristics of Patients With Arrhythmogenic Left Ventricular Cardiomyopathy: Combining Genetic and Histopathologic Findings.

BACKGROUND: Arrhythmogenic left ventricular cardiomyopathy (ALVC) is an under-characterized phenotype of arrhythmogenic cardiomyopathy involving the LV ab initio. ALVC was not included in the 2010 International Task Force Criteria for arrhythmogenic right ventricular cardiomyopathy diagnosis and data regarding this phenotype are scarce. METHODS: Clinical characteristics were reported from all consecutive patients diagnosed with ALVC, defined as a LV isolated late gadolinium enhancement and fibro-fatty replacement at cardiac magnetic resonance plus genetic variants associated with arrhythmogenic right ventricular cardiomyopathy and of an endomyocardial biopsy showing fibro-fatty replacement complying with the 2010 International Task Force Criteria in the LV. RESULTS: Twenty-five patients ALVC (53 [48-59] years, 60% male) were enrolled. T wave inversion in infero-lateral and left precordial leads were the most common ECG abnormalities. Overall arrhythmic burden at study inclusion was 56%. Cardiac magnetic resonance showed LV late gadolinium enhancement in the LV lateral and posterior basal segments in all patients. In 72% of the patients an invasive evaluation was performed, in which electroanatomical voltage mapping and electroanatomical voltage mapping-guided endomyocardial biopsy showed low endocardial voltages and fibro-fatty replacement in areas of late gadolinium enhancement presence. Genetic variants in desmosomal genes (desmoplakin and desmoglein-2) were identified in 12/25 of the cohort presenting pathogenic/likely pathogenic variants. A definite/borderline 2010 International Task Force Criteria arrhythmogenic right ventricular cardiomyopathy diagnosis was reached only in 11/25 patients. CONCLUSIONS: ALVC presents with a preferential involvement of the lateral and postero-lateral basal LV and is associated mostly with variants in desmoplakin and desmoglein-2 genes. An amendment to the current International Task Force Criteria is reasonable to better diagnose patients with ALVC.

Diagnostic Yield of Electroanatomic Voltage Mapping in Guiding Endomyocardial Biopsies.

BACKGROUND: Electroanatomic voltage mapping (EVM) is a promising modality for guiding endomyocardial biopsies (EMBs). However, few data support its feasibility and safety. We now report the largest cohort of patients undergoing EVM-guided EMBs to show its diagnostic yield and to compare it with a cardiac magnetic resonance (CMR)-guided approach. METHODS: We included 162 consecutive patients undergoing EMB at our institution from 2010 to 2019. EMB was performed in pathological areas identified at EVM and CMR. CMR and EVM sensitivity and specificity regarding the identification of pathological substrates of myocardium were evaluated according to EMB results. RESULTS: Preoperative CMR showed late gadolinium enhancement in 70% of the patients, whereas EVM identified areas of low voltage in 61%. Right (73%), left (19%), or both ventricles (8%) underwent sampling. EVM proved to have sensitivity similar to CMR (74% versus 77%), with specificity being 70% and 47%, respectively. In 12 patients with EMB-proven cardiomyopathy, EVM identified pathological areas that had been undetected at CMR evaluation. Sensitivity of pooled EVM and CMR was as high as 95%. EMB analysis allowed us to reach a new diagnosis, different from the suspected clinical diagnosis, in 39% of patients. The complications rate was low, mostly related to vascular access, with no patients requiring urgent management. CONCLUSIONS: EVM proved to be a promising tool for targeted EMB because of its sensitivity and specificity for identification of myocardial pathological substrates. EVM was demonstrated to have accuracy similar to CMR. EVM and CMR together conferred a positive predictive value of 89% on EMB.

Influence of pancreatic status on circulating plasma sterols in patients with cystic fibrosis.

