Ischemic Heart Disease Flashcards
What is the definition of ischemic heart disease?
Narrowing of one or more coronary arteries due to atherosclerosis
Also known as:
Coronary heart disease, coronary heart disease, atherosclerotic cardiovascular disease
What is a common outcome of ischemic heart disease?
Heart attack (myocardial infarction)
What percentge of deaths in Canada are due to a cardiovascular cause?
20% of deaths
Has MI risk declined in Canada?
Yes, 50 year olds have a lower MI risk vs. 50 year olds from decades away
Is the percentage of people who have lived through an MI increasing?
Yes, largely due to better healthcare and lower mortality rate
Do MIs increase death rate?
Yes
What is the death rate following an MI in patients over 80?
Almost 50% of MI patients over 80 will die within a year
What are the main types of cardiovascular diseases caused by artherosclerosis?
Ischemic heart disease
Cerebrovascular disease
Peripheral arterial disease
When do atherosclerotic plaque begin to build up?
Usually, start to build up early in one’s life.
These plaques can be present for decades without symptoms
What is the clinical presentation of coronary atherosclerosis?
Silent (asymptomatic) disease in most patients
Chronic, but stable angina
What are the classic signs of angina?
Dull, retrosternal discomfort/ache/heaviness
The pain may or may not radiate to jaw, neck, shoulders, arms
What is stable angina?
Stable angina is a problem of demand exceeding supply. The pain from ischemia will go away once resting
What is unstable angina?
Unstable angina is a result of inadequate supply regardless of demand. The pain from ischemia will not go away following rest
What are some triggers of stable angina?
SNS activity: Physical exertion, emotion
Exertion after a heavy meal: (reduced SNS and increased metabolic demands)
Metabolic demands: chills, fever, hyperthyroidism, tachycardia, exposure to cold, and hypoglycemia
Anemia: low oxygen content in blood (CO increases to rectify this issue)
Are coronary arteries supplied with blood during systole?
No, during systole the heart muscle contracts, including the coronary arteries that supply the heart with blood.
Only during diastole, when the heart is relaxed does blood flow into the coronary heart disease
How do atherosclerotic plaques cause stable angina?
Due to atherosclerotic plaques, the blood vessels are constricted. The constricted blood vessels limit supply, so the efferent vessels dilate to allow for more blood flow.
During exercise, the heart begins to beat faster and needs more blood supply, but the vessels have been maximally diated during rest due to the narrowed vessel. When demand increases, the efferent vessels cannot dilate any further causing supply to fall below demand.
What changes can relieve stable angina?
Stable angina is relieved by rest and nitroglycerin
What is the function of nitrate drugs?
A class of drugs that cause vasodilation. Nitrate drugs preferably dilate veins over arteries
They are all prodrugs and are converted into NO in the body
How is NO released endogenously?
NO is a paracrine hormone that is synthesized by endothelial cells to signal adjacent smooth muscle cells that surround vessels
How does NO treat stable angina?
NO reduces venous pressure. The consequence of this is preload or venous return is lower. This reduces heart workload, so CO declines. This reduced heart activity reduces demand to a level that can be accommodated with a lowered blood supply. This takes the heart muscle out of ischemia
How are different severities of angina ranked?
Class I angina is the lowest severity (walking, and climbing stairs does not cause angina, but prolonged exertion at work or recreation)
Class IV is the highest severity, and these patients have the inability to carry on any physical activity without discomfort
What are some pieces of information that would rule out angina in the diagnosis of chest pain?
Occurs after heavy meals
Associated with belching and gas
Relieved by food, liquids, antacids
Occurs with inspiration/expiration
What is a good diagnostic test for angina?
Excercise stress test
How are readings from a exercise stress test interpreted?
As the reading occurs, the treadmill increases incline and speed. Patients are asked to go to as long as they get tired or have chest pain.
If the patient can exercise without having angina during a prolonged session of exercise, we can rule out cardiac atherosclerosis
What does angina look like on an ECG chart?
Depression of the S-T segment of the ECG relative to the Q-R segment
What is the following step after a positive finding of ischemia in the stress test?
Coronary angiogram
Is stable angina a medical emergency?
No, as long as rest and NO resolves angina
What are some ways to evaluate coronary artery blood flow?
Cardiac catheterization and angiography
What is a common series of drugs prescribed to people with coronary artery disease?
ABCKDE
Antiplatelets
BP medications
Cholesterol-lowering medications
K-CKD
Diabetes medications
Exercise/diet/lifestyle changes
What are the goals of therapy for angina?
Goals of therapy should include both symptom relief and protection
What are some drugs that are indicated to prevent or reduce the frequency/intensity of stable angina episodes?
beta-blockers
DHP CCBs
Non-DHP CCBs
Nitrates
Ranolazine
How do beta-blocker prevent angina?
Reduce CO, which reduces demand in the heart tissue
b1 selective agents are preferred due to lower risk of:
ED
Peripheral circulation problems
Interaction with b2 agonists
What are some monitoring considerations in beta-blocker use?
Reduced HR and BP
Signs of poor CO
Reduced circulation (Reynauds’s)
Respiratory (Asthma)
Diabetes (mask hypoglycemia)
Are non-selective b-blockers and a-blockers used to treat stable angina?
Not typically used for stable angina (unless complications exist)