May 23, 2011

Sudden Killer
By Kim M. Norton
For The Record
Vol. 23 No. 10 P. 24

The genetic disorder hypertrophic cardiomyopathy takes the lives of young and old alike with little or no warning.

It seems as if at least once per month, a headline appears announcing the death of a young, otherwise healthy adult who suddenly collapsed and died following physical exercise. The media plays on the connection between hypertrophic cardiomyopathy (HCM) and young athletes, but making that connection is fallacious, according to experts who say anyone with the gene may be at risk.

What is probably most frightening about this genetic condition is that sudden death is the primary symptom, meaning if a child has HCM, a parent also possesses the gene and that puts him or her at risk for sudden death. Each year, approximately 1,300 to 1,500 people die from HCM, with 50% of those under the age of 54.

“The idea that HCM only affects young athletes is a bit of a fallacy portrayed in the media,” notes Lisa Salberg, founder and CEO of the Hypertrophic Cardiomyopathy Association (HCMA). “A basketball star collapsing after a game grabs headlines; the kid playing Xbox or the kid getting out of his car are not nearly as exciting.”

Roughly 600,000 people in the United States live with the condition, but only a small percentage of those are clinically recognized, says Robert Sorrentino, MD, director of Arrhythmia Services at Georgia Health Sciences University in Augusta. “Anticipating the risk in a population that is asymptomatic and is otherwise healthy is challenging. Even when children are screened before starting sports, they are still dying,” he says.

A Big Heart
The culprit behind HCM is the abnormal thickening of the heart muscle, causing the organ to become enlarged and preventing it from functioning properly. This thickening can cause blood flow obstruction to the point that the heart must work harder to pump blood. Electrical instability is also a possibility.

Either the obstruction of blood flow, which typically worsens with physical exertion, or the electrical instability can put a person with HCM at risk of sudden cardiac arrest, where the heart suddenly quivers then stops. There is no cure for HCM, but there are treatment options, including medication, surgery to remove an obstruction, and the insertion of an implantable cardioverter defibrillator (ICD).

“Once we can identify the gene for HCM in a particular family, it is easier to screen other family members. But genetic testing is not yet a secure means of diagnosing HCM because we are still learning about the disorder and it is not always familial,” says Sorrentino. And in some cases, HCM results from a genetic mutation that occurs when an egg is fertilized.

The best way to identify those who may have HCM is to focus on factors that can put a person at greater risk of sudden cardiac arrest. “With patients presenting anywhere from birth to age 90, evaluating a person’s risk of sudden cardiac death is our only means of early identification and treatment,” explains Salberg.

Risk Factors
Since it is financially unfeasible to screen each person for HCM with an electrocardiogram (EKG), many healthcare professionals opt for a paper survey to determine who may be at risk of sudden cardiac arrest. There are risk factors to identify those at the greatest risk of sudden cardiac arrest, including the following:

• a family history of sudden, unexplained death before the age of 50;

• a previous episode of cardiac arrest;

• previous episodes of identified ventricular tachycardia;

• unexplained, recent syncope;

• heart muscle that is thicker than 30 mm;

• an abnormal response to exercise, including a fall in blood pressure; and

• multiple nonsustained tachycardia events detected on an EKG Holter monitor.

“HCM plus any one of these risk factors puts a person at a high risk of sudden cardiac arrest, but more than one indicates an even higher risk of a cardiac event,” says Sorrentino, adding that patients who have survived a cardiac arrest event or are known to have episodes of ventricular tachycardia should strongly consider an ICD.

Another treatment option is pharmacologic intervention. “However, putting a patient with high blood pressure and HCM on a beta blocker does not reduce their risk of sudden death as effectively as an ICD,” Sorrentino says.

Another less common form of the condition is obstructive HCM, where the wall between the two ventricles of the heart become enlarged, obstructing blood flow. Under these circumstances, the obstruction can be surgically removed and the symptoms relieved, though the patient will still have HCM, explains Salberg.

