[Activity-initiated rate-adapted pacemaker therapy. Clinical results]

Area of Science:

• Cardiology
• Biomedical Engineering

Background:

• Patients with decreased exercise tolerance and suboptimal heart rate response to activity may benefit from advanced pacing.
• Activity-sensed pacing aims to optimize heart rate during physical exertion.

Purpose of the Study:

• To evaluate the clinical effectiveness of rate-adapted activity-sensed pacing (Activitrax system).
• To assess improvements in physical exercise tolerance in patients receiving this pacing mode.

Main Methods:

• Prospective study of 23 patients over a mean of 8.1 months.
• Activity-sensed pacing (Activitrax) used when spontaneous heart rate < 85 bpm during exercise and symptoms of reduced tolerance.
• Treadmill ergometry performed in both fixed-rate and rate-adapted modes for comparison.

Main Results:

• 11 of 17 patients showed lasting improvement in exercise tolerance after switching to rate-adapted pacing.
• Treadmill ergometry demonstrated a significant rise in exercise tolerance with rate-adapted pacing (P<0.01).
• Five patients experienced insufficient rate increases during static stress, indicating a limitation.

Conclusions:

• Rate-adapted activity-sensed pacing can enhance physical exercise tolerance in select patients.
• The system's effectiveness is limited by inadequate rate increases during static stress, necessitating careful patient selection.