Heart/Blood Vessels

Shock

Describe characteristics of hypovolemic shock

  • Decreased blood volume

  • Reduced by 15% of normal volume

  • Hemorrhage, burns, diarrhea, polyuria

Describe characteristics of cardiogenic shock

  • Inadequate cardiac pumping

  • Usually an MI

  • Causes decreased CO, hypotension, decreased oxygen to body, pulmonary edema

Describe characteristics of obstructive and distributive shock states

Obstructive shock:

  • A blockage of blood circulation that prevents adequate blood oxygenation

    • Tension pneumo

    • Vena cava compression

    • Pulmonary compression

    • Tumors

    • High positive end expiratory pressure

    • Right ventricular failure

    • Tumors

Distributive shock

  • Hypovolemia caused by redistribution of intravascular volume

  • Most common

    • Sepsis

    • Anaphalaxis

    • Pancreatitis

    • Toxic shock syndrome

    • Spinal cord injury

    • Endocrine disorders

    • Adrenal insufficiency

Describe compensatory mechanisms that occur in shock states

  • Metabolic acidosis

  • RAAS system

  • Shunt blood to heart and brain

  • Promote CO

Describe complications associated with all shock

  • Chest pain, SOB, diaphoresis, tachycardia, tachypnea, cool/clammy, poor peripheral perfusion, restlessness, decreased metal function, poor urine output

Heart Failure

Define the terms preload, afterload, and cardiac contractility and analyze the physiologic effect of each on cardiac output.

  • Preload

    • End-diastolic pressure, the amount of stretch at the END of diastole when the ventricles are filled and almost ready to contract

  • Afterload

    • Arterial pressure, the pressure that the ventricles need exert to contract and eject blood

  • Cardiac contractility

    • The heart’s ability to eject blood

  • Cardiac output

    • The quantity of blood pumped by the heart in a given period of time

    • Heart rate x stroke volume

  • Stroke volume

    • The volume of blood pumped out of the heart’s left ventricle during systole. SV = End diastolic volume - end systolic volume.

Describe common etiologies of heart failure.

  • Heart failure: inadequate ability of the heart to pump blood and maintain adequate circulation

  • Etiologies:

    • MI, structural defects, infection, inflammation, hypertension, fluid volume overload, anemia

Differentiate left versus right sided heart failure.

  • Left heart failure (congestive heart failure)

    • Left ventricle is impaired

    • Results in pulmonary congestion and edema (backflow into pulmonary veins)

    • Cyanosis, exercise intolerance, poor urinary output, fluid/sodium retention, anorexia

  • Right heart failure (cor pulmonale)

    • Right ventricle is impaired

    • Deoxygenated blood cannot move back to pulmonary circulation

    • Backflow into systemic circulation (SVC/IVC)

    • Lower extremity edema

    • Often a consequence of left heart failure

    • Dyspnea, syncope, chest pain, weight gain, jaundice, edema

Describe the physiologic compensatory mechanisms that result in the manifestations of heart failure.

  • Improved venous return

  • Sympathetic nervous system

  • RAAS system

  • Enlarged heart muscle

  • Eventually fails, and myocardium becomes non compliant

Cardiac Conduction

Describe the cardiac conduction system

  • Specialized cells that are responsible for conducting electrical impulses in the heart, making sure that the heart muscle contracts

  • Sinoatrial (SA) node

    • The heart’s pacemaker

    • In the right atrium

    • Causes atrial contraction and sets heartbeat

  • Atrioventricular (AV) node

    • Gatekeeper

    • Located between atria and ventricles

    • Delays impulse from atrial before it passes to ventricles, allowing atria to fully contract and pump blood to ventricles

  • Bundle of His (AV Bundle)

    • Nerve cells that carry electrical signals from AV node to ventricles

  • Purkinje fibers

    • Conducting fibers that allow ventricles to have coordinated contractions

Describe the phases of cardiac action potential

Describe characteristics of Normal Sinus Rhythm

Describe characteristics and the effects of select atrial dysrhythmias

Describe characteristics and effects of select ventricular dysrhythmias

Identify and explain diagnostic test

CAD/MI/Cardiomyopathy

Describe blood flow in the coronary circulation

  • There is a right and left coronary artery that supply blood to the heart itself. They branch off of the aorta and provide oxygenated blood to the heart. There is also collateral circulation, accessory arterial and venous branches that can help take over given that the primary coronary arteries/veins fail.

Define acute coronary syndrome (ACS)and or myocardial infarction

  • Acute coronary syndrome (ACS)

    • A group of conditions that reduces or stops blood flow to the heart

    • Can include unstable angina or MI

  • Myocardial infarction (MI)

    • The total occlusion of one or more coronary arteries, resulting in ischemia and death of myocardial (heart muscle) tissues

    • The heart can only last 20 MINUTES without oxygen

    • MEDICAL EMERGENCY!!!

Explain the relationship between CAD and atherosclerosis

  • Coronary artery disease (CAD)/Coronary heart disease (CHD)

    • CAD is a disease that involves the narrowing of the coronary arteries, which reduces the blood flow to the heart muscle

    • This can cause:

      • Impaired conduction

      • Impaired cardiac pumping

      • Heart failure

  • Atherosclerosis

    • This is the buildup of plaque in the arteries, which causes them to narrow

    • It is the primary cause of CAD

Differentiate angina/ischemia from myocardial infarction

  • Angina

    • Chest pain when the heart muscle does not get enough blood

    • Caused by narrowed coronary arteries

    • Does not cause permanent damage

    • No or minimal changes in EKG

  • Ischemia

    • A condition where blood flow to any part of the body is reduced or blocked

  • MI

    • The total occlusion of the coronary arteries leading to depleted oxygen to the heart muscle

    • Can cause permanent damage/death

    • Typically leads to EKG changes (STEMI), but can also produce none (NSTEMI)

Differentiate between the pathophysiologic changes that occur with select cardiomyopathies

  • Cardiomyopathy

    • A disease that impairs the heart muscle from pumping

  • Cardiac hypertrophy (hypertrophic cardiomyopathy)

    • Disease that makes the heart muscle really big because it has too many demands

    • Less effective pumping

    • Primary

      • Inherited non-sex link autosomal dominant trait

    • Secondary

      • From an underlying condition (usually HTN)

Identify risk factors for all CAD/MI/cardiomyopathy

  • Family history

  • SMOKING

  • Hypertension

  • High cholesterol

  • Diabetes

  • C-Reactive protein

  • Hyperhomocysteinemia

    • Increased risk of clots

Hypertension

Define terms associated with hypertension (HTN)

Describe Types of HTN, risk factors and etiologies

Describe HTN in special populations

Describe characteristics of orthostatic hypotension

Be able to explain and apply the Renin angiotensin system (RAS)

Identify diagnostic criteria