Difficulties in Screening
Despite calls for more screening, Sorrentino says HCM’s nature does not lend itself to the process. “We all know what to do in a lightning storm yet with all these precautions in place, people still get struck by lightning. As unfortunate as HCM is, it is not unlike a lighting strike,” he explains.

Medical researchers have yet to develop an easily implemented tool to detect HCM before it leads to tragedy. “[HCM] is not so easily detectable on a mass scale,” says Sorrentino. Although one in 500 may have HCM, it may be one in 1,000 who has clinically significant risk factors that require intervention, he adds.

In the wake of a recent string of HCM-related deaths of young athletes, some well-intentioned people have suggested that everyone should have an EKG to rule out the disorder. But as mentioned previously, such a strategy is not economically practical. The cost would be exorbitant to screen every person for HCM when such a small percentage would have risk factors, explains Salberg.

Student athletes must undergo a complete physical before taking the field, but there is a chance someone could receive a clean bill of health despite having HCM, says Salberg. “We need to ask if there is a family history of sudden death and if there was, we need to look into the details,” she says.

Sorrentino says some schools and communities have begun offering mass screenings to increase awareness about sudden cardiac death. Unfortunately, he says, there are drawbacks to this approach, including possible privacy issues, potentially tragic false-positive results, and psychological issues that go along with a life-changing diagnosis. “Oftentimes, these screenings will use quick-screen echocardiograms, but there is no clear data that supports that quick-screen echos can identify HCM, and 20% of kids who have HCM have completely normal EKGs,” says Salberg.

HIPAA also has a direct bearing on cases involving student athletes. “This becomes an especially sensitive topic under HIPAA,” Sorrentino says. “We need the patient’s permission to disclose personal health information and if the student is not giving us that permission, we are unable to share the information with the school which can lead to a tragic death.”

An ICD’s Far-Ranging Effects
An ICD is the best treatment option for a patient with the greatest risk of sudden cardiac arrest. The ICD has either one or two wires attached directly to one or more chambers of the heart. The wires carry electrical impulses from the heart to a computer in the ICD that monitors heart rhythm. If the ICD detects an abnormally fast rhythm, a low-energy electrical impulse is sent to restore the heart’s normal rhythm, according to the National Heart, Lung, and Blood Institute website.

If a patient is a candidate for an ICD, counseling is imperative. “If the patient is an adult, the ICD implantation can be life changing, and there are many factors to consider,” says Sorrentino, adding that ICD implant surgery itself carries risks, including the device itself.

An ICD is battery powered, with battery life ranging between five and seven years. Along with the battery, the leads, or wiring, also need to be replaced, typically between 10 and 20 years after installation. According to Sorrentino, other concerns include the risk of device recalls and the use of inappropriate therapies in which the patient may receive shocks for nonlethal events.

“The decision to implant an ICD in an adult is one thing but for kids, the decision is much more challenging,” says Sorrentino. While adults may be able to handle lifestyle changes, children typically have a more difficult time making the adjustment. For college-age students, the addition of an ICD can be devastating, especially if the patient is a student athlete on scholarship. In these cases, a diagnosis of HCM, even if it’s accompanied by the installation of an ICD, may preclude the patient from participating in sports, Sorrentino says.

HCM Awareness
In its bid to raise awareness about HCM and its risk factors, the HCMA has proposed a plan in which a sudden cardiac arrest risk assessment form is distributed to students three times during their educational careers.

“These screeners [forms] will follow the same 12-point questionnaire that athletes are required to complete before participating in a sport,” says Salberg. The forms would be sent home with students in second, eighth, and 10th grades to be completed by the parents. If any boxes are marked yes or unsure, the parent takes the form to the child’s physician to request a consult with a cardiologist for a more complete evaluation.

In taking this cautionary step, families can learn whether any members may have HCM or another condition that cause sudden cardiac arrest in the young and what are the best therapies to prevent a tragedy from occurring.

As HCM awareness has increased, there has been a corresponding jump in the number of specialty practices across the country. When Salberg founded the HCMA in 1996, there were only three programs that provided specialized care for HCM. That number has now grown to 28.

— Kim M. Norton is a New Jersey-based freelance writer specializing in healthcare-related topics for various trade and consumer publications.