Background—: Exercise testing is performed in patients with hypertrophic cardiomyopathy to evaluate blood pressure response, a risk factor for sudden cardiac death. The prognostic role of exercise gas exchange variables is unknown. Methods and Results—: Between 1998 and 2010, 1898 patients (age 47±15 years, range 16–86 years; 67% male) with hypertrophic cardiomyopathy underwent cardiopulmonary exercise testing. A total of 178 (9.4%) patients reached the primary end point of all-cause mortality or heart transplant (death/transplant) during a median follow-up of 5.6 years (interquartile range 2.6–8.9), giving an annual event rate of 1.6% per person year. Peak oxygen consumption (adjusted hazard ratio [HR] 0.82, 95% confidence interval [CI] 0.77–0.88, P <0.001), ventilatory efficiency (adjusted HR 1.10, 95% CI 1.00–1.22, P =0.049), and ventilatory anaerobic threshold (adjusted HR 0.82, 95% CI 0.70–0.96, P =0.016) were predictors of the primary outcome after correction for age, sex, left atrial size, nonsustained ventricular tachycardia, and ejection fraction. The overall adjusted death/transplant estimates for patients in the lowest quartile with peak oxygen consumption ≤15.3 mL/kg/min were 14% at 5 years and 31% at 10 years. Peak oxygen consumption (HR 0.81, 95% CI 0.77–0.86, P <0.01) and ventilation to carbon dioxide production (HR 1.10, 95% CI 1.08–1.13, P <0.001) were predictors of death because of heart failure or transplantation but not sudden cardiac death or implantable cardioverter defibrillator shocks. Conclusions—: Cardiopulmonary exercise testing provides prognostic information in patients with hypertrophic cardiomyopathy. Submaximal exercise parameters, such as ventilatory efficiency and anaerobic threshold, measured alone or in combination with peak oxygen consumption, predict death from heart failure.

Aims Plasma volume (PV) expansion hallmarks worsening chronic heart failure (CHF) but no non-invasive means of quantifying volume status exists. Because weight and haematocrit are related to PV, they can be used to calculate relative PV status (PVS). We tested the validity and prognostic utility of calculated PVS in CHF patients. Methods and results First, we evaluated the agreement between calculated actual PV (aPV) and aPV levels measured using ¹²⁵Iodine-human serum albumin. Second, we derived PVS as: [(calculated aPV – ideal PV)/ideal PV] × 100%. Third, we assessed the prognostic implications of PVS in 5002 patients from the Valsartan in Heart Failure Trial (Val-HeFT), and validated this in another 246 routine CHF outpatients. On analysis, calculated and measured aPV values correlated significantly in 119 normal subjects and 30 CHF patients. In the Val-HeFT cohort, mean (+SD) PVS was –9 ± 8% and related to volume biomarkers such as brain natriuretic peptide (BNP). Over 2 years, 977 (20%) patients died. Plasma volume status was associated with death and first morbid events in a ‘J-shaped’ fashion with the highest risk seen with a PVS > –4%. Stratification into PVS quartiles confirmed that a PVS > –4% was associated with increased mortality (unadjusted hazard ratio 1.65, 95% confidence interval 1.44–1.88, χ² = 54, P < 0.001) even after adjusting for 22 variables, including brain natriuretic peptide. These results were mirrored in the validation cohort. Conclusions Relative PVS calculated from simple clinical indices reflects the degree to which patients have deviated from their ideal PV and independently relates to outcomes. The utility of PVS-driven CHF management needs further evaluation.

To determine the relation between serum concentrations of N-terminal pro-brain natriuretic peptide (NT-proBNP) and prognosis in patients with hypertrophic cardiomyopathy (HCM). In total, 847 patients (53 ± 15 years; 67% male) with HCM (28% with left ventricular outflow tract obstruction ≥30 mmHg at rest) were followed for 3.5 years (IQR 2.5–4.5 years). The median NT-proBNP concentration was 78 pmol/L (range <5–1817 pmol/L and IQR 31−183 pmol/L). Sixty-eight patients (8%) reached the primary endpoint of all-cause mortality or cardiac transplantation. NT-proBNP concentration predicted long-term survival from the primary endpoint [area under the receiver operating characteristic curve of 0.78 (95% confidence interval 0.73−0.84)]. A serum concentration of ≥135 pmol/L was associated with an annual event rate of 6.1% (95% CI 4.4−7.7). Three independent predictors of primary outcome were identified in a multivariable Cox model: New York Heart Association class III/IV (HR 2.10, 95% CI 1.21−3.65, P = 0.008), ejection fraction (HR 0.98, 95% CI 0.96−1.00, P = 0.035), log NT-proBNP (HR 2.04, 95% CI 1.56−2.66, P < 0.001). Log NT-proBNP was a significant predictor of heart failure (HF) and transplant-related deaths (n = 23; HR 3.03, 95% CI 1.99−4.60, P < 0.001) but not sudden death or appropriate implantable cardioverter defibrillator shock (n = 11; HR 1.54, 95% CI 0.91−2.60, P = 0.111). In patients with ejection fraction ≥50% (n = 673), log NT-proBNP remained an independent predictor of the primary outcome (HR 2.11, 95% CI 1.54−2.90, P < 0.001). In patients with HCM, elevated NT-proBNP concentration is a strong predictor of overall prognosis, particularly HF-related death and transplantation.

