Cardiovascular System (Exam Two) Flashcards
What is an electrocardiogram (EKG)?
Recording of the electrical activity of the heart from various views
What are the benefits of an electrocardiogram (EKG)?
- Fast
- Easy
- Painless
What are the two types of electrocardiogram (EKG)?
- 12-lead-EKG
- 18-lead-EKG
What is the cardiac conduction pathway? What affects these electrical impulses?
- Electrical impulses used to generate the heartbeat
- Affected by electrolytes (i.e. sodium, potassium, calcium, magnesium)
What is the purpose of the cardiac conduction pathway?
Stimulate the mechanical cells of the heart to contract and perfuse the body
It is vital for electrolytes to be in appropriate range for which cardiac system to run effectively?
Cardiac Electrical System/Cardiac Conduction Pathway
Name the parts of the Cardiac Conduction Pathway in order.
- Sinoatrial (SA) Node (in wall of right atrium) –>
- Interatrial Bundles –>
- Left and Right Atria begin to contract –>
- Internodal Bundles –>
- Atrioventricular (AV) Node –>
- Bundle of His –>
- Purkinje Fibers
- Right and Left Ventricles begin to contract
Where is the Sinoatrial Node (SA) located?
In the wall of the right Atrium
The rate of the Sinoatrial Node (SA) is dictated by what?
The needs of the body
Which part of the Cardiac Conduction Pathway is known as the “pacemaker” of the heart?
Sinoatrial (SA) Node
If the Sinoatrial Node fails, which part of the Cardiac Conduction Pathway will initiate a heartbeat? What is the rate?
- Atrioventricular (AV) Node
- Rate of 40 to 60 beats per minute
- The body is able to function regularly at this rate
If the Sinoatrial (SA) Node and Atrioventricular (AV) Node fails, which part of the Cardiac Conduction Pathway will initiate a heartbeat? What is the rate?
- Bundle of His (right and left)
- Rate of 20-40 beats per minute
What is the cardiac cycle? What does it consist of?
- Period from the beginning of one heartbeat to the beginning of the next
- Depolarization and repolarization
What is depolarization?
Period of contraction
What is repolarization?
Period of rest
The smallest box on an EKG represents how many millimeters/seconds?
1mm = 0.04 seconds
The largest box on an EKG represents how many millimeters/seconds?
5mm = 0.20 seconds
Within one normal cardiac cycle, there is what?
- P wave
- QRS complex
- T wave
Which wave is first in the cardiac cycle?
HINT: PQRST
P wave
What does a P wave indicate?
- The SA node is firing
- Atrial depolarization
What are the normal characteristics of a P wave?
HINT: Think of a hill
- Rounded, upright
- Occur regularly
- Should be 1 P wave for every 1 QRS complex
- Symmetrical throughout EKG
What is the PR interval? What does it identify?
- The amount of time it takes for an impulse to travel from the SA node to the AV node
- Can identify if an electrical delay is present
When do you start and finish measuring for a PR interval on an EKG?
- Begin at the peak of the P wave
- End at the trough of the QRS interval (before Q starts going in downward position)
What is the normal measurement for the PR interval?
HINT: P”R” = “Respiratory Rate”
0.12 - 0.20 seconds
If the PR interval is >20 seconds, what does this indicate?
Electrical delay through the AV node
Which wave occurs in the middle of the cardiac cycle?
HINT: PQRST
QRS complex
What does a QRS complex represent?
Ventricular depolarization and atrial repolarization
When do you start and finish measuring for a QRS complex and QRS interval on an EKG?
- Begin at the trough of the Q
- End where the S trough returns back to the isoelectric line
What does the QRS interval indicate?
- The amount of time it takes for electrical impulse to travel from the AV node through the ventricle
- Occurs rapidly
What is the normal measurement for the QRS interval?
0.06 - 0.10 seconds
If the QRS interval is >0.10 seconds, what does this indicate?
Bundle branch block (block in ventricles)
Which wave occurs last in the cardiac cycle? HINT: PQRST
T wave
What does a T wave represent?
Repolarization of the ventricles
What are the normal characteristics of a T wave?
