MEDSURG 2 FINAL EXAM.
Medsurg 2 FINAL EXAM
Cardiac Assessment
Cardiac Conduction System
➢ Generates and transmits electrical impulses that stimulate contraction of the myocardium
➢ SA node AV node Bundle of his (branches into right and left) purkinjie fibers
➢ SA node which is the primary pacemaker of the heart
o A patient has a HR of 90. Means The SA node is working because normal HR is 60-100
o If the HR falls below the normal value, there is a problem!
➢ AV node which is the secondary pacemaker of the heart
o If the SA node malfunctions. The AV node will take over which has a lower rate such as 40-60 bpm
Cardiac Action Potential
Is the electrical cells generate and transmit impulses across the heart which will stimulate cardiac myocytes to contract. Stimulation of
these myocytes occurs due to the exchange of electrically charged particles (ions) across the channels located in the cell membrane
➢ In resting or polarized state
o Sodium is the primary extracellular ion
o Potassium is the primary intracellular ion
Terms of Cardiac Action Potential
o Depolarization: electrical activation of cell caused by influx of sodium into cell while potassium exits cell. THIS
CREATES A POSITIVELY CHARGED INTRACELLULAR SPACE AND NEGATIVELY CHARGED EXTRACEULAR
SPACE
o Repolarization: return of cell to resting state caused by re-entry of potassium into cell while sodium exits
o Refractory periods – cardiac cells must completely repolarize before they can depolarize AGAIN
o 2 phases of refractory period
o Effective refractory period: phase in which cells are incapable of depolarizing. It is completely unresponsive to ANY
electrical stimulus
o Relative refractory period: phase in which cells require stronger-than-normal stimulus to depolarize
Cardiac Hemodynamics
• HR x SV = Cardiac Output
• Cardiac output refers to the total amount of blood ejected by one of the ventricles in liters per minute.
• The cardiac output in a resting adult is 4 to 6 L/min but varies greatly depending on metabolic needs
• Cardiac output responds to changes in the metabolic demands of the tissues associated with stress, physical exercise,
and illness
o HR is affected by central nervous system activity and baroreceptor activity.
o HR is determined by rate and rhythm – if it is regular or irregular
o If HR is affected so is CO
o If the heart is not stretching enough – cardiac output is affected
o If the heart is not pumping – cardiac output is affected
• Stroke volume is determined by preload, afterload, and contractility
o Preload: refers to the degree of stretch of the ventricular cardiac muscle fibers at the end of diastole. The end of
Diastole is the period when filling volume in the ventricles is the highest and the degree of stretch on the muscle
fibers is the greatest (when it is filled with more and more blood = the greater the stretch = the greater the force
of contraction)
o Diastole is the relaxation/filling phase of the ventricles and once these have filled this is the preload. We can also
refer to preload as the EVD (it is at the end of the diastolic phase). Preload is the amount the ventricle stretched!
▪ Think of a balloon (such as the more air you blow in, the greater the stretch)
o Afterload: resistance to ejection of blood from the ventricles. This is the pressure required to overcome aortic
pressure. The higher the aortic pressure the harder the ventricles have to work – (the LV must overcome the
aortic pressure). The pressure in the ventricles work against to open the SL valves to pump blood out of the heart
o Contractility: refers to the force generated by the contracting myocardium (the more forceful the more blood that
is ejected)
• If there is an issue with cardiac output = perfusion issue because there is an issue with oxygenation and
flow components
• Low HR = CO is affected
• Increase in SV and HR = increase in CO
Age Related changes in cardiac
-Atria, LV, Valves (stiffen and no longer close properly), Conduction system, SNS (decreased response), aorta (stiffen), arteries
(stiffen), baroreceptor response (more sensitive)
,History and Physical
Health History which refers to the patient’s ability to recognize cardiac symptoms to know what to do when they occur it is essential
for effective self-care management
• Want CLEAR information when talking to the patient Chief complaint, Hx present illness & past medical history/social
history, Home meds, Nutrition, Allergies
Physical Assessment (Cardiac specific)
• General appearance, Skin and extremities
• Blood pressure pulse, and postural BP Below 30 is reduction in CO
• Arterial pulses rate, rhythm, amplitude
• Jugular venous pulsations fluid accumulation/overload
• Heart inspection and auscultation
• Any deviations from normal? Meaning changes in how the patient responds to how they are feeling. Such as a patient
with HF or circulatory issues will change their shoes due to their feet being swollen
o Heart as a pump
o Atrial/ventricular filling volumes
o Cardiac output
o Compensatory mechanisms
▪ What position does the patient lay in when they sleep?
