Ischemic Heart Disease (Exam 2) Flashcards
Define myocardial ischemia and is it reversible?
a condition of myocardial oxygen deficit: demand > supply. Due to decreased coronary artery perfusion. Usually reversible
Define myocardial injury and is it reversible?
occurs with ongoing ischemia. may be reversible or go on to infarction.
Define myocardial infarction and is it reversible?
progression of ischemia to irreversible cell death. causes permanent impairment of electrical activity and contraction. not reversible.
Identify the 3 main anatomic locations in the heart where acute MIs occur and list the coronary arteries that supply these areas.
Inferior infarct (diaphragmatic area): right coronary artery Lateral wall infarct (left lateral wall of the heart): left circumflex artery anterior infarct (anterior surface of left ventricle): left anterior descending artery.
what are the measurement characteristics of an abnormally elevated or depressed ST segment?
must be more than 1 mm (1 box) above or below the baseline.
During an acute MI how does the EKG evolve in regards to the t wave?
T wave peaking followed by t wave inversion
During an acute MI how does the EKG evolve in regards to the ST segment?
ST segment elevation (1 box or higher). happens during the change from ischemia to infarction and damage still usually reversible at this point.
During an acute MI how does the EKG evolve in regards to the Q wave?
Appearance of new q waves that are greater than .04 seconds in duration and > 1/3 the height of the QRS complex. these are usually seen several hours after the infarction and not reversible. can last for years and even life of patient.
What is the primary cause of ischemic heart disease?
atherosclerotic obstruction of coronary arteries
What is the artery that is involved in an anterior MI?
Left anterior descending artery
What is the artery that is involved in a lateral MI?
Left circumflex artery
What is the artery that is involved in an inferior MI?
90% Right coronary
10% Left circumflex
What EKG changes will you see in reversible ischemia?
ST depression-usually horizontal or down sloping (significant if >/= to 1 mm).
T wave flattening or inversions
Changes typically resolve.
What EKG changes will you see in complete infarction?
- ST elevation
- variable T wave changes
- initial changes typicaly followed later by Q waves (q waves are permanent and represent electrically dead area of muscle)
- New BBB
- Reciprocal EKG changes
Define reciprocal EKG changes.
mirror-image ST-T changes (usually ST depressions) in leads distant from the primary ST elevation.
Discuss the characteristics of pain encountered in an acute MI according to location and radiation.
location: substernal or left-sided
radiation: to neck, jaw, shoulders, left or both arms
Discuss the characteristics of pain encountered in an acute MI according to quality.
heaviness, pressure, tightness, squeezing
Discuss the characteristics of pain encountered in an acute MI according to relation to body movement.
usually unaffected by position change, body movement, deep breath
Discuss the characteristics of pain encountered in an acute MI according to associated emotional and physchological manifestations.
often brought on by physical exertion, emotional stress
Discuss the characteristics of pain encountered in an acute MI according to responsiveness to rest and/or NTG.
relieved by rest and/or NTG
Discuss the importance of the clinical evaluation in diagnosis of an acute MI.
History is the single most important tool of chest pain evaluation.
What should you ask about during your history if IHD is suspected?
Chest pain, associated symptoms, risk factors
What is the most important lab test to identify IHD and what is something you should keep in mind when evaluating it?
EKG, only 50% of acute MIs initially have classic ST evaluation. even a completely normal EKG doesn’t EXCLUDE acute MI. Must use EKG in conjuction with history, physical, and cardiac enzymes.
What is the importance of taking cardiac enzymes for diagnosis of IHD?
Early levels may be normal in acute MI.
Must follow serial enzymes to rule out MI.
Elevated cardiac enzymes ultimately confirm diagnosis of acute MI, but can’t rely on them early.
Normal serial enzymes rule out acute MI, but do not rule out possibility of underlyingischemic heart disease.
name the potential complications of acute MIs.
- dysrhythmia
- LV pump failure/cardiogenic shock
- papillary muscle insufficiency
- ventricular septal rupture
- cardiac rupture
- thromboembolism
- pericarditis
- ventricular aneurysm
- right ventricular infarction
what is the classic ECG evolution in MI?
- hyperacute T-waves
- giant R waves
- ST elevations
- Q waves
What steps/diagnostic tools should you use to diagnose IHD.
- History
- Physical exam
- ECG
- Cardiac Enzymes
- Chest xray
- echocardiogram
- radionuclide scan
- coronary angiogram
What symptoms are associated with an acute MI
SOB, diaphoresis, nausea/vomiting, palpitations, dizzy/lightheadedness
Why are diabetics in a special category when it comes to ischemic HD and MIs?
- Extensive comorbidites
- Often present asymptomatic or with very generalized concerns such as weakness
- Considered a micro vessel disease
