Mitral valve prolapse: arrhythmic risk during pregnancy and postpartum.

BACKGROUND AND AIMS: Arrhythmic mitral valve prolapse (AMVP) is linked to life-threatening ventricular arrhythmias (VAs), and young women are considered at high risk. Cases of AMVP in women with malignant VA during pregnancy have emerged, but the arrhythmic risk during pregnancy is unknown. The authors aimed to describe features of women with high-risk AMVP who developed malignant VA during the perinatal period and to assess if pregnancy and the postpartum period were associated with a higher risk of malignant VA. METHODS: This retrospective international multi-centre case series included high-risk women with AMVP who experienced malignant VA and at least one pregnancy. Malignant VA included ventricular fibrillation, sustained ventricular tachycardia, or appropriate shock from an implantable cardioverter defibrillator. The authors compared the incidence of malignant VA in non-pregnant periods and perinatal period; the latter defined as occurring during pregnancy and within 6 months after delivery. RESULTS: The authors included 18 women with AMVP from 11 centres. During 7.5 (interquartile range 5.8-16.6) years of follow-up, 37 malignant VAs occurred, of which 18 were pregnancy related occurring in 13 (72%) unique patients. Pregnancy and 6 months after delivery showed increased incidence rate of malignant VA compared to the non-pregnancy period (univariate incidence rate ratio 2.66, 95% confidence interval 1.23-5.76). CONCLUSIONS: The perinatal period could impose increased risk of malignant VA in women with high-risk AMVP. The data may provide general guidance for pre-conception counselling and for nuanced shared decision-making between patients and clinicians.

Implantable cardioverter defibrillator use in arrhythmogenic right ventricular cardiomyopathy in North America and Europe.

BACKGROUND AND AIMS: Implantable cardioverter-defibrillators (ICDs) are critical for preventing sudden cardiac death (SCD) in arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to identify cross-continental differences in utilization of primary prevention ICDs and survival free from sustained ventricular arrhythmia (VA) in ARVC. METHODS: This was a retrospective analysis of ARVC patients without prior VA enrolled in clinical registries from 11 countries throughout Europe and North America. Patients were classified according to whether they received treatment in North America or Europe and were further stratified by baseline predicted VA risk into low- (<10%/5 years), intermediate- (10%-25%/5 years), and high-risk (>25%/5 years) groups. Differences in ICD implantation and survival free from sustained VA events (including appropriate ICD therapy) were assessed. RESULTS: One thousand ninety-eight patients were followed for a median of 5.1 years; 554 (50.5%) received a primary prevention ICD, and 286 (26.0%) experienced a first VA event. After adjusting for baseline risk factors, North Americans were more than three times as likely to receive ICDs {hazard ratio (HR) 3.1 [95% confidence interval (CI) 2.5, 3.8]} but had only mildly increased risk for incident sustained VA [HR 1.4 (95% CI 1.1, 1.8)]. North Americans without ICDs were at higher risk for incident sustained VA [HR 2.1 (95% CI 1.3, 3.4)] than Europeans. CONCLUSIONS: North American ARVC patients were substantially more likely than Europeans to receive primary prevention ICDs across all arrhythmic risk strata. A lower rate of ICD implantation in Europe was not associated with a higher rate of VA events in those without ICDs.

Treatment-seeking behavior and cardiovascular morbidity among men with anabolic-androgenic steroid use: A cross-sectional study.

AIMS: To determine associations between anabolic-androgenic steroid (AAS) use-related morbidity including cardiovascular disease (CVD) and engagement to health services. METHODS: In this cross-sectional study, 90 males with at least 12 months cumulative current or former use of AAS were included. The participants were divided into a treatment-seeking group (TSG) and a non-treatment seeking group (non-TSG) based on their responses to a self-report web questionnaire. All participants were screened for symptoms that could be indicative of CVD through a clinical interview, and examined with blood samples, blood pressure measurements and transthoracic echocardiography. RESULTS: In the total sample (n = 90), mean age was 39 ± 11 years with cumulative AAS use of 12 ± 9 years. Among men in the TSG with current use there were higher prevalence of dyspnoea (50% vs 7%) and reduced left ventricular ejection fraction (LVEF) in conjunction with left ventricular hypertrophy (LVH) (36 vs. 9%) and/or high blood pressure (55% vs. 19%) compared to men in the non-TSG. Among men with current AAS use and established LVEF <50% (n = 25) or LVH (n = 21), 44% (11) and 43% (9) respectively, had never engaged health services due to AAS-related adverse effects. Deviant liver- and kidney parameters were frequently observed in the total sample but without between-group differences. CONCLUSIONS: Treatment-seeking behavior among current AAS users may be associated with increased levels of dyspnoea and established CVD. Despite objective signs of severe CVD among a substantial amount of study participants, it is of great concern that the majority had never sought treatment for AAS-related concerns.