Background Anderson–Fabry Disease (AFD) is an X linked lysosomal storage disorder caused by mutations in the α-galactosidase A gene. Some mutations are associated with prominent and, in many cases, exclusive cardiac involvement. The primary aims of this study were to determine the incidence of major cardiac events in AFD and to identify clinical and genetic predictors of adverse outcomes. Methods and results We studied 207 patients with AFD (47% male, mean age 44 years, mean follow-up 7.1 years). Fifty-eight (28%) individuals carried mutations that have been previously associated with a cardiac predominant phenotype. Twenty-one (10%) developed severe heart failure (New York Heart Association functional class (NYHA) ≥3), 13 (6%) developed atrial fibrillation (AF), 13 (6%) received devices for the treatment of bradycardia; there were a total of 7 (3%) cardiac deaths. The incidence of the primary endpoint (a composite of new onset AF, NYHA ≥ 3 symptoms, device insertion for bradycardia and cardiac death) was 2.64 per 100 person-years (CI 1.78 to 3.77). Age (HR 1.04, CI 1.01 to 1.08, p=0.004), Mainz Severity Score Index score (HR 1.05, CI 1.01 to 1.09, p=0.012) and QRS duration (HR 1.03, CI 1.00 to 1.05, p=0.020) were significant independent predictors of the primary endpoint. The presence of a cardiac genetic variant did not predict the primary end point. Conclusions AFD is associated with a high burden of cardiac morbidity and mortality. Adverse cardiac outcomes are associated with age, global disease severity and advanced cardiac disease but not the presence of cardiac genetic variants.

Background Anderson-Fabry disease (AFD) is an X-linked lysosomal storage disorder associated with bradyarrhythmias. We sought to examine the nature of conduction system abnormalities and the indications and determinants of anti-bradycardia pacing in patients with AFD. Methods and results We studied 204 patients with AFD (49% male, mean age 42 years) in an observational, longitudinal, retrospective cohort study. At baseline, 5 (2.5%) patients had pacemakers for the treatment of bradycardias [4/5 (80%) for atrioventricular disease; 1/5 (20%) for sinus node disease]. PR interval 200 ms in 6 (3%); QRS interval >120 ms 18 (9%); left QRS axis deviation in 16 (8%); and right-axis deviation in 2 (1%). Age was an independent determinant of prolonged PR interval, QRS duration and left QRS axis deviation. During follow-up (189 patients; 899 patient-years), 12 (6%) had a device implanted to treat spontaneously occurring bradyarrhythmias [5/12 (42%) for atrioventricular disease; 7/12 (58%) sinus node disease] with 8% 5-year cumulative incidence. Two independent predictors of future anti-bradycardia pacing were identified in a multivariable Cox model: QRS duration [hazard ratio (HR) 1.05, 95% confidence intervals (CI) 1.02–1.09, P= 0.001; receiver operating characteristic (ROC) curve c-statistic 0.726] and PR interval duration (HR 1.03, 95% CI 1.004–1.060, P= 0.023; ROC curve c-statistic 0.548). QRS duration ≥110 ms at baseline had a sensitivity of 64%, specificity of 84%, 49% positive predictive value, and 91% negative predictive value for identifying patients likely to require anti-bradycardia pacing. Conclusion In patients with AFD increasing age is associated with PR and QRS interval prolongation and left QRS axis deviation. Pacing for atrioventricular and sinus node disease is common and patients with QRS≥110 ms should be closely monitored for bradyarrhythmias.

Background: Hypertrophic cardiomyopathy (HCM) is characterized by a complex phenotype that is only partly explained by the biological effects of individual genetic variants. The aim of this study was to use proteomic analysis of myocardial tissue to explore the postgenomic phenotype. Methods: Label-free proteomic analysis was used initially to compare protein profiles in myocardial samples from 11 patients with HCM undergoing surgical myectomy with control samples from 6 healthy unused donor hearts. Differentially expressed proteins of interest were validated in myocardial samples from 65 unrelated individuals (HCM [n=51], controls [n=7], and aortic stenosis [n=7]) by the development and use of targeted multiple reaction monitoring-based triple quadrupole mass spectrometry. Results: In this exploratory study, 1586 proteins were identified with 151 proteins differentially expressed in HCM samples compared with controls ( P <0.05). Protein expression profiling showed that many proteins identified in the initial discovery study were associated with metabolism, muscle contraction, calcium regulation, and oxidative stress. Proteins downregulated in HCM versus controls included creatine kinase M-type, fructose-bisphosphate aldolase A, and phosphoglycerate mutase ( P <0.001). Proteins upregulated in HCM included lumican, carbonic anhydrase 3, desmin, α-actin skeletal, and FHL1 (four and a half LIM domain protein 1; P <0.01). Myocardial lumican concentration correlated with the left atrial area (ρ=0.34, P =0.015), late gadolinium enhancement on cardiac magnetic resonance imaging ( P =0.03) and the presence of a pathogenic sarcomere mutation ( P =0.04). Conclusions: The myocardial proteome of HCM provides supporting evidence for dysregulation of metabolic and structural proteins. The finding that lumican is raised in HCM hearts provides insight into the myocardial fibrosis that characterizes this disease.