Posterior Left Pericardiotomy for the Prevention of Postoperative Atrial Fibrillation After Cardiac Surgery - PALACS

Contribution To Literature:

The PALACS trial showed that posterior left pericardiotomy during open heart surgery was associated with a reduction in postoperative atrial fibrillation.


The goal of the trial was to evaluate posterior left pericardiotomy compared with no intervention among patients undergoing open heart surgery.

Study Design

  • Randomization
  • Parallel
  • Stratification

Participants undergoing open heart surgery were randomized to posterior left pericardiotomy (n = 212) versus no intervention (n = 208). Pericardiotomy was performed by making a 4-5 cm vertical incision from the left inferior pulmonary vein to the diaphragm.

  • Total number of enrollees: 420
  • Duration of follow-up: median 6 days
  • Mean patient age: 61 years
  • Percentage female: 24%
  • Percentage with diabetes: 21%

Inclusion criteria:

  • Patients at least 18 years of age undergoing open heart surgery for coronary artery bypass grafting (CABG), aortic valve replacement, and/or aortic repair

Exclusion criteria:

  • History of atrial fibrillation or arrhythmia
  • Mitral or tricuspid surgery
  • Reoperation

Principal Findings:

The primary outcome, postoperative atrial fibrillation, occurred at a rate of 18% in the pericardiotomy group compared with 32% in the no intervention group (p < 0.001).

Secondary outcomes:

  • Operative mortality: 1% in the pericardiotomy group vs. 1% in the no intervention group
  • Major adverse events: 3% in the pericardiotomy group vs. 2% in the no intervention group
  • Pericardial effusion: 12% in the pericardiotomy group vs. 21% in the no intervention group


Among patients undergoing open heart surgery for CABG, aortic valve replacement, and/or aortic repair, posterior left pericardiotomy was beneficial. Pericardiotomy was associated with a significant reduction in postoperative atrial fibrillation, without increasing the incidence of complications. This trial was adequately powered for a single-center study. A large confirmatory multicenter trial is needed to quantify potential clinical benefits from this intervention.


Gaudino M, Sanna T, Ballman KV, et al., on behalf of the PALACS Investigators. Posterior left pericardiotomy for the prevention of atrial fibrillation after cardiac surgery: an adaptive, single-center, single-blind, randomized, controlled trial. Lancet 2021;398:2075-83.

Presented by Dr. Mario F. Gaudino at the American Heart Association Virtual Annual Scientific Sessions (AHA 2021), November 14, 2021.

Clinical Topics: Arrhythmias and Clinical EP, Cardiac Surgery, Invasive Cardiovascular Angiography and Intervention, Pericardial Disease, Prevention, Implantable Devices, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Cardiac Surgery and Arrhythmias

Keywords: AHA Annual Scientific Sessions, AHA21, Arrhythmias, Cardiac, Atrial Fibrillation, Coronary Artery Bypass, Cardiac Surgical Procedures, Pericardial Effusion, Pericardiectomy, Reoperation, Secondary Prevention

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