PNC IV - Test 2 - ECG Interpretation - The Basics

*What is the time of ONE SMALL BOX?

0.04 seconds

***What is the measurement of the QRS complex in Figure 2?

0.06 (Rational: there is 1 whole boxes and 1 half box, so 0.02+0.04=0.06 seconds)

*A normal QRS complex measures ____________________________

0.06 to 0.12 seconds

*A normal PR interval measures ______________________

0.12-0.20 seconds

***What is the measurement for the QRS complex?

0.16 (Rational: there are 3 whole boxes and 2 half box, so 0.02+0.04+0.04+0.04+0.02=0.16 seconds)

*What is the measurement of the PR interval?

0.16 seconds (Rational: There are 4 small boxes, which when you add the boxes 0.04+0.04+0.04+0.04=0.16 seconds)

*What is the time of 5 small boxes?

0.20 seconds 5 small boxes = 1 large box = 0.20 seconds

*What is the measurement of the PR interval in this diagram?

0.28 seconds...note this is an abnormal PR interval (Rational: There are 7 small boxes, which when you add the boxes 0.04+0.04+0.04+0.04+0.04+0.04+0.04=0.28 seconds)

What area represents atrial contraction?

1

A patient is admitted with an acute MI. The nurse notes that his cardiac rhythm has changed from NSR to bradycardia with a rate of 45. 1. What assessments indicate that the patient is not tolerating the low heart rate? 2. Besides a MI, what drugs cause bradycardia?

1. Change in level of consciousness • Chest discomfort • Hypotension • Shortness of breath; respiratory distress • Pulmonary congestion; crackles • Rapid, slow, or weak pulse • Dizziness • Syncope • Fatigue • Restlessness 2. Medications such as digoxin or AV nodal blocking agents, including calcium channel blockers and beta blockers

What do abnormalities of the T wave indicate?

- myocardial ischemia or injury or - electrolyte imbalances.

***What are the causes of sinus bradycardia?

1. Well trained athlete 2. Beta blockers 3. Vagal stimulation (inhibits Sympathetic NS) 4. Brain injury Also: ✔︎ pain ✔︎ increased ICP ✔︎ sinus node disease ✔︎ hypothermia ✔︎ acidosis ✔︎ and certain drugs.

What area represents the T wave?

3

How many LARGE boxes does it take to make 1 second of time?

5

What area represents ventricle contraction?

7

What is pro-dysrhythmia?

A worsening of the original dysrhythmia or the developing of a new dysrhythmia from the drug therapy

*What could an ELEVATED ST segment indicate?

ACTIVE MI

What does a straight line on a ECG mean?

Absence of electrical activity isoelectric line

The SA node causes the atria or ventricles to contract?

Atria

*What is the PR interval?

Beginning of P wave to beginning of QRS complex. *PR-interval starts at atrial contraction and ends at the beginning of ventricle depolarization.

*Where does the black lead go on a 5 lead ECG?

Black LA - Left Arm Below left clavicle, mid-clavicular line

*Where does the brown lead go on a 5 lead ECG?

Brown - Chest lead is fourth intercostal space. R sternal border

The patient is being discharged with a dysrhythmia. What should the nurse tell the patient to avoid?

Caffeine Tobacco Alcohol Teaching: ▻ reducing high BP ▻ monitoring cholesterol levels ▻ losing weight ▻ following a heart-healthy diet ▻ stopping smoking ▻ engaging in regular physical activity as tolerated.

What is a symptom of decreased cardiac output, that indicates a decrease coronary artery perfusion? A.Cyanosis on lips B.Chest pain C.Dyspnea D.Low urine output

Chest pain - due to decreased blood flow to the heart

What assessment should the nurse include with a patient on an anti-dysrhythmia drug?

Close monitor ◼︎ ECG's ◼︎ Heart rate ◼︎ blood pressure ◼︎ heart rhythm ◼︎ skin temperature and color ◼︎ heart and lung sounds

When the AV node fires and causes the ventricles to contract - Is this called depolarization or repolarization?

Contract = Depolarization

When the SA node fires and causes the atria to contract - Is this called depolarization or repolarization?

Contract = Depolarization

Is depolarization during systole or diastole?

Depolarization = systole = contraction Repolarization = diastole = resting or filling phase

*Where does the green lead go on a 5 lead ECG?

