Accelerated Pacing and Cardiac Filling Pressures During Exercise in Patients With Heart Failure With Preserved Ejection Fraction

Heart failure with preserved ejection fraction (HFpEF) is a condition where the heart pumps strongly enough, but has trouble relaxing and filling with blood properly. This causes the pressure on the left side of the heart to rise, especially during activity, which can lead to symptoms like shortness of breath and fatigue. Even light activities such as walking or climbing stairs can be difficult, limiting daily life. Recent research suggests that increasing the heart rate in people with HFpEF may help lower this elevated pressure in the heart. Because patients usually experience their symptoms during exercise, this study aims to see whether, during light activity, increasing the heart rate in patients who already have a pacemaker by adjusting its settings, can reduce this elevated pressure in the heart. Furthermore, we will look at how increasing the heart rate affects the amount of blood the heart pumps each minute, another key factor in a person's ability to perform physical activity. The investigators will examine 20 patients using a heart catheter to measure pressures, along with breathing analyses. During the measurements, all patients will perform light-intensity cycling. If increasing the pacemaker rate lowers the pressure in the heart, this simple, non-drug-based intervention could improve daily functioning and comfort for thousands of patients with heart failure, justifying further long-term studies to evaluate effects beyond the immediate changes in heart pressures.