Clinical experience with Sensolog 703: a new activity sensing rate responsive pacemaker

Area of Science:

• Cardiology
• Biomedical Engineering
• Medical Devices

Background:

• Pacemakers are crucial for managing bradycardia and heart block.
• Rate-responsive pacemakers aim to optimize cardiac output during physical activity.
• Activity sensors in pacemakers detect physiological needs for rate adjustment.

Purpose of the Study:

• To evaluate the efficacy of the Sensolog 703, a novel activity sensing rate-responsive pacemaker.
• To assess improvements in exercise capacity and cardiac output compared to VVI pacing.
• To compare the rate response characteristics of Sensolog 703 with a Medtronic Activitrax pacemaker.

Main Methods:

• Implantation of Sensolog 703 in 11 patients with complete heart block and atrial arrhythmias.
• Assessment of exercise capacity using graded treadmill exercise (Bruce protocol).
• Measurement of cardiac output at peak exercise via continuous wave Doppler of aortic root blood flow.

Main Results:

• Significant improvement in exercise duration with Sensolog 703 compared to VVI pacing (462s vs 368s).
• Greater increase in peak exercise cardiac output with Sensolog 703 (93% vs 57% over resting).
• Both Sensolog 703 and Activitrax showed limitations in responding to varied inclines and isometric activities.

Conclusions:

• Sensolog 703 provides satisfactory rate response and improves exercise performance in patients with heart block.
• The pacemaker's reliance on body vibration for rate adjustment presents limitations.
• Further research is needed to refine activity sensing algorithms for optimal physiological response.