Green RL - Right Leg Right lowest rib cage area

What could a PR length that gets longer over time indicate?

Heart block

1 large square = 0.20 seconds 30 large squares X 0.20 seconds = 6 seconds How would you find the heart rate?

Identify the p-waves Beginning at the first p-wave start counting 30 large squares. Then count how many p-waves are between the 30 large squares. Take that number and multiple it by 10 and this is your heart rate. What is this heart rate? 80

How do you treat sinus tachycardia?

Immediately initiate cardioversion if unstable Treatment dependent on elimination of cause Decreasing anxiety Pain relief Antipyretics O2 Medications (e.g., sedatives, tranquilizers, antianxiety) Calcium channel blockers and beta-blockers

*What is ventricular tachycardia?

It is a tachycardia, or fast heart rhythm, that originates in one of the ventricles of the heart.

*What is sinus tachycardia?

It is defined as a sinus rhythm with a rate of greater than 100 BPM.

Number 9, what is this area known as?

J point

What can cause a decreased heart rate?

MI Digoxin calcium channel blockers beta blockers

How do you treat sinus bradycardia?

Maintain patent airway; assist breathing as needed Oxygen IV Atropine 0.5-1 mg bolus IV if patient has signs of poor perfusion May repeat to a total dose of 3 mg Then, epinephrine (2-10 mg/min) or dopamine (2-10 mg/kg/min) infusion while awaiting pacemaker Transcutaneous pacing for symptomatic bradycardia

References:

Nursing: A Concept-Based Approach to Learning (Vol. 1 & 2). (3rd ed.). (2019). Pearson Education, Inc.

Is a PR interval longer in a younger or older person?

Older

*If there is a problem with the atria - what will be affected on the ECG Strip?

P wave P-R interval

What area is labeled with the number 6?

PR interval

*What can an abnormal Q wave indicate?

Past MI

What area is labeled with the number 7?

QRS complex

*If there is a problem with the ventricles - what will be affected on the ECG strip?

QRS complex QRS duration T-wave or S-T segment.

*Where do you place a 5 lead EKG?

RA (white) LA (black) RL (green) (ground electrode) LL (red) V1-V6 (brown) chest

An example of sinus tachycardia:

Rate: 101-150 bpm Rhythm: regular P:QRS: 1:1 (with very fast rates, P wave may be hidden in preceding T wave) PR interval: 0.12-0.20 sec QRS complex: 0.6-0.10 sec TREATMENT: Treated only if symptomatic or patient is at risk for myocardial damage Treatment of underlying cause (e.g., hypovolemia, fever, pain) Possible administration of beta-adrenergic blockers or verapamil

An example of a sinus arrhythmia:

Rate: 60-100 bpm Rhythm: irregular, varying with respirations P:QRS: 1:1 PR interval: 0.12-0.20 sec QRS complex: 0.6-0.10 sec

An example of a normal sinus rhythm:

Rate: 60-100 bpm Rhythm: regular P:QRS: 1:1 PR interval: 0.12-0.20 sec QRS complex: 0.6-0.10 sec

An example of sinus bradycardia:

Rate: less than 60 bpm Rhythm: regular P:QRS: 1:1 PR interval: 0.12-0.20 sec QRS complex: 0.6-0.10 sec TREATMENT: Treated only if symptomatic Possible administration of IV atropine or isoproterenol, and/or pacemaker therapy

*Where does the red lead go on a 5 lead ECG?

Red LL - Left Leg Left lowest rib cage area

What is repolarize?

Repolarize = Relaxation

What are the electrical pathways of the heart?

SA node, AV node, Bundle of His, Purkinje fibers

The area labeled with the number 8 represent?

ST segment

What does the SA node do?

Sends out impulses that make the heart contract. Sino-atrial (SA) node fires and that impulse travels across the atria via all of the pathways and this causes the atria to contract (atrial depolarization).

Will the PR interval be longer or shorter in a fast heart rate?

Shorter

Describe sinus arrhythmia:

Sinus arrhythmia is a sinus rhythm in which the rate varies with respirations, causing an irregular rhythm. The rate increases during inspiration and decreases with expiration. Sinus arrhythmia is common in the very young and the very old. It can be caused by an increase in vagal tone, by digitalis toxicity, or by morphine administration.

