Cardio day 1 Flashcards
Describe the flow of electricity through the heart as well as the normal blood flow
o Electrical Flow:
o SA Node → AV Node → Bundle of His → Right and Left Bundle Branches → Purkinje Fibers.
o Blood Flow:
o Deoxygenated Blood:
o Superior/Inferior Vena Cava → Right Atrium → Tricuspid Valve → Right Ventricle → Pulmonary Valve → Pulmonary Artery → Lungs.
o Oxygenated Blood:
o Lungs → Pulmonary Veins → Left Atrium → Mitral Valve → Left Ventricle → Aortic Valve → Aorta → Systemic Circulation.
What are the 3 intrinsic factors that influence stroke volume
preload, afterload, contractility
Describe preload
Definition: Preload is the degree of stretch of the cardiac muscle fibers at the end of diastole, just before contraction. It reflects the volume of blood filling the ventricles.
Influence on SV: According to the Frank-Starling law of the heart, an increase in preload (more blood in the ventricles) results in a stronger contraction and increased stroke volume, up to a certain point.
Describe afterload
Definition: Afterload is the resistance the heart must overcome to eject blood during systole. It is influenced by systemic vascular resistance (SVR) and arterial pressure.
Influence on SV: Increased afterload (e.g., from high blood pressure) can reduce stroke volume because the heart has to work harder to eject blood. Conversely, decreased afterload can enhance stroke volume.
Describe contractility
Definition: Contractility refers to the intrinsic ability of the heart muscle to contract. It is independent of preload and afterload.
Influence on SV: Increased contractility (due to factors such as sympathetic stimulation or inotropic drugs) enhances stroke volume.
Decreased contractility (due to heart failure or negative inotropic agents) reduces stroke volume.
What are the 6 extrinsic factors that influence stroke volume
Heart rate, sympathetic nervous system, venous return, blood volume, aortic compliance, and medications/substances
Describe heart rate’s influence on stroke volume
While heart rate itself does not directly affect stroke volume, it can influence the total cardiac output (CO). Very high heart rates can reduce the time available for ventricular filling (diastole), potentially decreasing stroke volume
Describe Sympathetic Nervous System’s influence on stroke volume
Increased sympathetic activity boosts contractility and can increase stroke volume. It also has a positive chronotropic effect, which can indirectly influence stroke volume by affecting the filling time.
Describe venous return’s influence on stroke volume
An increase in venous return increases preload, which can enhance stroke volume through the Frank-Starling mechanism.
Describe Blood Volume’s influence on stroke volume
An increase in blood volume can lead to increased preload, thereby enhancing stroke volume. Conversely, reduced blood volume (e.g., due to dehydration or hemorrhage) can decrease stroke volume.
Describe aortic compliance’s influence on stroke volume
Definition: Aortic compliance refers to the ability of the aorta to stretch and accommodate the stroke volume.
Influence on SV: Decreased aortic compliance (e.g., due to aging or arteriosclerosis) can increase afterload and reduce stroke volume.
Describe Medications and Substances’ influence on stroke volume
Inotropic Agents: Medications such as digoxin or beta-agonists can increase contractility and stroke volume.
Vasodilators: Drugs that decrease systemic vascular resistance can reduce afterload and improve stroke volume.
Diuretics: By reducing blood volume, diuretics can decrease preload and potentially reduce stroke volume.
Define Stroke volume (SV)
is the amount of blood ejected from the left ventricle of the heart with each heartbeat.
Describe Cardiac output (CO)
the volume of blood pumped by the heart per minute and is a crucial indicator of heart function.
Factors Influencing Cardiac Output:
Stroke Volume (SV):
Preload: Affects ventricular filling and stroke volume.
Afterload: Affects the resistance against which the heart pumps.
Contractility: Affects the strength of heart muscle contractions.
Heart Rate (HR):
Autonomic Nervous System Activity: Influences heart rate.
Hormones and Medications: Affect heart rate and contractility.
Exercise: Can increase heart rate and stroke volume.
Blood Volume and Venous Return:
Blood Volume: Affects preload and cardiac output.
Venous Return: Influences preload and cardiac output.
Cardiac Function and Health:
Heart Size, Function, and Intracardiac Pressures: Affect overall cardiac output.
What is the difference between systole and diastole
systole is the contraction of a ventricle
diastole is the relaxation of the ventricle
How do you calculate cardiac output
CO = SV*HR
80 mL/beat*70 beats/min = 5600 mL /min=5.6L/min
What do positive chronotrope medications do?
Positive chronotropes speed things up (epi, atropine)
What do negative chronotrope medications do?
negative chronotropes slow them down (beta blocker)
What affects afterload
Afterload: Resistance ventricles must overcome to pump the blood influenced by (how tight the arteries are) :
Hypertension
Atherosclerosis
Vasoconstriction
What is a resting CO
resting is 5-6 L /min
Name an example of the heart compensating for an increased SV, by decreasing HR
Cardiovascular conditioning
Name an example of the heart compensating for compensate decreased SV by increasing the HR
Hypovolemia
How much urine should be produced an hour if the kidneys are being well perfused
need 30ml/hour
what does a chemistry panel tell us about heart function/health
Calcium: Abnormal calcium levels can affect heart rhythm and contractility. High calcium (hypercalcemia) can lead to arrhythmias, while low calcium (hypocalcemia) can also impact heart function and lead to muscle cramps or spasms.
Potassium (K+): Potassium is essential for proper heart rhythm, muscle function, and nerve transmission. High potassium (hyperkalemia) can cause dangerous cardiac arrhythmias, while low potassium (hypokalemia) can also affect heart rhythm and muscle function.