Programmed Ventricular Stimulation as an Additional Primary Prevention Risk Stratification Tool in Arrhythmogenic Right Ventricular Cardiomyopathy: A Multinational Study.

BACKGROUND: A novel risk calculator based on clinical characteristics and noninvasive tests that predicts the onset of clinical sustained ventricular arrhythmias (VA) in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) has been proposed and validated by recent studies. It remains unknown whether programmed ventricular stimulation (PVS) provides additional prognostic value. METHODS: All patients with a definite ARVC diagnosis, no history of sustained VAs at diagnosis, and PVS performed at baseline were extracted from 6 international ARVC registries. The calculator-predicted risk for sustained VA (sustained or implantable cardioverter defibrillator treated ventricular tachycardia [VT] or fibrillation, [aborted] sudden cardiac arrest) was assessed in all patients. Independent and combined performance of the risk calculator and PVS on sustained VA were assessed during a 5-year follow-up period. RESULTS: Two hundred eighty-eight patients (41.0±14.5 years, 55.9% male, right ventricular ejection fraction 42.5±11.1%) were enrolled. At PVS, 137 (47.6%) patients had inducible ventricular tachycardia. During a median of 5.31 [2.89-10.17] years of follow-up, 83 (60.6%) patients with a positive PVS and 37 (24.5%) with a negative PVS experienced sustained VA (P<0.001). Inducible ventricular tachycardia predicted clinical sustained VA during the 5-year follow-up and remained an independent predictor after accounting for the calculator-predicted risk (HR, 2.52 [1.58-4.02]; P<0.001). Compared with ARVC risk calculator predictions in isolation (C-statistic 0.72), addition of PVS inducibility showed improved prediction of VA events (C-statistic 0.75; log-likelihood ratio for nested models, P<0.001). PVS inducibility had a 76% [67-84] sensitivity and 68% [61-74] specificity, corresponding to log-likelihood ratios of 2.3 and 0.36 for inducible (likelihood ratio+) and noninducible (likelihood ratio-) patients, respectively. In patients with a ARVC risk calculator-predicted risk of clinical VA events <25% during 5 years (ie, low/intermediate subgroup), PVS had a 92.6% negative predictive value. CONCLUSIONS: PVS significantly improved risk stratification above and beyond the calculator-predicted risk of VA in a primary prevention cohort of patients with ARVC, mainly for patients considered to be at low and intermediate risk by the clinical risk calculator.

Beneficial effects of exercise initiated before development of hypertrophic cardiomyopathy in genotype-positive mice.

The effect of exercise on disease development in hypertrophic cardiomyopathy (HCM) genotype-positive individuals is unresolved. Our objective was to test the effect of exercise training initiated before phenotype development on cardiac fibrosis, morphology, and function in a mouse model of HCM. Genotype-positive Myh6 R403Q mice exposed to cyclosporine A (CsA) for induction of HCM (HCM mice) were allocated to high-intensity interval treadmill running or sedentary behavior for 6 wk. CsA was initiated from week 4 of the protocol. Cardiac imaging and exercise testing were performed at weeks 0, 3, and 6. After protocol completion, arrhythmia provocation was performed in isolated hearts, and left ventricles (LVs) were harvested for molecular biology and histology. Exercised HCM mice ran farther and faster and exhibited attenuated left atrial (LA) dilatation compared with sedentary mice. Exercised HCM mice had no difference in fibrosis compared with sedentary HCM mice despite lower expression of key extracellular matrix (ECM) genes collagen 1 and 3, fibronectin, and lysyl oxidase, accompanied by increased activation of Akt, GSK3b, and p38. Exercise did not have negative effects on LV function in HCM mice. Our findings indicate mild beneficial effects of exercise initiated before HCM phenotype development, specifically lower ECM gene expression and LA dilatation, and importantly, no detrimental effects.NEW & NOTEWORTHY Genotype-positive hypertrophic cardiomyopathy (HCM) mice had beneficial effects of exercise initiated before phenotype development. Exercised HCM mice had increased exercise capacity, smaller left atria, no increase in hypertrophy, or reduction of function, and a similar degree of fibrosis despite reduction of central extracellular matrix (ECM) genes, including collagens, compared with sedentary HCM mice.

