EKG learning outcomes and outline PDF

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NURSING PROCESS 3: EKG LEARNING OUTCOMES 9/3

Notes: (Scroll for learning outcomes) 

Cardiac website (pretty good): https://www.healio.com/cardiology/learnthe-heart/ecg-review/ecg-topic-reviews-and-criteria/sinus-bradycardia-review

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Depolarization occurs when the normally negatively charged cells within the heart muscle develop a positive charge.

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Contractility is the ability of atrial and ventricular muscle cells to shorten their fiber length in response to electrical stimulation, causing sufficient pressure to push blood forward through the heart. In other words, contractility is the mechanical activity of the heart.

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The electrocardiogram (ECG) provides a graphic representation, or picture, of cardiac electrical activity.

Leads 

An imaginary line joining these two poles is called the lead axis. The direction of electrical current flow in the heart is the cardiac axis.

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The relationship between the cardiac axis and the lead axis is responsible for the deflections seen on the ECG pattern

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The baseline is the isoelectric line. It occurs when there is no current flow in the heart after complete depolarization and also after complete repolarization. Positive deflections occur above this line, and negative deflections occur below it.

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Deflections represent depolarization and repolarization of cells.

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Electrodes, consisting of a conductive gel on an adhesive pad, are placed on specific sites on the body and attached to cables connected to an ECG machine or to a monitor. The cardiac electrical current is transmitted via the electrodes and through the lead wires to the machine or monitor, which displays the cardiac electrical activity.

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A lead provides one view of the heart's electrical activity. Multiple leads, or views, can be obtained.

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Lead systems are made up of a positive pole and a negative pole.

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The standard 12-lead ECG consists of 12 leads (or views) of the heart's electrical activity.

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6 leads are called limb leads, while the other 6 are called chest leads.

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With a 12-lead ECG, four leads are placed on the limbs, and six are placed on the chest, eliminating the need to move any electrodes about the chest o Position is crucial for an accurate EKG o Electrodes are not placed on the limbs due to continuous monitoring o For an ambulatory patient, the ECG cable is attached to a battery-operated transmitter (a telemetry system) held in a pouch.

Lead Interpretation:

1. Describe the three electrophysiological characteristics of the heart. (1) automaticity – is the ability of cardiac cells to generate an electrical impulse spontaneously and repetitively

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(2) excitability – the ability of the cell to respond to an electrical impulse that begins in pacemaker cells

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(3) conductivity – the ability to transmit an electrical impulse from one cell to the next

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2. Correlate the normal components of the normal ECG with physiologic events of the heart.  

Impulses from the sinus node move directly through atrial muscle and lead to atrial depolarization, which is reflected in a P wave on the electrocardiogram (ECG). Here T-cells (transitional cells) cause impulses to slow down or be delayed in the AV node before proceeding to the ventricles. This delay is reflected in the PR segment on the ECG.

3. Define the ECG as a waveform that represents the cardiac electrical event in relation to the lead depicted. 

The cardiac electrical current is transmitted via the electrodes and through the lead wires to the machine or monitor, which displays the cardiac electrical activity.

4. Describe the purpose of the utilization of different leads. 

A 12-lead ECG consists of three bipolar limb leads (I, II, and III), three unipolar limb leads (AVR, AVL, and AVF), and six unipolar chest leads, also called precordial or V leads

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Unipolar limb leads: R for right arm, L for left arm, and F for foot (left leg). Unipolar limb leads consist of a positive electrode only. The positive electrode is at one end of the lead axis. The other end is the center of the electrical field, at about the center of the heart.

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Standard bipolar limb leads consist of three leads (I, II, and III) that each measure the electrical activity between two points and a fourth lead (right leg) that acts as a ground electrode. Of the three measuring leads, the right arm is always negative, the left leg is always positive, and the left arm can be either positive or negative.

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There are six unipolar chest leads (V), determined by the placement of the chest electrode.

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The fifth (chest) electrode on a monitor system is the positive, or exploring, electrode and is placed in one of six designated positions to obtain the desired chest lead.

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With a 12-lead ECG, four leads are placed on the limbs, and six are placed on the chest, eliminating the need to move any electrodes about the chest

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ECG Placement Video: https://youtu.be/YuztwZOccfc

5. Analyze the elements of an ECG rhythm strip in an organized system: atrial rate, atrial rhythm, ventricular rhythm, QRS complex and shape, QRS duration, P wave and shape, and P: QRS ratio.

