The Effect of Ligament of Marshall Excision During Minimally Invasive Cardiac Surgery-Coronary Artery Bypass Grafting (MICS-CABG) on the Prevention of Postoperative New-Onset Atrial Fibrillation: A Multicenter, Prospective, Randomized, Triple-Blinded Study

After heart bypass surgery, many patients develop a heart rhythm problem called postoperative atrial fibrillation, or POAF for short. This issue happens to 20%-40% of all bypass patients. Even with smaller, less invasive surgical cuts or robot-assisted heart bypass operations, between 4.8% and 18.4% of people still get POAF.

When POAF occurs, patients usually stay in the hospital longer and face higher medical bills. It also raises chances of serious complications like stroke, heart failure and heart attacks, and lowers long-term survival rates. Stopping POAF early is therefore key to helping patients recover better after surgery.

POAF comes from two main causes: personal health risks and stress from the surgery itself. Older age, high blood pressure, heart failure, lung disease, diabetes and overweight all make people more likely to develop irregular heart rhythms after an operation. Surgical trauma also plays a big role: cutting the breastbone, fluid building up around the heart, inflammation from heart-lung machines, pulling or stitching heart tissue, and unbalanced nerve signals during recovery can all spark POAF. Earlier studies have shown simple surgical adjustments can lower POAF risk safely, giving us a good basis to improve current surgery methods.

The Ligament of Marshall is a fibrous bundle-like structure left over from heart development before birth. Its special tissue structure makes it easy to trigger chaotic heart beats. It holds muscle tissue that creates looping abnormal electrical signals, plus nerve clusters that overactivate the body's stress response after surgery - this is a major cause of POAF. Doctors who fix irregular heart rhythms with catheter burns already target this ligament to stop repeat atrial fibrillation. Major heart surgery for long-term irregular heartbeats also routinely cuts this ligament without adding extra surgical risks.

Our study will collect real clinical data to deepen the understanding of POAF and partial denervation therapy. Cutting the Ligament of Marshall during minimally invasive cardiac surgery-coronary artery bypass grafting (MICS-CABG) is an easy, low-risk step with no extra risk of collateral injury. We hope this method can lower the chance of irregular heartbeats after surgery, reduce the need for rhythm-control drugs and their side effects, and help patients maintain stable heart function and better daily life right after surgery.

For MICS-CABG, doctors do not need extra complicated steps to see and cut the Ligament of Marshall. We only make a small cut between the ribs on the left chest. After pericardial incision and suspension, this fibrous bundle-like structure is clearly visible and simple to operate on. Compared with traditional open-heart surgery that splits the whole breastbone, this small-cut approach avoids rough handling of the left heart and lessens overall surgical stress on patients.