Long-term neuromuscular electrical stimulation in heart transplantation candidates with cardiac pacemakers

Purpose: Neuromuscular electrical stimulation (NMES) in patients with pacemakers is controversial because of potential electromagnetic field interference and subsequent pacemaker failure. Twenty percent of heart transplantation candidates have cardiac pacemakers. The first description of long-term NMES in pacemaker patients is presented. Materials and Methods: After a thorough safety procedure six male patients suffering from chronic heart failure with implanted bipolar cardiac pacemakers received long-term NMES treatment of thigh muscles to improve endurance capacity while waiting on a donor heart. NMES protocol consisted of biphasic, symmetric, constant voltage impulses of 0.5 ms pulse width at a frequency of 15 Hz, 2 s on and 4s off, applied to both knee extensor and flexor muscles through surface electrodes. The patients performed NMES themselves as home treatment four hours a day during 10 weeks. After the treatment period a check-up of pacemaker function was performed. Results: During the NMES treatment period every patient received 336000 on and off phases (alltogether 2 016 000) and 5 040 000 biphasic electrical pulses (alltogether 30240000) without adverse events, Check-up of the pacemaker function after the stimulation period revealed no changes in the pacemaker parameters. Conclusions: This is the first presentation of a long-term NMES in pacemaker patients. Long-term NMES treatment of thigh muscles seems to be safe in patients with bipolar pacemakers as shown in this observation. Especially for pacemaker patients suffering from severe chronic heart failure NMES treatment would be an alternative to active endurance training, while waiting for a donor heart.