Cardiovascular System Notes

Foundational Concepts in Cardiovascular System

  • EKG is a separate recording.

  • Foundational concepts need to be reviewed for cardiovascular.

  • Cardiovascular is intertwined with every other body system.

  • Cardiovascular has a more visual component compared to neurological.

  • Visualize blood inside blood vessels and the heart.

  • Use a picture of the cardiovascular system (8.5x11 recommended).

  • Tracing a drop of blood through the heart is a helpful visual aid.

  • Cardiopulmonary system is the most important part.

  • Everything is built on these concepts.

Medications

  • Basic cardiovascular drugs are given daily to patients with cardiovascular disorders.

Blood Flow

  • Veins flow into the vena cava.

  • Vena cava empties into the right side of the heart.

  • Liver cleans the blood before it goes to the vena cava.

  • Blood goes from the right side of the heart into the lungs to get oxygenated, then to the left side, and then the left side pumps it out to the body.

  • Whatever happens in the heart can affect the lungs and vice versa.

  • COPD can cause right-sided heart failure due to high pressure in the lungs.

  • Blood flow order: Veins -> Right side -> Lungs -> Left side -> Arteries.

  • Heart's job is to propel blood forward and keep it moving.

Arteries and Veins

  • Arteries take oxygenated blood to the tissues or organs.

  • A for arteries, A for away: Arteries take blood away from the heart.

  • Arteries take blood to the tissues.

  • Most arteries take oxygenated blood to the tissues.

  • Veins take deoxygenated blood to the heart.

Preload and Afterload

  • Preload: Amount of stretch of the heart muscle as it fills up prior to contraction.

  • Analogy: Water balloon stretching as it fills.

  • Preload is mainly affected by blood volume and venous return.

  • Dehydration can drop preload, fluid volume overload can increase preload.

  • Diuretics affect preload by lowering the volume.

  • Afterload: Amount of resistance the heart has to pump against to get the blood out.

  • Analogy: How squeezed or constricted the neck of a water balloon is.

  • Afterload is mainly affected by the patency of the blood vessels.

  • Hypertension is one of the biggest causes of increased afterload.

  • Vasoconstriction or hypertension increases afterload.

  • Atherosclerosis also increases afterload.

  • Increased afterload is one of the big causes of left-sided heart failure.

  • Hypertension and atherosclerosis cause the heart to wear out pumping against resistance.

  • Vasodilating drugs (beta blockers, calcium channel blockers, ACE inhibitors, ARBs, nitroglycerin) decrease afterload.

Cardiac Output

  • Cardiac output: Amount of blood pumped out of the heart every minute.

  • Formula: Cardiac Output = Stroke Volume \times Heart Rate

  • Stroke volume: How much blood the heart can get out with every squeeze.

  • Heart rate: How many squeezes per minute.

  • Symptoms of decreased cardiac output are like those of decreased perfusion.

  • Decreased cardiac output means less volume going to the kidneys, so they conserve fluid.

  • Kidney conservation is the reason for fluid volume overload in heart failure.

  • In heart failure, the left ventricle is unable to get the blood out to the body sufficiently.

  • Kidneys conserve fluid, leading to a pile-up of volume on the venous side, causing congestion.

  • Symptoms of decreased cardiac output include: low urine output, low blood pressure, shortness of breath, confusion, lethargy, chest pain, cold/cyanotic/pale skin, weak pulse, dizziness, and tiredness.

Blood Pressure

  • Blood pressure is affected by the volume circulating times the diameter of the blood vessel.

  • The more constricted the vessels, the higher the pressure, and vice versa.

Renin-Angiotensin System

  • Result of the system is vasoconstriction, excretion of potassium, and retention of salt and water.

  • ACEs and ARBs block the system, causing vasodilation, retention of potassium, and excretion of salt and water.

  • ACEs and ARBs are good for heart failure because vasodilation decreases the workload of the heart.

  • ACEs and ARBs work in different parts of the system but have the same result.

  • Calcium channel blockers are usually not used in heart failure because they have been linked to poor outcomes.

  • Peripheral edema is helped with diuretics.

  • Fluid excretion from ACEs and ARBs helps more with blood pressure than edema.

Beta Blockers and the Sympathetic Nervous System

  • Sympathetic nervous system increases heart rate and blood pressure (fight or flight).

  • Peripheral blood vessels constrict to push blood to vital organs.

  • Beta blockers block the sympathetic nervous system, lowering heart rate and blood pressure.

Heart Failure

  • Heart muscle can no longer contract strong enough (systolic) or cannot fill/expand enough (diastolic).

  • Either way, cardiac output drops.

  • Causes: Anything that damages, destroys, or overworks the heart cells.

  • Overworking the heart muscle causes it to get bigger (hypertrophy), which makes the space inside smaller.

