Sudden Cardiac Arrest - Is There Hope?
Aug 6, 2009 | The HWN Team | Insider
image by: freestocks.org
Sudden cardiac arrest mortality remains high even in the setting of bystander CPR and AEDs. Routine placement of AEDs in the homes of patients who are at risk for SCA may be worth it but we still have a long way to go!
On June 25, 2009, Michael Jackson, well-known as the King of Pop, died of cardiac arrest. Cardiovascular disease (CVD) is the leading cause of mortality in the U.S. and the majority of CVD deaths are attributable to Sudden Cardiac Arrest (SCA) which claims more than 250,000 lives each year. One person dies of SCA-related events every two minutes. This is equivalent to more 650 deaths each day. Each year, more people die from SCA than from breast cancer, lung cancer, stroke, or AIDS combined. SCA mortality is high. 95% of SCA cases are fatal. Two-thirds of SCA events occur in people without any previous indications of heart disease.
According to the American Heart Association (AHA) Sudden Cardiac Arrest occurs when electrical impulses in the heart become rapid or chaotic, which causes the heart to suddenly stop beating. Strictly speaking, SCA can be seen as a power failure of the heart. And as power failure goes, SCA occurs suddenly and without warning. The blood supply to the rest of the body ceases and without the blood supply, the oxygen supply is also cut off, resulting in tissue damage and death. Because of its suddenness, cardiac arrest is also called sudden death or sudden cardiac arrest (SCA) or sudden cardiac death.
Cardiac arrest is not a heart attack. It is a widespread misconception that SCA is synonymous to a heart attack. In order to educate the public, the AHA and the Sudden Cardiac Arrest Coalition (SCAC) are quick to point out the difference. A heart attack or myocardial infarction occurs when the arterial supply or coronary arteries are compromised or blocked, thus cutting off the blood supply to the heart. And if allowed to continue will eventually lead to infarction or injury to the heart muscles. "The term "massive heart attack" is often wrongly used in the media to describe sudden death." The SCAC has a beautiful analogy to explain to the general public: "If you think of your heart as a house – SCA would be a problem with the electricity; a heart attack would be a problem with the plumbing."
Cardiac arrest is not heart failure. In the same way, cardiac arrest is not the same as heart failure. Heart failure is a long-term condition wherein the heart weakens over time, cannot keep with the workload of pumping blood, and fails. In cardiac arrest the electrical failure of the heart is sudden and unexpected, whereas heart failure is progressive but slow, thus allowing time for heart failure patients to eventually be considered as possible heart transplant candidates.
Every one can suffer from SCA but some people are more at risk than others.
- Gender and age. SCA deaths are more common among women aged 35 to 44 years old compared to men of the same age. Women have also a less chance of recovering from SCA than men.
- Race and ethnicity. African Americans have a much higher risk to suffer from SCA-related events than whites and other ethnic groups. They also have less than a 1% chance of surviving, much lower compared to the 5% survival chance in the general population.
- Underlying conditions. Some underlying conditions especially heart problems make people more susceptible to SCA than others. Yet, even healthy individuals without any health problems may suffer from SCA.
What can cause cardiac arrest? There many things that can cause the heart to stop abruptly. The electrical system of the heart regulates the rate and rhythm of the heart beat. From time to time, the electrical system gets disrupted, causing abnormal rhythms called arrhythmias.Most of the cardiac arrests that lead to sudden death occur when the electrical impulses in the diseased heart become rapid (ventricular tachycardia) or chaotic (ventricular fibrillation) or both. This irregular heart rhythm (arrhythmia) causes the heart to suddenly stop beating. Some cardiac arrests are due to extreme slowing of the heart. This is called bradycardia.
So what causes the electrical system of the heart to fail?
Cardiovascular disease. People with cardiovascular problems have a high risk of SCA. According to the AHA, in 90% of adult victims of sudden cardiac death, two or more major coronary arteries are narrowed by fatty buildups. Scarring from a prior heart attack is found in two-thirds of victims.
Electric shock/electrocution. A strong electric shock, e.g. electrocution and lighting strikes can cause the heart to stop. Conversely, it also takes an electric shock to restart the heart.
Respiratory arrest. When people cannot breathe during to choking, suffocation, drowning, or injury, SCA can also occur.
Strenuous physical activity. There are cases of athletes suddenly collapsing during training or competitions. This may be caused by underlying heart abnormalities. Adrenaline released during intense physical activity acts as a triggering mechanism for arrhythmia and sudden death.
Medications. Certain drugs, prescription or illegal, can interfere with heart rhythms. When taken in excessive amounts, certain medications can completely stop the heart, resulting in SCA. Some of these drugs are performance-enhancing drugs used in sports, prescription drugs for heart problems, pain, and sleeping disorders especially insomnia and illegal and "recreation" drugs.
Trauma. Certain injuries can cause SCA. A strong sudden blow to the heart during sports competition for example, can cause a condition called Commotio cordis that can trigger ventricular fibrillation and lead to SCA. An injury that damages the heart can also lead to cardiac arrest.
Unknown causes. Unfortunately, a lot of cases of SCA are put down to unknown causes, often in young, healthy people with no apparent heart disease or other risk factors.