Ventricular arrhythmias in arrhythmic mitral valve syndrome-a prospective continuous long-term cardiac monitoring study.

AIMS: Arrhythmic mitral valve syndrome is linked to life-threatening ventricular arrhythmias. The incidence, morphology and methods for risk stratification are not well known. This prospective study aimed to describe the incidence and the morphology of ventricular arrhythmia and propose risk stratification in patients with arrhythmic mitral valve syndrome. METHODS: Arrhythmic mitral valve syndrome patients were monitored for ventricular tachyarrhythmias by implantable loop recorders (ILR) and secondary preventive implantable cardioverter-defibrillators (ICD). Severe ventricular arrhythmias included ventricular fibrillation, appropriate or aborted ICD therapy, sustained ventricular tachycardia and non-sustained ventricular tachycardia with symptoms of hemodynamic instability. RESULTS: During 3.1 years of follow-up, severe ventricular arrhythmia was recorded in seven (12%) of 60 patients implanted with ILR [first event incidence rate 4% per person-year, 95% confidence interval (CI) 2-9] and in four (20%) of 20 patients with ICD (re-event incidence rate 8% per person-year, 95% CI 3-21). In the ILR group, severe ventricular arrhythmia was associated with frequent premature ventricular complexes, more non-sustained ventricular tachycardias, greater left ventricular diameter and greater posterolateral mitral annular disjunction distance (all P < 0.02). CONCLUSIONS: The yearly incidence of ventricular arrhythmia was high in arrhythmic mitral valve syndrome patients without previous severe arrhythmias using continuous heart rhythm monitoring. The incidence was even higher in patients with secondary preventive ICD. Frequent premature ventricular complexes, non-sustained ventricular tachycardias, greater left ventricular diameter and greater posterolateral mitral annular disjunction distance were predictors of first severe arrhythmic event.

Disease progression rate is a strong predictor of ventricular arrhythmias in patients with cardiac laminopathies: a primary prevention cohort study.

AIMS: Cardiac disease progression prior to first ventricular arrhythmia (VA) in LMNA genotype-positive patients is not described. METHODS AND RESULTS: We performed a primary prevention cohort study, including consecutive LMNA genotype-positive patients from our centre. Patients underwent repeated clinical, electrocardiographic, and echocardiographic examinations. Electrocardiographic and echocardiographic disease progression as a predictor of first-time VA was evaluated by generalized estimation equation analyses. Threshold values at transition to an arrhythmic phenotype were assessed by threshold regression analyses. We included 94 LMNA genotype-positive patients without previous VA (age 38 ± 15 years, 32% probands, 53% females). Nineteen (20%) patients experienced VA during 4.6 (interquartile range 2.1-7.3) years follow up, at mean age 50 ± 11 years. We analysed 536 echocardiographic and 261 electrocardiogram examinations. Individual patient disease progression was associated with VA [left ventricular ejection fraction (LVEF) odds ratio (OR) 1.4, 95% confidence interval (CI) 1.2-1.6 per 5% reduction, left ventricular end-diastolic volume index (LVEDVi) OR 1.2 (95% CI 1.1-1.3) per 5 mL/m2 increase, PR interval OR 1.2 (95% CI 1.1-1.4) per 10 ms increase]. Threshold values for transition to an arrhythmic phenotype were LVEF 44%, LVEDVi 77 mL/m2, and PR interval 280 ms. CONCLUSIONS: Incidence of first-time VA was 20% during 4.6 years follow up in LMNA genotype-positive patients. Individual patient disease progression by ECG and echocardiography were strong predictors of VA, indicating that disease progression rate may have additional value to absolute measurements when considering primary preventive ICD. Threshold values of LVEF <44%, LVEDVi >77 mL/m2, and PR interval >280 ms indicated transition to a more arrhythmogenic phenotype.

Lifetime exercise dose and ventricular arrhythmias in patients with mitral valve prolapse.

