The tragic death of Jaco van Zyl, 15, who had taken part in a major cycling event in Port Elizabeth barely 24 hours before, has once again focused the public's attention on the issue of sudden cardiac death. What are the causes, and who is at risk? What, if anything, can be done to prevent this?
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"What makes sudden cardiac death so frightening is that those who die in this way appear to be very healthy and have often experienced no sign of preceding heart problems," says Dr Andrzej Okreglicki, cardiologist at Groote Schuur Hospital.
It is often intense activity, such as a sports match, that brings on this attack And, yes, someone can be resuscitated after having suffered what is known as “sudden cardiac death”, says Dr Okreglicki.
What is sudden cardiac death?
Sudden cardiac death (also called sudden arrest) is an umbrella term for many different causes of cardiac arrest in young people. It is defined as an event resulting from an abrupt loss of heart function. The time and mode of death are unexpected and not due to violence or trauma. If death occurs within six hours in a young person who has not had any sign of heart problems, it is classified as sudden cardiac death. In many cases death occurs within minutes after the symptoms appear.
According to rough estimates, sudden cardiac death claims the lives of as many as 2000 young South Africans per year who are seemingly healthy, shows no signs of heart disease and who are unaware that they indeed have an existing heart condition.
Possible causes
The most common underlying cause (in about 90 percent of cases) of sudden cardiac arrest in all people ranging from 4 to 64 years of age is coronary artery disease.
However, in young adults, other heart abnormalities are more likely to be the cause of sudden cardiac death. Conditions which if undetected, can lead to sudden cardiac death, include ion channelopathies (such as long QT, Brugada and Lev-Lenegre’s syndromes), hypertrophic cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy, myocarditis, coronary artery disease, Wolff Parkinson White syndrome, coronary artery anomalies, Marfan syndrome, restrictive cardiomyopathy, endocardial firboelastosis and tachycardia.
Although all these conditions can lead to sudden cardiac death, most cardiac arrests in young people are due to electrical and conduction problems affecting the heart rhythm or thickening of the heart muscle (hypertrophic cardiomyopathy).
Electrical and conduction problems (such as ion channelopathies) may be inheritable and may lead to irregularities in electrical impulses. The impulse may then become too rapid (tachycardia), too chaotic (ventricular fibrillation) or both. These irregular heart rhythms (arrhythmia) may cause the heart to abruptly stop beating. An extremely slow heart beat (bradycardia) may also cause sudden cardiac arrest.
Hypertrophic cardiomyopathy is also a rare genetic condition. It involves disproportionate heart muscle enlargement compared with little or no chamber enlargement. This leads to an enlarged heart that resists normal filling with blood. Some people with this condition also develop abnormal pressure differences within the heart.
Often, the increase in adrenaline levels during intense physical activity act as a trigger for sudden cardiac death in the presence of existing heart abnormalities.
The incorrect use of some heart medications (such as some antiarrhythmics, antihypertensives, antihistamines, antidepressants and antibiotics), as well as drug abuse, may also lead to abnormal heart rhythms and sudden death.
The symptoms
It is important to note that almost all these heart conditions may be free of any symptoms, and may go undetected for years, or till a relative suddenly collapses and dies. In the case of electrical and conduction problems, affected children and young adults may suffer unexplained black outs, but appear otherwise healthy.
Other, similarly unexplained symptoms may include muscle weakness and congenital deafness.
Who is at risk?
Since it may be inheritable, all the relatives of the victim may also be at risk of sudden cardiac death. It is essential to evaluate family members to detect an underlying treatable condition as early as possible.
Tests such as a scan or a genetic test could indicate whether a family member is at risk. Since children often don't develop this condition until they are nine or 10 years old, they may need to be retested at a later stage if they tested negative at a young age.
Both men and women can be affected, but young men seem to have a higher risk of death resulting from the thickening of the heart muscle.
Can sudden cardiac death be prevented?
If you act very quickly and can get the victim’s heart beating again within four to six minutes after arrest, before brain death sets in, you may save his/her life. Normal heart beat must be restored with an electrical shock (with the use of a defibrillator) or with cardiopulmonary resuscitation (CPR). A victim’s chances of survival are reduced by seven to 10 percent with every minute that passes without the heart beating.
Particularly patients with hypertrophic cardiomyopathy, have no symptoms that could alert bystanders to the presence of heart problems and therefore to quick action.
Defibrillators (at a cost of R25 000) are found more and more frequently at gyms and airports, and sometimes other public places. If defibrillators were present at sports grounds, they could have saved the lives of athletes who suddenly collapsed, says Dr Okreglicki.
As soon as a heart condition is diagnosed, a doctor and pharmacist may inform the patient exactly which medications to avoid. - (Health24)
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