Electrical Stimulation Improves Exercise Tolerance in Patients With Advanced Heart Failure on Continuous Dobutamine Use

Quadriceps and calf muscles of both legs were simultaneously stimulated using self adhesive surface rectangular electrodes. During all session period, the patients were maintained in the supine Fowler 45º position. Stimulation parameters were set up as follows: biphasic current of 40 Hz, 400-µs pulse duration, mode "on-time" 10s and "off-time" 20s and maximal amplitude of 60 mA. The stimulation intensity was progressively increased according to the patient tolerance until a muscular contraction was observed. Stimulation was performed twice a day; the session duration was 60 min.

each session consisted of breathing exercises and global active exercises of the upper and lower limbs in bed. The treatment was applied twice a day during the hospitalization period. The protocol was interrupted if the patient had signs or symptoms suggestive of poor tolerance to exercise: 1) cyanosis, pallor, dizziness, nausea or pre-syncope; 2) chest pain; 3) bradycardia; 4) a drop in systolic blood pressure \>15 mmHg in comparison to baseline; 5) an excessive rise in systolic blood pressure defined as \>200 mmHg; 6) a rise in diastolic blood pressure during exercise \>110 mmHg; 7) fatigue rated ≥6/10 on the perceived exertion Borg scale (PEB); and/or 8) electrocardiographic signs of cardiac ischemia or ventricular arrhythmias.