AIMS: Patients with mitral valve prolapse (MVP) have high risk of life-threatening ventricular arrhythmias (VAs). Data on the impact of exercise on arrhythmic risk in these patients are lacking. We explored whether lifetime exercise dose was associated with severe VA and with established risk factors in patients with MVP. Furthermore, we explored the circumstances at the VA event. METHODS AND RESULTS: In this retrospective cohort study, we included patients with MVP and assessed lifetime exercise dose as metabolic equivalents of task (MET) hours/week. Severe VA was defined as sustained ventricular tachycardia or fibrillation, aborted cardiac arrest, and appropriate shock by a primary preventive implantable cardioverter defibrillator. We included 136 MVP patients (48 years [interquartile range (IQR) 35-59], 61% female), and 17 (13%) had previous severe VA. The lifetime exercise dose did not differ in patients with and without severe VA (17 MET h/week [IQR 9-27] vs. 14 MET h/week [IQR 6-31], P = 0.34). Lifetime exercise dose > 9.6 MET h/week was a borderline significant marker for severe VA (OR 3.38, 95% CI 0.92-12.40, P = 0.07), while not when adjusted for age (OR 2.63, 95% CI 0.66-10.56, P = 0.17). Ventricular arrhythmia events occurred most frequently during wakeful rest (53%), followed by exercise (29%) and sleep (12%). CONCLUSION: We found no clear association between moderate lifetime exercise dose and severe VA in patients with MVP. We cannot exclude an upper threshold for safe levels of exercise. Further studies are needed to explore exercise and risk of severe VA.

Genotype-phenotype correlation in arrhythmogenic right ventricular cardiomyopathy-risk of arrhythmias and heart failure.

BACKGROUND: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is predominantly caused by desmosomal genetic variants, and clinical hallmarks include arrhythmias and systolic dysfunction. We aimed at studying the impact of the implicated gene(s) on the disease course. METHODS: The Nordic ARVC Registry holds data on a multinational cohort of ARVC families. The effects of genotype on electrocardiographic features, imaging findings and clinical events were analysed. RESULTS: We evaluated 419 patients (55% men), with a mean follow-up of 11.2±7.4 years. A pathogenic desmosomal variant was identified in 62% of the 230 families: PKP2 in 41%, DSG2 in 13%, DSP in 7% and DSC2 in 3%. Reduced left ventricular ejection fraction (LVEF) ≤45% on cardiac MRI was more frequent among patients with DSC2/DSG2/DSP than PKP2 ARVC (27% vs 4%, p<0.01). In contrast, in Cox regression modelling of patients with definite ARVC, we found a higher risk of arrhythmias among PKP2 than DSC2/DSG2/DSP carriers: HR 0.25 (0.10-0.68, p<0.01) for atrial fibrillation/flutter, HR 0.67 (0.44-1.0, p=0.06) for ventricular arrhythmias and HR 0.63 (0.42-0.95, p<0.05) for any arrhythmia. Gene-negative patients had an intermediate risk (16%) of LVEF ≤45% and a risk of the combined arrhythmic endpoint comparable with DSC2/DSG2/DSP carriers. Male sex was a risk factor for both arrhythmias and reduced LVEF across all genotype groups (p<0.01). CONCLUSION: In this large cohort of ARVC families with long-term follow-up, we found PKP2 genotype to be more arrhythmic than DSC2/DSG2/DSP or gene-negative carrier status, whereas reduced LVEF was mostly seen among DSC2/DSG2/DSP carriers. Male sex was associated with a more severe phenotype.

A new prediction model for ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy.

AIMS: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC) is characterized by ventricular arrhythmias (VAs) and sudden cardiac death (SCD). We aimed to develop a model for individualized prediction of incident VA/SCD in ARVC patients. METHODS AND RESULTS: Five hundred and twenty-eight patients with a definite diagnosis and no history of sustained VAs/SCD at baseline, aged 38.2 ± 15.5 years, 44.7% male, were enrolled from five registries in North America and Europe. Over 4.83 (interquartile range 2.44-9.33) years of follow-up, 146 (27.7%) experienced sustained VA, defined as SCD, aborted SCD, sustained ventricular tachycardia, or appropriate implantable cardioverter-defibrillator (ICD) therapy. A prediction model estimating annual VA risk was developed using Cox regression with internal validation. Eight potential predictors were pre-specified: age, sex, cardiac syncope in the prior 6 months, non-sustained ventricular tachycardia, number of premature ventricular complexes in 24 h, number of leads with T-wave inversion, and right and left ventricular ejection fractions (LVEFs). All except LVEF were retained in the final model. The model accurately distinguished patients with and without events, with an optimism-corrected C-index of 0.77 [95% confidence interval (CI) 0.73-0.81] and minimal over-optimism [calibration slope of 0.93 (95% CI 0.92-0.95)]. By decision curve analysis, the clinical benefit of the model was superior to a current consensus-based ICD placement algorithm with a 20.3% reduction of ICD placements with the same proportion of protected patients (P < 0.001). CONCLUSION: Using the largest cohort of patients with ARVC and no prior VA, a prediction model using readily available clinical parameters was devised to estimate VA risk and guide decisions regarding primary prevention ICDs (www.arvcrisk.com).

