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Background: Exercise is associated with sustained ventricular arrhythmias (VA) in Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC) but is not included in the ARVC risk calculator (arvcrisk.com). The objective of this study is to quantify the influence of exercise at diagnosis on incident VA risk and evaluate whether the risk calculator needs adjustment for exercise., Methods: We interviewed ARVC patients without sustained VA at diagnosis about their exercise history. The relationship between exercise dose 3 years preceding diagnosis (average METh/wk) and incident VA during follow-up was analyzed with time-to-event analysis. The incremental prognostic value of exercise to the risk calculator was evaluated by Cox models., Results: We included 176 patients (male, 43.2%; age, 37.6±16.1 years) from 3 ARVC centers, of whom 53 (30.1%) developed sustained VA during 5.4 (2.7-9.7) years of follow-up. Exercise at diagnosis showed a dose-dependent nonlinear relationship with VA, with no significant risk increase <15 to 30 METh/wk. Athlete status, using 3 definitions from literature (>18, >24, and >36 METh/wk), was significantly associated with VA (hazard ratios, 2.53-2.91) but was also correlated with risk factors currently in the risk calculator model. Thus, adding athlete status to the model did not change the C index of 0.77 (0.71-0.84) and showed no significant improvement (Akaike information criterion change, <2)., Conclusions: Exercise at diagnosis was dose dependently associated with risk of sustained VA in ARVC patients but only above 15 to 30 METh/wk. Exercise does not appear to have incremental prognostic value over the risk calculator. The ARVC risk calculator can be used accurately in athletic patients without modification.

Background Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited condition associated with ventricular arrhythmias and myocardial dysfunction; however, limited data exist on identifying patients at highest risk. The purpose of the study was to determine whether measures of right ventricular (RV) dysfunction on echocardiogram including RV strain were predictive of structural disease progression in ARVC. Methods and Results A retrospective analysis of serial echocardiograms from 40 patients fulfilling 2010 task force criteria for ARVC was performed to assess structural progression defined by an increase in proximal RV outflow tract dimensions (parasternal short or long axis) or decrease in RV fractional area change. Echocardiograms were analyzed for RV free-wall peak longitudinal systolic strain using 2-dimensional speckle tracking. Risk of structural progression and 5-year change in RV outflow tract measurements were compared with baseline RV strain. Of the 40 ARVC patients, 61% had structural progression with an increase in the mean parasternal short-axis RV outflow tract dimension from 36.2 to 38.5 mm ( P =0.022) and 68% by increase in parasternal long-axis RV outflow tract dimension from 36.1 to 39.2 mm ( P =0.001). RV fractional area change remained stable over time. Baseline RV strain was significantly associated with the risk of structural progression and 5-year rate of change. Patients with an RV strain more positive than -20% had a higher risk (odds ratio: 18.4; 95% CI, 2.7-125.8; P =0.003) of structural progression. Conclusions RV free wall strain is associated with the rate of structural progression in patients with ARVC. It may be a useful marker in determining which patients require closer follow-up and treatment.

Introduction: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is an inherited cardiomyopathy, characterized by right ventricular dysfunction and ventricular arrhythmias. Premature ventricular contractions (PVCs) are an important measure in determining disease severity and constitute a minor criterion in the 2010 Task Force Criteria for the diagnosis of ARVD/C. Little information is available regarding the variability in PVCs., Methods and Results: Patients (n = 40) from the Johns Hopkins ARVD/C registry, meeting diagnostic criteria were included. Single lead continuous 12-lead electrocardiogram (ECG) monitors (Zio® Patches) were applied to monitor PVC counts. Detailed demographic, phenotypic, and structural information were obtained from registry data. ECG monitors were worn for a mean period of 159.3 hours (±39.3). Average 24-hour PVC count in this population was 1,090.5 (interquartile range = 1,711). One-way analysis of variance demonstrated statistically significant interday variance in mean hourly PVC counts in 76% of ARVD/C-positive subjects (28/37, 3 cases excluded due to insufficient data). Eleven individuals (27.5%) had maximum 24-hour PVC counts of >500 with a corresponding minimum 24-hour PVC count of <500. The average 24-hour PVC count for each patient was derived for each day recorded. The 24-hour PVC count placed 89.6% of counts (223/249) on the correct side of the 500-PVC count., Conclusion: Statistically significant variation between 24-hour PVC counts is present in the ARVD/C population. However, 24-hour ECG monitoring was sufficient to identify 89.6% of 24-hour periods to the correct grouping based on 2010 Task Force Criteria., (© 2014 Wiley Periodicals, Inc.)

