Cardiovascular Part 1 Flashcards
Define Ischemic Heart Disease
A collective term used to refer to various diseases characterized by inability of the coronary arteries to deliver adequate oxygen to meet the needs of the myocardium
What is by far the leading cause of ischemic heart disease?
Coronary artery disease (CAD)
(also known as coronary heart disease [CHD] or atherosclerosis of the coronary arteries)
What is atherosclerosis characterized by?
the formation of elevated plaques called atheromas in the intima of coronary arteries
What may atheromas progress to?
calcification, ulceration with thrombosis, and intraplaque hemorrhage
There is significant evidence linking atherosclerosis to what?
hyperlipidemia, particularly hypercholesterolemia (elevated serum cholesterol levels)
What are other causes of ischemic heart disease?
- Thromboemboli
- Coronary artery vasospasm
- Conditions that increase cardiac work load and oxygen demand
What are the major clinical manifestations of ischemic heart disease?
- Chronic ischemic heart disease
- Angina pectoris
- Myocardial infarction
What is the most common clinical form of the ischemic heart disease
Chronic ischemic heart disease (stable ischemic heart disease)
What is the clinical progression of chronic ischemic heart disease?
- often initially clinically silent (asymptomatic)
- may eventually lead to the insidious onset of (predominantly left-sided) congestive heart failure, and is also associated with a significantly increased risk of angina pectoris, myocardial infarction, or sudden cardiac death
What is angina pectoris?
A syndrome of episodic, paroxysmal, substernal or precordial chest pain or discomfort resulting from myocardial ischemia
Three distinct forms of angina pectoris
- Stable (classic) angina
- Unstable angina (also known as pre-infarction angina*)
- Variant angina
What is stable angina caused by?
a fixed coronary artery obstruction secondary to atherosclerosis
What are signs and symptoms of stable (classic) angina?
Episodic, paroxysmal, substernal or precordial pressure, heaviness, pain or discomfort usually brought on by exertion and relieved by rest or nitrates (nitroglycerin)
Stable angina attacks are of ______ (usually no longer than 15 to 20 minutes), are _____ and usually follow a _____ that is associated with a temporary increase in demands on the heart
- limited duration
- predictable
- precipitating event
How are stable angina symptoms relieved?
by decreasing the cardiac metabolic demand (i.e., rest from exertion) or by administration of nitroglycerin
What is unstable angina (pre-infarction angina)?
Attacks occur more frequently, are longer, and produce more severe symptoms than those in stable angina. The anginal pain also is more easily provoked and may occur at rest
the symptoms of unstable angina are often indistinguishable from
those of non-ST segment elevation myocardial infarction (NSTEMI)
patients experiencing symptoms of unstable angina usually require medical evaluation / hospitalization to rule-out ______
NSTEMI
(non-ST segment elevation myocardial infarction)
Unstable angina is usually defined by the presence of least one of three features:
(1) Anginal pain occurs at rest (or with minimal exertion) and usually lasting longer than 20 minutes
(2) Anginal pain is severe, and of new onset
(3) Anginal pain that occurs with a crescendo pattern
What is variant angina also known as?
Prinzmetal’s angina or vasospastic angina
What is the most important mechanism in variant angina?
Coronary artery vasospasm, with or without superimposed CAD
What are some signs and symptoms of variant angina?
Chest pain/discomfort is very similar or identical to that described in stable (classic) angina, but occurs at rest
What is Myocardial infarction (MI)
a clinical syndrome characterized by symptoms of myocardial ischemia, persistent electrocardiographic (ECG) changes, and release of biomarkers of myocardial necrosis resulting from an insufficient supply of oxygenated blood to an area of the heart
What is myocardial infarction (MI) a result of?
irreversible myocardial injury, occurring as a result of prolonged ischemia.
What is the underlying cause of MI?
The underlying cause essentially always is a complete interruption of regional myocardial blood flow
MI most frequently involves the _____ ventricle
left
What is the leading cause of MI?
Coronary artery atherosclerosis
The initiating factor in most cases of MI is what?
sudden disruption of partially occlusive coronary artery atherosclerotic plaque
What are some mechanisms of injury that cause Coronary artery atherosclerosis
- Rupture, fissuring, or ulceration of plaques
- hemorrhage into the core of plaques
How are MI commonly classified?
- The degree of ventricular wall involvement
- The location of the infarct within the heart or the specific artery involved:
- The presence or absence of ST segment elevation on the ECG
______ infarctions involve the full thickness of the ventricle. They typically result in _____ elevation on the ECG
- Transmural
- ST segment
Subendocardial infarctions are MIs limited to the _____ of the myocardium
inner-third
What type of infarct is most common in MI?
Infarcts resulting from a blockage of the left anterior descending coronary artery are most common
T/F MI associated with (ST segment elevation) MI (STEMI) are more common and should be distinguished from non-ST segment elevation MI (NSTEMI)
True
What is acute myocardial infarction (AMI)
used for MIs characterized by profound, acute transmural myocardial ischemia affecting relatively large areas of myocardium and associated with ST segment elevation on the ECG
What is the pathogenesis of Myocardial Infarction (MI)? (5 steps)
- An atheromatous plaque is suddenly disrupted
- Platelets adhere, aggregate, and are activated
- Growing (propagating) thrombus
- thrombus can evolve to completely occlude the coronary artery lumen
- Myocardial necrosis begins at approximately 30 minutes after occlusion of a coronary artery
What does the gross and microscopic appearance of an MI depends on?
The age of the injury
In MI, areas of damage progress through a highly characteristic sequence of morphologic changes from ______, to acute and then chronic _____, to ________
- coagulative necrosis
- inflammation
- fibrosis
What does myocardial necrosis proceed to?
proceeds invariably to scar formation without any significant regeneration
What is Acute MI most often characterized by?
a sudden onset of chest pain that is similar to the pain of angina but is more severe and prolonged, generally lasting more than 15 to 20 minutes, and is unrelieved by nitroglycerin
Specific symptoms of myocardial infarction include:
- Premonitory pain
- Pain of infarction
- Other associated symtoms
How many patients of MI have premonitory pain?
One-third of patients give a history of alteration in the pattern of angina, recent onset of typical or atypical (unstable) angina, or unusual “indigestion” or pressure or squeezing felt in the chest.
When do most infarctions of AMI occur? What is the most common symotpom?
- Most infarctions occur at rest
- chest pain/discomfort
______ has little effect in reliving chest pain in an AMI
Nitroglycerin
What are associated symptoms of AMI?
- cold sweat (diaphoresis)
- feel weak and apprehensive
- Light-headedness
- syncope
- dyspnea
- orthopnea
- cough
- wheezing
- nausea and vomiting
- abdominal bloating
AMIs may also be ______ (“silent”) or have _____ (unrecognized) symptomatology
- painless
- atypical
Who is more prone to painless or atypical MI?
Elderly patients, female patients and those with diabetes
the diagnosis of MI has rested on the triad of what?
(1) ischemic-type chest discomfort
(2) ECG abnormalities, and
(3) elevated serum cardiac markers.
What has assumed the primary role in confirming the diagnosis of AMI
Serum cardiac markers (also called cardiac isoenzymes)
What have been shown to be specific indicators of MI and have gained acceptance as the primary diagnostic criterion for MI.
Cardiac-specific Troponins T and I (cTnT, cTnI)