Electrical markers and arrhythmic risk associated with myocardial fibrosis in mitral valve prolapse.

AIMS: We aimed to characterize the substrate of T-wave inversion (TWI) using cardiac magnetic resonance (CMR) and the association between diffuse fibrosis and ventricular arrhythmias (VA) in patients with mitral valve prolapse (MVP). METHODS AND RESULTS: TWI was defined as negative T-wave ≥0.1 mV in ≥2 adjacent ECG leads. Diffuse myocardial fibrosis was assessed by T1 relaxation time and extracellular volume (ECV) fraction by T1-mapping CMR. We included 162 patients with MVP (58% females, age 50 ± 16 years), of which 16 (10%) patients had severe VA (aborted cardiac arrest or sustained ventricular tachycardia). TWI was found in 34 (21%) patients. Risk of severe VA increased with increasing number of ECG leads displaying TWI [OR 1.91, 95% CI (1.04-3.52), P = 0.04]. The number of ECG leads displaying TWI increased with increasing lateral ECV (26 ± 3% for TWI 0-1leads, 28 ± 4% for TWI 2leads, 29 ± 5% for TWI ≥3leads, P = 0.04). Patients with VA (sustained and non-sustained ventricular tachycardia) had increased lateral T1 (P = 0.004), also in the absence of late gadolinium enhancement (LGE) (P = 0.008). CONCLUSIONS: Greater number of ECG leads with TWI reflected a higher arrhythmic risk and higher degree of lateral diffuse fibrosis by CMR. Lateral diffuse fibrosis was associated with VA, also in the absence of LGE. These results suggest that TWI may reflect diffuse myocardial fibrosis associated with VA in patients with MVP. T1-mapping CMR may help risk stratification for VA.

Complications of implantable cardioverter-defibrillator treatment in arrhythmogenic right ventricular cardiomyopathy.

AIMS: Treatment with implantable cardioverter-defibrillators (ICD) is a cornerstone for prevention of sudden cardiac death in arrhythmogenic right ventricular cardiomyopathy (ARVC). We aimed at describing the complications associated with ICD treatment in a multinational cohort with long-term follow-up. METHODS AND RESULTS: The Nordic ARVC registry was established in 2010 and encompasses a large multinational cohort of ARVC patients, including their clinical characteristics, treatment, and events during follow-up. We included 299 patients (66% males, median age 41 years). During a median follow-up of 10.6 years, 124 (41%) patients experienced appropriate ICD shock therapy, 28 (9%) experienced inappropriate shocks, 82 (27%) had a complication requiring surgery (mainly lead-related, n = 75), and 99 (33%) patients experienced the combined endpoint of either an inappropriate shock or a surgical complication. The crude rate of first inappropriate shock was 3.4% during the first year after implantation but decreased after the first year and plateaued over time. Contrary, the risk of a complication requiring surgery was 5.5% the first year and remained high throughout the study period. The combined risk of any complication was 7.9% the first year. In multivariate cox regression, presence of atrial fibrillation/flutter was a risk factor for inappropriate shock (P < 0.05), whereas sex, age at implant, and device type were not (all P > 0.05). CONCLUSION: Forty-one percent of ARVC patients treated with ICD experienced potentially life-saving ICD therapy during long-term follow-up. A third of the patients experienced a complication during follow-up with lead-related complications constituting the vast majority.

Mutation location and IKs regulation in the arrhythmic risk of long QT syndrome type 1: the importance of the KCNQ1 S6 region.

