Rogue Gene Causes Sudden Cardiac Death

Researchers at Baylor College of Medicine (BCM) and Texas Children’s Hospital in Houston have discovered a genetic link to sudden cardiac death. The researchers found that a malfunctioning gene causes an electrical imbalance which in turn triggers a heart rhythm disorder which can be fatal.

The heart contracts due to electrical impulses that originate in the top of the right atrium and then travel through the muscle fibers. When these electrical impulses are disrupted it leads to cardiac arrest. However the genetic and molecular basis of this condition is not fully understood.

When the study investigators discovered a gene called Caveolin-3, they took the first step towards unraveling the secret behind sudden cardiac death. Caveolin-3 is believed to influence the electrical-muscular impulses that drive the heart’s rhythm. When this gene mutates, it can trigger long QT syndrome related arrhythmia.

This is a hereditary disorder that can occur even in healthy people and at any age. It is also responsible for increasing the risk of sudden cardiac disorder. The effect of the mutation might be multiplied due to medications for certain other conditions like asthma and lead to increased risk of cardiac arrhythmia.

“This is part of a totally new concept in which the structural part of the heart is intertwined and connected with the electrical part,” said first author Dr. Matteo Vatta, Assistant Professor of Pediatrics at BCM and pediatric cardiac researcher at Texas Children’s Hospital. “This is the missing link between the heart’s electrical and muscular activities.”

Conventionally, long QT syndrome has been treated by targeting ion channels or proteins governing the membrane structure. Proteins that regular the heart’s electrical impulses via these channels have never been taken into account.

Caveolin-3 is known to regulate the cardiac sodium channel which is an important protein for the heart. In response to even minor fluctuations in the electrical field, it can bring about rapid changes in the structure of the heart. Caveolin-3 can also get disrupted by heart muscle disease.

Cardiomyopathies – muscle diseases of the heart cause more than 300,000 cases of sudden cardiac death in the United States alone each year. If muscle disease is discounted as a reason for sudden cardiac death, the only other leading cause is electrical abnormality.

“Many people that have arrhythmia abnormalities take medications that do not work,” said Dr. Vatta. “Perhaps they should target the other proteins that are modulating the ion channels rather than the ion channel itself.” The results of Dr. Vatta and his team’s research have been published in the journal Circulation.

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