How can death from SCA be prevented? Not easy, in fact, 95% of SCA cases are fatal. To have a chance of surviving, victims of SCA must receive life-saving defibrillation within the first 4 to 6 minutes of an attack, when brain and organ damage start to occur. Some studies suggest that the survival rate for SCA can increase up to 90% when electroshock is delivered within a very short period after an SCA attack. Following are ways to restart the heart during SCA:
1. Defibrillators. These are the so-called paddles applied to the chest to deliver an electric shock to make the heart beat again. Defibrillators are only available in emergency services and hospitals and can only be operated by medical professionals.
2. Automatic External Defibrillators (AEDs) are battery-operated portable defibrillators that can be used to deliver a life-saving electric shock. Current AEDs are designed to be operable by almost anybody, even without formal medical training. As soon as it is activated, visual and audio cues give the operator instructions on how to operate. AEDs are now widely available in public places where crowds tend to gather, e.g. sports events, concerts, etc. The article AEDs - Truth or Fiction? examines this issue in detail.
3. Implantable Cardioverter Defibrillators (ICDs) are implanted in patients who have a high risk for cardiac arrest from recurrent, sustained ventricular tachycardia or fibrillation. An ICD automatically reacts to irregular rhythms of the heart and applies an electrical jolt to restore normal heart rhythms. According to the SCAC, ICDs are 98% effective at protecting those at risk for SCA, but only 35 percent of patients who require this device have one. However, there have been cost-benefit issues regarding ICDs. According to a New York Times article "in the last two years the number of patients receiving defibrillators has actually declined, as more doctors and patients decide the risks and uncertainties the devices pose may outweigh their potential benefits." More recently, the European Society of Cardiology (ESC) issued a statement on driving restrictions for patients implanted with ICDs.
4. Cardiopulmonary resuscitation (CPR) works by attempting to maintain the blood flow to the heart and the brain until more effective defibrillation can be performed. About 80% of SCA cases happen at home, just like in the case of Michael Jackson. Therefore, CPR needs to be performed by bystanders, family members, and people, even without medical training. Unfortunately, only a third of out-of-hospital SCA victims receive bystander CPR and many SCA victims die before the arrival of emergency services. Immediate effective bystander CPR can double or even triple a victim's dismal survival chances. A 2008 online survey by the AHA revealed that 80% of respondents said they were willing and able to do something to help if they witnessed a medical emergency. At most, roughly four in ten are extremely or very likely to perform CPR on an adult (39%) or child (37%) they know personally. However, only a few (12%-20%) are confident that they would know when it is appropriate to perform CPR or use an AED.
So, what could have caused Michael Jackson's cardiac arrest? As expected in such a high profile case, rumors, theories and speculations still abound. Some of the possible causes based on Jackson's personal and medical history (Source: heartwire) include:
Overdose of prescription medications. Expectedly this is the most popular theory but without a toxicology report, this remains speculative. It seems that Jackson was on prescription painkillers and two that may possibly be implicated in his death are Demerol (meperidine) and Oxycontin (oxycodone). Dr Douglas Zipes of Indiana University Medical School, Indianapolis tells heartwire: "It's really where I would go, but it's all very speculative at this point. We know that depending on the type of painkillers, they can depress respiration. The initial stories are that he gradually slowed his respiratory rate and stopped breathing. That can create hypoxia, which can produce ventricular fibrillation." The use of Diprivan for his insomnia has also been implicated. Without an official toxicology report, all these however, remain as speculations.
Complications from lupus. It is not a well-known fact, but Jackson seemed to have been suffering from lupus, an inflammatory disease that can also affect the heart and lead to a heart block.
Other heart diseases. A heart attack has also been speculated but the singer did not have a history of heart disease and no other heart conditions were detected during the most recent routine physical exam.
Stress. It cannot be denied that Jackson was under too much stress. He was having major financial problems and he was busy preparing for an international concert tour about to start in two weeks. The tour was critical because it would have allegedly saved him from financial ruin.
It is without doubt that SCA is a major and deadly health concern. Advocacy groups including the American Heart Association and the Sudden Cardiac Arrest Coalition composed of at least 30 health organizations are actively involved in bringing this issue to the forefront. There are even those who advocate the routine placement of AEDs in the homes of patients who are at high risk for SCA. Yet SCA mortality remains high even in the setting of bystander CPR and AEDs. WE have a long way to go!
- American Heart Association.American Heart Association Survey Reveals Americans Lack Confidence in Lifesaving Skills for Common Cardiac Emergency
- American Heart Association. National CPR/AED Awareness Week Fact Sheet
- American Heart Association. Sudden Cardiac Death.
- Brady GH et al., Amiodarone or an Implantable Cardioverter–Defibrillator for Congestive Heart Failure. New England Journal of Medicine. Volume 352:225-237 January 20, 2005
- CBSNews. Jackson's Heart OK, Doc's Lawyer Says.June 29,2009.
- Elber, A. AP Source: Jackson suffered a heart attack. Associated Press, June 26, 2009.
- Feder BJ. Defibrillators Are Lifesaver, but Risks Give Pause. The New York Times September 12, 2008
- O'Riordan M. Mainly medical unknowns regarding Michael Jackson's apparent cardiac arrest. June 29, 2009. heartwire.
- Stiles S. ESC issues statement on driving restrictions for ICD patients. June 22, 2009. heartwire.
- Sudden Cardiac Arrest Coalition. Cardiac Arrest Fast Facts and Sudden Cardiac Arrest Foundation. SCA and Heart Attack: Understanding the Difference.
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