AIMS: Mutation type, location, dominant-negative IKs reduction, and possibly loss of cyclic adenosine monophosphate (cAMP)-dependent IKs stimulation via protein kinase A (PKA) influence the clinical severity of long QT syndrome type 1 (LQT1). Given the malignancy of KCNQ1-p.A341V, we assessed whether mutations neighbouring p.A341V in the S6 channel segment could also increase arrhythmic risk. METHODS AND RESULTS: Clinical and genetic data were obtained from 1316 LQT1 patients [450 families, 166 unique KCNQ1 mutations, including 277 p.A341V-positive subjects, 139 patients with p.A341-neighbouring mutations (91 missense, 48 non-missense), and 900 other LQT1 subjects]. A first cardiac event represented the primary endpoint. S6 segment missense variant characteristics, particularly cAMP stimulation responses, were analysed by cellular electrophysiology. p.A341-neighbouring mutation carriers had a QTc shorter than p.A341V carriers (477 ± 33 vs. 490 ± 44 ms) but longer than the remaining LQT1 patient population (467 ± 41 ms) (P < 0.05 for both). Similarly, the frequency of symptomatic subjects in the p.A341-neighbouring subgroup was intermediate between the other two groups (43% vs. 73% vs. 20%; P < 0.001). These differences in clinical severity can be explained, for p.A341V vs. p.A341-neighbouring mutations, by the p.A341V-specific impairment of IKs regulation. The differences between the p.A341-neighbouring subgroup and the rest of LQT1 mutations may be explained by the functional importance of the S6 segment for channel activation. CONCLUSION: KCNQ1 S6 segment mutations surrounding p.A341 increase arrhythmic risk. p.A341V-specific loss of PKA-dependent IKs enhancement correlates with its phenotypic severity. Cellular studies providing further insights into IKs-channel regulation and knowledge of structure-function relationships could improve risk stratification. These findings impact on clinical management.

Sex differences in disease progression and arrhythmic risk in patients with arrhythmogenic cardiomyopathy.

AIMS: We aimed to assess sex-specific phenotypes and disease progression, and their relation to exercise, in arrhythmogenic cardiomyopathy (AC) patients. METHODS AND RESULTS: In this longitudinal cohort study, we included consecutive patients with AC from a referral centre. We performed echocardiography at baseline and repeatedly during follow-up. Patients' exercise dose at inclusion was expressed as metabolic equivalents of task (MET)-h/week. Ventricular arrhythmia (VA) was defined as aborted cardiac arrest, sustained ventricular tachycardia, or appropriate therapy by implantable cardioverter-defibrillator. We included 190 AC patients (45% female, 51% probands, age 41 ± 17 years). Ventricular arrhythmia had occurred at inclusion or occurred during follow-up in 85 patients (33% of females vs. 55% of males, P = 0.002). Exercise doses were higher in males compared with females [25 (interquartile range, IQR 14-51) vs. 12 (IQR 7-22) MET-h/week, P < 0.001]. Male sex was a marker of proband status [odds ratio (OR) 2.6, 95% confidence interval (CI) 1.4-5.0, P = 0.003] and a marker of VA (OR 2.6, 95% CI 1.4-5.0, P = 0.003), but not when adjusted for exercise dose and age (adjusted OR 1.8, 95% CI 0.9-3.6, P = 0.12 and 1.5, 95% CI 0.7-3.1, P = 0.30, by 5 MET-h/week increments). In all, 167 (88%) patients had ≥2 echocardiographic examinations during 6.9 (IQR 4.7-9.8) years of follow-up. We observed no sex differences in deterioration of right or left ventricular dimensions and functions. CONCLUSION: Male AC patients were more often probands and had higher prevalence of VA than female patients, but not when adjusting for exercise dose. Importantly, disease progression was similar between male and female patients.

Genetic Variant Score and Arrhythmogenic Right Ventricular Cardiomyopathy Phenotype in Plakophilin-2 Mutation Carriers.

INTRODUCTION: Whether detailed genetic information contributes to risk stratification of patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) remains uncertain. Pathogenic genetic variants in some genes seem to carry a higher risk for arrhythmia and earlier disease onset than others, but comparisons between variants in the same gene have not been done. Combined Annotation Dependent Depletion (CADD) score is a bioinformatics tool that measures the pathogenicity of each genetic variant. We hypothesized that a higher CADD score is associated with arrhythmic events and earlier age at ARVC manifestations in individuals carrying pathogenic or likely pathogenic genetic variants in plakophilin-2 (PKP2). METHODS: CADD scores were calculated using the data from pooled Scandinavian and North American ARVC cohorts, and their association with cardiac events defined as ventricular tachycardia/ventricular fibrillation (VT/VF) or syncope and age at definite ARVC diagnosis were assessed. RESULTS: In total, 33 unique genetic variants were reported in 179 patients (90 males, 71 probands, 96 with definite ARVC diagnosis at a median age of 35 years). Cardiac events were reported in 76 individuals (43%), of whom 53 had sustained VT/VF (35%). The CADD score was neither associated with age at cardiac events (HR 1.002, 95% CI: 0.953-1.054, p = 0.933) nor with age at definite ARVC diagnosis (HR 0.992, 95% CI: 0.947-1.039, p = 0.731). CONCLUSION: No correlation was found between CADD scores and clinical manifestations of ARVC, indicating that the score has no additional risk stratification value among carriers of pathogenic or likely pathogenic PKP2 genetic variants.

