February 22, 2011 | 2
The day Patti’s heart tissue died
From the increased strength and frequency of meowing, Patti took the cue from her feline alarm clock that it was morning. Although the sun was just rising, the gentle breeze wandering through her window indicated that it was to be another beautiful September day. Patti got out of bed, threw on her slippers, and made her way into the kitchen, where she barely had an opportunity to put on the kettle before her persistent cat demanded all of the attention. Although it was only 6 A.M., Patti was gearing up for her busy schedule.
Several years into her retirement, this recently widowed 73-year-old plump grandmother of 15 and great grandmother of two found herself involved in many social activities sponsored by her local church. Today was the big senior sing-a-long breakfast and Patti was eager to eat, sing, and be merry amongst friends. And, later that evening, Patti had accepted an invitation to dine with Stella at her home, where she would socialize with Stella’s family and meet the newest grandbaby. Today, Patti thought, was going to be a good day.
Patti made her way to her church’s dining hall around 9 A.M. The aroma of pancakes and coffee and the sounds of Hank Williams and Glenn Miller already conjured up thoughts of happiness. Patti located her friends, grabbed a plate of food, and joined them in a robust rendition of "In the Mood." In between acts, Patti and her friends took turns sharing stories about where they were when they first heard this song or that, with the conversation eventually morphing into a wallet-sized display of grandchildren. Before they knew it, several hours had passed and it was time to wrap things up.
By the time Patti got home, it was after 1 P.M. Instead of turning on the television or doing any chores, Patti decided to take a few minutes to relax. She was trying to reflect on her wonderful morning but, all of a sudden, something was keeping her from focusing. She sat down and had a sip of water but felt no relief. Instead, she began to feel tightness in her chest. Although this tightness wasn’t painful, Patti did not dismiss it. As the minutes passed, Patti began to sweat profusely and the tightness began to radiate down her arms. She became short of breath. Without hesitation, she grabbed the tiny two by four–inch "Heart Attack Warning Signs" pamphlet from the American Heart Association that was attached to her refrigerator bulletin board, reading it carefully. By 2 P.M., a dissolvable tablet of nitroglycerin was being shoved under Patti’s tongue as the ambulance in which she was traveling carefully rushed to the nearest hospital. There was no doubt that Patti was having a heart attack.
A heart attack explained
A heart attack, also called a myocardial infarction (MI), is the number-one cause of death worldwide and is characterized by the restriction of blood supply to a particular area of the heart, setting off a series of events that can be fatal. Like all tissues in our body, the cells that make up the heart require a substantial amount of oxygen in order to maintain proper function, with the delivery of oxygen to these tissues being dependent upon sufficient blood flow. When this process is compromised in the heart, the resulting oxygen deprivation will damage the heart tissue, often irreversibly. The tightness that Patti experienced in her chest was an indication that her heart tissue was being damaged as a consequence of diminished oxygen supply.
Even when the area of damage is relatively small, it can affect the mechanical function of the entire heart, introducing irregularities in the heart’s rhythm – referred to by physicians as "arrhythmias" – that can negatively affect cardiac output. In an attempt to maintain normal operating function of the circulatory system during a heart attack, our bodies will elicit a number of compensatory cascades. This includes the stimulation of the sympathetic nervous system, classically defined as the "fight-or-flight" response, which is associated with increased sweating.
Also, some heart attack sufferers experience a rapid increase in their heart rate to try and satisfy increased oxygen demands, further perpetuating impaired cardiac function. As the mechanical performance of the heart decreases, the pressure in the heart can increase, leading to fluid build up in the lungs. This, combined with a reduction of oxygenated blood circulating through the body, explains why Patti exhibited a shortness of breath during her heart attack. However, there is more than one way to have a heart attack. Because there are different nerves that feed into the heart at different locations, sometimes the parasympathetic nervous system, or the "rest and digest" response, is turned on. When this happens, a heart attack can mimic indigestion, making it difficult to ascertain what is actually happening.
In addition to chest discomfort, shortness of breath, sweating, and arm pain, other telltale signs of a heart attack are tightness in the neck and jaw, fatigue and/or fainting, and nausea. It has been shown that the rate of survival is directly related to response time so if you suspect that you might be having a heart attack, seek immediate medical assistance. Our nation’s 911 service is there for a reason, folks. Don’t be foolish.
