Methods
A retrospective analysis was performed in consecutive patients treated
at our institution with an LVEF ≤ 50 % presenting with new-onset
non-ischemic HF. The definition of TCM included: 1) heart rate on
admission > 100 beats/min and evidence of prolonged
elevated heart rate; 2) recovery of LVEF after the restoration of sinus
rhythm or rate control (> 5 % absolute increase in LVEF
[9]); and 3) exclusion of other causes of HF. The decision to
perform EMB was based on clinical criteria and indications, as described
previously [10,11,12,13]. Cardiomyopathies were defined according to
classification criteria from the American Heart Association and the
European Society of Cardiology [12,13,14]. Coronary artery disease
as the cause of the reduced LVEF had to be excluded using coronary
angiography before a patient was eligible for inclusion in the study.
All patients were medically treated according to current guidelines,
depending on the degree of HF symptoms and LVEF development [15].
LVEF was estimated by echocardiography using the modified Simpson’s rule
with images obtained from apical 4- and 2-chamber views. The study
conformed to the principles outlined in the Declaration of Helsinki, and
the local ethics committee approved the research protocol.