▪ Tripod position patient is leaning forward. This is an indication of respiratory distress
MOST common clinical manifestation
• Ask why the pt would feel like this?
• Chest pain
• SOB, dyspnea fluid overload/pulmonary issue can lead to dyspnea
• Peripheral edema
• Weight gain
• Abd distention
• Fatigue
• Dizziness, Syncope, Changes LOC due to perfusion and oxygenation issues (brain likes oxygen)
• We know diuretic is working if the pt is peeing a lot and they feel less fatigue/dyspnea
Chest Pain
• Identify Quantity, location, quality, radiation, duration of pain , Associated S/S
• Assess for other cardiac conditions and for other significant conditions
• Angina Pectoris: uncomfortable pressure, squeezing, or fullness in substernal chest area. It can radiate across chest to
the medial aspect of one of both arms and hands, jaw, shoulders, upper back, or epigastrium. (BOOK)
• ACS: is the same as angina pectoris. Pain and discomfort ranges from mild to severe associated with SOB, diaphoresis,
palpitations, unusual fatigue, and n/v (BOOK)
• Pericarditis: sharp, severe substernal or epigastric pain which can radiate to necks, arms, and back.
• Pneumonia, pulmonary embolism sharp, severe substernal or epigastric pain arising from interior portion of pleura
• Hiatal hernia, GERD substernal pain described as sharp, burning, or heavy. Often mimics angina and can radiate to
neck, arm, or shoulders.
• Costochondritis musculoskeletal disorders. This is a sharp or stabbing pain localized in anterior chest. Most often is
unilateral and can radiate across chest to epigastrium or back
• Vascular
Diagnostic (laboratory values)
Hematologic Studies
• CBC identifies the total number of white and red blood cells and platelets and measures the Hgb and Hct. The CBC is
carefully monitored in a patient with cardiovascular disease
• Hct: 45%
• Hgb: 15%
• Platelets: 150,000-450,000
• WBC: 4,500-10,500
• RBC: 5
Cardiac Biomarker –
• serum biomarkers (can be used for a diagnosis of an MI)
• CK: 22-198 U/L. A high amount = damage
• CK-MB: 0-3. Elevated CK-MB is indicator of acute MI; the level begins to increase within a few hours.
• Myoglobin: 0-85 ng/mL. This is a protein which can tell if tissues are damaged
• Troponin: 0-0.4. This is a protein that is a marker for the heart. Elevated means the patient is having a problem with their
heart such as a heart attack
, • Myocardial cells that become necrotic from prolonged ischemia or trauma release specific enzymes (mentioned above).
These substances leak into the interstitial spaces of the myocardium and are carried by the lymphatic system into
general circulation
• This bundle becomes important, timing is important. Look at when do you see these levels start to rise (usually within
4- 6hrs), when do they peak (15-20hrs), and when should you start to see a resolution (2-3 days)
• If levels are not coming down, can mean that injury is extending….
Blood Chemistry
• BUN: 10-20 mg/dL An elevated BUN can mean dehydration
• Creatinine: 0.7-1.4 mg/dL This is a good indicator for renal function
• Sodium: 135-145 mEq/L Low or high do not directly affect cardiac function
• Potassium: 3.5-5 mEq/L Plays a major role in cardiac electrophysiologic function
o Hypo: dysrhythmia, life-threatening ventricular tachycardia or ventricular fibrillation and predispose patients
taking digitalis preparations to digitalis toxicity
o Hyper: heart block, asystole, life threatening ventricular dysrhythmia
• Magnesium (this is sometimes ADDED, it is not always on the blood chemistry): 1.8-3.0 mg/dL This is necessary for the
absorption of calcium, maintenance of potassium stores, metabolism of adenosine triphosphate. It plays a major role in
protein and carb synthesis
o Hypo: atrial and ventricular tachycardias
o Hyper: depress contractility and excitability of the myocardium, causing heart block and if severe, asystole
• Calcium: 8.5-10.5 mg/dL This is necessary for blood coagulation, neuromuscular activity, and automaticity of the nodal
cells
o Hypo: slow nodal function and impair myocardial contractility which can put the patient at risk for a heart attack
o Hyper: ventricular fibrillation
Coagulation studies
• Injury to a vessel wall or tissue can initiate the formation of a thrombus. This injury activates the coagulation cascade
o PTT: 60-70 seconds Measures the activity of intrinsic pathway and is used to assess the effects of heparin
o aPTT: 20-39 seconds
o PT: 9.5-12 seconds. This is used to monitor the level of anticoagulation with warfarin
