RESUMEN
AIMS: We compared pacing rate adaptation based on closed loop stimulation (CLS) or accelerometer sensor (AS) during acute mental and physical stress in the same patient. METHODS AND RESULTS: One month after Protos (Biotronik, Germany) pacemaker implantation, 131 chronotropically incompetent patients were randomized to AS or CLS for 3 months with crossover. Arithmetic and 6 min walk tests were performed in the non-rate-adaptive mode and AS and CLS rate-adaptive modes, respectively. At the end, patients had to select the individually preferred pacemaker sensor. Heart rate during mental stress was higher (3.0 +/- 9.2 bpm) in the CLS than in the AS mode (P = 0.004). Benefit in the walking distance compared with non-rate-adaptive pacing was similar for the two modes: added 27 +/- 96 m (AS, P = 0.013) and 30 +/- 116 m (CLS, P = 0.025). At the end of the walk, heart rate was higher by 4.8 +/- 21.4 bpm in AS than in CLS (P = 0.049). Twice as many patients preferred CLS over AS (P < 0.01). CONCLUSION: The arithmetic test was associated with a significantly higher heart rate for CLS than for AS, showing a greater sensitivity of CLS-based rate adaptation to mental stress. Performance during physical stress was comparable. Patients preferred CLS.