Background Patients with cystic fibrosis (CF) have a reduced intestinal absorption of cholesterol and in a preliminary study we observed differences in plasma sterol profile between patients with pancreatic sufficiency (PS) and those with pancreatic insufficiency (PI). Therefore, we hypothesized that the sterol analysis may contribute to study the digestion and absorption state of lipids in patients with CF. To this aim we evaluated plasma sterols in a significant number of adult patients with CF in relation to the pancreatic status. Methods Beside cholesterol, we measured phytosterols and lathosterol as markers of intestinal absorption and hepatic biosynthesis, respectively, by gas-chromatography in plasma of adult CF patients with pancreatic sufficiency (PS-CF, n = 57), insufficiency (PI-CF, n = 97) and healthy subjects (control group, CT, n = 71). Results PI-CF patients had cholesterol and phytosterols levels significantly lower than PS-CF and CT (p < 5 × 10-10) suggesting a reduced intestinal absorption of sterols related to PI. Instead, lathosterol was significantly higher in PI-CF patients than PS-CF and CT (p < 0.0003) indicating an enhanced cholesterol biosynthesis. In PI-CF patients, phytosterols positively correlate with vitamin E (p = 0.004). Both the classes of molecules need cholesterol esterase for the intestinal digestion, thus the reduced levels of such lipids in serum from PI-CF patients may depend on a reduced enzyme activity, despite the pancreatic enzyme supplementation in all PI-CF patients. Conclusions A plasma sterols profile may be useful to evaluate the metabolic status of lipids in adult patients with CF and could help to manage the pancreatic enzyme supplementation therapy.

X-Ray Exposure in Cardiac Electrophysiology: A Retrospective Analysis in 8150 Patients Over 7 Years of Activity in a Modern, Large-Volume Laboratory.

BACKGROUND: Only a few studies have systematically evaluated fluoroscopy data of electrophysiological and device implantation procedures. Aims of this study were to quantify ionizing radiation exposure for electrophysiological/device implantation procedures in a large series of patients and to analyze the x-ray exposure trend over years and radiation exposure in patients undergoing atrial fibrillation ablation considering different technical aspects. METHODS AND RESULTS: We performed a retrospective analysis of all electrophysiological/device implantation procedures performed during the past 7 years in a modern, large-volume laboratory. We reported complete fluoroscopy data on 8150 electrophysiological/device implantation procedures (6095 electrophysiological and 2055 device implantation procedures); for each type of procedure, effective dose and lifetime attributable risk of cancer incidence and mortality were calculated. Over the 7-year period, we observed a significant trend reduction in fluoroscopy time, dose area product, and effective dose for all electrophysiological procedures (P<0.001) and a not statistically significant trend reduction for device implantation procedures. Analyzing 2416 atrial fibrillation ablations, we observed a significant variability of fluoroscopy time, dose area product and effective dose among 7 different experienced operators (P<0.0001) and a significant reduction of fluoroscopy use over time (P<0.0001) for all of them. Considering atrial fibrillation ablation techniques, fluoroscopy time was not different (P = 0.74) for radiofrequency catheter ablation in comparison with cryoablation, though cryoablation was still associated with higher dose area product and effective dose values (P<0.001). CONCLUSIONS: Electrophysiological procedures involve a nonnegligible x-ray use, leading to an increased risk of malignancy. Awareness of radiation-related risk, together with technological advances, can successfully optimize fluoroscopy use.

Left Atrial Appendage Isolation in Patients With Longstanding Persistent AF Undergoing Catheter Ablation: BELIEF Trial.

