Novel blood test predicts sudden death risk patients who would benefit from ICDs

August 27, 2012

A novel blood test that predicts sudden death risk in heart failure patients is set to help physicians decide which patients would benefit from implantable cardioverter defibrillators (ICDs). The findings were presented at the ESC Congress 2012 today, August 26, by Professor Samuel Dudley from Chicago, IL, US.

Approximately 5 million patients in the US have heart failure, a condition where the heart is unable to pump blood adequately, and nearly 550,000 people are diagnosed annually. Heart failure is the single most common cause of admission to hospitals in the US.

ICDs, which are devices similar to , can monitor and treat abnormal heartbeats and are surgically implanted in patients with severe heart failure to prevent . "The problem is that more than half of the patients who get them don't need them, and nearly half of the patients who would benefit don't get one," said Professor Dudley, who is professor of medicine and physiology at the University of Illinois at Chicago College of Medicine and principle investigator of the study.

The clinical trial presented at the ESC Congress 2012 showed that a blood test can predict which patients will need a in the next year. The test, called PulsePredic, discriminates with high predictive power who will or will not need an ICD to prevent abnormal heartbeats and subsequent sudden death.

The simple identifies changes in the gene message () for the SCN5A gene, which is known to be involved in sudden death. The increase in the changed gene message was able to predict who would have a sudden death episode requiring defibrillation. "The test predicts whether you will have sudden death from heart failure and whether you will need a defibrillator in the next year," said Professor Dudley.

The SCN5A gene encodes for proteins, called voltage-gated , responsible for generating the main current for in the heart. Alterations in the sodium current, either up or down, lead to arrhythmias.

Professor Dudley and his team evaluated the new blood test in 180 adult patients, including 135 patients with heart failure and 45 patients without heart failure as controls. Patients with congenital heart disease, infections, and inflammatory conditions were excluded.

The SCN5A gene was measured in heart muscle cells and white blood cells. The changes in the gene message were able to predict who would have a sudden death episode requiring defibrillation. who had abnormal heartbeats that would normally cause sudden death had significantly higher levels of these gene variants compared to patients who did not have abnormal heartbeats. The amount of variants in the blood had excellent predictive power to determine arrhythmic risk, suggesting that a for sudden and the need for an ICD is possible.

Figure 1 shows the distributions of the C type SCN5A variant (VC) in controls, patients with (HF) and no sudden death (i.e. no ICD shocks), and patients with HF and a sudden death episode (i.e. with ICD shocks). The separation of the distributions of patients with and without a sudden death episode allows for a discriminatory test.

Figure 2 is a receiver operating characteristic (ROC) curve which shows that the discriminatory power of the C or D type variants of SCN5A as measured by the area under the curve are equivalent and much higher than an ejection fraction of less than or equal to 20%.

"This is the first test of its kind," said Professor Dudley. "It is amazing stuff, with promise to change dramatically the way we direct treatments to patients at risk for sudden death."

The next steps in the development of the test will be to carry out a larger trial and work with regulatory agencies to receive approval for clinical use.

Explore further: Gene variant may predict sudden cardiac death risk for blacks

Related Stories

Gene variant may predict sudden cardiac death risk for blacks

May 11, 2011
(Medical Xpress) -- Researchers at Duke University Medical Center have pinpointed a common gene variant in blacks that may be associated with the development of life-threatening heart arrhythmias. The finding may help determine ...

Wearable defibrillator can prevent death in people with arrhythmias

November 13, 2011
A wearable defibrillator can prevent sudden death in people with dangerous heart arrhythmias, according to research presented at the American Heart Association's Scientific Sessions 2011.

Recommended for you

How genes and environment interact to raise risk of congenital heart defects

October 19, 2017
Infants of mothers with diabetes have a three- to five-fold increased risk of congenital heart defects. Such developmental defects are likely caused by a combination of genetic and environmental factors. However, the molecular ...

Mouse studies shed light on how protein controls heart failure

October 18, 2017
A new study on two specially bred strains of mice has illuminated how abnormal addition of the chemical phosphate to a specific heart muscle protein may sabotage the way the protein behaves in a cell, and may damage the way ...

Newborns with trisomy 13 or 18 benefit from heart surgery, study finds

October 18, 2017
Heart surgery significantly decreases in-hospital mortality among infants with either of two genetic disorders that cause severe physical and intellectual disabilities, according to a new study by a researcher at the Stanford ...

Saving hearts after heart attacks: Overexpression of a gene enhances repair of dead muscle

October 17, 2017
University of Alabama at Birmingham biomedical engineers report a significant advance in efforts to repair a damaged heart after a heart attack, using grafted heart-muscle cells to create a repair patch. The key was overexpressing ...

Physically active white men at high risk for plaque buildup in arteries

October 17, 2017
White men who exercise at high levels are 86 percent more likely than people who exercise at low levels to experience a buildup of plaque in the heart arteries by middle age, a new study suggests.

High blood pressure linked to common heart valve disorder

October 17, 2017
For the first time, a strong link has been established between high blood pressure and the most common heart valve disorder in high-income countries, by new research from The George Institute for Global Health at the University ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.