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.