BACKGROUND: Longstanding persistent (LSP) atrial fibrillation (AF) is the most challenging type of AF. In addition to pulmonary vein isolation, substrate modification and triggers ablation have been reported to improve freedom from AF in patients with LSPAF. OBJECTIVES: This study sought to assess whether the empirical electrical isolation of the left atrial appendage (LAA) could improve success at follow-up. METHODS: This was an open-label, randomized study assessing the effectiveness of empirical electrical left atrial appendage isolation for the treatment of LSPAF. Patients were randomly assigned to undergo empirical electrical left atrial appendage isolation along with extensive ablation (group 1; n = 85) or extensive ablation alone (group 2; n = 88). Recurrence of atrial arrhythmias was the primary endpoint. Secondary endpoints included cardiac-related hospitalization, all-cause mortality, and stroke at follow-up. RESULTS: Major clinical characteristics were not different between the 2 groups. At 12-month follow-up, 48 (56%) patients in group 1 and 25 (28%) in group 2 were recurrence free after a single procedure (unadjusted hazard ratio [HR] for recurrence with standard ablation: 1.92; 95% confidence interval [CI]: 1.3 to 2.9; log-rank p = 0.001). After adjusting for age, sex, and left atrial size, standard ablation was predictive of recurrence (HR: 2.22; 95% CI: 1.29 to 3.81; p = 0.004). During repeat procedures, empirical electrical left atrial appendage isolation was performed in all patients. After an average of 1.3 procedures, cumulative success at 24-month follow-up was reported in 65 (76%) in group 1 and in 49 (56%) in group 2 (unadjusted HR: 2.24; 95% CI: 1.3 to 3.8; log-rank p = 0.003). CONCLUSIONS: This randomized study showed that both after a single procedure and after redo procedures in patients with LSPAF, empirical electrical isolation of the LAA improved long-term freedom from atrial arrhythmias without increasing complications. (Effect of Empirical Left Atrial Appendage Isolation on Long-term Procedure Outcome in Patients With Persistent or Longstanding Persistent Atrial Fibrillation Undergoing Catheter Ablation [BELIEF]; NCT01362738).

Scar Homogenization Versus Limited-Substrate Ablation in Patients With Nonischemic Cardiomyopathy and Ventricular Tachycardia.

BACKGROUND: Scar homogenization improves long-term ventricular arrhythmia-free survival compared with standard limited-substrate ablation in patients with post-infarction ventricular tachycardia (VT). Whether such benefit extends to patients with nonischemic cardiomyopathy and scar-related VT is unclear. OBJECTIVES: The aim of this study was to assess the long-term efficacy of an endoepicardial scar homogenization approach compared with standard ablation in this population. METHODS: Consecutive patients with dilated nonischemic cardiomyopathy (n = 93), scar-related VTs, and evidence of low-voltage regions on the basis of pre-defined criteria on electroanatomic mapping (i.e., bipolar voltage <1.5 mV) underwent either standard VT ablation (group 1 [n = 57]) or endoepicardial ablation of all abnormal potentials within the electroanatomic scar (group 2 [n = 36]). Acute procedural success was defined as noninducibility of any VT at the end of the procedure; long-term success was defined as freedom from any ventricular arrhythmia at follow-up. RESULTS: Acute procedural success rates were 69.4% and 42.1% after scar homogenization and standard ablation, respectively (p = 0.01). During a mean follow-up period of 14 ± 2 months, single-procedure success rates were 63.9% after scar homogenization and 38.6% after standard ablation (p = 0.031). After multivariate analysis, scar homogenization and left ventricular ejection fraction were predictors of long-term success. During follow-up, the rehospitalization rate was significantly lower in the scar homogenization group (p = 0.035). CONCLUSIONS: In patients with dilated nonischemic cardiomyopathy, scar-related VT, and evidence of low-voltage regions on electroanatomic mapping, endoepicardial homogenization of the scar significantly increased freedom from any recurrent ventricular arrhythmia compared with a standard limited-substrate ablation. However, the success rate with this approach appeared to be lower than previously reported with ischemic cardiomyopathy, presumably because of the septal and midmyocardial distribution of the scar in some patients.

Feasibility of combined unipolar and bipolar voltage maps to improve sensitivity of endomyocardial biopsy.

BACKGROUND: Endomyocardial biopsy (EMB) has a low sensitivity. Electroanatomic voltage mapping (EVM) is effective in guiding EMB thanks to its ability in identifying and locating low-voltage regions. The analysis of unipolar EVM can correlate with epicardial pathological involvement. We evaluated the unipolar EVM in EMB areas to determine whether it can increase EMB sensitivity in diagnosing epicardial diseases. METHODS AND RESULTS: We performed endocardial bipolar EVM-guided EMBs in 29 patients and we analyzed unipolar EVM at withdrawal sites. Eighty myocardial samples were collected (mean, 2.8±0.9; median, 3 fragments per patient) and 60 were suitable for histological analysis. Ten specimens (17%) were collected from an area with discordant normal bipolar/low-voltage unipolar EVM and they were diagnostic or suggestive for arrhythmogenic right ventricular dysplasia/cardiomyopathy in 6 patients, for myocarditis and sarcoidosis in 1 patient each. Six samples (10%) were collected from an area with discordant low-voltage bipolar/normal unipolar EVM and they showed nonspecific features. The sensitivity of unipolar EVMs for a diagnostic biopsy finding EMB was significantly higher compared with bipolar EVMs analyzed according to samples (P<0.01) and patients (P=0.008). The specificity of unipolar EMB was better than bipolar EMB when analyzed for all samples (P=0.0014) but the difference did not reach statistical significance when analyzed by patient (P=0.083). The diagnostic yield was 63.3% for the bipolar and 83.3% for the unipolar EVM. CONCLUSIONS: These findings suggest that use of a combined bipolar/unipolar map may be able to improve the diagnostic yield of endomyocardial ventricular biopsy.

Ventricular arrhythmias induced by long-term use of ephedrine in two competitive athletes.

Ephedrine is a sympathomimetic substance used by sportsmen as a doping substance because of its stimulating and slimming effects. We report two cases of ventricular arrhythmias induced by abuse of ephedrine in two competitive athletes. Endomyocardial biopsies guided by electroanatomic mapping revealed contraction-band necrosis, a myocardial injury frequently observed in cases of catecholamine excess. Our cases suggest that long-term abuse of ephedrine may result in myocardial damage, and that these structural alterations may promote areas of slow conduction favoring re-entrant ventricular tachyarrhythmias and a long-lasting risk of ventricular arrhythmias.

Simultaneous assessment of contact pressure and local electrical coupling index using robotic navigation.

PURPOSE: Contact with cardiac tissue is a determinant of lesion efficacy during atrial fibrillation (AF) ablation. The Sensei®X Robotic Catheter System (Hansen Medical, CA) has been validated for contact force sensing. The electrical coupling index (ECI) from the EnSite Contact™ system (St. Jude Medical, MN) has been validated as an indicator of tissue contact. We aimed at analyzing ECI behavior during radiofrequency (RF) pulses maintaining a stable contact through the robotic navigation contact system. METHODS: In 15 patients (age, 59 ± 12) undergoing AF ablation, pulmonary vein (PV) isolation was guided by the Sensei®X System, employing the Contact™ catheter. RESULTS: During the procedure, we assessed ECI changes associated with adequate contact based on the IntelliSense® force-sensing technology (Hansen Medical, CA. Baseline contact (27 ± 8 g/cm(2)) ECI value was 99 ± 13, whereas ECI values in a noncontact site (0 g/cm(2)) and in a light contact site (1-10 g/cm(2)) were respectively 66 ± 12 and 77 ± 10 (p < 0.0001). Baseline contact ECI values were not different depending on AF presentation (paroxysmal AF, 98 ± 9; persistent AF, 100 ± 9) or on cardiac rhythm (sinus rhythm, 97 ± 7; AF,101 ± 10). In all PVs, ECI was significantly reduced during and after ablation (ECI during RF, 56 ± 15; ECI after RF, 72 ± 16; p < 0.001). A mean reduction of 32.2% during RF delivery and 25.4% immediately after RF discontinuation compared with baseline ECI was observed. CONCLUSIONS: Successful PV isolation is associated with a significant decrease in ECI of at least 20 %. This may be used as a surrogate marker of effective lesion in AF ablation.

Catheter ablation of atrial fibrillation in hypertrophic cardiomyopathy: long-term outcomes and mechanisms of arrhythmia recurrence.