Magnesium: Magnesium is essential for the normal functioning of cardiac ion channels, including those that regulate sodium, potassium, and calcium influx and efflux in heart cells. Adequate magnesium levels help maintain a regular heart rhythm and prevent arrhythmias (irregular heartbeats). Magnesium deficiency is associated with increased vascular resistance and higher blood pressure.
What is BNP
Definition: B-type natriuretic peptide (BNP) is a hormone produced by the heart’s ventricles in response to increased pressure and stretching of the heart muscle.
Production: BNP is released when the heart is under stress, such as in heart failure, and helps regulate blood pressure and fluid balance by promoting vasodilation (widening of blood vessels) and increasing sodium excretion through the kidneys.
Name the most commonly known cardiac enzyme and what it indicates
Troponin
Proteins involved in muscle contraction. They are highly specific to cardiac muscle. Troponin levels rise within a few hours after myocardial injury and can remain elevated for several days. They are the most sensitive and specific markers for myocardial infarction (MI or heart attack).
Describe the importance of total cholesterol lab findings
High Total Cholesterol: Elevated total cholesterol levels can be a marker of increased risk for cardiovascular diseases, including atherosclerosis (hardening of the arteries), coronary artery disease, and heart attacks.
LDL Cholesterol: High levels of LDL cholesterol are particularly concerning as they contribute to the formation of atherosclerotic plaques in the arteries, which can lead to reduced blood flow and increased risk of heart disease.
HDL Cholesterol: Low levels of HDL cholesterol are associated with a higher risk of cardiovascular disease, as HDL helps remove LDL cholesterol from the bloodstream.
Describe the importance of triglyceride lab findings
High triglycerides usually mean you aren’t metabolizing energy stores from food correctly. High tri can contribute to the formation of atherosclerotic plaques and are often seen in conditions such as metabolic syndrome, diabetes, and obesity.
What is the purpose of an echocardiogram
look at heart structure and measure output and check valve function
Why would you perform a cardiac stress test
looking for abnormal change in rhythm during exercise
What is a Percutaneous Transluminal Coronary Angioplasty (PTCA)
go in with a balloon and widen the narrowed artery
What is a Directional Coronary Atherectomy (DCA):
screws plaque out of the artery
What do you need to ensure as a nurse prior to your patient’s cardiac cath
ensure that the patient does not have allergy to iodine/shellfish before procedure
Describe the post-cardiac cath procedure protocol
Vital signs every 15 minutes x 4
every 30 minutes x 2
then every hour x4
then every 4 hours
PERFORM NEURO CHECKS EVERY TIME
Describe the post-cardiac cath procedure protocol WHEN THE FEMORAL ARTERY WAS ACCESSED
Patient has to lay flat for prescribed time (usually 6 hours)
How do you assess a patient’s pulse and sensation is intact after a cardiac cath procedure
check a pulse site that is DISTAL to the catheter insertion site
Where does the borrowed vein attach on the heart during a CABG procedure
Attach borrowed vascular at aorta and place the other end BELOW WHERE BLOACKAGE IS so the tissue gets direct perfusion
Describe the best-case post-op CABG outcome
Extubated as soon as possible (as soon as 4 to 8 hours after surgery)
Pt meets VS parameters set by the surgeon
After stable and extubated, patient is encouraged to walk and move as much as possible
discharge by post-op day 2-3
How do you monitor for adequate perfusion
Level of consciousness, blood pressure, UrineOP, cap refill etc.
Medications that lower heart rate include:
Beta-blockers (e.g., atenolol, metoprolol)
Calcium channel blockers (e.g., verapamil, diltiazem)
Digoxin
Antiarrhythmics (e.g., amiodarone, sotalol)
Centrally acting agents (e.g., clonidine)
Describe the cardiac diet
Low saturated fat (lean meat)
high complex carbohydrate diet (oatmeal)
High fiber diet (reduces fat in blood)
Possible fluid or sodium restriction
Diabetes control (hypergly effects outcomes)
No alcohol (causes cardiomegaly) or Smoking
Describe the symptoms of coronary artery disease
Angina Pectoris: Chest pain or discomfort, often described as a squeezing or pressure sensation, that occurs when the heart muscle does not get enough oxygen-rich blood. It may radiate to the left arm, neck, jaw, or back.
Shortness of Breath: Especially during physical activity or stress.
Fatigue: Unusual tiredness, particularly during physical exertion.
Palpitations: Irregular or rapid heartbeats
Nausea or Indigestion: Often mistaken for gastrointestinal issues.
Sweating: Excessive sweating or cold sweat, particularly with chest pain.
Asymptomatic CAD:
Silent Ischemia: Some individuals may not experience noticeable symptoms but may still have underlying CAD, especially in individuals with diabetes.
Describe lab findings of coronary artery disease
Lipid Profile:
Total Cholesterol: Elevated levels increase CAD risk.
Low-Density Lipoprotein (LDL) Cholesterol: High levels are associated with increased risk of atherosclerosis.
High-Density Lipoprotein (HDL) Cholesterol: Low levels are a risk factor for CAD.
Triglycerides: Elevated levels can also contribute to cardiovascular risk.
2.2 Cardiac Biomarkers:
Troponin: Elevated levels may indicate myocardial injury, such as in acute coronary syndrome.
BNP: Elevated levels can suggest heart failure, which may be associated with CAD.
Other Tests:
Fasting Blood Glucose or HbA1c: Elevated levels may indicate diabetes, a risk factor for CAD.
High-Sensitivity C-Reactive Protein (hs-CRP): Elevated levels may indicate inflammation associated with CAD.