  • Damaging or destroying heart cells weakens the squeezing ability.

  • Hypertension makes the heart work harder.

  • Coronary artery disease decreases oxygen to the heart muscle.

  • Heart valve issues overstress the heart muscle (e.g., aortic stenosis).

  • AFib (irregularity) can wear out the heart muscle.

  • Right side of the heart would be affected by pulmonary hypertension and would lead to right sided heart failure.

  • Symptoms of congestion occur where the blood came from.

  • Left-sided failure leads to congestion in the lungs while right-sided failure leads to systemic congestion (the blood backs up into the veins).

  • Left sided heart failure can lead to pulmonary hypertension, which can cause right sided heart failure.

  • Right-sided failure: Blood came from the venous system, so you'll have systemic symptoms of congestion. Jugular vein distention, hepatomegaly, peripheral edema, nausea, anorexia.

  • Left-sided failure: Pulmonary congestion. Shortness of breath, crackles, orthopnea, the need to sit up or lean forward.

  • Left-sided failure: Weakness, fatigue, confusion, decreased pulses. Signs and symptoms of decreased cardiac output.

  • Crackles, minor shortness of breath, are common - increasing shortness of breath is not.

Acute Pulmonary Edema

  • Pink frothy sputum is a very serious and ominous finding during pulmonary edema.

  • What to do:

    • Diuretics

    • Sit them up to expand lungs

    • Nitroglycerin

    • High oxygen

    • IV loop diuretics like furosemide.

    • High Fowler's with legs down

    • Oxygen

  • Regular Heart Failure: Diuretics, ACEs, ARBs, beta blockers, nitrates, digoxin.

A-Fib

  • Treated more in depth in the EKG recording.

Atherosclerosis

  • Formation of plaque within the walls of the arteries.

  • Arteriosclerosis is the result of plaque hardening.

  • Atherosclerosis can lead to blood clot formation and narrow blood vessels.

  • Labs:

    • High LDL, low HDL, high cholesterol and triglycerides.

    • Teaching

      • Eat healthy to lower LDL

      • Exercise 3-4 times a week for 30 mins at a time to increase HDD.

  • Blood pressure is expected to go up.

Coronary Artery Disease

  • Coronary arteries supply the heart muscle with blood.

  • Coronary artery disease involves the creation of plaque within the walls of the coronary arteries, reducing blood flow to the heart muscle.

  • Angina: Chest pain due to decreased blood flow to the heart muscle.

  • Stable angina: Predictable chest pain that occurs with exertion and is relieved by rest or nitroglycerin.

  • Unstable angina: Unexpected chest pain that occurs at rest or with minimal exertion and is not relieved by rest or nitroglycerin.

  • Angina can lead to myocardial infarction.

Myocardial Infarction (Heart Attack)

  • Heart cells are dying due to lack of oxygen.

  • Labs:

    • Elevated troponin (most specific).

    • Elevated CKMB.

    • Elevated myoglobin (least specific).

  • EKG changes:

    • ST elevation.

    • T wave inversion.

    • Pathologic Q waves.

Valvular Disorders

  • Stenosis: Narrowing of the valve.

  • Regurgitation: Leaking of the valve.

  • Mitral valve stenosis: Narrowing of the mitral valve.

  • Mitral valve regurgitation: Leaking of the mitral valve.

  • Aortic valve stenosis: Narrowing of the aortic valve.

  • Aortic valve regurgitation: Leaking of the aortic valve.

Arrhythmias

  • Bradycardia: Slow heart rate (less than 60 bpm).

  • Tachycardia: Fast heart rate (greater than 100 bpm).

  • Atrial fibrillation (A-Fib): Irregular heart rate due to chaotic electrical activity in the atria.

  • Ventricular tachycardia (V-Tach): Fast heart rate due to rapid electrical activity in the ventricles.

  • Ventricular fibrillation (V-Fib): Chaotic electrical activity in the ventricles, leading to cardiac arrest.

Pacemakers and Implantable Cardioverter-Defibrillators (ICDs)

  • Pacemaker: Electronic device that stimulates the heart to beat.

  • ICD: Electronic device that delivers an electrical shock to the heart to stop life-threatening arrhythmias.

Cardiac Catheterization

  • Invasive procedure to visualize the heart and blood vessels.

  • Stent placement: Placement of a small mesh tube to open up a blocked artery.

  • Angioplasty: Procedure to open up a blocked artery using a balloon.

Congenital Heart Defects

  • Heart defects that are present at birth.

  • Ventricular septal defect (VSD): Hole

  • Ventricular septal defect (VSD): Hole in the wall separating the ventricles.

  • Atrial septal defect (ASD): Hole in the wall separating the atria.

  • Tetralogy of Fallot: Combination of four heart defects.

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