AV Nodal Ablation With Conduction System Pacing Versus Cardiac Resynchronization for Symptomatic Heart Failure Patients With Atrial Fibrillation

• Study Rationale:

Therapeutic options for patients with symptomatic HF and AF that is not suitable for rhythm control are limited to pharmacological rate control and/or AV node ablation plus CRT implantation (Class IIa, Level of Evidence B). CSP is gaining more and more attention, and it has the advantage of utilizing the native conduction system to activate both ventricles simultaneously. This would achieve more physiologically synchronized ventricular contraction and circulation dynamics. We hypothesize that conduction system pacing would be as efficient as CRT pacing in patients with symptomatic heart failure and AF that is not suitable for rhythm control who are receiving the "ablate and pace" treatment strategy.

+Objective:

• Primary Objective:

To compare AV node ablation with conduction system pacing versus AV node ablation with cardiac resynchronization therapy (CRT) among the trial population with respect to the hierarchical composite endpoint of all-cause mortality, HF hospitalization or unplanned/urgent HF visit, and ≥5 point improvement (increase) in the Kansas City Cardiomyopathy Questionnaire (KCCQ) score.

• Secondary Objectives:

To determine the effect of AV node ablation with conduction system pacing compared to AV node ablation with cardiac resynchronization therapy (CRT) among the trial population in the following outcomes:

-≥5 point improvement (increase) in the Kansas City Cardiomyopathy Questionnaire (KCCQ) score.

• Quality of life measures (EQ-5D and AFEQT questionnaires). -HF hospitalization or unplanned/urgent HF visit. -Cardiovascular related hospitalization. -All-cause mortality. -Cardiovascular related mortality. Tertiary (Exploratory) Objectives: To determine the effect of AV node ablation with conduction system pacing compared to AV node ablation with cardiac resynchronization therapy (CRT) among the trial population in the following outcomes:
• Duration of hospitalization for cardiovascular causes
• Worsening heart failure (NYHA class at baseline,1 year and at end of follow-up),
• Healthcare costs and cost-effectiveness,
• Trends of NT-proBNP levels at baseline and follow up
• Change in left ventricular ejection fraction (LVEF) at baseline and 1 year
• Change in renal function metrics (Glomerular Filtration Rate (GFR), Creatinine (Cr) and blood Urea levels (BUN)) at baseline and 1 year.
• Change in urine Microalbumin (by urine dipstick) at baseline and 1 year (only in the subgroup analysis).
• Change in measured arterial stiffness index measured by the photoplethysmography (PPG) signals through a non-invasive blood-volume sensing wearable bracelet, at baseline and 1 year (only in the subgroup analysis).
• Short-term safety outcomes: This includes the composite of short-term (i.e. within 3 months) post procedure related complications (i.e. Cardiac tamponade, Pneumothorax, postoperative wound infection, Pocket hematomas, lead dislodgment, vascular injury, Thromboembolism, and Pericarditis).
• Long term safety outcomes: This includes the composite of long-term (i.e. within 3 years) post procedure related complications (Device and Lead integrity related complications (i.e. lead dislodgment, lead malfunction, generator malfunction, lead related infections)).

• Study design:

The APAF-CSP trial is a prospective, multicenter, international, randomized, open-label, non-inferiority, parallel-arms trial. Patients who have atrial fibrillation (AF), that is not suitable for rhythm control, and a history of at least one hospitalization or unplanned/urgent care visit due to heart failure within the last 2 years, regardless of left ventricular ejection fraction or QRS duration, will be invited to participate. The trial will take place in 23 participating hospitals in Europe (Netherlands, Germany, Italy and France).

+Study population: Adult patients aged 18 years or older, with confirmed AF that is unsuitable for rhythm control and symptomatic HF (with a history of at least one hospitalization or unplanned/urgent care visit due to HF exacerbation within the 2 years before enrolment), regardless of left ventricular ejection fraction or QRS duration, will be invited to participate in this trial. Based on sample size estimations, the trial needs 292 patients with a median follow-up of 2.5 years.

+Intervention: All patients meeting the inclusion criteria and not meeting any exclusion criteria will be randomized in a 1:1 ratio to undergo either AV node ablation with CSP or AV node ablation with CRT implantation. Throughout the trial, patients will be followed up at predefined intervals for endpoint data collection.

+Main study endpoint: The hierarchical primary composite endpoint is the composite of all-cause mortality, HF hospitalization or unplanned/urgent HF visit, and ≥5 point improvement (increase) in the Kansas City Cardiomyopathy Questionnaire (KCCQ).

+Nature and extent of the burden and risks associated with participation, benefit and group relatedness: AV node catheter ablation and pacemaker implantation, whether CRT or CSP, are well-established and safe techniques. They are well-known for their efficiency for rate control in the appropriate population. The follow-up assessments will be conducted either physically (i.e. patient visits) and/or (when possible) remotely (i.e. telephone encounter) to minimize patient effort. Additional study procedures, such as transthoracic echocardiography and blood sample collection, will be performed at baseline during the screening assessment and during the 1-year follow-up visit. These procedures are part of usual clinical care for these patients undergoing AV nodal ablation with pacemaker implantation. Consequently, the additional effort and time to fill out a few "Quality-of-Life" questionnaires are determined to be the main extra burden that consumes time for both the patient and the treating physician. However, this increased burden is non-invasive and will be highlighted in the consent/participation form. In pre-selected centers (subgroup analyses), a urine sample for the microalbumin check will be collected at baseline and the 1-year visit. Furthermore, the vascular stiffness index (VSI) will be measured by a wearable bracelet. This VSI measurement will be performed at the baseline visit and at the 1-year follow up visit, where the participant will be asked to wear the device for 30 minutes (during the visit). The VSI recording and urine microalbumin check are painless, non-invasive and fully funded by the study. The patient will not be required to come for an extra visit to the study site for the sole reason of this recording or for the urine sample, and instead, this is incorporated into the scheduled study visits. However, the increased burden of providing a urine sample and wearing the bracelet during the visit is fully acknowledged and will be highlighted in the consent/participation forms.

Inclusion criteria

• Age 18 years or above.
• Patient is diagnosed with AF and deemed not amenable to rhythm control. This diagnosis of AF will be demonstrated by at least one Electrocardiograph (ECG) showing AF that was performed within one year prior to enrollment.
• Has history of stable heart failure (regardless left ventricular ejection fraction) and has a history of at least one HF related hospitalization or emergency room/urgent care visit within 2 years prior to enrollment, despite being on maximally tolerable guideline directed medical therapy.
• Willing and capable to provide informed consent.

Exclusion criteria

• NYHA functional class IV.
• Severe concomitant non-cardiac disease.
• Patient who require any cardiac surgical intervention.
• Previously implanted pacing devices (pacemaker/ICD/CRT) with ≥40% pacing burden.
• Any of the following within the 3 months prior to enrollment:

• Myocardial infarction
• Unstable angina
• Percutaneous coronary intervention
• Stroke or TIA
• Significant bleeding
• Pericarditis/effusions
• Coronary artery bypass surgery/atriotomy within 6 months prior to enrolment.
• Women who are pregnant or breastfeeding.