o INR: 2-3.5 This can be used to measure warfarin (professor said this is clinical). It is a laboratory value used to
see how long blood takes to form a clot
▪ A 1 there is NOT enough anticoagulation medication
▪ A 2 there is ENOUGH medication on board
BNP
• Is a neurohormone that helps regulate BP and fluid volume. It is secreted from the ventricles in response to increased
preload with resulting ventricular pressure
• This is very specific for HF (over 100)
• A BNP greater than 100 is suggestive of
HF Cholesterol:
• Normal < 200 mg/dL
• LDL: < 130 mg/dL. This is the primary transporter of cholesterol and triglycerides into the cell. A high level of this can
be bad because it can lead to heart disease, diabetes, and CAD
• HDL: > 40 mg/dL
C-reactive protein
• Protein produced by the liver in response to systemic inflammation
• People with high hs-CRP levels (3 mg/L or greater) may be at greatest risk for CVD compared to people with moderate (1
to 3 mg/L) or low (less than 1 mg/L)
Homocysteine
• Linked to atherosclerosis because it can damage the endothelial lining of the arteries and promote thrombus formation
• A 12-hour fast is necessary before drawing a blood sample for an accurate serum
• Elevated homocysteine is indicative of a high risk for CAD, stroke, and peripheral vascular disease
• Test results are interpreted as optimal (less than 12 mcmol/L), borderline (12 to 15 mcmol/L) and high risk (greater than
15 mcmol/L)
ECG
• Electrical currents of the heart
• 12-lead ECG is used to diagnosed dysrhythmia, conduction, abnormalities, chamber enlargement, as well as
myocardial ischemia injury, or infarction
Continuous ECG
• Used when patient is at risk for dysrhythmia
• Detects abnormalities in the heart rate and rhythm
Assessment
, • Meds, nutrition, elimination, activity, exercise, sleep, rest, self-perception/concept, roles, relationships, sexuality,
reproduction, coping, stress tolerance, prevention strategies, General appearance
• Bp pulse pressure, postural BP changes
• Arterial pulses pulse rate, rhythm, amplitude(force)- regular/irregular
• JVD indicative of fluid overload
• Heart inspection/palpation/auscultation
o S1, S2 (S3, S4)
o S3 normally found in HF (or fluid overload)
o S4 specific to CAD
• Assessment of lungs respiratory overlap if pt has fluid overload
• Assessment of abdomen ascites (how it impacts breathing and overload of heart)
Diagnostic Evaluation
Imaging:
Chest X-ray
• size, position, contour of heart
• reveals cardiac/pericardial calcifications
• assists in diagnosis other
conditions Fluoroscopy
ECG
• Electrical activity of heart (12 lead- 12 different views of heart)
• Diagnoses Dysrhythmias, conduction abnormalities, chamber enlargement, myocardial ischemia, infarction, injury,
electrolyte imbalances
• Continuous ECG Standard care for pt w/ continuous monitoring
o Monitors more than 1 lead at a time, monitors ST segments, provides visuals/audible alarms
Cardiac Stress Testing
Noninvasive procedure to evaluate response to stress.
We are increasing the demand/workload of the heart on purpose since abnormalities are more than likely to be detected during times of
stress/demand.
The test is terminated when target HR is achieved or when the patient c/o myocardial ischemia
Exercise:
o Walks on a treadmill, bike, arm crank
o Exercise intensity increases
o Patient monitoring (EKG, VS)
o Terminate test when Target HR achieved or when ischemia occurs
Pharmacologic:
o Physical disability/deconditioned
o Persantine and Adenocard IV
o Mimic effects of stress
o Dobutamine if no tolerance to exercise
*GOAL of both tests put stress on heart to determine if any of these 6 are present
Used to determine the following:
• Presence of CAD
• Cause of chest pain ischemia??
• Functional capacity of the heart after an MI or surgery
• Effectiveness of antianginal or antiarrhythmic medications
• Occurrence of dysrhythmias
• Specific goals for physical fitness program
Contraindications:
• Severe aortic stenosis, Acute myocarditis or pericarditis, Severe HTN, Suspected left main disease, Heart failure
• Unstable angina this is a precursor for MI
• MI within 48 hours
Complications: AMI, cardiac arrest, heart failure, and unstable angina.
o If the patient is having chest pain, the test must be stopped
immediately Nursing Interventions:
• NPO x 4 hours, Avoid stimulants such as caffeine and tobacco, Meds with sips of water
• May instruct to hold beta blocking agents, theophylline, aminophylline before test (these drugs lower HR)
• Appropriate attire, Sensations with medications
Cardiac Evaluations