Introduction: The traditional description of the Triangle of Dysplasia in Arrhythmogenic Right Ventricular Dysplasia/Cardiomyopathy (ARVD/C) predates genetic testing and excludes biventricular phenotypes., Methods and Results: We analyzed Cardiac Magnetic Resonance (CMR) studies of 74 mutation-positive ARVD/C patients for regional abnormalities on a 5-segment RV and 17-segment LV model. The location of electroanatomic endo- and epicardial scar and site of successful VT ablation was recorded in 11 ARVD/C subjects. Among 54/74 (73%) subjects with abnormal CMR, the RV was abnormal in almost all (96%), and 52% had biventricular involvement. Isolated LV abnormalities were uncommon (4%). Dyskinetic basal inferior wall (94%) was the most prevalent RV abnormality, followed by basal anterior wall (87%) dyskinesis. Subepicardial fat infiltration in the posterolateral LV (80%) was the most frequent LV abnormality. Similar to CMR data, voltage maps revealed scar (<0.5 mV) in the RV basal inferior wall (100%), followed by the RV basal anterior wall (64%) and LV posterolateral wall (45%). All 16 RV VTs originated from the basal inferior wall (50%) or basal anterior wall (50%). Of 3 LV VTs, 2 localized to the posterolateral wall. In both modalities, RV apical involvement never occurred in isolation., Conclusion: Mutation-positive ARVD/C exhibits a previously unrecognized characteristic pattern of disease involving the basal inferior and anterior RV, and the posterolateral LV. The RV apex is only involved in advanced ARVD/C, typically as a part of global RV involvement. These results displace the RV apex from the Triangle of Dysplasia, and provide insights into the pathophysiology of ARVD/C., (© 2013 Wiley Periodicals, Inc.)

Background: Exercise-related ventricular tachycardia (VT) and high burden of premature ventricular contractions (PVCs) are common in arrhythmogenic right ventricular dysplasia/cardiomyopathy. We hypothesized that VT in arrhythmogenic right ventricular dysplasia/cardiomyopathy shows a high degree of association with the PVC at baseline., Methods and Results: The study population included 16 consecutive arrhythmogenic right ventricular dysplasia/cardiomyopathy patients with recurrent VT who underwent catheter ablation. Median age of the patients was 27 years (range, 18-66) and 50% were men. All patients had frequent ectopy at baseline with a median PVC count of 7275 (range, 1353-19 084). During EP study, a total of 27 VTs were induced, of which 16 (59%) occurred during high-dose isoproterenol infusion. VT morphology was identical to the baseline PVCs in all the VTs induced during high-dose isoproterenol infusion. Focal ablation at the site of earliest activation and 12/12 pace map of the PVC eliminated the VT in all cases. Target site for focal ablation localized to scar border. Cumulative freedom from VT after ablation was 85.2% and 74.5% at 1 and 2 years, respectively, which was associated with a reduction in PVC count., Conclusions: We report a high degree of association between PVCs at baseline and the VTs induced during catecholamine infusion. These VTs originated from the border region of scar most commonly in the right ventricular outflow tract and right ventricle basal regions. These findings highlight the importance of catecholamine challenge and PVC mapping, which can in turn facilitate ablation of the VT in arrhythmogenic right ventricular dysplasia/cardiomyopathy.

