Assessment of the Cardiovascular System Flashcards

Anatomy and Physiology of the Heart

  • Location and Position of the Heart: The heart is centrally located within the thoracic cavity, acting as the primary pump for the cardiovascular system.

  • Layers of the Heart:

    • Pericardium: The outermost protective sac surrounding the heart.

    • Epicardium: The visceral layer of the pericardium.

    • Myocardium: The muscular middle layer responsible for pumping action.

    • Endocardium: The inner lining of the heart chambers.

  • Heart Chambers and Great Vessels:

    • Chambers: Right atrium, left atrium, right ventricle, and left ventricle.

    • Vessels: Pulmonary artery, aorta, superior vena cava (SVC), inferior vena cava (IVC), and pulmonary veins.

    • Heart Valves:

      • Atrioventricular Valves (AV): Include the Tricuspid valve (right side) and the Mitral (Bicuspid) valve (left side).

      • Semilunar Valves: Include the Pulmonic valve and the Aortic valve.

  • Coronary Vessel Circulation: Supplies oxygenated blood to the myocardium.

    • Left Anterior Descending (LAD)

    • Circumflex

    • Right Coronary Artery (RCA)

Blood Flow Dynamics

  • Connection of Systems: The heart acts as the bridge connecting systemic circulation and pulmonary circulation. All blood returning from systemic circulation must pass through the pulmonary circuit to exchange carbon dioxide (CO2CO_2) for oxygen (O2O_2).

  • Step-by-Step Sequence of Blood Flow:

    1. Entry: Blood from the upper body enters through the superior vena cava; blood from the lower body enters through the inferior vena cava.

    2. Right Atrium: Blood enters the right atrium.

    3. Right Ventricle Filling: The right atrium contracts, forcing blood through the open tricuspid valve into the relaxed right ventricle.

    4. Tricuspid Closure: As the right ventricle contracts, the tricuspid valve closes to prevent backflow into the atrium.

    5. Pulmonary Circulation: The pulmonary semilunar valve opens; the right ventricle pumps blood into the pulmonary artery toward the lungs.

    6. Gas Exchange: Blood travels through lung tissues (alveoli) to exchange CO2CO_2 for O2O_2.

    7. Left Atrium: Oxygenated blood returns via the main pulmonary veins into the left atrium.

    8. Left Ventricle Filling: The left atrium contracts, moving blood through the open bicuspid (mitral) valve into the left ventricle.

    9. Mitral Closure: As the left ventricle contracts, the bicuspid valve closes.

    10. Systemic Distribution: The aortic semilunar valve opens, and the left ventricle pumps blood into the aorta for distribution to all body cells and tissues.

    • Note: Systemic circulation begins at the left ventricle, while pulmonary circulation begins at the right ventricle.

Electrophysiology and Conduction

  • Properties of Cardiac Cells:

    • Automaticity: The ability to generate an electrical impulse independently without external nervous system stimulation.

    • Excitability: The ability of cells to respond to an electrical stimulus.

    • Conductivity: The ability to propagate an electrical impulse from one cell to the next.

    • Contractility: The mechanical activity or squeezing response of the heart.

  • Conduction System Sequence:

    1. Sinoatrial (SA) Node (Primary pacemaker)

    2. Atrioventricular (AV) Node

    3. Bundle of His

    4. Bundle Branches

    5. Purkinje Fibers

  • Depolarization Process:

    • The heart begins in a polarized or resting state.

    • Electrical stimulation changes cell permeability.

    • Conductivity rapidly moves depolarization across cells.

    • Cells must return to a state of internal negativity (resting state) for subsequent depolarization to occur.

Mechanical Properties and Cardiac Output

  • Cardiac Output (CO): The total volume of blood pumped by the left ventricle in one minute.

    • Formula: CardiacOutput=stroke volume×heart rateCardiac Output = \text{stroke volume} \times \text{heart rate}

    • Example: 70 ml×75 beats/min=5250 ml/min70\text{ ml} \times 75\text{ beats/min} = 5250\text{ ml/min}

  • Definitions of Components:

    • Heart Rate (HR): The number of times ventricles contract per minute, determined by the Autonomic Nervous System (Parasympathetic and Sympathetic).

    • Stroke Volume (SV): The amount of blood ejected by the left ventricle during a single contraction.

  • Factors Affecting Cardiac Output:

    • Preload: The volume of blood in the ventricles at the end of diastole (degree of myocardial stretch).

      • Starling’s Law of the Heart: Stroke volume increases in response to an increase in the volume of blood filling the heart (i.e., increased preload=increased CO\text{increased preload} = \text{increased CO}).

      • Increased in: Hypervolemia, regurgitation of valves, and Heart Failure.

    • Afterload: The resistance the ventricles must pump against to circulate blood.

      • Afterload is higher for the left ventricle than the right ventricle.

      • Increased afterload=decreased CO\text{Increased afterload} = \text{decreased CO}.

      • Increased in: Hypertension and Vasoconstriction.

    • Contractility: The force of contraction (inotropic state).

      • Timing: 1/31/3 systole (contraction); 2/32/3 diastole (resting and filling).

      • Increased contractility=increased CO\text{Increased contractility} = \text{increased CO}.