Registered Nurse RN video link: https://youtu.be/QAQiK-zRtl0 Complexes that make up a normal ECG consist of: a P wave, a QRS complex, a T wave, and possibly a U wave.  

Segments include the PR segment, the ST segment, and the TP segment. Intervals include the PR interval, the QRS duration, and the QT interval

Atrial rate: The atrial rate is indicated by the frequency of the P waves. It is measured by time intervals between P waves Atrial rhythm: P-wave shape (variances can be bad, like indicate a-fib) Ventricular rhythm: QRS complex P Wave: represents atrial depolarization P Wave shape: shape of the P wave is usually consistent and may be a positive, negative, or biphasic (both positive and negative) deflection, depending on the lead selected PR Segment: delay of the electrical impulse travelling through the AV node; isoelectric line from the end of the P wave to the beginning of the QRS complex 

QRS o o o

PR Interval: https://youtu.be/MTh-phU9DD8 It represents the time required for atrial depolarization, the impulse delay in the AV node, and the travel time to the Purkinje fibers & is measured from the beginning of the P wave to the end of the PR segment (normally measures 5 small blocks, 0.20 sec) Complex: represents ventricular depolarization Q Wave- abnormalities can indicate cell death R Wave- first positive deflection S wave- negative deflection (not present in all leads)

QRS Duration- represents the time required for depolarization of both ventricles. It is measured from the beginning of the QRS complex to the J point (0.04-0.12 seconds, or 3 blocks) ST Segment: normally an isoelectric line and represents early ventricular repolarization. It occurs from the J point to the beginning of the T wave

T Wave: follows the ST segment and represents ventricular repolarization. It is usually positive, rounded, and slightly asymmetric QT Interval: represents the total time required for ventricular depolarization and repolarization. The QT interval is measured from the beginning of the Q wave to the end of the T wave Artifact- interference U Wave: follows the T wave and may result from slow repolarization of ventricular Purkinje fibers

ECG Rhythm Analysis Steps

1. 2. 3. 4. 5. 6. 7. 8.

Determine the heart rate Determine the heart rhythm Analyze the P-waves Measure the PR interval Measure the QRS duration Examine the ST segment Assess the T-wave Measure the QT interval

6. Identify the ECG criteria and causes for sinus rhythms: normal, bradycardia and tachycardia. Normal sinus rhythm: the rhythm originating from the sinoatrial (SA) node (dominant pacemaker) that meets these ECG criteria

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ECG Criteria (Normal): Rate: Atrial and ventricular rates of 60 to 100 beats/min Rhythm: Atrial and ventricular rhythms regular P waves: Present, consistent configuration, one P wave before each QRS complex • PR interval: 0.12 to 0.20 second and constant • QRS duration: 0.04 to 0.10 second and constant

Sinus dysrhythmias: The sinoatrial (SA) node in the right atrium is the pacemaker in all sinus dysrhythmias. Sinus Tachycardia - when the rate of SA node discharge is more than 100 beats/min

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continued increases in heart rate decrease coronary PERFUSION time, diastolic filling time, and coronary PERFUSION pressure while increasing myocardial oxygen demand

Causes: anxiety, pain, stress, fever, anemia, hypoxemia, hyperthyroidism, drugs, dehydration, hypovolemic shock, myocardial infarction (MI), infection, heart failure, epinephrine, atropine, caffeine, alcohol, nicotine, cocaine, aminophylline, and thyroid medications

Sinus Bradycardia - When the sinus node discharge rate is less than 60 beats/min  Sinus bradycardia increases coronary PERFUSION time, but it may decrease coronary perfusion pressure. However, myocardial oxygen demand is decreased Causes: carotid sinus massage, vomiting, suctioning, Valsalva maneuvers, ocular pressure, pain, hypoxia, inferior wall MI, beta-adrenergic blocking agents, calcium channel blockers, digitalis, lyme disease, ELECTROLYTE disturbances, neurologic disorders, and hypothyroidism NCLEX Question During routine suctioning of a client with a tracheostomy, the client becomes diaphoretic and nauseous, and the heart rate decreases to 39 beats/min. What is the nurse's best action at this time? A. Continue to clear the airway. B. Stop suctioning the patient. C. Administer atropine. D. Call the health care provider immediately.

