Myocardial Infarction

By Taylor Tisch

Background Info:

Structure of arteries, veins, and capillaries

The walls of arteries and veins have three layers or tunics:


  • An outer layer (tunica adventitia) of connective tissue with collagen fibers.
  • A middle layer (tunica media) of circularly arranged smooth muscle and elastic fibers.
  • An inner layer (tunica intima), consisting of a specialized simple squamous epithelium, often called the endothelium, that lines all blood vessels and the endocardium of the heart. The basement membrane, a subendothelial layer composed of connective tissue, supports the endothelium. Capillaries consist of an endothelium which is only one cell thick
  • Blood Flow: Arteries- away from heart, Veins- towards the heart, Capillaries- where gas exchange occurs
How a Normal Heart Pumps Blood -- The Children's Hospital of Philadelphia
Conducting System Of The Heart

Electrocardiogram (ECG) Test

is the graphic record of the heart's electrical activity


  • A normal ECG has 3 waves: P wave, QRS complex, and the T wave
  • These waves represent the electrical activity that regulates the contraction/relaxation of the atria/ventricle
  • Depolarization: the electrical activity that triggers contraction of the heart muscle
  • Repolarization: begins just before the relaxation phase of cardiac muscle activity

Blood Pressure

Blood pressure is the force of blood against the walls of arteries. Blood pressure is recorded as two numbers—the systolic pressure (as the heart beats) over the diastolic pressure (as the heart relaxes between beats)


Factors that influence Blood Pressure:

  • Blood Volume: The higher the volume, the more pressure exerted on vessel walls
  • Strength of <3: Higher the heartbeat, the higher the pressure
  • Heart rate: The higher the rate, the higher the pressure
  • Blood Thickness: Less than normal thickness decreases pressure
  • Resistance to Blood Flow: affected by many factors

5 factors that influence blood pressure:

  • Genetics
  • Age/weight
  • Tobacco usage
  • Pregnancy
  • Medication

TESTS:

  • Cardiac Cycle: All the blood pumped from the ventricle in one minute
  • Stroke Volume: All the blood pumped from the ventricle in one beat
  • Pulse: A rhythmical throbbing of the arteries as blood is propelled through them.
  • Normal Heart Sounds: the normal heart sound (sounds like “lub dub”.) Cause: Valves opening and closing and blood flowing

Blood Tests:

a lab analysis performed on a blood sample used to determine psychological and biochemical states, such as disease, illness content, drug effectiveness, and organ function
  • Hematocrit test: indicates whether you have too few or too many red blood cells
  • WBC Count: measures the number of white blood cells (WBCs).
  • Platelet count: measures the number of platelets in your blood

This patient has Myocardial Infarction

Gender: Male

Age: 55

Weight: 256

The Cause: Smoker, Lack of Exercise, Unhealthy Diet, Note: Heart Condition runs in family

Tests:

  • EKG: Shows series of abnormalities Ex. Elevation between the T and S wave interval
  • Pulse: Very fast rate
  • Blood Pressure: Blood pressure dropped very low
  • Stroke Volume: Decreased
  • Cardiac Output: Decreased
  • Heart Sounds: irregular (galloping sound)
  • WBC Count: normal
  • Hematocrit: normal
  • Platelet Count: normal

Possible Solutions: Angioplasty – a surgical procedure used to open the arteries. Thrombolytic Therapy – drugs that destroy blood clots that may be used when angioplasty is not an option. Also stop smoking, excerise daily, and eat a healthy diet.

Work Cited

"Heart Tests." Welcome to HeartSite.com. N.p., n.d. Web. 13 Mar. 2013. <http://www.heartsite.com/html/Tests.html>.

"Heart attack - MayoClinic.com." Mayo Clinic. N.p., n.d. Web. 13 Mar. 2013. <http://www.mayoclinic.com/health/heart-attack/DS00094>.

"National Center for Biotechnology Information." National Center for Biotechnology Information. N.p., n.d. Web. 13 Mar. 2013. <http://www.ncbi.nlm.nih.gov>.

"Prentice Hall School." Prentice Hall Bridge page. N.p., n.d. Web. 13 Mar. 2013. <http://www.phschool.com/science/biology_place/biocoach/cardio>.

"What Is A Heart Attack? What Causes A Heart Attack?." Medical News Today: Health News. N.p., n.d. Web. 13 Mar. 2013. <http://www.medicalnewstoday.com/articles/151444.php>.