Cardiac Flashcards
How much does the average heart weigh?
About 200-300grams
How much fluid is usually in the pericardium?
About 20ml
Where do the top 3 arteries of the Aorta go to?
The brain
When do the coronary arteries fill with blood to supply the myocardium?
During diastole
Do Tachycardic conditions affect blood flow to the heart?
Yes, Tachycardia prevents proper supply of oxygenated blood to myocardium
What is the heart rate of a heart rate that is relying on the AV node for nerve impulses
40-60bpm
What is the heart rate of heart that is relying on the bundle of his and purkinje fibers?
20-40bpm
Where is potassium located in regard to the sarcomere?
Potassium is inside the sarcomere
What occurs when a sarcomere depolarizes and repolarizes?
Depolarization: Calcium channels open and Na and Ca enter the sarcomere and potassium leaves.
Repolarization: Na and Ca leave and K enters the Sarcomere
What is Stroke Volume?
The amount of blood ejected from the heart with each ventricular contraction. (about 60-130ml)
What is Cardiac Output?
SV x HR- about 4-6L per minute
What is Ejection Fraction?
The percent of end-diastolic volume ejected with each heartbeat.
SV/ End Diastolic Volume
About 55-65% of total blood volume
What 3 factors affect Stroke Volume?
Preload
Afterload
Contractility
What is Preload?
Degree of muscle stretch of the cardiac muscle fibers at the end of diastole
What is Afterload?
The resistance to ejection of blood from the ventricle
Affected by Systemic Vascular Resistance and Pulmonary Vascular Resistance
What increases Preload?
Hypervolemia
Regurgitation of Cardiac valves
What increases Afterload?
Hypertension
Vasoconstriction
Afterload increases the workload of the Heart
What is Contractility?
Cardiac Muscle forces
Inotropic capabilities
What is Starling’s Law of the Heart?
Stroke Volume of the Heart increases when End Diastolic Volume increases and all other factors remain constant.
What is Hydrostatic Pressure?
Driving force of heart, tends to push fluid out of the capillary.
What is Oncotic Pressure?
Pressure exerted by plasma proteins, tends to pull fluid into capillaries
What is Filtration Pressure?
Net force on fluid, determined by balance between Hydrostatic and Oncotic Pressure.
HP>OP-Fluid leaves capillary
OP>HP-Fluid enters capillary
What are the 4 Cardiac Tissue functions?
Automaticity: The ability of cardiac
cells to initiate and electrical impulse
Excitability: ability to respond to an electrical impulse and generate action potential
Conductivity-ability to transmit impulse from one cell to another.
Contractility: Ability of cardiac tissue to shorten in response to impulse
Define the effective and relative refractory period.
Effective refractory Period: phase when cells are incapable of depolarizing
Relative refractory Period: phase in which cells require a larger than normal stimulus to depolarize
What is the number 1 and number 2 compliant when assessing a cardiac patient.
Chest pain, and dyspnea
Where do Men and Women typically experience their cardiac pain?
Men: Left arm
Women: can vary, pain in neck and shoulders
What are other common things to look for when assessing a cardiac patient?
Fatigue Nocturia- Fluid backup and is being released by kidneys Cyanosis Hemoptysis Pain or Parasthesia in extremities Jugular Vein Distention Pallor in exteremities Distal pulses diminished or absent Slow capillary refill
Where is the best location to listen for S1?
Midclavicular Line, 5th intercostal space
Where is the best location to listen for S2?
Pulmonic or Aortic Area
S3/S4 sound like what?
Like Horse Gallops
What do Heart Murmurs sound like?
Sounds like a “whoosh”
bell is better for auscultation
What diagnostic tests are performed when caring for a cardiac patient?
CBC Serum Cholesterol Creatine Kinase Troponin BNP C-reactive protein establishes baseline to see if there is damage
What further tests can be performed?
Holter Test 12 lead ECG-only snapshot of heart X-ray Echocardiogram Stress Tests Cardiac Catheterization-allows visulization of all 4 chambers Transesophageal
Where is the preferred site for Cardiac Catheterization?
The Radial artery but can go through femoral
What is the nurses responsibilities during diagnostic procedures?
Make sure patient understands what happens during procedure.
Make sure patient didn’t take blood thinner before procedure.
Monitor for bleeding
Check pulses distal to insertion site
Make sure patient adheres to bed rest 2-6hrs after procedure
What is Heart Dysrhythmia?
Heart beat isn’t functioning properly
potential to alter blood flow
Can cause disturbances of both rate and rhythm
What are the 5 common components of an ECG?
P wave PR interval QRS complex ST segment T wave
What is the measure of time of each individual square in a ECG?
About 0.04 secs and 5 together equals 0.2 secs
How do you calculate the HR based on a 6 sec time strip from an ECG?
Count the R segments and multiply by 10
What is the P wave?
Impulse produced from SA Node that creates atrial contraction
What is the PR interval?
Time between Atrial Repolarization and Ventricular Depolarization
What is the QRS complex?
The conduction from the atrioventricular bundle to the Purkinje fibers to stimulate ventricular contraction
What is the ST segment?
The heart’s resting period
What is the T wave?
Ventricular repolarization
What is the way to analyze an ECG strip?
Start from the left and make sure that each QRS complex is the same.
ST segment elevation is a sign of myocardial infarction.
What is necessary to look for when analyzing an ECG strip?
Are P waves occurring regularly
Is there a P wave for every QRS
Are P waves smooth, round, and upright?
Do all P waves look similar
How long should the PR interval and QRS complex be?
PR interval- 0.12-0.2
QRS complex= less than 0.12 secs
What is Normal Sinus Rhythm?
P wave for every QRS
T wave present
60-100bpm
uniform P waves
What is Sinus Bradycardia?
Meets all requirements for Normal Sinus Rhythm but HR is slow
What is important to look for in care of the patient with Sinus Bradycardia?
Check if on Digoxin, Beta-blockers, or calcium channel inhibitors
May need pacemaker
What is Sinus Tachycardia?
Meets all requirements except for HR which is faster than 100 bpm
What is important to look for when caring of the patient with Sinus Tachycardia?
Could be secondary to exercise, nicotine, ETOH, cocaine, amphetamines, and caffeine
Can lead to Pulmonary Edema
Can be a signal of massive heart damage (impending heart failure shock)
What is Sinus Arhythmia?
Normal except for irregular Heart Rhythm
What is PAC?
Premature Atrial Contraction
What are the characteristics of PAC in and ECG strip?
PAC gets sort of connected with T wave and is spiky in appearance
PAC puts the QRS closer together
PAC doesn’t allow the T wave to finish
