Population
Prospective cohort study between May 2017 and September 2019. We included consecutive outpatients over 18 years, followed at the heart failure unit in a tertiary hospital in Bahia, Brazil. The indication for CRT was based on the following criteria: patients age over 18 years, under appropriate medical treatment, presenting NYHA II to IV with left ventricular ejection fraction (LVEF) less than 35% and a QRS duration > 150ms or 120–150ms with proven dyssynchrony by echocardiogram (??). Patients with previously implanted pacemakers or implantable cardioverter-defibrillators (ICD) who developed this criteria, with or without need for continuous ventricular pacing, were also considered for CRT (upgrade group).
Demographic, laboratory and echocardiographic data were collected at the time of the hospitalization for the procedure. All patients were hospitalized electively for the procedure and the New York Heart Association (NYHA) functional class was assessed at the time of the hospitalization. Left ventricular ejection fraction was measured on transthoracic echocardiograms using the Simpson’s method at the time of the CRT implantation, and after 6 months. Chronic renal disease was defined as renal clearance, estimated using Cockroft and Gault’s formula, <60mL/min/1.73m2. Atrial fibrillation was defined at the time of the procedure by baseline electrocardiogram. Chagas disease was confirmed by serology (ELISA and IFI).
Patients were excluded if they had a chronic systemic inflammatory disease, malignant neoplasia under treatment, who declined to give informed consent or who refused the procedure.