Sinus Bradycardia vs Sinus Tachycardia

7. Describe the medical treatment and nursing care for sinus bradycardia and sinus tachycardia. 

Sinus Tachycardia TX: o The desired outcome is to decrease the heart rate to normal levels by treating the underlying cause. Remind the patient to remain on bedrest if the tachycardia is causing hypotension or weakness. Teach the patient to avoid substances that increase cardiac rate, including caffeine, alcohol, and nicotine. Help patients develop stressmanagement strategies or refer the patient to a mental health professional.

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Sinus Bradycardia TX: o administer drug therapy with atropine 0.5mg IV, increase intravascular volume via IV fluids, and apply oxygen, o transcutaneous or transvenous pacing to increase the heart rate o Permanent pacemaker is final option

8. Identify the ECG criteria and causes of atrial dysrhythmias: atrial fibrillation and atrial flutter

Atrial Fibrillation

Atrial Flutter 9. Describe the medical treatment and nursing management of atrial dysrhythmias: atrial fibrillation and atrial flutter Treatment/ Interventions A-fib

Treatment/Interventions A-flutter

10. Identify the ECG criteria and causes of ventricular dysrhythmias: premature ventricular complex, ventricular tachycardia, ventricular bi-, tri-, quad-gemeny, ventricular fibrillation, idoventricular. (combining with objective #11) 11. Describe the medical treatment and nursing management of ventricular dysrhythmias: premature ventricular complex, ventricular tachycardia, ventricular bi-, tri-, quad-gemeny, ventricular fibrillation, and idoventricular.

Premature Ventricular Complex o also called premature ventricular contractions o Causes: result from increased irritability of ventricular cells o seen as early ventricular complexes followed by a pause o QRS complexes may be same shape or different shapes o PVCs frequently occur in repetitive rhythms, such as bigeminy (two), trigeminy (three), and quadrigeminy (four) o

Three or more successive PVCs are usually called nonsustained ventricular tachycardia (NSVT)

o Premature ventricular contractions are common, and their frequency increases with age. *notify HCP is patient experiences chest pain*

Nclex interventions (not much):  Identify the cause and treat on the basis of the cause.  Evaluate oxygen saturation to assess for hypoxemia, which can cause PVCs  Evaluate electrolytes, particularly the potassium level because hypokalemia can cause PVCs  Oxygen and medication may be prescribed in the case of acute myocardial ischemia or MI

Ventricular Tachycardia     

V tach, occurs with repetitive firing of an irritable ventricular ectopic focus, usually at a rate of 140 to 180 beats/min (nclex says 140-250) or more Causes: VT may result from increased automaticity or a re-entry mechanism Usually a sustained rhythm R/F: ischemic heart disease, MI, cardiomyopathy, hypokalemia, hypomagnesemia, valvular heart disease, heart failure, drug toxicity (e.g., steroids), or hypotension. In patients who go into cardiac arrest, VT is commonly the initial rhythm before deterioration into ventricular fibrillation (VF) as the terminal rhythm!

Nursing Interventions  administer oxygen and confirm the rhythm via a 12-lead ECG.  Amiodarone (Cordarone), lidocaine, or magnesium sulfate may be given. Pulseless client: defibrillation and CPR

Idioventricular rhythm: very similar to ventricular tachycardia except the ventricular rate is less than 60 beats per minute

Ventricular Fibrillation        

sometimes called V fib, is the result of electrical chaos (go crazy go stupud) in the ventricles and is life threatening! Impulses from many irritable foci fire in a totally disorganized manner so ventricular contraction cannot occur There are no recognizable ECG deflections The ventricles quiver, consuming a lot of o2 There is no cardiac output or pulse and no perfusion This rhythm is rapidly fatal if not successfully ended within 3 to 5 minutes Client lacks BP, pulse, respirations, and consciousness Respiratory and metabolic acidosis develop. Seizures may occur. Within minutes, the pupils become fixed and dilated, and the skin becomes cold and mottled

Nursing Interventions  Antidysrhythmics (meds)  Initiate CPR until defibrillator is available  Client is defibrillated with 120-200 joules  Administer oxygen

12. Utilize the nursing process as a framework for the care of patients with dysrhythmias. *See care such as defibrillators, etc on powerpoint slides. Won’t do notes on this objective*...