BackgroundArrhythmogenic right ventricular dysplasia/cardiomyopathy is characterized by ventricular arrhythmias and sudden cardiac death. Once the diagnosis is established, risk stratification to determine whether implantable cardioverter‐defibrillator (ICD) placement is warranted is critical.Methods and ResultsThe cohort included 312 patients (163 men, age at presentation 33.6±13.9 years) with definite arrhythmogenic right ventricular dysplasia/cardiomyopathy who received an ICD. Over 8.8±7.33 years, 186 participants (60%) had appropriate ICD therapy and 58 (19%) had an intervention for ventricular fibrillation/flutter. Ventricular tachycardia at presentation (hazard ratio [HR]: 1.86; 95% confidence interval [CI], 1.38–2.49; P<0.001), inducibility on electrophysiology study (HR: 3.14; 95% CI, 1.95–5.05; P<0.001), male sex (HR: 1.62; 95% CI, 1.20–2.19; P=0.001), inverted T waves in ≥3 precordial leads (HR: 1.66; 95% CI, 1.09–2.52; P=0.018), and premature ventricular contraction count ≥1000/24 hours (HR: 2.30; 95% CI, 1.32–4.00; P=0.003) were predictors of any appropriate ICD therapy. Inducibility at electrophysiology study (HR: 2.28; 95% CI, 1.10–4.70; P=0.025) remained as the only predictor after multivariable analysis. The predictors for ventricular fibrillation/flutter were premature ventricular contraction ≥1000/24 hours (HR: 4.39; 95% CI, 1.32–14.61; P=0.016), syncope (HR: 1.85; 95% CI, 1.10–3.11; P=0.021), aged ≤30 years at presentation (HR: 1.76; 95% CI, 1.04–3.00; P<0.036), and male sex (HR: 1.73; 95% CI, 1.01–2.97; P=0.046). Younger age at presentation (HR: 3.14; 95% CI, 1.32–7.48; P=0.010) and high premature ventricular contraction burden (HR: 4.43; 95% CI, 1.35–14.57; P<0.014) remained as independent predictors of ventricular fibrillation/flutter. Complications occurred in 66 participants (21%), and 64 (21%) had inappropriate ICD interventions. Overall mortality was low at 2%, and 4% underwent heart transplantation.ConclusionThese findings represent an important step in identifying predictors of ICD therapy for potentially fatal ventricular fibrillation/flutter and should be considered when developing a risk stratification model for arrhythmogenic right ventricular dysplasia/cardiomyopathy.

BackgroundPrior studies have shown a close link between exercise and development of arrhythmogenic right ventricular cardiomyopathy. How much exercise restriction reduces ventricular arrhythmia (VA), how genotype modifies its benefit, and whether it reduces risk sufficiently to defer implantable cardioverter‐defibrillator (ICD) placement in arrhythmogenic right ventricular cardiomyopathy are unknown.Methods and ResultsWe interviewed 129 arrhythmogenic right ventricular cardiomyopathy patients (age: 34.0±14.8 years; male: 60%) with ICDs (36% primary prevention) about exercise participation. Exercise change was defined as annual exercise duration and dose in the 3 years before clinical presentation minus that after presentation. The primary outcome was appropriate ICD therapy for VA. During the 5.1 years (interquartile range: 2.7–10.8 years) after presentation, 74% (95/129) patients reduced exercise dose and 85 (66%) patients experienced the primary outcome. In multivariate analyses, top tertile reduction in exercise duration and dose were both associated with less VA (duration: hazard ratio: 0.23 [95% confidence interval, 0.07–0.81]; dose: hazard ratio: 0.14 [95% confidence interval, 0.04–0.44]). Greater reduction in exercise dose conferred greater reduction in VA (P=0.01 for trend). Patients without desmosomal mutations and those with primary‐prevention ICDs benefited more from exercise reduction (P=0.16 and P=0.06 for interaction); however, 58% (18/31) of athletes who reduced exercise dose by >80% still experienced VA.ConclusionsExercise restriction should be recommended to all arrhythmogenic right ventricular cardiomyopathy patients with ICDs. Patients who are “gene‐elusive” and those with primary‐prevention devices may particularly benefit. Exercise reduction is unlikely to reduce arrhythmia sufficiently in high‐risk patients to alter decision‐making regarding ICD implantation.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C) is an inherited cardiomyopathy characterized by ventricular arrhythmias, right ventricular dysfunction, and sudden cardiac death. Since the first description of ARVD/C in 1982, there have been major advances in the diagnosis and management of the disease. For instance, the discovery of desmosomal abnormalities as a genetic basis for ARVD/C; the importance of proband status and ventricular ectopy for risk stratification of patients at risk for sudden cardiac death; and the critical role that exercise plays in the development and progression of ARVD/C, just to name a few. From a treatment perspective, the placement of implantable cardioverter defibrillators in those at risk for sudden cardiac death and ablation techniques have also evolved over time. In 2010, an update of the 1994 Task Force Diagnostic criteria for ARVD/C was published with the hope to increase diagnostic sensitivity. This update incorporates new knowledge and technology to assess structural cardiac abnormalities and is the standard for diagnosis today.

