Brugada syndrome

Definitions & Key takeaways

Brugada syndrome is a potentially life-threatening condition that can cause sudden cardiac death. The condition is characterized by abnormal heart rhythms (arrhythmias) on ECG and a predisposition to developing ventricular fibrillation, a particularly dangerous type of arrhythmia. People with Brugada syndrome often have no symptoms, making the condition difficult to diagnose. However, in some cases, people with the condition may experience episodes of palpitations, fatigue, and shortness of breath.

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Introduction0:00–0:28

Brugada syndrome is named after two Spanish brothers, Pedro and Joseph Brugada who recognized a specific pattern of ventricular fibrillation on the electrocardiogram or ecg of previously healthy individuals who had a sudden death.
They identified this as Ricardo Syndrome and found that some cases could be traced back to a specific genetic cause. Many individuals with Brugada syndrome don't have an identifiable genetic cause.

Pathophysiology0:28–1:43

But in some individuals, there is one, the most well known cause is a mutation in the gene S CN five A. The SE N five A mutation is inherited in an autosomal dominant pattern, meaning a single mutation is enough to cause the disease.
The gene codes for sodium ion channels in the cell membranes of cardiac muscle cells and a faulty sodium ion channel affects the heart cell's ability to conduct an action potential.
So the mutation results in some regions of the heart having abnormal repolarisation. In some cases, the heart might have a normal rhythm but then develop a Brugada Syndrome rhythm in the presence of certain medications like sodium channel blockers.
On an electrocardiogram. Brugada syndrome typically has SS T elevations which are often a sign of ventricular strain as well as right bundle branch block, which indicates that the ventricles aren't depolarizing normally.
As a result, these regions become susceptible to a reentrant loop, which is when depolarization signals start going around and around in a loop, causing a ventricular tachycardia and sometimes ventricular fibrillation, ventricular fibrillation, sometimes called VFIB means that the heart's muscle fibers start quivering because they're not contracting at the same time.

Complications1:43–2:43

Normally, an electrical signal spreads fast enough so that all of the muscle fibers in the ventricles contract almost at the same time, which essentially looks like a single coordinated contraction.
If they don't all contract at the same time, not much gets accomplished. It's kind of like a rowboat.
It works best when everyone rows at the same time. Right.
Well, with VFIB, all of the rows, stop rowing together and just row whenever they want. And a rowboat just moves in circles and eventually sinks just like the robot.
If the heart's not squeezing anymore. And it's just squirming around like a bag of worms, which is actually used to describe what it looks like.
Then you can probably guess that this situation is extremely dangerous since your body and especially your brain isn't getting fresh oxygen, meaning ventricular fibrillation can lead to death within minutes of onset and this is called sudden cardiac death.

Symptoms and treatment2:43–3:14

Individuals with Brugada syndrome are usually healthy and then die suddenly. In some cases, individuals survive their first episode of an arrhythmia which might cause palpitations shortness of breath and fatigue and then they're diagnosed other times, family members of somebody that dies, get diagnosed with a genetic test.
Individuals with Brugada syndrome can have a cardiac defibrillator implanted so that it can take over in case they develop a ventricular fibrillation.
All right. As a quick recap, Brugada syndrome is usually identified based on an ECG tracing and is a cause of sudden cardiac death.

Review3:14–3:43

Some cases have been linked to a gene mutation in SCN five A which encodes a sodium channel found on cardiac muscle cells.
Ultimately, Brugada syndrome can lead to ventricular fibrillation, which is when the ventricles contract in an uncoordinated way.
And in some cases, a defibrillator is implanted to prevent sudden cardiac death.