Sudden Cardiac Death: Genetic Testing Unraveling the Mystery


BALTIMORE, Md. (Ivanhoe Newswire)— Sudden cardiac death is the biggest cause of cardiac death in the United States. While some people may have symptoms leading up to cardiac arrest, like a racing heart or dizziness, many have no symptoms at all. Now, scientists want to know how a person’s genetic makeup could provide an early warning for people at high risk.

When someone goes into sudden cardiac arrest, time becomes the enemy.

“Usually, it’s variable probably on the order of minutes, is all somebody has really to start getting CPR before the brain and other vital organs start to die, and it’s an irreversible process then,” Aloke Finn, MD, an interventional cardiologist at the University of Maryland School of Medicine, told Ivanhoe.

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And in almost half of all cardiac deaths, experts find no sign of heart disease. Now, Dr. Finn and his colleagues say they’ve pinpointed the cause for some unexplained deaths. Dr. Finn and his team performed genetic tests on 400 deceased patients, mostly in their forties, who died unexpectedly.

“What we can do is we can extract DNA from the organs of those people, and we can sequence that DNA for certain cardiac genes. We found about 20 percent of the people dying of so-called unexplained, sudden cardiac death carried pathologic, or pathologic mutations in certain cardiac genes, which suggest they had underlying undetected, cardiac disorder,” Dr. Finn shared.

Dr. Finn says the findings may open the door to important questions about the potential to save lives with genetic screening, especially for patients with a family history of sudden cardiac death.

Right now, there are no clear guidelines on screening and treating patients with the genetic mutations that might make them vulnerable to sudden cardiac death. Dr. Finn says more research is needed to address the health needs of these patients.

Contributors to this news report include: Cyndy McGrath, Producer; Kirk Manson, Videographer; Roque Correa, Editor.

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REPORT:       MB #4947

BACKGROUND: Sudden cardiac death (SCD) is a sudden, unexpected death caused by loss of heart function. SCD is the largest cause of natural death in the United States, causing about 325,000 adult deaths each year. SCD is responsible for half of all heart disease deaths and occurs most frequently in adults in their mid-30s to mid-40s. It does affect men twice as often as women, and is rare in children, affecting only 1 to 2 per 100,000 children each year. Most SCDs are caused by abnormal heart rhythms called arrhythmias. The most common life-threatening arrhythmia is ventricular fibrillation, which is an erratic, disorganized firing of impulses from the ventricles, or the heart’s lower chambers. When this occurs, the heart is unable to pump blood and death will occur within minutes if left untreated.


GENETICS AND SCD RISKS: A patient should be familiar with their medical past and family history. If there is a family member with arrhythmias, heart failure, or amyloidosis and connective tissue disorders, a medical evaluation and possibly an echocardiogram or a cardiac MRI to diagnose whether the patient shares this condition and would benefit from early treatment, may be needed. There can also be an elevated risk for cardiovascular disease if family members have diabetes, high blood pressure, or high cholesterol, which can have genetic predispositions. Lifestyle also plays an important role. If someone is overweight, smokes, has a nutrient-poor diet or doesn’t exercise, then no matter how good your family history is, these lifestyle factors will negatively impact health in the long run.


NEW RESEARCH TO PREVENT SCD: Assistant professor of biomedical sciences, Stephen Chelko, with Florida State University College of Medicine, has developed a better understanding of the pathological characteristics behind arrhythmogenic cardiomyopathy (ACM), a disease that leads to SCD. He has also discovered some promising avenues for prevention. Individuals with ACM possess a mutation causing arrhythmias, which ordinarily are non-fatal if managed and treated properly. Studies show that exercise in these individuals not only amplifies those arrhythmias but causes extensive cell death. Chelko says, “This novel study unravels a pathogenic role for exercise-induced, mitochondrial-mediated cell death in ACM hearts.” This finding opens avenues for the development of new therapeutic options to prevent myocyte cell death, cardiac dysfunction and pathological progression.






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Doctor Q and A

Read the entire Doctor Q&A for Aloke Finn, MD, Interventional Cardiologist

Read the entire Q&A