Could the patient have sinus tachycardia or sinus bradycardia during sleep?

Sinus bradycardia

*What could sinus tachycardia be an early sign for?

Sinus tachycardia may be an early sign of cardiac dysfunction, such as heart failure. Tachycardia is detrimental in patients with cardiac disease because it increases cardiac work and oxygen use.

When interpreting an ECG strip - what do you do after you determine the heart rate?

Step two - Determine regularity. Do the complexes march across the strip at regular intervals? This is done for both the atrial rate (P wave to P wave) and the ventricular rate (R wave to R wave).

What represents ventricular repolarization (resting of the ventricles)?

T wave

T. or F. Rate varies with sinus arrhythmia:

TRUE Rate varies with respirations Inspire = increase Expire = decrease

T. or F. NEVER stop an anti-dysrhythmia drug abruptly.

TRUE. It can be deadly

What is the purpose of an ECG?

The ECG is a picture of how the electricity in the heart is flowing. If there is a problem in the flow (conduction) then it will show up on the ECG as an abnormal wave or interval.

What is the atrial kick?

The atria contract toward the end of ventricular diastole and push the remaining blood into the ventricles

Why do we measure the PR interval ?

The length of time the impulse takes from the SA node to the AV node.

Bradycardia decreases or increases organ perfusion?

The slowed heart rhythm may cause a decrease in cardiac output, resulting in hypotension and decreased organ perfusion.

What is the u wave?

The u-wave sometimes is seen after the t-wave. This is thought to be caused by the relaxation of the Purkinje fibers.

*What is the ST segment?

This segment starts at the J-point. The J-point is where you start to see an upward stroke after the S wave. The segment ends at the beginning of the T-wave. The ST-segment represents when the ventricles are relaxing, also called repolarizing.

True or False: A U-wave may be present after the T-wave but this is not very common.

True

*What does the measurement of the QRS complex tell us?

Ventricle contraction The QRS duration tells you how long it takes the impulse to travel from the AV node through the ventricles.

What does number 3 represent?

Ventricle relaxation

The AV node causes the atria or ventricles to contract?

Ventricles

What does the T wave represent?

Ventricular repolarization = regain energy to contract again

*Where does the white lead go on a 5 lead ECG?

White RA - Right Arm Below right clavicle, mid-clavicular line

Is this a normal sinus rhythm? Atrial rate: PR interval: QRS width: Ventricular rate:

Yes Normal sinus rhythm; regular configuration, uniform P wave precedes each QRS Atrial rate: 60-100 PR interval: 0.12-0.2 second QRS width: less than (<) 0.12 second Ventricular rate: 60-100

What is tachycardia?

fast heart rate > 100

What is the common reason for a NARROW QRS complex?

sinus tachycardia

What is bradycardia?

slow heart rate < 60

What is the common reason for a WIDE QRS complex?

ventricular tachycardia

Describe how the heart fills with tachycardia:

•The fast heart rhythm may cause a decrease in cardiac output because of the shorter filling time for the ventricles.

Why might prolonged tachycardia result in heart failure?

•The fast heart rhythm may cause a decrease in cardiac output because of the shorter filling time for the ventricles.

*How might the patient present with sinus bradycardia?

↬ decreased CO ↬ decreased LOC ↬ syncope (fainting) ↬ hypotension

*How might the patient present with sinus tachycardia ?

✓ heart is "racing," ✓ shortness of breath ✓ dizziness

***What are common signs & symptoms of a cardiac dysrhythmias?

✷ lightheadedness ✷ dizziness ✷ fluttering ✷ racing or slow heartbeat ✷ shortness of breath ✷ chest discomfort or pain ✷ syncope

***Why might a patient have sinus tachycardia?

➝ pain ➝ fever ➝ increased oxygen demand/hypoxia ➝ hypovolemia Also: exercise excitement anxiety anemia hyperthyroidism MI heart failure cardiogenic shock pulmonary embolism caffeine intake and certain drugs, such as atropine, epinephrine (Adrenalin), or isoproterenol (Isuprel)

What are the benefits to anti-dysrhythmia drugs?

⬇︎ blood pressure in hypertensive clients ⬇︎ edema regular pulse rate improved regularity