Domain 5: EKG Preparation & Electrodes

Patient Preparation for EKG

Includes gathering patient history, proper positioning, skin preparation, and correct lead placement.

Basic Functions of an EKG Machine

Amplifies electrical impulses from the heart and records them as waveforms.

3-Lead EKG Placement

Uses three electrodes (positive, negative, and ground) primarily for continuous heart monitoring.

5-Lead EKG Placement

Uses five electrodes to provide multiple monitoring views of the heart.

12-Lead EKG Placement

Uses 10 physical electrodes to produce 12 distinct electrical views (leads) of the heart.

EKG Special Considerations: Mastectomy

Avoid placing electrodes or blood pressure cuffs on the side of a previous mastectomy.

EKG Special Considerations: Right-Sided Heart & Posterior Chest

Requires placing chest leads on the right thorax or the back to evaluate specific infarctions.

EKG Special Considerations: Amputations

Place electrodes on the remaining portion of the limb or symmetrically on the torso.

EKG Special Considerations: Pediatric Patients

Use smaller electrodes, place them closer together to avoid overlapping, and use modified lead placements if necessary.

V1 Electrode Placement

Fourth intercostal space at the right sternal border.

V2 Electrode Placement

Fourth intercostal space at the left sternal border.

V3 Electrode Placement

Midway between V2 and V4 electrode placements.

V4 Electrode Placement

Fifth intercostal space at the left midclavicular line.

Skin Preparation for Electrode Placement

Clean the skin with alcohol, clip excessive hair, and ensure the skin is dry for optimal electrical conduction.

Cardiac Conduction System Pathway

SA node → AV node → Bundle of His → right and left bundle branches → Purkinje fibers.

Sinoatrial (SA) Node

The natural pacemaker of the heart, initiating electrical impulses.

Atrioventricular (AV) Node

Delays electrical impulses briefly to allow the ventricles to fill with blood.

Basic Life Support (BLS) Core Components

Early recognition of cardiac arrest, high-quality CPR, and early defibrillation with an AED.

Adult BLS Compression-to-Ventilation Ratio

30 chest compressions to 2 rescue breaths.

Signs of Cardiopulmonary Compromise

Chest pain, shortness of breath, tachypnea, hypotension, diaphoresis, and cyanosis.

Symptoms of Cardiopulmonary Compromise

Palpitations, dizziness, anxiety, nausea, and severe fatigue.

Wandering Baseline Artifact

Caused by patient movement, respiration, or poor skin prep; resolved by securing electrodes and cleaning skin.

Somatic Tremor Artifact

Appears as fuzzy, erratic baseline caused by muscle tension or shivering; resolved by having the patient relax or lie still.

Electrical Interference (AC) Artifact

Appears as sharp, uniform spikes caused by nearby electronic devices; resolved by unplugging non-essential electronics.

Interrupted Baseline Artifact

Caused by a detached electrode or broken lead wire; resolved by checking and securing all lead connections.

Artifact Resolution Techniques

Includes checking lead connections, ensuring proper skin prep, eliminating electrical sources, and calming the patient.

P Wave Characteristics

Represents atrial depolarization; typically upright and smooth in lead II.

QRS Complex Characteristics

Represents ventricular depolarization; normal duration is 0.06 to 0.10 seconds.

ST Segment Characteristics

Represents early ventricular repolarization; should lie along the isoelectric baseline.

T Wave Characteristics

Represents ventricular repolarization; typically upright and rounded.

U Wave Characteristics

Represents late ventricular repolarization; follows the T wave, small and rounded.

Recognizing Dysrhythmias

Identifying irregular heart rates, abnormal rhythms, or unusual waveform morphologies on an EKG.

Reporting Dysrhythmias

Promptly notifying the provider, documenting the finding, and closely monitoring patient vitals.

Ventricular Tachycardia (V-Tach)

A rapid, life-threatening heart rhythm originating in the ventricles; can present with or without a pulse.

Ventricular Fibrillation (V-Fib)

A chaotic, quivering heart rhythm resulting in no cardiac output; requires immediate CPR and defibrillation.

Emergency Response to V-Tach/V-Fib

Activate the emergency response system, retrieve an AED, begin high-quality CPR, and defibrillate immediately if indicated.

Defibrillation Protocol

Delivers an electrical shock to terminate pulseless ventricular tachycardia or ventricular fibrillation and restore a normal rhythm.

EKG Machine Paper Speed

Standard paper speed is typically 25 mm/s, with 50 mm/s used for faster heart rates to better visualize waveforms.

EKG Machine Sensitivity Setting

Controls the amplitude or height of the waveform tracing (e.g., 1/2, 1, 2) to ensure clear visualization.

EKG Machine Galvanometer Function

Converts electrical current from the heart into mechanical motion to move the stylus.

EKG Machine Thermal Recorder

Uses heat to burn the waveform tracing onto heat-sensitive EKG paper.

EKG Calibrating Signal (Standardization)

A 1 mV signal that produces a 10 mm deflection to ensure the machine is recording accurately.

