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

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

Neuromuscular Electrical Stimulation Improves Exercise Tolerance in Patients With Advanced Heart Failure on Continuous Dobutamine Use - A Randomized Controlled Trial

The purpose of this study is to determine whether neuromuscular electrical stimulation can improve exercise tolerance for patients with heart failure and continuous dobutamine use in a hospital.

Patients in this group were subject to regular Physical Therapy Sessions in the hospital and 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.

Lower limb 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. 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. Heart rate, blood pressure, respiratory rate and pulse oximetry were monitored throughout the sessions, in all patients.

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.

Functional capacity was evaluated using the 6-minute walk test (6MWT), by a single evaluator blinded to the group allotment, in accordance with American Thoracic Society criteria.

For all patients, the inotropic intravenous dose was adjusted daily by a single clinician (prescriber) blinded to the group allocation. Weaning from inotropic support was performed by the prescriber based on the improvement of clinical signs (level of consciousness, peripheral perfusion and blood pressure).

Inclusion Criteria: Advanced heart failure (Stage D - Left ventricle ejection fraction <30%) New York Heart Association class III-IV Standard medical therapy for heart failure management Continuous inotropic infusion Exclusion Criteria: Unstable angina pectoris Recent (6 months) acute coronary syndrome Arrythmias Chronic renal failure Diabetes Mellitus Peripheral vascular diseases Inability to walk

No subject data will be made public. However, all participants were given the principal investigator's e-mail address and phone number in order to ask questions or receive their assessment results.