What is HFpEF? In heart failure with preserved ejection fraction (HFpEF), the heart pumps well but struggles to relax and fill with blood between beats. This raises the pressure inside the heart, especially during physical activity, causing symptoms like shortness of breath and fatigue - even with light activities like walking or climbing stairs.
What is this study about? Recent research suggests that a higher heart rate may help lower this elevated pressure. Many HFpEF patients already have a pacemaker. This study investigates whether simply increasing the pacemaker rate during light exercise can reduce the pressure in the heart.
How does the study work? We wille measure heart pressures in 20 patients in rest and while cycling using a heart catheter and monitor their breathing. Throughout these measurements, we will gradually increase the pacemaker rate step by step.
Why does this matter? If a higher pacemaker rate successfully lowers heart pressure, this could offer a simple, drug-free way to improve daily functioning and comfort for thousands of patients with HFpEF, justifying further long-term studies to evaluate effects beyond the immediate changes in heart pressures.
Voluntary written informed consent of the participant has been obtained prior to any screening procedures
At least 18 years of age at the time of signing the Informed Consent Form (ICF)
EF >= 45% and HFA-PEFF score >= 5 (Heart Failure Association-Pre-test assessment, Echocardiography and natriuretic peptide, Functional testing, Final etiology; heart failure association of the European Society of Cardiology and the Heart Failure Association (34))
EF >= 45% and H2FPEF score >= 6 (Heavy, Hypertensive, Atrial fibrillation, Pulmonary hypertension, Elder, Filling pressure; Mayo Clinic group (35)))
None
Single group
Accelerated pacing with AV-delay optimization during rest and light intensity cycling
Other interventionPatients will undergo one resting and one exercise protocol (25 Watts). During each protocol, the pacemaker rate will be gradually increased in three stages: +20, +40, +60 bpm at rest and +10, +30, +50 bpm during exercise. At each stage, intracardiac pressures and shear-wave velocity will be measured. In a final fourth stage, the pacemaker rate returns to the level associated with the lowest filling pressure, after which blood oxygen levels and oxygen uptake are assessed to calculate cardiac output.
Pulmonary capillary wedge pressure (PCWP), measured using a Swan-Ganz catheter (pulmonary artery catheter).
The change in PCWP at each pacing frequency (+20 bpm, +40 bpm, +60 bpm) with its corresponding optimal AV-delay at rest, compared to baseline PCWP. The change in PCWP at each pacing frequency (+10 bpm, +30 bpm, +50 bpm) using dynamic AV-delay programming, while avoiding truncation, compared to baseline PCWP during exercise (cycle ergometry at 25 W) Baseline PCWP is calculated as the average of the measurements before and after each accelerated pacing-on step, using the intrinsic HR or baseline atrial pacing rate as the reference HR, as applicable
Cardiac output, measured using the direct Fick principle
The change in CO, measured by the direct Fick principle, at the pacing frequency corresponding to the greatest reduction in PCWP compared to the reference HR at rest and during exercise (cycling at 25 Watts)
Shear wave velocity, measured via echocardiographically obtained myocardial shear waves following mitral valve closure
The change in shear wave velocity (SWV) at each pacing rate compared to the reference heart rate at rest and during exercise (cycling at 25 Watts) The shear wave velocity at the reference heart rate is defined as the average of the SWV at the reference heart rate heart rate before and after each pacing step.
Peripheral oxygen extraction
The change in peripheral oxygen extraction, measured by the oxygen uptake divided by the cardiac output, at the pacing frequency corresponding to the greatest reduction in pulmonary capillary wedge pressure compared to peripheral oxygen extraction at the reference heart rate at rest and during exercise (cycling at 25 Watts)
Stroke volume
The change in stroke volume, measured by the cardiac output divided by the heart rate, at the pacing frequency corresponding to the greatest reduction in pulmonary capillary wedge pressure compared to stroke volume at the reference heart rate at rest and during exercise (cycling at 25 Watts)
Click on the lead sponsor to view all of their trials.
Universitaire Ziekenhuizen KU Leuven
Lead sponsor
Hartcentrum Hasselt
Collaborator