While the algorithm differentiates arrhythmic risk well overall, it did not distinguish ventricular fibrillation/flutter risks of patients with Class I and IIa implantable cardioverter-defibrillator indications. Limited differentiation was seen for primary prevention cases. As these are vital uncertainties in clinical decision-making, refinements to the algorithm are suggested prior to implementation.

Background Despite growing use of the subcutaneous implantable cardioverter‐defibrillator (S‐ ICD ), its clinical role in arrhythmogenic right ventricular cardiomyopathy/dysplasia ( ARVC /D) patients remains undefined. We aim to elucidate the cardiac phenotype, implant characteristics, and long‐term efficacy regarding appropriate therapy and complications in ARVC /D patients with an S‐ ICD implant. Methods and Results A transatlantic cohort of ARVC /D patients who underwent S‐ ICD implantation was analyzed for clinical characteristics, S‐ ICD therapy, and long‐term outcome including device‐related complications. The cohort included 29 patients (52% male, 76% probands, 59% with ARVC /D‐associated mutation, 59% primary prevention [no prior sustained ventricular arrhythmias], and 45% first‐generation S‐ ICD devices). At implant, all inducible patients (27/29) had conversion of induced ventricular fibrillation. Two patients (7%) had superficial infections of the incision site that were treated conservatively. Over a median follow‐up of 3.16 years (interquartile range: 2.21–4.51 years), all episodes (6 patients, 4% per year) of sustained ventricular arrhythmias were appropriately detected and treated. Six patients (21%) experienced 39 inappropriate shocks, with 3 requiring device explantation. Oversensing of noncardiac signal (n=4; especially myopotentials) and cardiac signal (n=4) was the most frequent etiology. No lead or device dislodgement, infection, skin erosion, or explantation related to need for antitachycardia pacing was noted. Conclusions S‐ ICD can effectively treat both induced and spontaneous ventricular arrhythmias in patients with ARVC /D. The rate of inappropriate shocks, although considerable, is comparable to that in ARVC /D patients treated with transvenous ICD s. When they occurred, inappropriate shocks were primarily due to cardiac and, uniquely, noncardiac oversensing. We suggest potential strategies for minimizing inappropriate therapy.

Catheter-related atrial thrombosis is a potentially deadly complication of central venous catheters. Options for treatment include surgical thrombectomy, systemic anticoagulation, and systemic thrombolysis, but the optimal method of treatment remains unknown. We describe a 48-year-old woman with a large right atrial thrombus who was successfully treated with localized recombinant tissue plasminogen activator (tPA). She was treated with an 18-hour infusion of localized low-dose tPA administered through her central venous catheter. The dimensions of the thrombus decreased from 30 × 16 × 22 mm to 10 × 8 × 5 mm after treatment with tPA, corresponding to an associated 96% reduction in thrombus volume. No major bleeding complications were observed. Catheter-directed thrombolysis provides the theoretical advantage of a decreased rate of major bleeding by reducing the exposure to and duration of high-dose systemic thrombolytic therapy. To our knowledge, this is the second case report describing the use of this novel therapy. Although no guidelines for the treatment of atrial thrombosis or consensus on the optimal regimen for catheter-directed thrombolysis (and intensity of concomitant anticoagulation) exist, we believe that this intervention may be a well-tolerated alternative to systemic thrombolysis and surgery in certain patients.

Background: Data are lacking with concern to the prevalence and management of aspirin (ASA) hypersensitivity. Objective: To study the prevalence, different types of reactions, and implications for clinical management of ASA hypersensitivity in a cardiology practice. Methods: We conducted an electronic medical record review of 11,375 individuals, 5052 (44%) in the ambulatory setting, and 6323 (56%) admitted for percutaneous coronary intervention (PCI), from January 2012 to December 2013. Results: The prevalence of ASA hypersensitivity was 1.88% (n = 214). Skin reactions were the most common (40 [19%]), followed by angioedema (10 [4.6%]), respiratory (9 [4.2%]), and anaphylaxis (6 [2.8%]). No records were found for 74 patients (34.5%), and 69 patients (32.2%) were mistakenly labeled as allergic for having gastrointestinal symptoms. Of the 214 patients who had documented ASA hypersensitivity, 108 individuals (50.46%) had coronary artery disease. The medications at discharge were the following: ASA (30 [14%]), thienopyridine (48 [22%]), a combination of ASA and thienopyridine (13 [6%]), anticoagulation only (26 [12%]), and no antiplatelet (97 [43%]). Conclusion: ASA hypersensitivity is often not documented correctly or is often misdiagnosed or not appropriately managed. There is a need for improved management of ASA hypersensitivity, including appropriate referral for ASA desensitization and combating unnecessary avoidance in patients with intolerance due to adverse effects.

Arrhythmogenic right ventricular dysplasia/cardiomyopathy is an inherited cardiomyopathy characterised by ventricular arrhythmias and an increased risk of sudden cardiac death. Arrhythmogenic right ventricular dysplasia/cardiomyopathy diagnosis is based on criteria that take into account electrical and structural cardiac abnormalities, as well as mutation analysis. Appropriate pharmacological therapy and the prevention of sudden death with implantable defibrillators are important in the management of these patients. Exercise is considered an important environmental factor for the development and progression of the disease.