Background: The reported complication rate of catheter ablation of atrial fibrillation (AF) varies., Objective: Our goal was to assess temporal trends and the effect of both institutional and individual operators' experience on the incidence of complications., Methods: All patients undergoing AF ablation at Johns Hopkins Hospital between February 2001 and December 2010 were prospectively enrolled in a database. Major complications were defined as those that were life-threatening, resulted in permanent harm, required intervention, or significantly prolonged hospitalization., Results: Fifty-six major complications occurred in 1190 procedures (4.7%). The majority of complications were vascular (18; 1.5%), followed by pericardial tamponade (13; 1.1%) and cerebrovascular accident (12; 1.1%). No cases of death or atrioesophageal fistula occurred. The overall complication rate decreased from 11.1% in 2002 to 1.6% in 2010 (P <.05). On univariate analysis, demographic and clinical factors associated with the increased risk of complications were CHADS(2) score of ≥2 (hazard ratio [HR] = 2.5; 95% confidence interval [CI] = 1.4-4.4; P = .002), female gender (HR = 2.0; 95% CI = 1.2-3.5; P = .014), and age (HR = 1.03; 95% CI = 1.0-1.1; P = .042). Gender and CHADS(2) score of ≥2 remained independent predictors of complication on multivariable analysis., Conclusion: The complication rate of catheter ablation of AF decreased with increased institutional experience. Female gender and CHADS(2) score of ≥2 are significant independent risk factors for complications and should be considered when referring patients for AF ablation., (Copyright © 2011 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Purpose: Esophageal injury is a potential complication with radiofrequency ablation in the posterior wall of the left atrium (LA). The "box isolation" method isolates the posterior LA wall including the pulmonary veins without ablation on the posterior LA wall. This study compares the acute and long-term efficacy of the box isolation method with conventional circumferential pulmonary vein isolation (PVI) for catheter ablation of AF., Methods: Twenty-nine patients (age 60 ± 9 years, 62% male, 79% paroxysmal) with drug refractory AF underwent catheter ablation. Sixteen of the 29 patients (55%) underwent box isolation. Recurrence of AF was detected by checking the daily recorded rhythm strip on a portable home ECG monitor, irrespective of the symptoms. Mean follow-up duration was 10 ± 2 months., Results: Complete isolation of the posterior LA using box isolation lesions was achieved in three of 16 (19%) patients. The other 13 patients underwent creation of additional lesions until all PVs were isolated. Of the 16 patients who underwent box isolation, four patients (25%) had complete success, six patients (38%) had improvement, and the remaining six patients (37%) had failure. Of the 13 patients who underwent the standard PV isolation, two patients (15%) had complete success, eight patients (62%) had improvement, and the remaining three patients (23%) had failure (p = 0.44)., Conclusion: In this pilot study, the efficacy of box isolation is similar to the circumferential PVI for catheter ablation of AF. Few patients achieved PVI with box method alone. Based on these results, we do not recommend the box isolation strategy.

