1. Heart Disease Myocardial Infarction

2.  Heart attack  Leading cause of death in the US  Usually caused by an occluded vessel  Males more often affected until later in life

3. Assuming the individual survives the MI:  18 to 24 hours:  The damaged heart tissue will appear pallor (white in color, not pink)  2 to 4 days:  The dead tissue will appear yellow- brown and soft

4.  10 days:  Scar tissue forms at the margin of the infarction  Called metaplasia

7. Metaplasia  Transformation of one type of mature differential (specialized) cell into another type (due to injury)  Scar tissue (fibroblast cells) forms—you can often see the nuclei of these cells

8. Symptoms:  Intense, crushing pain located below the sternum  Pain often radiates down left shoulder, arm, or jaw  Breathlessness  Anxiety  Nausea  Vomiting  Perspiration

9.  Many people do not realize they are having heart attacks  Mistake symptoms for indigestion

10.  After the onset of a MI, there may be no obvious problems  Or  Arrhythmias or pump failure may occur

11.  Before we begin arrhythmias, how does a normal heart function and how does the pattern appear on an EKG?

12.  Each heartbeat originates as an electrical impulse from a small area of tissue in the right atrium: sinus node –Impulse is a wave of negative ions

14.  The impulse travels cell by cell to the atrioventricular node —a cluster of cells in the center of the heart (the only electrical connection between the heart chambers)  It travels along the Bundle of HIS

15.  The impulse is delayed at the atrioventricular node until the atria fully contract.  The atria fully contract before the ventricles are stimulated.

16. Heart

17.  An EKG consists of 12 leads that can pick up these negative ion waves  We mainly focus on only one lead (called lead 2)

18. Normal Heart Pattern on an EKG ©http://students.med.nyu.edu/erclub/ekgexpl0.html

19.  P wave: atria depolarize (contract releasing the ions)  QRS complex: ventricles depolarize –Spike appears because there are many more heart cells depolarizing  T wave: repolarization of the ventricles –Getting ready for the next heartbeat

20.  PQRS: indicate systole  T: indicates diastole

21.  http://www.youtube.com/watch?v=lI QXzgesdDg

22.  How would an atrial problem look on an EKG?  How would a ventricular problem look on an EKG?

23.  Deep Q  Shows an old infarction  Person had a MI in the past  The deeper the Q, the greater the infarction

24. Arrhythmia  Irregular heartbeat  This is what usually kills the individual

25.  The MI acts as an extra pacemaker— releases negative ions  Heart diagram on board

27.  There are different types of arrhythmias  Can be seen on an EKG

28.  People die because the cells cannot control these ions, not because of the damage to the heart

29. Types of Arrhythmias  Flutter  Mild quivering of atria or ventricles  Fibrillation  Entire chamber of the heart undergoes quivering with chaotic impulses –Can affect the atria or the ventricles

30. Types of Arrhythmias  Atrial fibrillation  Atria only pumps approximately 30% of blood into ventricles—the rest “falls out” (churning)  Most people survive this  Problem? thrombus may form

31.  Thrombus may form

32. Types of Arrhythmias  Most individuals are on an anticoagulant  Usually seen in older people  Not typically associated with MIs

33. Types of Arrhythmias  Ventricular fibrillation  Very dangerous—why?  No blood is really pumping

34. Types of Arrhythmias  On board  How would you describe this to a doctor?  ST problem —elevated ST segment  Very significant problem  The heart is in ischemia usually die to a clot

36.  Nicknamed Tombstone Effect –Looks like a headstone  If you can get the person anti- thrombolic drugs soon enough, he should be okay

38.  How do we stop fibrillation?  Defibrillate  “Knocks” out all of the ions and starts over  Person flat lines—heart stops and then restarts itself with a normal pattern

40.  Only use a defibrillator if the person is in fibrillation  Can implant a defibrillator into a person’s chest

41. Types of Arrhythmias  PVC: pre-ventricular contraction  Has been seen in teenagers, but most outgrow it  Not good in older people

43. Types of Arrhythmias  Tachycardia  Any heart rate faster than 100 beats/min  Brachycardia  A slow rhythm, less than 60 beats/min

45. Treatment for Arrhythmias  Treatment: Pacemaker  Can speed up the heart, slow down the heart, assist with irregular beating

46. Implanted Defibrillator

47.  For severe arrhythmias a pacemaker with a defibrillator may be implanted.

48. Long QT Syndrome

49. Ruptured Septum after MI ©http://www-tc.pbs.org/wgbh/nova/heart/images/aneurysm.jpeg?Log=0

50. For MI Lab Normal Heart Tissue

51. 3 Days After MI

52. Normal vs. Infarction

53. Vocabulary  Intercellular spaces:  Edema:  Leukocytes:

54. Vocabulary  Metaplasia:  Ischemia:  Infarction: