Ischemia Myocardial ischemia(MI) ECG and effects of ischemia

Ischemia Types Effects of Ischemia, Myocardial ischemia(MI) ECG ,vertebrobasilar ischemia and other metabolic changes

  • A temporary deficiency of blood flow to an organ or tissue,
  • Normal muscle contraction and relaxation af­fected
  • Angina pectoris has been considered the cardinal symptom of myocardial ischemia for more than two centuries.

 

Ischemic Heart Disease (IHD) 1

Ischemia Types Effects of Ischemia, Myocardial ischemia(MI)

  • LVF (left ventricular failure)
  • Papillary muscle dysfunction ~MR ~LV dilata-
  • LVF
  • Angina pectoris
  • Myocardial necrosis and scarring
  • MI
  • Akinesis
  • Dyskinesis.
  • between 25 and 45 percent of patients with acute and chronic ischemic syndromes have evidence of myocardial ischemia during daily life,

 

Ischemia Myocardial 2

Types Effects of Ischemia, Myocardial ischemia(MI) ECG

Types of Ischemia

 

myocardial ischemia (MI):

  • evidence of myocardial ischemia in the absence of chest discomfort or other anginal equivalents.
  • An inadequate supply of blood and oxygen to meet the metabolic demands of the heart muscle.
  • Exercise testing or ambulatory monitoring shows transient ST segment changes

 

vertebrobasilar ischemia:

  • Inadequate blood flow through the arteries that supply nutrients and oxygen to the structures at the base of the brain (esp. the brain stem and cerebellum).

lower limb ischemia:

  • An inadequate blood flow to one or both legs due either to chronic arterial obstruction caused by atherosclerosis or to acute obstruction caused by embolism.

 

Metabolic Changes

   

  • Accumulation of lactic acid, depletion (wash out) of high energy phosphates, oxygen and creatine phos­phate.
  • In the presence of oxygen, fatty acid and glucose are metabolized to carbon dioxide and water.
  • Fatty acids, glucose O2 co2 —–> and H20.
  • In absence of oxygen fatty acids and glucose are metabolized to lactic acid which  promotes coronary spasm,
  • Changes are reversible up to 10 minutes .
  • after 20 minutes changes are irreversible.

 

Ischemia Myocardial ecg 1

Ischemia Types Effects of Ischemia, Myocardial ischemia(MI) ECG

 

ECG Changes

   

  • typical changes of angina / IHD are:
  • ST depression
  • T inversion
  • These are seen in contiguous leads like 2, 3, AVF, ferior wa or I, L, V5,V6 (lateral wall).
  • severe ischemia, ST elevation is seen and indi­:c~es transmural ischemia; it may evolve into ‘: myocardial infarction).
  • eIedrical instabilit~ads to arrhythmias – VT-(ven­:-icular tachycardia) -.and VF-(ventricular fibril~ation).
  • death occurs due to pump failure or ventricular :tachyarrhythymias.