BACKGROUND: Pulmonary vein (PV) antrum isolation in patients with hypertrophic cardiomyopathy and atrial fibrillation (AF) has been reported to have satisfactory results at the mid- and short-term follow-up. We determined the outcomes at the long-term follow-up of PV antrum isolation in these patients. METHODS AND RESULTS: We enrolled 43 patients with hypertrophic cardiomyopathy and AF (28% paroxysmal AF). PV antrum isolation (paroxysmal AF) and posterior wall isolation with complex fractionated atrial electrogram ablation (persistent and longstanding persistent AF) were the end points at the time of the index procedure and for repeat procedures during the first year of follow-up. In case of recurrent arrhythmia >1 year, high-dose isoproterenol challenge was used to disclose non-PV trigger sites. During the first year, the success rate reached 91% (mean of 1.6 procedures). After a median follow-up of 42 months (range, 38-48 months), 49% of the patients remained free from AF/atrial tachycardia. All patients underwent an additional procedure. PV antrum and posterior wall remained isolated in 82% of the cases, and extra-PV triggers were documented in all patients and targeted for ablation. After a median follow-up of 15 months (range, 8-19 months) subsequent to the last procedure, 94% of the patients remained free from AF/atrial tachycardia off antiarrhythmic drugs. CONCLUSIONS: PV isolation in patients with hypertrophic cardiomyopathy is feasible and safe, although is not effective in preventing late (≥1 year) AF recurrences in ≈50% of patients. Non-PV triggers seem to be responsible of late recurrences, which supports the appropriateness of a more extensive ablation beyond PV isolation to improve the long-term arrhythmia-free survival.

Endo-epicardial homogenization of the scar versus limited substrate ablation for the treatment of electrical storms in patients with ischemic cardiomyopathy.

OBJECTIVES: This study investigated the impact on recurrences of 2 different substrate approaches for the treatment of these arrhythmias. BACKGROUND: Catheter ablation of electrical storms (ES) for ventricular arrhythmias (VAs) has shown moderate long-term efficacy in patients with ischemic cardiomyopathy. METHODS: Ninety-two consecutive patients (81% male, age 62 ± 13 years) with ischemic cardiomyopathy and ES underwent catheter ablation. Patients were treated either by confining the radiofrequency lesions to the endocardial surface with limited substrate ablation (Group 1, n = 49) or underwent endocardial and epicardial ablation of abnormal potentials within the scar (homogenization of the scar, Group 2, n = 43). Epicardial access was obtained in all Group 2 patients, whereas epicardial ablation was performed in 33% (14) of these patients. RESULTS: Mean ejection fraction was 27 ± 5. During a mean follow-up of 25 ± 10 months, the VAs recurrence rate of any ventricular tachycardia (VTs) was 47% (23 of 49 patients) in Group 1 and 19% (8 of 43 patients) in Group 2 (log-rank p = 0.006). One patient in Group 1 and 1 patient in Group 2 died at follow-up for noncardiac reasons. CONCLUSIONS: Our study demonstrates that ablation using endo-epicardial homogenization of the scar significantly increases freedom from VAs in ischemic cardiomyopathy patients.

Fragmented and delayed electrograms within fibrofatty scar predict arrhythmic events in arrhythmogenic right ventricular cardiomyopathy: results from a prospective risk stratification study.

BACKGROUND: Islets of myocytes within fibrofatty scars represent the substrate for reentrant ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy (ARVC). Electroanatomic mapping can reliably identify such areas. OBJECTIVE: To prospectively test the association between late and fragmented electrograms within scar and arrhythmic events in patients with ARVC. METHODS: High-density right ventricle electroanatomic mapping was performed in 32 patients with ARVC without history of cardiac arrest or sustained ventricular arrhythmias. Standard definitions of electroanatomic scars and fragmented, isolated, and very late potentials were used. All patients received an implantable cardioverter-defibrillator for the primary prevention of sudden death. RESULTS: After a mean follow-up of 25 ± 7 months, 12 (38%) patients received appropriate implantable cardioverter-defibrillator shock for sustained ventricular arrhythmias. With the exception of a higher rate of previous syncope (P = .053), patients with arrhythmic events at follow-up did not differ from those who remained free from arrhythmic events in terms of other clinical variables, including cardiac magnetic resonance findings. Electroanatomic scars were present in all patients. The distribution and extent of electroanatomic scars were similar in the 2 groups (38 ± 25 cm(2) vs 33 ± 20 cm(2); P = .51). However, patients with implantable cardioverter-defibrillator shock had a higher prevalence of fragmented electrograms (92% vs 20%; P <.001), of isolated late potentials (75% vs 20%; P = .004), and of very late potentials (67% vs 25%; P = .030). Fragmented electrograms were the only variable independently associated with arrhythmic events at follow-up (hazard ratio 21; P = .015). CONCLUSION: The presence of fragmented and delayed electrograms within the scar predicts arrhythmic events in ARVC.