High penetrance and similar disease progression in probands and in family members with arrhythmogenic cardiomyopathy.

AIMS: We aimed to assess structural progression in arrhythmogenic cardiomyopathy (AC) patients and mutation-positive family members and its impact on arrhythmic outcome in a longitudinal cohort study. METHODS AND RESULTS: Structural progression was defined as the development of new Task Force imaging criteria from inclusion to follow-up and progression rates as annual changes in imaging parameters. We included 144 AC patients and family members (48% female, 47% probands, 40 ± 16 years old). At genetic diagnosis and inclusion, 58% of family members had penetrant AC disease. During 7.0 [inter-quartile range (IQR) 4.5-9.4] years of follow-up, 47% of family members without AC at inclusion developed AC criteria, resulting in a yearly new AC penetrance of 8%. Probands and family members had a similar progression rate of right ventricular outflow tract diameter (0.5 mm/year vs. 0.6 mm/year, P = 0.28) by mixed model analysis of 598 echocardiographic examinations. Right ventricular fractional area change progression rate was even higher in family members (-0.6%/year vs. -0.8%/year, P < 0.01). Among 86 patients without overt structural disease or arrhythmic history at inclusion, a first severe ventricular arrhythmic event occurred in 8 (9%), of which 7 (88%) had concomitant structural progression. Structural progression was associated with higher incidence of severe ventricular arrhythmic events adjusted for age, sex, and proband status (HR 21.24, 95% CI 2.47-182.81, P < 0.01). CONCLUSION: More than half of family members had AC criteria at genetic diagnosis and yearly AC penetrance was 8%. Structural progression was similar in probands and family members and was associated with higher incidence of severe ventricular arrhythmic events.

Pregnancies, ventricular arrhythmias, and substrate progression in women with arrhythmogenic right ventricular cardiomyopathy in the Nordic ARVC Registry.

AIMS: Women with arrhythmogenic right ventricular cardiomyopathy (ARVC) are at relatively lower risk of ventricular arrhythmias (VAs) than men, but the physical burden associated with pregnancy on VA risk remains insufficiently studied. We aimed to assess the risk of VA in relation to pregnancies in women with ARVC. METHODS AND RESULTS: We included 199 females with definite ARVC (n = 121) and mutation-positive family members without ascertained ARVC diagnosis (n = 78), of whom 120 had at least one childbirth. Ventricular arrhythmia-free survival after the latest childbirth was compared between women with one (n = 20), two (n = 67), and three or more (n = 37) childbirths. Cumulative probability of VA for each pregnancy (n = 261) was assessed from conception through 2 years after childbirth and compared between those pregnancies that occurred before (n = 191) or after (n = 19) ARVC diagnosis and in mutation-positive family members (n = 51). The nulliparous women had lower median age at ARVC diagnosis (38 vs. 42 years, P < 0.001) and first VA (22 vs. 41 years, P < 0.001). Ventricular arrhythmia-free survival after the latest childbirth was not related to the number of pregnancies. No pregnancy-related VA was reported among the family members. Women who gave birth after ARVC diagnosis had elevated risk of VA postpartum (hazard ratio 13.74, 95% confidence interval 2.9-63, P = 0.001), though only two events occurred during pregnancies. CONCLUSION: In women with ARVC, pregnancy was uneventful for the overwhelming majority and the number of prior completed pregnancies was not associated with VA risk. Pregnancy-related VA was primarily related to the phenotypical severity rather than pregnancy itself.

A new prediction model for ventricular arrhythmias in arrhythmogenic right ventricular cardiomyopathy.