EKG Equipment Maintenance and Cleaning Requirements

Disinfecting leads and cables between patients, wiping down the machine exterior with approved cleaning agents, and inspecting for frayed wires or damage.

Node (Cardiac Conduction)

Specialized cardiac tissue, such as the SA and AV nodes, that generates and conducts electrical impulses.

Lead (EKG)

An electrical view of the heart's activity created by measuring the difference between electrodes.

Patch/Electrode (EKG)

A sticky sensor attached to the skin to detect and transmit the heart's electrical signals to the machine.

Normal Sinus Rhythm (NSR)

A regular heart rhythm with a rate of 60 to 100 bpm.

Sinus Bradycardia

A regular rhythm with a heart rate of less than 60 beats per minute.

Sinus Tachycardia

A regular rhythm with a heart rate greater than 100 beats per minute.

Atrial Fibrillation

An irregularly irregular rhythm characterized by a chaotic baseline and absent P waves.

Atrial Flutter

A rhythm showing a characteristic sawtooth flutter wave pattern instead of P waves.

Asystole

A flatline rhythm representing total lack of electrical and cardiac activity.

Pulseless Electrical Activity (PEA)

An organized electrical rhythm on the EKG where the patient has no pulse.

Premature Ventricular Contraction (PVC)

An early, wide QRS complex occurring without a preceding P wave.

Premature Atrial Contraction (PAC)

An early heart beat originating in the atria, resulting in an abnormally timed and shaped P wave.

Junctional Rhythms

Rhythms originating from the AV junction, characterized by absent, inverted, or retrograde P waves and a normal QRS.

Supraventricular Tachycardia (SVT)

A rapid heart rhythm originating above the ventricles, typically with a rate greater than 150 bpm and narrow QRS complexes.

PVC Bigeminy

A pattern where every other heartbeat is a premature ventricular contraction (PVC).

PVC Trigeminy

A pattern where every third heartbeat is a premature ventricular contraction (PVC).

V5 Electrode Placement

Fifth intercostal space at the left anterior axillary line.

V6 Electrode Placement

Fifth intercostal space at the left midaxillary line.

EKG Ground Electrode (RL)

Placed on the right leg, serving as a reference electrode to reduce electrical interference.

Artifact Troubleshooting Order

Check the patient first, then check equipment connections if artifact persists.

EKG Interpretation Steps

Determine rate, rhythm, evaluate P waves, PR interval, QRS duration, and ST segment.

Ischemia

Inadequate blood supply to the heart muscle, often appearing as ST-segment depression or T-wave inversion on an EKG.

Infarction

Tissue death caused by a localized lack of oxygenated blood, typically represented by ST-segment elevation on an EKG.

Ectopic Beat

An abnormal heartbeat originating from a site other than the sinoatrial node.

Myocardium

The thick middle muscular layer of the heart wall responsible for pumping blood.

Pericardium

The protective, fluid-filled membranous sac enclosing the heart.

Syncope

Temporary loss of consciousness and postural tone, commonly known as fainting.

Angina Pectoris

Chest pain or pressure caused by transient myocardial ischemia.

Bradyarrhythmia

An abnormally slow heart rate accompanied by an irregular cardiac rhythm.

Tachyarrhythmia

An abnormally rapid heart rate accompanied by an irregular cardiac rhythm.

Depolarization

The electrical activation of cardiac cells caused by the influx of ions, leading to muscle contraction.

Repolarization

The return of cardiac cells to their resting electrical state following depolarization.

Deoxygenated Blood Entry

Enters the right atrium via the superior and inferior vena cava.

Right Atrium to Right Ventricle

Blood flows through the tricuspid valve into the right ventricle.

Right Ventricle to Lungs

Pumps blood through the pulmonary valve and pulmonary arteries to the lungs for oxygenation.

Oxygenated Blood Return

Returns from the lungs via the pulmonary veins into the left atrium.

Left Atrium to Left Ventricle

Blood flows through the mitral (bicuspid) valve into the left ventricle.

Left Ventricle to Body

Pumps oxygenated blood through the aortic valve and aorta to the rest of the body.

Right Bundle Branch Block (RBBB)

A conduction delay or block in the right bundle branch, often presenting with an RSR' pattern in lead V1.

Left Bundle Branch Block (LBBB)

A conduction delay or block in the left bundle branch, often presenting with broad, notched R waves in lateral leads like V5 and V6.

Einthoven's Triangle

A triangular arrangement of the three standard limb leads (Lead I, II, and III) on the frontal plane used to record the heart's electrical activity.

aVR Lead Placement

Augmented vector right; positive electrode on the right arm, with negative reference combining left arm and left leg.

aVL Lead Placement

Augmented vector left; positive electrode on the left arm, with negative reference combining right arm and left leg.

aVF Lead Placement

Augmented vector foot; positive electrode on the left leg, with negative reference combining right arm and left arm.

Lead I Placement

Measures potential between the right arm (negative) and left arm (positive).

Lead II Placement

Measures potential between the right arm (negative) and left leg (positive).

Lead III Placement

Measures potential between the left arm (negative) and left leg (positive).