The durability of pulmonary vein isolation using the visually guided laser balloon catheter: multicenter results of pulmonary vein remapping studies.

BACKGROUND: The visually guided laser ablation (VGLA) catheter is a compliant, variable-diameter balloon that delivers laser energy around the pulmonary vein (PV) ostium under real-time endoscopic visualization. While acute PV isolation has been shown to be feasible, limited data exist regarding the durability of isolation. OBJECTIVE: We sought to determine the durability of PV isolation following ablation using the balloon-based VGLA catheter. METHODS: The VGLA catheter was evaluated in patients with paroxysmal atrial fibrillation (3 sites, 10 operators). Following transseptal puncture, the VGLA catheter was advanced through a 12-F deflectable sheath and inflated at the target PV ostium. Under endoscopic guidance, the 30° aiming arc was maneuvered around the PV and laser energy was delivered to ablate tissue in a contiguous/overlapping manner. At ∼3 months, all patients returned for a PV remapping procedure. RESULTS: In 56 patients, 202 of 206 PVs (98%) were acutely isolated. At 105 ± 44 (mean ± SD) days, 52 patients returned for PV remapping at which time 162 of 189 PVs (86%) remained isolated and 32 of 52 patients (62%) had all PVs still isolated. On comparing the operators performing <10 vs ≥ 10 procedures, the durable PV isolation rate and the percentage of patients with all PVs isolated were found to be 73% vs 89% (P = .011) and 57% vs 66% (P = .746), respectively. After 2 procedures and 12.0 ± 1.9 months of follow-up, the drug-free rate of freedom from atrial fibrillation was 71.2%. CONCLUSIONS: In this multicenter, multioperator experience, VGLA resulted in a very high rate of durable PV isolation with a clinical efficacy similar to that of radiofrequency ablation.

Imaging of scar in patients with ventricular arrhythmias of right ventricular origin: cardiac magnetic resonance versus electroanatomic mapping.

INTRODUCTION: Assessment of late gadolinium enhancement (LGE) at cardiac magnetic resonance is often used to detect scar in patients with arrhythmias of right ventricular (RV) origin. Recently, electroanatomic mapping (EAM) has been shown to reliably detect scars corresponding to different cardiomyopathic substrates. We compared LGE with EAM for the detection of scar in patients with arrhythmias of RV origin. METHODS AND RESULTS: Thirty-one patients with RV arrhythmias and biopsy-proven structural heart disease (18 ARVC and 13 myocarditis), and 5 with idiopathic RV outflow tract arrhythmias underwent LGE analysis and EAM with scar validation through EAM-guided endomyocardial biopsy. EAM scars were present in 23 (64%) patients (all with structural heart disease), whereas LGE was present only in 12 (33%). In 2 cases, EAM provided a false-positive diagnosis of a small scar in the basal perivalvular area. LGE correctly diagnosed EAM scar in 48% of patients, resulting in high positive (92%) but low negative (50%) predictive values. The distribution of LGE was significantly associated with the distribution of EAM scars (P < 0.001 in the free wall, P = 0.003 in the outflow tract, and P = 0.023 in the posterior/inferior wall). Presence of LGE reflected a higher extension of EAM scars (34.4 ± 16.5% vs 7.9 ± 10.1% of the RV area, P < 0.001). At receiver operating characteristic (ROC) analysis, an extension of scar ≥20% of the RV area was the best cut-off value to detect LGE (sensitivity 83%, specificity 92%). Of note, LGE missed 10 of 11 (91%) patients with EAM scars <20% of RV area. CONCLUSIONS: LGE is significantly less sensitive than EAM in identifying RV cardiomyopathic substrates. Absence of LGE does not rule out the presence of small scars, and EAM with biopsy should be considered to increase the diagnostic yield.

