CPCT - EKG Certification Study Guide

Patient Preparation

• Identifying the Patient: Use a minimum of two identifiers to confirm the patient's identity. Acceptable identifiers include:
  • Name
  • Date of birth
  • Telephone number
  • The last four digits of their Social Security number (full SSN should not be recited for privacy).
  • For cognitively impaired patients, a family member or caregiver can validate their identity.
• Interviewing the Patient:
  • Gather pertinent medical, social, surgical, and medication histories before performing an EKG.
  • In acute-care, much of this might already be in the patient’s record, but review it.
  • Medical History: Includes information about previous acute disorders, ongoing chronic disorders, and current signs/symptoms.
  • Social History: Helps determine the patient’s risk for cardiac disorders.

Social History Questions:

• Do you smoke? If so, how many packs per day? If you quit smoking, how long ago did you quit?
• Do you drink alcohol or use recreational drugs? How much? What kind?
• Do you lead a stressful life? Have you had any major life changes (caring for a sick loved one, divorce, unemployment, relocation)? What do you do to cope with stress?
• Do you exercise? If so, how often, and what type of exercise?
• What do you eat? Does your diet include high amounts of fat, sodium, or caffeine?
• Do you work? If so, what is your work environment like? Does it expose you to chemicals or require you to wear a respirator?

Medical History Questions:

• Do you have a history of heart attack, stroke, blood clots, high blood pressure, heart failure, heart-rhythm problems, or any other heart conditions?
  • Heart failure: Disorder where the heart fails to efficiently pump blood, leading to severe complications.
• Do you have diabetes or lung disease?
• Are you pregnant?
• Do you have any allergies, including medication, food, and environmental allergies?
• Do you have any symptoms?
  • Use the mnemonic OPQRST (onset, provocation, quality, radiation, severity, time) to describe the symptom.
    • Example: For chest pain, ask when it began, what relieves or worsens it, if it is sharp/burning/dull, how severe the pain is, and when it began.
• Symptoms to Ask About:
  • Chest pain
  • Shortness of breath
  • Swelling of the legs and feet
  • Palpitations or racing heart: Sensations of rapid or irregular heartbeat felt in the chest or throat.
  • Fluttering or sensations of skipping beats
  • Fainting
  • Fatigue or weakness
  • Pallor
  • Coughing up blood
  • Pain in limbs, jaw, or between shoulder blades
  • Indigestion or heartburn not associated with eating

Surgical History Questions:

• Have you ever had heart surgery?
• Have you had any other surgeries?

Medication History Questions:

• Do you have any allergies to medications?
• Have you had any serious adverse reactions to medications?
• What medications do you currently take?
• Do you take any over-the-counter medications, herbal supplements, or vitamins?
• Do you take birth control pills or erectile dysfunction medications?

Disrobing, Gowning, and Draping

• Protect patients’ privacy and ensure comfort.
• Have patients undress from the waist up and ensure lower legs/ankles are accessible (adjust socks for lead placement).
• Provide a gown with the opening in the front.
• Patients should remove pantyhose or tights.
• Use a light drape or blanket after lead attachment.
• Always ask if an additional cover is desired.
• Remove jewelry (bracelets, necklaces) that might interfere with electrode placement or lead wires.
• Turn off electronic devices (cell phones) to prevent artifacts on the EKG tracing.
• Assure patients they will feel no discomfort; the machine measures and records electrical activity without causing electrical shocks.

Gathering Supplies

• Electrodes (usually 10 per package)
• Leads with clips or connectors
• EKG graph paper (if necessary)
• Alcohol wipes, electrolyte pads
• Gauze pads, tissues (for drying skin)
• Scissors and shaving equipment (for excess body hair)
• Pillows, blankets, gowns (for privacy and comfort)

Preparing the Patient

• Preparation might take longer than the test itself.
• Have patients empty their bladder before the test.
• Patients should rest for at least 10 minutes (preferably 30) before starting the EKG.
• Instruct patients to avoid applying lotions, powders, oils, or ointments to the skin before testing.
• Clean and dry skin is important; use alcohol wipes, soap and water, or electrolyte pads at attachment sites to reduce artifacts.
• Clip or shave excess chest hair with patient permission (clipping preferred to avoid injury/infection).

