RESUMO
BACKGROUND: Cardiac troponins (cTns) and biomarkers of inflammation are elevated in heart failure (HF) and predict cardiovascular risk. Whether these biomarkers associate with risk of ventricular arrhythmias (VAs) is unclear. OBJECTIVES: This study sought to assess whether cTnT, growth differentiation factor 15 (GDF-15), interleukin-6 (IL-6), and C-reactive protein (CRP) concentrations are associated with incident VA. METHODS: In a prospective, observational study of patients treated with implantable cardioverter-defibrillator, cTnT, GDF-15, IL-6, and CRP were measured at baseline and after 1.4 ± 0.5 years and were associated with implantable cardioverter-defibrillator-detected incident VA, HF hospitalizations, and mortality. RESULTS: This study included 489 patients aged 66 ± 12 years and 83% were men. Median concentrations of cTnT were 15 (Q1-Q3: 9-25) ng/L at inclusion, and higher concentrations were associated with higher age, male sex, diabetes mellitus, coronary artery disease, and HF. During 3.1 ± 0.7 years of follow-up, 137 patients (28%) had ≥1 VA. cTnT concentrations were associated with an increased VA risk (per log-unit, HR: 1.63; 95% CI: 1.31-2.01; P < 0.001), also after adjustment for age, sex, body mass index, coronary artery disease, HF, renal function, and left ventricular ejection fraction (P < 0.001). GDF-15, IL-6, and CRP concentrations were not associated with incident VA, but all (including cTnT) were associated with HF hospitalization and mortality. Changes in cTnT, GDF-15, IL-6, and CRP from baseline to 1.4 years were not associated with subsequent VA. CONCLUSIONS: Higher concentrations of cTnT, GDF-15, IL-6, and CRP associate with HF hospitalization and death, but only cTnT predict incident VA. These findings suggest that myocardial injury rather than inflammation may play a pathophysiological role in VA and sudden cardiac death.
RESUMO
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.
