The heart is one of the most important organs in your body, and in some ways the most familiar; we know we have to keep it healthy to live well, most of us know someone who has had a heart problem or even a heart attack, and it's one of the few organs that we can actually feel as it functions (just put your hand in the middle of your chest!). But there are some things that you may not know about your heart that can help you understand why it's so important. 1. Athletes actually appear to have smaller hearts. The heart is a muscle, as are your biceps. But while striving for big muscles might be an athlete's visible goal, on x-ray a really good athlete's heart looks SMALLER than average. That's a sign of an efficient heart - a heart that pumps blood well squeezes very hard to send as much blood as possible to the body with every beat. An enlarged heart, in contrast, may indicate that the heart's having to work too hard because of muscle damage or the increased effort of moving blood through clogged arteries. 2. The "lub-dub" that your heart makes when beating is the sound of heart valves closing. The human heart has four chambers with valves - little one-way doors - between them. If the heart is working correctly, you hear "lub" when blood first enters the heart and 'dub" after it leaves. If doctor hears a 'swish" or "gurgle" - murmurs - instead of a thump, that may be a sign that the valves aren't working as well as they should. Extra sounds (lub-dadub) sometimes indicate uncoordinated valve action (indicating heart injury) but it may be just be the sign of a young and athletic heart. 3. The heart needs blood, just like all your other organs. The heart fills with blood and then pumps the blood to the body about once a second or more. But it doesn't take nutrients and oxygen directly from the blood before pumping it; instead it pumps the heart through a series of blood vessels called arteries. Each organ has groups of arteries that deliver oxygen and nutrients to it - including the heart! These are called "coronary" arteries; if these arteries are narrowed or damaged, the heart may have trouble receiving the nutrients and oxygen it needs to live. 4. Heart cells (myocytes) are precious. Unlike skin, which quickly heals after most injuries, if heart cells are injured or killed during a myocardial infarction (or "heart attack") they are difficult to repair or replace. For many years, in fact, it was believed that you only had one set of myocytes, and once damaged, they could never be replaced. Recent research suggests that there may be cells in the heart (stem cells) that can develop into myocytes if needed, but how they are triggered and how long it takes them to repair damaged tissue isn't known. It is known however that heart damage is difficult to overcome, so prevention is an important part of taking care of your heart. 5. Your heart is a piece of electronic equipment. Myocytes use electrical signals as a means of communicating with one another and coordinating the beating of the heart. The flow of electricity is recordable by an electrocardiograph (ECG). An ECG of a damaged heart can be comparing the flow of electrical waves in the heart to waves in the normal heart to determine what sort of damage has been done. In addition, if there is significant damage to the electrical communication between heart cells, an artificial pacemaker (usually called a pacemaker) may be implanted in the heart to coordinate the electrical signals used and keep the heart beat regular and coordinated. Many hospitals request that cell phones not be used in certain locations in the hospital because of artificial pacemakers - in rare cases, cell phones have been known to interfere with the functioning of pacemakers. Pacemaker users are recommended to use their cell on the opposite side from where their pacemaker is implanted. Kajstura J, "Myocyte growth in the failing heart," Surgical Clinics of North America Volume 84, issue 1, p 161-177, 2004 von Harsdorf, R. "Regenerative capacity of the myocardium: implications for treatment of heart failure," Lancet, Volume 363, issue 9417, p 1306-1313, 2004 Myerson, S. and Mitchell, A, "Mobile phones in hospitals," British Medical Journal, Volume 326, pages 460-461, 2003 |