Ablation of ventricular arrhythmias in arrhythmogenic right ventricular dysplasia/cardiomyopathy: arrhythmia-free survival after endo-epicardial substrate based mapping and ablation.

BACKGROUND: In patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy, freedom from ventricular arrhythmias (VAs) after endocardial ablation is limited. We compared the long-term freedom from recurrent VAs by using endocardial-alone ablation versus endo-epicardial substrate-based ablation. METHODS AND RESULTS: Forty-nine patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy undergoing ablation of ventricular tachycardia (VT) were divided into 2 groups: endocardial-alone ablation (group 1, n = 23) and endo-epicardial ablation (group 2, n = 26). All patients had an implantable cardioverter-defibrillator (ICD). Conventional and 3D mappings were used to determine the mechanism of induced VTs and to identify area of "scar" or "abnormal" myocardium. All critical sites responsible for VTs and points with "abnormal" potential were targeted for ablation from endocardium (group 1) or from both endocardium and epicardium (group 2). The procedural end point was noninducibility of sustained, monomorphic VT with isoproterenol. The presence of frequent premature ventricular contractions at the end of ablation was recorded. Patients were followed up by ECG, Holter, and ICD interrogation. After a follow-up of at least 3 years, freedom from VAs or ICD therapy was 52.2% (12/23) in group 1 and 84.6% (22/26) in group 2 (P = 0.029), with 21.7% (5/23) and 69.2% (18/26) patients off antiarrhythmic drugs (P < 0.001), respectively. Compared with patients with no premature ventricular contractions after ablation, patients with frequent premature ventricular contractions after ablation were more likely to have VA recurrence/ICD therapy [3/33 (9%) versus 12/16 (75%); log-rank P<0.001]. CONCLUSIONS: An endo-epicardial-based ablation strategy achieves higher long-term freedom from recurrent VAs off antiarrhythmic therapy in patients with arrhythmogenic right ventricular dysplasia/cardiomyopathy when compared with endocardial-alone ablation. The presence of ≥ 10 premature ventricular contractions per minute after ablation is associated with more VA recurrence.

Right ventricular substrate mapping using the Ensite Navx system: Accuracy of high-density voltage map obtained by automatic point acquisition during geometry reconstruction.

BACKGROUND: Contact point-to-point electroanatomic mapping (Pt-Map) is a validated tool to evaluate right ventricular (RV) substrate. When using the EnSite NavX system (St. Jude Medical, St Paul, Minnesota), geometry reconstruction by dragging the mapping catheter (Geo-Map) allows for quicker acquisition of a large number of points and better definition of anatomy, but it is not validated for substrate mapping. OBJECTIVE: This study evaluates the feasibility and accuracy of Geo-Map. METHODS: Thirteen patients (mean age 38 +/- 12 years) with RV arrhythmias and an apparently normal heart underwent cardiac magnetic resonance imaging (MRI), Pt-Map, and Geo-Map. The 2 maps were compared in terms of mapping procedural time, radiation time, and total number of points acquired. We finally compared the number and characteristics of low-potential areas on each patient's Pt-Map, Geo-Map, and cardiac MRI. RESULTS: Geo-Map required significantly shorter mapping and radiation times in comparison to Pt-Map (12.4 +/- 4.6 vs. 31.9 +/- 10.1 and 5.8 +/- 2.1 vs. 12.1 +/- 3.9, P <.001). Furthermore, Geo-Map was based on a significantly higher density of points in comparison to Pt-Map (802 +/- 205 vs. 194 +/- 38, P <.001). Taking into consideration the total number of RV regions analyzed, the Pt-Map and Geo-Map disagreed in 2 of 65 (3%) regions (P = NS), which only Geo-Map identified as low-potential areas and indeed corresponded to wall motion abnormalities on MRI. CONCLUSION: Voltage maps obtained through RV geometry acquisition have accuracy comparable to that of conventional point-by-point mapping in detecting low-voltage areas, have a good correlation with MRI wall motion abnormalities, and allow a significant reduction in procedural time and x-ray exposure.