BackgroundElevated N‐terminal pro‐B‐type natriuretic peptide (NT‐proBNP) concentrations predict heart failure (HF) and mortality, but whether NT‐proBNP predicts ventricular arrhythmias (VA) is not clear.HypothesisWe hypothesize that high NT‐proBNP concentrations associate with the risk of incident VA, defined as adjudicated ventricular fibrillation or sustained ventricular tachycardia.MethodsIn a prospective, observational study of patients treated with implantable cardioverter defibrillator (ICD), we analyzed NT‐proBNP concentrations at baseline and after mean 1.4 years in association to incident VA.ResultsWe included 490 patients (age 66 ± 12 years, 83% men) out of whom 51% had a primary prevention ICD indication. The median NT‐proBNP concentration was 567 (25–75 percentile 203–1480) ng/L and patients with higher concentrations were older with more HF and ICD for primary prevention. During mean 3.1 ± 0.7 years, 137 patients (28%) had ≥1 VA. Baseline NT‐proBNP concentrations were associated with the risk of incident VA (hazard ratio [HR]: 1.39, 95% confidence interval [95% CI]: 1.22–1.58, p < .001), HF hospitalizations (HR: 3.11, 95% CI: 2.53–3.82, p < .001), and all‐cause mortality (HR: 2.49, 95% CI: 2.04–3.03, p < .001), which persisted after adjusting for age, sex, body mass index, coronary artery disease, HF, renal function, and left ventricular ejection fraction. The association with VA was stronger in secondary versus primary prevention ICD indication: HR: 1.59 (95% CI: 1.34–1.88 C‐statistics 0.71) versus HR: 1.24, 95% CI: 1.02–1.51, C‐statistics 0.55), p‐for‐interaction = 0.06. Changes in NT‐proBNP during the first 1.4 years did not associate with subsequent VA.ConclusionsNT‐proBNP concentrations are associated with the risk of incident VA after adjustment for established risk factors, with the strongest association in patients with a secondary prevention ICD indication.
Introduction QRS fragmentation (fQRS), defined as the presence of additional spikes within the QRS complex, has been associated with myocardial conduction abnormalities and arrhythmogenicity. Objective We aimed to assess whether fQRS is associated with incident ventricular arrhythmias (VA) in high‐risk patients treated with implantable cardioverter‐defibrillator (ICD) for primary and secondary prevention. Methods In a prospective observational multicenter study, we included 495 patients treated with ICD. fQRS was analyzed according to previously validated criteria, by two physicians blinded for outcome data. Incident VA were obtained from ICD recordings. Results ECG recordings interpretable for fQRS were available in 459 patients (93%), aged 66 ± 12 years with left ventricular ejection fraction 40% ± 13%. fQRS was present in 52 patients (11%) with comparable baseline characteristics to patients without fQRS, except higher age, higher prevalence of coronary artery disease (CAD), lower prevalence of cardiomyopathy, and more frequently a secondary prevention ICD indication. Among patients with native QRS, those with fQRS had similar QRS duration and axis to those without fQRS. During 3.1 ± 0.7 years follow‐up, 126 patients (28%) had ≥1 VA . fQRS was associated with increased risk of VA (HR 3.41 [95% CI 2.27–5.13], p < .001), which persisted after adjusting for age, gender, sex, BMI, CAD, heart failure, renal function, ICD indication, QRS duration, QRS axis, Q waves, and bundle branch block. fQRS was more strongly associated with VA in patients with a primary (HR 6.05 [95% CI 3.16–11.60]) versus secondary (HR 2.39 [95% CI 1.41–4.04]) ICD indication (p‐for‐interaction = .047). Conclusions fQRS is associated with threefold increased risk of VA in high‐risk patients, independent of established risk factors.
Background Cardiac myosin-binding protein C (cMyC), a cardiac contractile protein, is a novel biomarker of myocardial injury, rising earlier and disappearing faster than cardiac troponins. It is a promising biomarker for use in triage of patients with chest pain presenting in the emergency department. It also has prognostic significance in patients with heart failure. However, the effects of systematic exercise training on plasma levels of cMyC has previously not been evaluated. Purpose The aim of this study was to assess the effect of a 12-week exercise training program on changes in plasma levels of cMyC in patients with chronic symptomatic heart failure with reduced ejection fraction (HFrEF). The changes in plasma levels of cMyC in an intervention group, performing structured exercise programs, were compared to those in a control group, instructed to perform regular recommended exercise (RRE) according to current guidelines. Methods This was a post hoc analysis of the SMARTEX-HF trial in 215 patients with symptomatic HF with Left Ventricular Ejection Fraction (LVEF) <35% and NYHA II-III. The patients were randomly assigned to High Intensity Interval Training (HIIT, n=77), Moderate Continuous Training (MCT, n=65) or RRE, (n=73) for 12 weeks. HIIT and MCT groups constituted the intervention group (IG). Measurements and clinical data were acquired before and after the 12-week intervention. Statistical analysis We divided the patients in two groups with Δ VO2Peak above and below the median of the sample. The absolute changes of cMyC were then compared between the two groups. Mann-Whitney U test was used to compare continuous variables between the groups. Chi-squared test and Fisher exact test were used to compare categorical variables, as appropriate. A two-tailed p<0.05 was considered significant. Results There were no differences in changes of cMyC plasma levels, measured at baseline and after the intervention, between patients in the IG and RRE-group (p=0.580). When dividing the entire study population according to Δ VO2Peak higher or lower than median value 0.48 ml/kg/min, we found a statistically significant greater reduction of cMyC values after 12 weeks of exercise training for those with higher than median Delta VO2Peak values compared to those with lower values (p=0.012). This finding was even stronger for the percentage change in cMyC levels (p=0.004 between groups). Conclusion In patients with symptomatic chronic HFrEF performing a structured 12-week exercise training program, a greater increase in Δ VO2Peak is significantly associated with a reduction in cMyC, suggesting cMyC may provide a dynamic measure of cardiorespiratory state. FUNDunding Acknowledgement Type of funding sources: Public Institution(s). Main funding source(s): Central Norwegian Health authority,Norwegian University of Science and Technology Baseline characteristics Boxplot cMyC vs peak VO2
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