Introduction
Randomized controlled trials supports the clinical efficacy and safety
of cardiac resynchronization therapy (CRT) in patients with moderate or
severe heart failure and ventricular dyssynchrony.1-2Guidelines from international cardiology societies provide strong
recommendations for CRT specially in symptomatic patients with left
bundle branch block (LBBB) and a QRS duration
>150ms.3 However, some questions remain
about its effectiveness in specific etiologies, such as Chagas
Cardiomyopathy (CC), since most of the published trials about on the
subject did not include a significant number of this population.
Upgrade for a CRT from a conventional pacemaker have become increasingly
common in HF patients, since right ventricular pacing may aggravate left
ventricular function.4 Despite this, there are still
concerns about this practice, considering that the decision to proceed
to upgrade is supported by small observational studies. Recent studies
suggest that clinical response and survival are impaired in patients
undergoing CRT upgrade compared to de novo implantations.5-6
Thus, the aim of this study is to compare the short-term mortality
between upgrade and de Novo CRT implantation in a population with heart
failure and clinical indication for this device, comparing its results
between individuals with Chagas Cardiomyopathy and not.