Nutritional Status Trajectory in Children and Adolescents With Repaired Tetralogy of Fallot: A Retrospective Longitudinal Cohort Study From a Latin American Tertiary Center

The Heart's Long Journey: Why a Growing Body Matters for a Repaired Heart

Imagine your heart as the engine of a high-performance car. For most of us, this engine runs smoothly from the day we're born. But for some children, the engine is built with a few extra parts missing or a few pipes connected in the wrong way. This is called a congenital heart defect. One of the most common of these is a condition called Tetralogy of Fallot (ToF). Think of it as a car with a clogged exhaust pipe and a leaky valve. Fortunately, modern medicine has become incredibly good at fixing these engines. Surgeons can perform "repairs" that patch the holes and clear the pipes, allowing these children to grow up and live long, active lives.

However, just because the engine is fixed doesn't mean the car is immune to other problems. As these children grow into teenagers and young adults, they face a new challenge: their bodies are getting bigger, and sometimes, they are getting heavier. In the world of nutrition, we use a special ruler called a "Z-score" to measure if a child is growing at the right speed for their height. If the number goes up too fast, it means they are gaining excess weight. Why does this matter for a repaired heart? Because a heavier body is like adding a heavy trailer to that car. It forces the engine to work harder, pumping more blood to move the extra weight. For a heart that has already been through surgery and scarring, this extra workload can be dangerous over time, potentially leading to wear and tear or even heart failure later in life. So, the big question for doctors is: Are these kids gaining weight at the same rate as everyone else, or is their unique history changing how their bodies grow?

The Study: Tracking the Growth of 70 Young Hearts

This study, conducted by a team of researchers in Chile, decided to play detective with the growth charts of 70 children and teenagers who had successfully repaired Tetralogy of Fallot. They looked back at medical records from 2015 to 2024, tracking these patients as they aged from about 5 years old up to 18. The researchers wanted to see if the "growth engine" of these kids was running differently than the general population.

The Big Surprise: Less Weight, But a Faster Climb
When the researchers checked the final numbers, they found something interesting. At the end of the study, about 31.4% of these children had excess weight (which includes being overweight or obese). This is actually lower than the national average for Chilean kids, where over half (51.4%) are carrying extra weight. So, in a way, these heart patients were "lighter" than their neighbors.

However, the story changes when you look at the journey rather than just the destination. Even though they started out lighter, their weight was climbing faster than expected. The researchers measured the "Z-score" (that special ruler for growth) and found it went up significantly. It started at an average of -0.09 and rose to 0.31 by the end of the follow-up period. To put it simply: while they weren't the heaviest kids in the room, they were gaining weight at a rapid pace. In fact, about 12.9% of the kids who started out with a healthy weight or were even a bit underweight ended up with excess weight by the time the study finished.

Who Was Gaining the Most?
The team also looked to see if the type of heart repair or the specific heart anatomy made a difference. They found that kids with the most complex heart defects—specifically those with a condition called pulmonary atresia with major aortopulmonary collateral arteries (PA-MAPCAs)—started out with lower weight scores. This makes sense, as these kids often have more surgeries and longer hospital stays, which can stunt growth. But here is the twist: the group that needed the most complex repairs was the one that showed the biggest jump in weight over time. It's as if their bodies, after surviving a tough battle, were suddenly trying to catch up and grow very quickly.

The Heart's Reaction (Or Lack Thereof)
The researchers also checked the hearts themselves using ultrasound images (echocardiograms) to see if this weight gain was already causing damage. Surprisingly, the heart sizes and pumping strength looked stable and normal throughout the study. The heart didn't seem to be struggling yet. However, the authors warn us not to get too comfortable. They suggest that standard heart measurements might be hiding the truth. Because these kids are getting heavier, their bodies are bigger, and the math used to measure the heart might be "normalizing" the numbers, making a slightly enlarged heart look normal when it's actually working too hard. The heart might be quietly straining under the weight, even if the pictures look okay for now.

What This Means for the Future
The main takeaway from this paper is a call to action. Even though these children have lower rates of obesity than the general public, their weight is creeping up in a way that worries the doctors. The authors suggest that we shouldn't just wait for these kids to become obese before we act. Instead, doctors should be watching their growth trajectories closely, like a mechanic watching a speedometer. If a child's weight is climbing too fast, they might need help with nutrition and exercise before the extra weight starts to damage the repaired heart.

The study doesn't prove that weight gain will break the heart in these specific kids, but it strongly suggests that the risk is real and growing. It highlights the need for a team approach—where heart doctors and nutritionists work together—to keep these young hearts running smoothly as their bodies change. The goal is to catch the problem early, before the "trailer" gets too heavy for the engine to handle.