    • Heart Rate Effects:

      • Slight increase in HR: Increases CO (CO=increased HR×SVCO = \text{increased HR} \times SV).

      • Extreme increase in HR: Decreases CO because filling time is reduced (CO=increased HR×decreased SVCO = \text{increased HR} \times \text{decreased SV}).

Nervous System Control and Aging

  • Sympathetic Nervous System: Controls all heart components by releasing Norepinephrine.

    • Causes positive chronotropic (increased HR) and positive inotropic (increased contractility) effects.

  • Cardiovascular Changes Associated with Aging:

    • Decreased vessel elasticity.

    • Increased calcification of vessels.

    • Impaired valve function.

    • Decrease in muscle tone (including the heart).

    • Decrease in baroreceptor response to blood pressure (BP) changes.

    • Decreased conduction ability of the heart.

Cardiovascular System Assessment

  • Patient History:

    • Obtain demographic data, family history, and genetic risks.

    • Assess Modifiable Risk Factors vs. Nonmodifiable Risk Factors.

    • Review Medical History and previous treatments for Cardiovascular Disease (CVD).

  • Current Health Problems (Symptoms):

    • Pain or discomfort.

    • Dyspnea, Dyspnea on Exertion (DOE), Orthopnea, Paroxysmal Nocturnal Dyspnea (PND).

    • Fatigue, Palpitations, Edema, Syncope, Extremity pain.

  • Fluid Balance Indicator: Weight is the best indicator of fluid balance.

    • Conversion: 2.2 lb=1 kg=1 L of fluid2.2\text{ lb} = 1\text{ kg} = 1\text{ L of fluid}

  • Physical Assessment:

    • Skin: Cyanosis, temperature, and moisture.

    • Extremities: Clubbing, edema, and color.

    • Pulses: Venous and arterial pulses.

Precordium and Auscultation

  • Precordium Assessment: Involves inspection, palpation, and auscultation of the area over the heart.

  • Heart Sounds:

    • Normal heart sounds (S1,S2S_1, S_2).

    • Gallops: Ventricular Gallop (S3S_3) and Atrial Gallop (S4S_4).

    • Murmurs and Pericardial friction rubs.

  • 5 Areas for Listening (Auscultation):

    • Aortic: Right 2nd Intercostal Space.

    • Pulmonic: Left 2nd Intercostal Space.

    • Erb’s Point (S1,S2S_1, S_2): Left 3rd Intercostal Space.

    • Tricuspid: Lower Left Sternal Border (4th Intercostal Space).

    • Mitral: Left 5th Intercostal Space, Medial to Midclavicular Line.

    • Mnemonic: "All People Enjoy Time Magazine"

Gender and Laboratory Diagnostic Considerations

  • Gender Health Considerations:

    • Women may experience a "Triad of Symptoms": weakness/fatigue, indigestion, and a "strangling" sensation.

    • Risk is higher in postmenopausal women.

    • Waist and abdominal obesity are greater risk factors than hip and thigh obesity.

  • Serum Markers of Myocardial Damage:

    • Troponin: Troponin T and Troponin I.

    • Creatine Kinase (CK): Specifically CK-MB.

    • Myoglobin.

    • Serum Lipids.

  • Additional Laboratory Tests:

    • Blood coagulation studies.

    • Arterial Blood Gas (ABG).

    • Complete Blood Count (CBC): Monitoring H&H (Hemoglobin and Hematocrit), WBC, and RBC.

Diagnostic and Hemodynamic Monitoring

  • Diagnostic Tests:

    • Electrocardiography (ECG).

    • Electrophysiologic study (EPS).

    • Exercise electrocardiography (Stress Test).

    • Echocardiography: Pharmacologic stress echocardiogram or Transesophageal echocardiogram (TEE).

    • Lexiscan.

    • Cardiac Catheterization (routes via femoral vein, SVC, IVC, pulmonary artery, or right ventricle).

  • Hemodynamic Monitoring:

    • Purpose: Identify abnormal physiology and intervene before organ failure or death.

    • Arterial Line: Placed in radial or femoral artery; measures blood pressure and allows for blood sampling.

    • Central Venous Pressure (CVP): Placed in internal jugular (CVC); serves as an indicator of fluid volume.

    • Phlebostatic Axis: The zero point for the transducer; located at the 4th intercostal space and the midaxillary line.

Focused Cardiovascular Assessment Checklist

  • Obtain vital signs, including pulse oximetry and rhythm strip.

  • Elicit cardiovascular history.

  • Assess chest shape/symmetry and landmarks (Aortic, Pulmonic, Erb’s point, Tricuspid, Mitral, and Point of Maximum Impulse [PMI]).

  • Auscultate using the diaphragm at all landmarks.

  • Repeat auscultation using the bell, noting S1,S2S_1, S_2, and extra sounds.

  • Turn client to the left side when using the bell to detect extra heart sounds.

  • Grade peripheral pulses: carotid, temporal, brachial, radial, femoral, popliteal, dorsalis pedis, and posterior tibial.

  • Assess for edema (peripheral/central) and recent weight gain.

  • Inspect skin color and check for postural hypotension or paradoxical blood pressures.

  • Document and report all pertinent observations.