Heart Attack (Myocardial Infarction)

  • Medical Author:
    Daniel Lee Kulick, MD, FACC, FSCAI

    Dr. Kulick received his undergraduate and medical degrees from the University of Southern California, School of Medicine. He performed his residency in internal medicine at the Harbor-University of California Los Angeles Medical Center and a fellowship in the section of cardiology at the Los Angeles County-University of Southern California Medical Center. He is board certified in Internal Medicine and Cardiology.

  • Medical Editor: Jay W. Marks, MD
    Jay W. Marks, MD

    Jay W. Marks, MD

    Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.

  • Medical Editor: Charles Patrick Davis, MD, PhD
    Charles Patrick Davis, MD, PhD

    Charles Patrick Davis, MD, PhD

    Dr. Charles "Pat" Davis, MD, PhD, is a board certified Emergency Medicine doctor who currently practices as a consultant and staff member for hospitals. He has a PhD in Microbiology (UT at Austin), and the MD (Univ. Texas Medical Branch, Galveston). He is a Clinical Professor (retired) in the Division of Emergency Medicine, UT Health Science Center at San Antonio, and has been the Chief of Emergency Medicine at UT Medical Branch and at UTHSCSA with over 250 publications.

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What are the risk factors for atherosclerosis and heart attack?

Factors that increase the risk of developing atherosclerosis and heart attacks include increased blood cholesterol, high blood pressure, use of tobacco, diabetes mellitus, male gender (although women may still be very much at risk -- see section at end of article), and a family history of coronary heart disease. While family history and male gender are genetically determined, the other risk factors can be modified through changes in lifestyle and medications.

  • High Blood Cholesterol (Hyperlipidemia). A high level of cholesterol in the blood is associated with an increased risk of heart attack because cholesterol is the major component of the plaques deposited in arterial walls. Cholesterol, like oil, cannot dissolve in the blood unless it is combined with special proteins called lipoproteins. (Without combining with lipoproteins, cholesterol in the blood would turn into a solid substance.) The cholesterol in blood is either combined with lipoproteins as very low-density lipoproteins (VLDL), low-density lipoproteins (LDL) or high-density lipoproteins (HDL).

    The cholesterol that is combined with low-density lipoproteins (LDL cholesterol) is the "bad" cholesterol that deposits cholesterol in arterial plaques. Thus, elevated levels of LDL cholesterol are associated with an increased risk of heart attack.

    The cholesterol that is combined with HDL (HDL cholesterol) is the "good" cholesterol that removes cholesterol from arterial plaques. Thus, low levels of HDL cholesterol are associated with an increased risk of heart attacks.

    Measures that lower LDL cholesterol and/or increase HDL cholesterol (losing excess weight, diets low in saturated fats, regular exercise, and medications) have been shown to lower the risk of heart attack. One important class of medications for treating elevated cholesterol levels (the statins) have actions in addition to lowering LDL cholesterol which also protect against heart attack. Most patients at "high risk" for a heart attack should be on a statin no matter what the levels of their cholesterol.
  • High Blood Pressure (Hypertension). High blood pressure is a risk factor for developing atherosclerosis and heart attack. Both high systolic pressure (the blood pressure as the heart contracts) and high diastolic pressure (the blood pressure as the heart relaxes) increase the risk of heart attack. It has been shown that controlling hypertension with medications can reduce the risk of heart attack.
  • Tobacco Use (Smoking). Tobacco and tobacco smoke contain chemicals that cause damage to blood vessel walls, accelerate the development of atherosclerosis, and increase the risk of heart attack.
  • Diabetes (Diabetes Mellitus). Both insulin dependent and noninsulin dependent diabetes mellitus (type 1 and 2, respectively) are associated with accelerated atherosclerosis throughout the body. Therefore, patients with diabetes mellitus are at higher risk for reduced blood flow to the legs, coronary heart disease, erectile dysfunction, and strokes at an earlier age than nondiabetic subjects. Patients with diabetes can lower their risk through rigorous control of their blood sugar levels, regular exercise, weight control, and proper diets.
  • Male Gender. Men are more likely to suffer heart attacks than women if they are less than 75 years old. Above age 75, women are as likely as men to have heart attacks.
  • Family History of Heart Disease. Individuals with a family history of coronary heart diseases have an increased risk of heart attack. Specifically, the risk is higher if there is a family history of early coronary heart disease, including a heart attack or sudden death before age 55 in the father or other first-degree male relative, or before age 65 in the mother or other female first-degree female relative.
Medically Reviewed by a Doctor on 10/29/2015

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