AIMS: Arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVC) is characterized by ventricular arrhythmias (VAs) and sudden cardiac death (SCD). We aimed to develop a model for individualized prediction of incident VA/SCD in ARVC patients. METHODS AND RESULTS: Five hundred and twenty-eight patients with a definite diagnosis and no history of sustained VAs/SCD at baseline, aged 38.2 ± 15.5 years, 44.7% male, were enrolled from five registries in North America and Europe. Over 4.83 (interquartile range 2.44-9.33) years of follow-up, 146 (27.7%) experienced sustained VA, defined as SCD, aborted SCD, sustained ventricular tachycardia, or appropriate implantable cardioverter-defibrillator (ICD) therapy. A prediction model estimating annual VA risk was developed using Cox regression with internal validation. Eight potential predictors were pre-specified: age, sex, cardiac syncope in the prior 6 months, non-sustained ventricular tachycardia, number of premature ventricular complexes in 24 h, number of leads with T-wave inversion, and right and left ventricular ejection fractions (LVEFs). All except LVEF were retained in the final model. The model accurately distinguished patients with and without events, with an optimism-corrected C-index of 0.77 [95% confidence interval (CI) 0.73-0.81] and minimal over-optimism [calibration slope of 0.93 (95% CI 0.92-0.95)]. By decision curve analysis, the clinical benefit of the model was superior to a current consensus-based ICD placement algorithm with a 20.6% reduction of ICD placements with the same proportion of protected patients (P < 0.001). CONCLUSION: Using the largest cohort of patients with ARVC and no prior VA, a prediction model using readily available clinical parameters was devised to estimate VA risk and guide decisions regarding primary prevention ICDs (www.arvcrisk.com).

Implantable cardioverter-defibrillators in previously undiagnosed patients with catecholaminergic polymorphic ventricular tachycardia resuscitated from sudden cardiac arrest.

AIMS: In patients with catecholaminergic polymorphic ventricular tachycardia (CPVT), implantable cardioverter-defibrillator (ICD) shocks are sometimes ineffective and may even trigger fatal electrical storms. We assessed the efficacy and complications of ICDs placed in patients with CPVT who presented with a sentinel event of sudden cardiac arrest (SCA) while undiagnosed and therefore untreated. METHODS AND RESULTS: We analysed 136 patients who presented with SCA and in whom CPVT was diagnosed subsequently, leading to the initiation of guideline-directed therapy, including ß-blockers, flecainide, and/or left cardiac sympathetic denervation. An ICD was implanted in 79 patients (58.1%). The primary outcome of the study was sudden cardiac death (SCD). The secondary outcomes were composite outcomes of SCD, SCA, appropriate ICD shocks, and syncope. After a median follow-up of 4.8 years, SCD had occurred in three patients (3.8%) with an ICD and none of the patients without an ICD (P = 0.1). SCD, SCA, or appropriate ICD shocks occurred in 37 patients (46.8%) with an ICD and 9 patients (15.8%) without an ICD (P < 0.0001). Inappropriate ICD shocks occurred in 19 patients (24.7%) and other device-related complications in 22 patients (28.9%). CONCLUSION: In previously undiagnosed patients with CPVT who presented with SCA, an ICD was not associated with improved survival. Instead, the ICD was associated with both a high rate of appropriate ICD shocks and inappropriate ICD shocks along with other device-related complications. Strict adherence to guideline-directed therapy without an ICD may provide adequate protection in these patients without all the potential disadvantages of an ICD.

QT prolongation predicts short-term mortality independent of comorbidity.

AIMS: A prolonged corrected QT interval (QTc) ≥500 ms is associated with high all-cause mortality in hospitalized patients. We aimed to explore any difference in short- and long-term mortality in patients with QTc ≥500 ms compared with patients with QTc <500 ms after adjustment for comorbidity and main diagnosis. METHODS AND RESULTS: Patients with QTc ≥500 ms who were hospitalized at Telemark Hospital Trust, Norway between January 2007 and April 2014 were identified. Thirty-day and 3-year all-cause mortality in 980 patients with QTc ≥500 ms were compared with 980 patients with QTc <500 ms, matched for age and sex and adjusting for Charlson comorbidity index (CCI), previous admissions, and main diagnoses. QTc ≥500 ms was associated with increased 30-day all-cause mortality [hazard ratio (HR) 1.90, 95% confidence interval (CI) 1.38-2.62; P < 0.001]. There was no significant difference in mortality between patients with QTc ≥500 ms and patients with QTc <500 ms who died between 30 days and 3 years; 32% vs. 29%, P = 0.20. Graded CCI was associated with increased 3-year all-cause mortality (CCI 1-2: HR 1.62, 95% CI 1.34-1.96; P < 0.001; CCI 3-4: HR 2.50, 95% CI 1.95-3.21; P < 0.001; CCI ≥5: HR 3.76, 95% CI 2.85-4.96; P < 0.001) but was not associated with 30-day all-cause mortality. CONCLUSION: QTc ≥500 ms is a powerful predictor of short-term mortality overruling comorbidities. QTc ≥500 ms also predicted long-term mortality, but this effect was mainly caused by the increased short-term mortality. For long-term mortality, comorbidity was more important.