The atherosclerotic trigger
Even though a heart attack can occur over a span of hours or even minutes, this potentially deadly event is often the climax of a life-long narrative starring genetics, diet, and lifestyle. The most common cause of a heart attack is when arteries become "clogged" in a complex process that can start as early as childhood. The underlying mechanism is a progressive disease called atherosclerosis and, etymologically speaking, the literal translation of "atherosclerosis" is the "hardening of the arteries." More specifically, this condition is hallmarked by the accumulation of "plaques" made up of cholesterol, cellular debris, and other fatty material along the lining of blood vessels, causing the blood vessels to thicken and harden.
A major contributor to the development of atherosclerosis is having high cholesterol, particularly in the form of LDL or "bad" cholesterol. Existing primarily in our bloodstream, excessive amounts of LDL pose a problem for us as these particles will attach to the lining of our blood vessels and contribute to plaque formation. The more LDL that is in circulation, the harder it becomes for our body to remove the LDL particles from the blood vessel walls, ultimately leading to cholesterol accumulation and the development of atherosclerosis. Over time, the build up of these cholesterol-rich plaques will restrict the amount of blood flowing through our arteries. The narrowing of the arteries feeding the heart will reduce the amount of necessary oxygen and nutrients that are available for proper heart function and contribute to the development of coronary heart disease (CHD). In Patti’s situation, the plaque in one of her arteries was stressed to the point that it exploded, releasing a blood clot that became lodged in a coronary artery and significantly blocked blood flow to her heart, inducing a heart attack.
Although we cannot change our genetic predisposition to developing atherosclerosis and/or coronary heart disease, we can make choices that benefit our cardiovascular health. Perhaps most importantly, it is crucial to maintain a healthy weight. Of course, there is no magic bullet for staying trim and, sometimes, it can seem difficult. However, when your life is on the line, the choices might become easier. Eating a balanced diet that is full of healthy fruits and vegetables, fiber-rich whole grains, and a weekly serving of cold-water fish along with regular exercise regimen can help keep LDL levels at bay. However, sometimes diet and exercise are not sufficient for keeping LDL levels within a normal range. When this is the situation, doctors will recommend statin-treatment, a medical intervention that has been integral in the war against coronary heart disease. Also, refraining from smoking can have a huge impact on heart health. For more ways to promote a heart healthy lifestyle, check out The American Heart Association’s Web site.
Why it has become personal
The entire history of my research career has revolved around lipid metabolism as it relates to overall cardiac health and disease. On a daily basis, I read about or directly examine the effects of altered cholesterol balance and often take a first-hand look at atherosclerotic plaques in mice models. I sit in on seminars discussing the clinical implications of coronary heart disease and will dissect our society into those that have it and those that don’t. Another heart attack victim (for whatever reason) had been just another addition to the "n" count, only adding to statistical confidence. But, when the story became real, that all changed.
Patti is not a fictional character. She is a living, breathing person who really is a grandmother of 15 and a great-grandmother of two. In fact, her great-grandchildren are actually my very own children. It became real because "Patti" is my grandmother. Although Patti is not her real name (we had a little fun by changing the names around a bit), the events described above are a true account of the hours leading up to Patti’s heart attack. I can’t tell you how fortunate I feel about being able to share this story with you, a story that was told to me after the fact. Today "Patti" is alive and healing and is changing her lifestyle for the better. Not everyone gets a second chance and my family will never forget how lucky we really are.
American Heart Association. Guide to Myocardial infarction Treatment, Recovery, Prevention. New York: Time Books, 1996.
Cotran R. S., Kumar V., Robbins S. L. (eds): Robbins Pathologic Basis of Disease. 5th ed. Philadelphia: WB Saunders, 1994.
Hansson G. K. Inflammation, Atherosclerosis, and Coronary Artery Disease. N Engl J Med. 2005; 352:1685-1695
Thygesen K., Alpert J. S., and White H. D. Joint ESC/ACCF/AHA/WHF Task Force for the Redefinition of Myocardial Infarction:Universal Definition of Myocardial Infarction. Circulation. 2007;116:2634-2653.
White H. D., Chew D. P. Acute myocardial infarction. Lancet. 2008;372:570-584.
About the Author: Jeanne Garbarino is a postdoctoral researcher in the Laboratory of Biochemical Genetics and Metabolism at The Rockefeller University in N.Y.C. where she studies how cholesterol moves around in cells. When not at the bench, you can find her loitering at the intersection of motherhood and science on her blog The Mother Geek or tweeting her matronly geekery as @themothergeek.
The views expressed are those of the author and are not necessarily those of Scientific American.