- Upright, rounded
- Above the isometric line
The time from depolarization of the ventricles to repolarization of the ventricles is known as what?
ST segment
When will the nurse check the ST segment?
When a patient complains of chest pain
List the steps to analyze an EKG?
- Check regularity of the rhythm (i.e. regular, irregular, regularly irregular, irregularly irregular)
- Check heart rate
- Check characteristics of P wave
- Check consistency of PR interval (0.12 - 0.20)
- Check consistency of QRS interval (0.06 -0.10)
How do you determine the regularity of the rhythm on an EKG?
R-to-R Spacing
What are the characteristics of a normal sinus rhythm?
- Regular rhythm
- Regular heart rate
- Rounded, upright P wave
- P wave and QRS interval ratio is 1:1
- PR interval is 0.12 - 0.20
- QRS interval is 0.06 - 0.10
How should the nurse intervene if the patient presents with a normal sinus rhythm?
- DO NOTHING!
- Intervention is not needed for this patient
What is an arrhythmia?
- Abnormal heart rhythm
- Also called a dysrhythmia
Arrhythmias can result in what?
- Increased heart rate
- Decreased heart rate
- Early beats
- Late beats
- Atrial fibrillation
- Ventricular fibrillation
What are rhythms that arise from the SA node called?
Sinus rhythm (i.e. normal sinus rhythm, sinus bradycardia, sinus tachycardia)
What is sinus bradycardia?
Sinus rhythm with a heart rate of <60 bpm
What are the causes of sinus bradycardia?
- Athletic individuals
- Medications
- Electrolyte imbalance
- MI
- Hypothyroidism
- Sleep apnea
- Problems with SA node
What are the signs and symptoms of sinus bradycardia?
- Asymptomatic
- Hypotension
- Diminished pulse
- Fatigue
- Dizziness
- Syncope
What is the first-defense treatment for a patient with symptomatic sinus bradycardia?
IV Atropine
Describe the characteristics of sinus bradycardia on an EKG?
- Slowed rhythm
- Slowed heart rate
- Rounded, upright P wave
- P wave and QRS interval ratio is 1:1
- R-to-R Spacing is father apart
What is sinus tachycardia?
Sinus rhythm with a heart rate of >100 bpm
What are the causes of sinus tachycardia?
- Shock
- Medications
- Dehydration
- Infection
- Anxiety
- Electrolyte imbalance
What are the signs and symptoms of sinus tachycardia?
- Asymptomatic
- Angina
- Syncope
- Dizziness
- Palpitations
- SOB
- Anxiety
What medications can be used to treat sinus tachycardia?
- Beta Blockers
- Calcium Channel Blockers
- Adenosine
Describe the characteristics of sinus tachycardia on an EKG?
- Rapid rhythm
- Rapid heart rate
- Rounded, upright P wave
- P wave and QRS interval ratio is 1:1
- R-to-R Spacing is closer together
What is occurring during an atrial arrhythmia?
- The atria is initiating impulses faster than the SA node
- Usually faster than 100 bpm
Which wave is associated is with atrial arrhythmias?
P wave
What is the most common form of arrhythmia?
Premature Atrial Contraction (PAC)
What causes a premature atrial contraction (PAC)? HINT: “Early” beat
- Premature discharge of the electrical impulse in the atria
- Occurs prematurely/earlier than the normal beat should have occured
What characteristics will a P wave present with in a premature atrial contraction (PAC) on an EKG?
- Flatter
- Peaked
- Notched
In a premature atrial contraction (PAC), will the P wave always be followed by a QRS complex
- No, a QRS complex will not always follow the P wave
- P wave may occur outside of the cardiac cycle or in the T wave
What are the causes of a premature atrial contraction (PAC)?
- Hypoxia
- Smoking cigarettes
- Heart failure
- Electrolyte imbalances
- Caffeine
- Alcohol
- Medications
- Fatigue
- Stress
- Anxiety
What are the signs and symptoms of a premature atrial contraction (PAC)?
- Asymptomatic
- Palpitations
- Dizziness
What are the treatment options for premature atrial contraction (PAC)?
- Often no treatment
- Lifestyle changes (i.e. stop smoking)
What is happening with electrical impulses during atrial fibrillation?
