PFA is an emerging non-thermal ablation technology with favorable procedural safety; however, recent studies have raised concerns about peri-procedural hemolysis and subsequent AKI after PFA. This study is a single-center, open-label, randomized controlled trial designed to evaluate whether standardized peri-procedural intravenous hydration can reduce the risk of acute kidney injury (AKI) after pulsed field ablation (PFA) for atrial fibrillation (AF).

Eligible adult patients with symptomatic paroxysmal or persistent AF scheduled for PFA will be randomly assigned in a 1:1 ratio to either a standardized hydration strategy or a control strategy without routine prophylactic hydration. The hydration group will receive 0.9% saline at 2 mL/kg/h from entry into the electrophysiology laboratory until 12 hours after the procedure, while the control group will receive no routine preventive hydration and will be treated with fluids only if clinically indicated.

The primary outcome is any in-hospital AKI defined according to Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Secondary endpoints include in-hospital AKI severity by KDIGO stage, in-hospital persistent moderate-to-severe AKI, in-hospital renal replacement therapy, changes in renal function after the procedure, and clinical outcomes through 30 and 90 days, including all-cause death, persistent AKI, renal replacement therapy, all-cause rehospitalization, and composite major adverse events.

Pulsed field ablation (PFA) has rapidly emerged as a promising non-thermal catheter ablation technology for the treatment of atrial fibrillation (AF). Although its overall safety profile appears favorable, increasing evidence suggests that peri-procedural hemolysis may occur after PFA. In some patients, this hemolysis may contribute to acute kidney injury (AKI), which has become an important safety concern in contemporary PFA practice. Peri-procedural hydration may represent a practical kidney-protective strategy by maintaining renal perfusion and promoting clearance of hemolysis-related pigments and other nephrotoxic factors. However, no randomized controlled trial has evaluated whether routine standardized hydration reduces the risk of AKI after AF ablation with PFA.

The HYDRATE-PFA trial is a single-center, open-label, superiority, parallel-group randomized controlled trial designed to assess whether a standardized peri-procedural hydration strategy can reduce the risk of AKI after PFA for AF. A total of 290 adult patients with symptomatic paroxysmal or persistent AF who are scheduled to undergo PFA will be enrolled at Beijing Anzhen Hospital, Capital Medical University. Participants will be randomized in a 1:1 ratio to either a standardized peri-procedural hydration group, or a control group without routine prophylactic hydration.

Participants assigned to the hydration group will receive 0.9% sodium chloride intravenously at 2 mL/kg/h starting when the participant enters the electrophysiology laboratory and continuing until 12 hours after the procedure. The infusion rate may be reduced or interrupted if there is evidence of fluid overload, hypoxemia, pulmonary congestion, or any other safety concern judged by the investigator. Participants assigned to the control group will not receive routine preventive hydration; intravenous fluids may be given only when clinically indicated, such as for suspected hemoglobinuria, rising serum creatinine, oliguria.

For all participants, blood and urine samples will be collected at baseline, immediately after the procedure, and 24 hours after the procedure, with additional in-hospital testing if clinically indicated. Participants will also be followed at 30 days and 90 days after randomization by clinic visit or telephone contact.

The primary endpoint is any in-hospital AKI, defined according to KDIGO criteria (an increase in serum creatinine of at least 0.3 mg/dL within 48 hours or an increase to at least 1.5 times baseline). Secondary endpoints include in-hospital AKI severity by KDIGO stage, in-hospital persistent moderate-to-severe AKI, in-hospital renal replacement therapy, changes in renal function after the procedure, and clinical outcomes through 30 and 90 days, including all-cause death, persistent AKI, renal replacement therapy, all-cause rehospitalization, and composite major adverse events.

Inclusion Criteria:

Participants must meet all of the following criteria:

• Age ≥18 years.

• Symptomatic paroxysmal atrial fibrillation (AF) or persistent AF:

  1. Paroxysmal AF: AF that terminates spontaneously or with intervention within 7 days of onset, and meets both of the following:

     1. At least 2 symptomatic paroxysmal AF episodes within 6 months before enrollment;
     2. At least 1 documented AF episode by electrocardiogram (ECG) or Holter monitoring within 12 months before enrollment.

  2. Persistent AF: AF lasting >7 days and ≤365 days, and meets both of the following:

     1. At least 1 symptomatic persistent AF episode within 6 months before enrollment;
     2. Persistent AF documented within 12 months before enrollment by either Holter monitoring or 2 ECGs obtained at least 7 days apart.

• Failure of antiarrhythmic drug (AAD) therapy, defined as inadequate efficacy and/or intolerance to at least 1 Class I or Class III AAD.

• Planned to undergo pulsed field ablation (PFA).

• Willing and able to provide written informed consent.

• Willing and able to comply with study procedures, including in-hospital assessments and 30-day and 90-day follow-up.

Exclusion Criteria:

Participants meeting any of the following criteria will be excluded:

• AF due to a reversible cause, such as hyperthyroidism or perioperative/cardiothoracic surgery-related AF.
• No oral anticoagulation for at least 3 weeks before ablation.
• Intracardiac thrombus.
• Contraindication to anticoagulant therapy or iodinated contrast media.
• Significant valvular heart disease, including moderate or severe aortic stenosis, severe aortic regurgitation, moderate or severe mitral stenosis, or severe mitral regurgitation.
• Myocardial infarction within 3 months before enrollment.
• Cardiac surgery within 3 months before enrollment.
• New York Heart Association (NYHA) class III or IV congestive heart failure.
• Left ventricular ejection fraction (LVEF) <35%.
• Hypertrophic cardiomyopathy.
• Severe liver disease (Child-Pugh score >7).
• Stage 4 or 5 chronic kidney disease (eGFR <30 mL/min/1.73 m²).
• History of kidney transplantation.
• Need for renal replacement therapy (RRT) at enrollment or any history of prior RRT.
• Intravascular iodinated contrast administration within 7 days before enrollment.
• Active systemic infection.
• Known pregnancy or breastfeeding.
• Participation in another clinical trial that may affect the results of this study.
• Unwillingness or inability to comply with study procedures and follow-up, including participants considered by the investigator to be at substantial risk for poor adherence.