Clinical Research Directory

Inclusion Criteria: * Patients with symptomatic bradycardia who meet the indication for permanent pacemaker implantation and fulfill one of the following conditions: 1. Sick sinus syndrome with or without impaired atrioventricular conduction 2. Persistent or permanent atrial fibrillation with slow ventricular response 3. Chronotropic incompetence * Patients diagnosed with heart failure with left ventricular ejection fraction ≥ 50% on transthoracic echocardiography with at least one of the following: * H2FPEF score ≥ 6 or HFA-PEFF score ≥ 5 * N-terminal pro-B-type natriuretic peptide ≥ 300 pg/mL (sinus rhythm) or ≥ 600 pg/mL (atrial fibrillation) * Prior hospitalization for heart failure or documented use of loop diuretics for heart failure symptoms Exclusion Criteria: * Patients expected to have a ventricular pacing burden ≥ 20% without sufficient capture of cardiac physiologic pacing, which includes biventricular pacing, His bundle pacing, and left bundle branch area pacing. (Sufficient cardiac physiologic pacing is defined as a paced QRS duration ≤ 140 ms.) * Patients not expected to achieve sufficient pacing dependency, defined as: 1. In sinus rhythm: baseline atrial rate \> 60 bpm on Holter monitoring or inpatient ECG monitoring 2. In atrial fibrillation/flutter: baseline ventricular rate \> 60 bpm on Holter monitoring or inpatient ECG monitoring * Patients with contraindications to permanent pacemaker implantation * Patients with moderate or greater valvular stenosis or regurgitation. * Patients with dyspnea not attributable to heart failure, due to uncontrolled comorbid conditions * Pregnant or breastfeeding women. * Patients who have refused active treatment.