Sudden cardiac death


What is Sudden Cardiac Death?

Sudden Cardiac Death (SCD) is a swift and unexpected death caused by a heart condition or mechanism, which may or may not be obvious. SCD varies in its range of definition. Usually, though, it applies to a situation where the person, who was thought to be free of heart disease, or only had a “mild” heart disease, suddenly died.

What causes these sudden deaths?

In the age range between 40 and older, the vast majority is due to coronary artery disease (heart “attacks”). In 20 percent (one out of five) of those who develop symptoms of coronary artery disease, and even among those with advanced coronary artery disease, the first symptom of the disease is sudden death. In those younger than forty years old, including teenagers, sudden death from “no apparent reason” is usually due to fatal ventricular arrythmia (heart irregularity), which could be brought on by electrolyte imbalance and other factors, and in some cases, to totally unknown cause. Brugada Syndrome, discussed below, is one such demise from a fatal heart rhythm abnormality.

Can illegal drugs cause sudden death?

Yes. Other “recreational” drugs could also lead to sudden death, many by causing deadly heart irregularity. Among some individuals, cigarette smoking could cause heart rhythm problems that lead to cardiac arrest. Thank God, this is rare.

What is a “Widow-Maker” heart disease?

As the name implies, this particular condition results in sudden deaths among men, leaving their wives widows. This is usually due to a severe blockage of the left main coronary artery. If the left main coronary artery is blocked, all the left ventricular muscles are deprived of blood causing a massive acute heart attack, followed by sudden death. Even a single coronary blockage, if severe enough, could be dangerous, and deadly, depending on the portion of the heart that suffers.

Could Mitral Valve Prolapse cause sudden death?

Yes, but, fortunately, very rarely. Mitral Valve Prolapse is a condition where this valve on the left side of the heart (between the left upper and left lower chamber) is kind of “limp” and “weak” resulting in a slightly or moderately leaking Mitral Valve. This condition is generally benign and does not require surgery in majority of cases. Medications and some lifestyle changes are the therapies of choice.

What are the usual symptoms prior to SCD?

Interviews with family of the victims usually reveal some angina (chest discomfort or tightness), or heart irregularity, and/or shortness of breath, and worsening of the symptoms over a few days or a few hours before sudden collapse and death in 75 percent of these people. Some of these symptoms may even be confused with indigestion, fatigue, muscle pains, or depression. Self-denial (of symptoms) makes this condition treacherous. Anyone with any of these symptoms should consult their physicians without delay. In many cases, the first symptom is cardiac arrest.

Does a normal EKG preclude SCD?

No, a plain resting EKG that is reported as normal does not eliminate the possibility of Sudden Cardiac Death, especially among patients with coronary artery disease, whether previously diagnosed or still undetected. This is the reason why a Stress EKG, preferably with Thallium, or Stress Echocardiography, are recommended to find out how the heart would behave under stress. These are more accurate and significant tests compared to a simple resting EKG. A plain EKG is only helpful if it shows abnormal findings. If it is “normal,” it does not have an accurate diagnostic value, and thus, cannot be depended upon for prognostication.

What is Brugada Syndrome?

Brugada Syndrome is a baffling condition where a young person, who appears to be healthy, unexpectedly develops cardiac arrest, for no apparent reason. Most victims do not survive the episode. This condition is now believed to be responsible for countless sudden deaths among young people — athletes, students, etc., — who suddenly dropped dead.

Did the victims have any prior symptoms?

No, majority of victims did not have any prior symptoms. They were “in good health” when suddenly they collapsed, went into coma, and later died, or instantly died on the spot. Three Doctors Brugada (R, P & J) and their colleagues at the Unitat d’Aritmies, Hospital Clinic, in Barcelona, Spain, were the first to describe the syndrome in November 1992. The characteristic EKG findings in this syndrome was first described in 1980 among six patients who had cardiac arrest and were successfully resuscitated. It was not recognized at that time as a disease entity, but those were classic victims of Brugada Syndrome.

How does one prevent Brugada Syndrome?

Since this disease entity has now been “described,” which makes diagnosis of this entity possible, everyone, especially those with a family history of unexplained sudden cardiac arrest, should be tested, starting with an EKG, and some “provocative” tests (with disopyramide, flecainide, ajmaline, procainamide) done to reproduce the characteristic Brugada EKG findings.

Can genetic testing help?

Since this disease is secondary to a mutation of SCN5A gene of chromosome 3 that has a dominant autosomic transmission pattern, with genetic defect in the alpha subunit of the sodium channel, genetic testing may be in order. However, 30% to 80% of patients will have negative (normal) gene screening in spite of overt or latent clinical Brugada Syndrome.

What’s the treatment for Brugada Syndrome?

If one is diagnosed to have Brugada Syndrome, an automatic implantable cardiac-pacemaker defibrillator (AICD) may be implanted, which will pace the heart and increase the rate if the rate goes down (awake or when asleep, 24/7), shocks and jolts the heart back to normal rhythm, when the heart goes to ventricular fibrillation. Hundreds of thousands of people worldwide have AICD to prevent sudden death from a variety of causes. None of the available drugs today are effective against Brugada Syndrome. When diagnosis is made, which may be missed a lot of time, then, cardiac arrest may be prevented with AICD.

Can other sudden cardiac deaths be prevented?

Since most of these SCDs are due to coronary artery disease, primary prevention should be aimed at warding off coronary artery disease before it develops, like avoidance of cigarette smoking, obesity, sedentary lifestyle; and the management of high blood pressure, diabetes, and elevated cholesterol, if these are present. Secondary prevention is by early diagnosis and treatment of coronary artery disease, and any medically significant heart irregularity present. Where indicated, coronary angioplasty or bypass may be done. AICD implantation should be considered for those with a history of recurrent cardiac arrests.

***

Philip S. Chua, MD, FACS, FPCS, Cardiac Surgeon Emeritus in Northwest Indiana and chairman of cardiac surgery from 1997 to 2010 at Cebu Doctors University Hospital, where he holds the title of Physician Emeritus in Surgery, is based in Las Vegas, Nevada. He is a Fellow of the American College of Surgeons, the Philippine College of Surgeons, and the Denton A. Cooley Cardiovascular Surgical Society. He is the chairman of the Filipino United Network – USA, a 501(c)(3) humanitarian foundation in the United States. Email: scalpelpen@gmail.com

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