Acute Left Ventricular Dysfunction and Severe Functional Mitral Regurgitation After Complete Surgical Closure of a Large Secundum Atrial Septal Defect in a Child: Intraoperative Rescue With a Fenestrated Native Pericardial Patch

The human heart is a pump that must adapt to the volume of blood it receives. In a healthy heart, the left side pushes blood to the body, while the right side sends blood to the lungs. Sometimes, a hole exists between the two upper chambers, known as the atria. This hole, called an atrial septal defect, allows blood to flow from the left side to the right side, bypassing the body and flooding the right heart and lungs. Over time, this extra volume stretches the right side of the heart, while the left side receives less blood than usual and can become somewhat unused or "underfilled." When surgeons close this hole, they stop the extra flow, forcing all the blood from the lungs to return directly to the left side. For most people, this change is smooth and the heart adjusts quickly. However, for a small number of patients, the left side of the heart may struggle to handle this sudden increase in volume, leading to a dangerous drop in pumping power.

This story follows a twelve-year-old girl who underwent surgery to close a large hole in her heart. Before the operation, her heart was functioning well enough, with the left side pumping normally despite the hole. The surgical team closed the defect completely using a patch made from cow tissue. Immediately after the heart was restarted, the girl's condition collapsed. Her heart stopped pumping effectively, and a valve that should have been tight began to leak severely. The surgeons faced a critical moment: the heart could not support the body without the machine that was circulating her blood. By using a specialized ultrasound camera inside the heart, they discovered the valve was structurally sound but failing because the heart was overwhelmed by pressure. They realized that closing the hole completely had been too much for her heart to handle at that moment.

To save the patient, the surgeons had to reverse their initial success. They reopened the chest, removed the cow patch, and replaced it with a patch made from the girl's own heart lining. Crucially, they did not seal this new patch completely. Instead, they cut a hole about ten millimeters wide in the center of the patch. This small opening allowed some blood to flow back to the right side of the heart, acting as a pressure release valve. This adjustment worked. The pressure in the left side of the heart dropped, the leaking valve stopped, and the heart began to pump strongly enough to sustain her life without the machine. The girl survived the surgery and left the hospital with a small, intentional hole remaining in her heart, allowing her heart to recover and adapt to the new flow conditions over time.

The case highlights a specific and rare complication where a heart that looks healthy on paper cannot tolerate the sudden change in blood flow caused by closing a large hole. The girl's heart had been dealing with a massive flow of blood for years, with a ratio of three parts of blood going to the lungs for every one part going to the body. When the hole was sealed, all that blood was forced into the left side at once. The left ventricle, which had been relatively empty, suddenly faced a volume it could not push out. This caused the pressure inside the heart to spike, which in turn distorted the shape of the heart muscle and pulled the mitral valve open, causing it to leak. The surgeons confirmed this was not a broken valve but a functional problem caused by the pressure, as the valve looked normal when they inspected it directly.

The solution required a shift in strategy from a complete fix to a controlled compromise. The team first tried a small five-millimeter opening in the cow patch, but it was not enough to relieve the pressure. Only when they enlarged the opening to ten millimeters using the girl's own tissue did the heart stabilize. This ten-millimeter gap allowed just enough blood to escape back to the right side to keep the left side from being overwhelmed, while still sending the majority of blood to the body. The use of the girl's own tissue for the patch was part of the procedure, but the key factor was the size of the opening, which was tailored specifically to her body's immediate reaction.

This event was captured in real-time using transesophageal echocardiography, a technique where an ultrasound probe is passed down the throat to get a clear view of the heart from the inside. This tool allowed the surgeons to see the heart's chambers, measure the pressure, and watch the valve move with every heartbeat. They saw the heart struggle when the hole was closed, and they saw it recover when the opening was created. The data showed that the left ventricle's pumping strength dropped from sixty percent to between twenty and twenty-five percent immediately after the closure, and the chamber enlarged significantly. After the rescue procedure, the pumping strength recovered to between thirty-five and forty percent, and the leaking valve became mild.

The paper concludes that while closing a large hole is usually safe, some hearts may need a period of adjustment. In this case, the surgeons learned that a complete seal was not the right answer for this specific patient at that specific time. The creation of a controlled leak, or fenestration, served as a safety valve. The authors note that the ten-millimeter size was a specific solution for this girl and should not be considered a standard size for everyone. The case demonstrates that when a heart fails to adapt to a sudden change in blood flow, the best course of action may be to provide a temporary escape route, allowing the heart to recover its strength before attempting a complete closure later. The girl's heart continued to heal, and by the time she left the hospital, the leak had improved, and her heart size had decreased, suggesting that the heart was beginning to adapt to its new reality.