Introduction: Patients with chronic kidney disease (CKD) have increased morbidity following invasive procedures. We hypothesized that patients with CKD have higher complication rates following device implantation than patients with normal renal function., Methods: We reviewed the medical records of patients undergoing ICD or pacemaker implantation from August 2004 to August 2007. The estimated glomerular filtration rate (GFR) was calculated using the Cockroft-Gault equation. Those with GFR ≥ 90 cc/min served as controls. The remainder was grouped according to American Kidney Foundation stages of CKD. Bleeding complications were defined as need for pocket exploration or blood transfusion; cardiac tamponade; or hematoma requiring pressure dressing, change in medications or prolonged hospitalization. Infection was defined as infection of the pocket or lead system, or development of bacteremia/sepsis within 60 days., Results: There were 82 bleeding complications (5.7%) and 7 infections (0.5%) temporally related to device implantation in 1,440 patients. End-stage renal disease (ESRD), defined as GFR < 15 mL/min or need for dialysis, was identified in 32 patients. Infection rates were significantly higher in patients with ESRD versus controls (12.5% vs 0.2%; P < 0.0001). A significant increase in bleeding complications was observed in ESRD versus controls (21.9% vs 3.2%, respectively; P<0.0001). Bleeding complications were considerably greater than controls in moderate (GFR 30-59 mL/min) and severe (GFR 15-29 mL/min) CKD (7.4% and 9.8% vs 3.2%, respectively; P < 0.005)., Conclusion: ESRD markedly increases bleeding and device-related infections. The risk of both complications parallels the severity of CKD. Further research is needed to reduce adverse outcomes in this high-risk population., (© 2011 Wiley Periodicals, Inc.)

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is an inherited form of cardiomyopathy with low penetrance and variable expressivity. Dominant mutations and rare polymorphisms in desmosome genes are frequently identified. We reasoned that individuals with earlier onset disease would have more frequent desmosome gene mutations and rare polymorphisms. Three groups were compared: Young with symptoms attributable to ARVD/C or a diagnosis of ARVD/C at age of 21 years or earlier, Middle with first symptoms or diagnosis age of 22-49 years, and Late with first symptoms or diagnosis at age of 50 or more years. deoxyribonucleic acid (DNA) sequence analysis was performed on five cardiac desmosome genes, and the presence of mutations and rare missense polymorphisms was compared among the three groups. In the entire Young cohort, 20 (67%) had one or more cardiac desmosome gene mutations. The prevalence of cardiac desmosome gene mutations was similar in the Middle (48%) and Late (53%) cohorts (P = 0.23). Similar numbers of individuals in each cohort had more than one desmosome gene mutation, although the numbers are too small for statistical comparisons. The prevalence of certain rare missense DNA variants was not different among the cohorts (P = 0.71), yet these rare missense alleles were more prevalent in the overall study cohort of 112 ARVD/C participants compared to 100 race-matched controls (P = 0.027). The presence of these variants did not associate with the age of onset of ARVD/C or ventricular tachycardia. These findings highlight the complex interplay of environmental and genetic factors contributing to this condition.

Objectives: This study sought to evaluate the outcomes of radiofrequency catheter ablation (RFA) of ventricular tachycardia (VT) in arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) patients. Particular focus was placed on defining the single-procedure efficacy over long-term follow-up., Background: ARVD/C is an inherited cardiomyopathy characterized by VT and right ventricular dysfunction. Prior single-center studies have reported conflicting results concerning the efficacy of RFA of VT in ARVD/C patients., Methods: The study population comprised 24 patients (age 36 +/- 9 years, 11 male), enrolled in the Johns Hopkins ARVD registry, who underwent 1 or more RFA procedures for treatment of VT. Patients were followed up for 32 +/- 36 months (range 1 day to 12 years). Recurrence was defined as the documentation of VT subsequent to the procedure., Results: A total of 48 RFA procedures were performed using 3-dimensional electroanatomical (n = 10) or conventional (n = 38) mapping. Of these procedures, 22 (46%), 15 (31%), and 11 (23%) resulted in elimination of all inducible VTs, clinical VT but not all, and none of the inducible VTs, respectively. Forty (85%) procedures were followed by recurrence. The cumulative VT recurrence-free survival was 75%, 50%, and 25% after 1.5, 5, and 14 months, respectively. The cumulative VT recurrence-free survival did not differ by procedural success, mapping technique, or repetition of procedures. There was 1 procedure-related death., Conclusions: Our study shows a high rate of recurrence in ARVD/C patients undergoing RFA of VT. This likely reflects the fact that ARVD/C is a diffuse cardiomyopathy with progressively evolving electrical substrate. Further studies are needed to define the precise role of RFA of VT in ARVD/C.