Short-term Effects of Dapagliflozin on Peak VO2 in HFrEF

It will be done with cycle ergometer (CORTEX Metamax3B), starting with 10W of power and increasing 10W every minute. During the test, heart rate, rhythm and blood pressure will be monitored. Gas exchange data shall be evaluated every 10 seconds and the peak oxygen consumption (peak VO2) shall be considered the maximum value obtained during the last 20 seconds of exercise. The main parameters to be determined are: maximum functional capacity, peak VO2, slope of the VE/VCO2 ratio, and chronotropic incompetence variables. It will be performed by a trained cardiologist blind to study treatment at baseline and at 30 and 90 days after treatment initiation.

The following parameters will be evaluated: a)left ventricular volumes; b) left ventricular systolic function; and c)left atrial volume and E/e' ratio. It will be performed by a trained cardiologist blind to study treatment at baseline and at 30 and 90 days after treatment initiation.

Assessment of the quality of life through the Minnesota Living with Heart Failure Questionnaire (MLHFQ), Spanish version. It will be completed at baseline and at 30 and 90 days after treatment initiation. The score of the questionnaire is 0 to 105 points.

It will be performed in an area equipped for cardiopulmonary resuscitation. Subjects will be asked not to perform a vigorous physical exercise in the previous 2 hours. They will be allowed to have a light meal before the test. Before the test, the vital signs will be determined in a seated position after a rest of 10 minutes. Subjects will be instructed to walk at their own pace to cover as much distance as possible in 6 minutes. It will be performed by a trained nurse blind to study treatment at baseline and at 30 and 90 days after treatment initiation.

Evaluation of signs and symptoms of heart failure