- Electrical impulses initiated randomly from ectopic sites
- Atria over rides the SA node as the pacemaker
- Atrial rate chaotic and rapid = atria quiver
Why is the ventricular rate usually regular with atrial fibrillation?
- The AV node blocks most of the ectopic/random impulses sent by the atria
- Ventricular rate then has the ability to be regular (between 60-100 bpm)
What type of action is occurring within the atria during atrial fibrillation?
- The atria is quivering/fibrillating due to the rapid & chaotic rate from ectopic impulses
- Due to the quivering/fibrillating, the atria cannot complete the diastole and systole phases completely
What type of rhythm is atrial fibrillation?
Irregularly irregular
What happens with blood flow in the atria during atrial fibrillation?
- Blood remains in the atrial chambers because it is unable to empty out (due to quivering)
- Blood stasis within the atria results in increased risk for developing a thrombus
- Increased risk for developing a stroke
What percentage of stroke patients have an underlying atrial fibrillation rhythm?
15% to 20%
What is persistent atrial fibrillation?
Patient is constantly in atrial fibrillation
What is paroxysmal atrial fibrillation?
Patient is going in and out of atrial fibrillation
What is atrial fibrillation RVR? What is the priority nursing concern with atrial fibrillation RVR?
- Atrial fibrillation with a heart rate >100
- Priority: control the heart rate
What are the signs and symptoms of atrial fibrillation RVR?
- Hypotension
- Dizziness
- Pulse deficit
- Chest pain
- Palpitations
- Fatigue
List the risk factors for developing atrial fibrillation?
- Older age (65 y/o or greater at increased risk)
- Smoker
- Heart disease
- Heart failure
- Hypertension
- Hyperthyroidism
- MI
- Cardiac surgery
- Medications
- COPD
- Unknown
What medications should be used to combat atrial fibrillation?
*Anticoagulants
- Beta Blocker
- Calcium Channel Blocker
- Digoxin
Which “anticoagulant” is not an approved medication to use for atrial fibrillation?
Aspirin
What are the treatment options for atrial fibrillation?
- Cardioversion
- Cardiac ablation
- Surgery (i.e. maze procedure)
What must the patient be on prior to having a cardioversion? For how long?
- Anticoagulant
- 4 to 6 weeks prior to procedure
What characteristics will atrial fibrillation present with on an EKG?
- Wavy pattern (atria quivering)
- No P wave
- Irregular rhythm
- Irregular heart rate
- PR interval cannot be determined
- QRS interval is present and normal
What is atrial flutter?
Atria are contracting appropriately at an exceedingly rapid rate of 250 - 350 beats per minute
What type of rhythm is atrial flutter?
Regularly irregular
In atrial flutter, the rapid P waves on an EKG are called what?
F waves
What are the causes of atrial flutter?
- CHF
- MI
- Valve disorders
- Hypertension
- Post-CABG
- COPD
- Rheumatic/ischemic heart disease
- Pulmonary embolism
What are the signs and symptoms of atrial flutter?
- Palpitations
- Angina
- Dyspnea
What are the treatment options for atrial flutter?
- Medications (i.e. Calcium Channel Blocker, Beta Blocker, Digoxin)
- Cardioversion
- Cardiac ablation
What characteristics will atrial flutter present with on an EKG?
- Identical “sawtooth” like pattern
- Sawtooth F wave and QRS complex ratio is 4:1
- Regular rhythm
- Irregular heart rate
- PR interval cannot be determined
- QRS interval is present and normal
What are ventricular arrhythmias?
- Abnormal heart beat that originates in the ventricles
- Causes heart to beat too fast
What are premature ventricular contractions (PVCs)?
- Extra abnormal heartbeat that originates in the ventricle(s)
- Ventricles fire prematurely before the SA node causing a wide QRS interval
- Very common
What are the signs and symptoms of premature ventricular contractions (PVCs)
-Increased awareness of heartbeat (i.e. flip-flop, pounding, fluttering, jumping, skipping beats, missing beats
What characteristics will premature ventricular contractions (PVCs) present with on an EKG?
- Regular rhythm
- Rapid heart rate
- No P wave present on PVC beat
- QRS interval appears widened