Positioning

• Patient positioning affects waveform and diagnostic interpretation. Document any adjustments.
• 12-Lead EKG:
  • Assist patients to a supine position without pillows.
  • If the patient has orthopnea (difficulty breathing while lying down) or respiratory problems, is in late pregnancy, or has back/cardiac issues, use a pillow under the head/knees or raise the head of the bed to a 45° angle.
  • Have patients lie with arms at their sides and relax their shoulders.
  • For tremors, place palms downward and tuck hands under hips or cross arms on the abdomen.
  • Late-stage pregnancy might require side positioning with a pillow supporting the back.
• 3- or 5-Lead EKG and Telemetry:
  • Used for ongoing monitoring or emergency transports.
  • Help patients assume a comfortable, relaxed position (sitting, standing, or lying).

Identification and Resolution of Artifacts

• Common causes of artifacts include body movement or substances on the skin.
• Unrelated causes involve mechanical issues and electrical factors.
• EKG machines have filters (usually set at 40 Hz) to reduce artifacts from muscle tremors or slight movements.
• For patients with pacemakers, adjusting the filter might be necessary to visualize pacemaker spikes.
• The filter removes artifacts on EKG paper but does not affect electronic interpretation.

Wandering Baseline

• The baseline is a flat line representing repolarization (relaxation) between cardiac cycles.
• Improper electrode placement can cause a wandering baseline, with wavelike up-and-down movements.
• Causes:
  • Movement of cables or leads
  • Patient movement
  • Loose electrodes
  • Dry electrodes
  • Labored breathing
  • Improper skin preparation (lotions, oils, gel)
• Eliminate wandering baseline by repositioning limb leads on fleshy areas.
• Avoid issues by:
  • Instructing the patient to ensure the skin is free of topical substances.
  • Cleaning attachment sites prior to the procedure.
  • Educating the patient on what to expect.
  • Providing clear directions on how to breathe and when not to talk.

Somatic Tremor

• Muscle movement appears as uneven spikes on EKG tracing.
• Spikes are erratic due to inconsistent electrical voltage.
• Causes are both controllable (shivering) and uncontrollable (seizure activity).
• Reduce shivering by offering a light blanket and maintaining a warm temperature.
• Explain the procedure thoroughly to reduce anxiety-related movement; encourage deep, slow breaths.
• For medical disorders like Parkinson’s disease (a progressive, degenerative central nervous system disorder causing muscle spasms and shakiness), place palms in a prone position under buttocks or crossed over the abdomen.
• Do not perform an EKG during an active seizure unless directed by a provider.

Alternating Current (AC) Interference

• Electronic devices near the patient (especially cell phones) can cause electrical interference, creating uniform small spikes.
• Electrical wires in walls/ceiling/floor and nearby medical equipment can also cause AC interference.
• Turn off cell phones and move them away from the patient.
• Pull the examination table away from the wall.
• Ensure the ground prong of the three-prong plug is tight.
• If AC interference persists, try unplugging the EKG machine to run on battery power.

Interrupted Baseline

• A non-continuous baseline indicates an interruption in the electrical connection.
• The stylus might move strongly up/down or create a flat line.
• Causes:
  • Patient movement dislodges an electrode.
  • A lead wire is broken or loose.
• Prevent by regularly observing/maintaining lead wires and double-checking connections before starting.

Life-Threatening Dysrhythmias

• Key interventions for cardiac arrest are CPR and early defibrillation (sending an electrical shock to the heart to restore acceptable rhythm).
• Maintain CPR certification and know how to use an AED.

Ventricular Fibrillation (VF)

• VF causes dizziness, a feeling of impending doom, chest discomfort, shortness of breath, seizure activity, and death.
• Immediate Action:
  • Call for help (code blue).
  • Initiate CPR.
  • Have someone bring the AED.
  • Assist the rapid response team and document accordingly.

Ventricular Tachycardia (VT)

• VT often causes a precipitous drop in blood pressure and level of consciousness due to decreased cardiac output.
• VT can deteriorate to a pulseless rhythm or VF.
• Symptoms: Dizziness, a feeling of impending doom, chest discomfort, and shortness of breath.
• Response: Same as for VF.

Asystole

• Complete cessation of electrical activity in the heart.
• Common causes: Large pulmonary embolism, large myocardial infarction, respiratory arrest, hypoxia, overdose.
• Other causes: Hypothermia (body temperature below the expected range), acidosis (increased hydrogen ion concentration in the blood, lowering pH), electrolyte abnormalities, tension pneumothorax (accumulation of air/gas in the pleural space from lung laceration or chest wall opening), and trauma.
• If you see asystole on the EKG, observe the patient. If you see breathing and there is a pulse, switch to another lead and see if you have a rhythm.
• When a patient’s rhythm deteriorates to asystole, call for help and begin CPR. the AED might convert the rhythm back to normal sinus.

Complete Heart Block

• Patients with third-degree AV block can progress to cardiac arrest.
• Monitor cardiac output carefully, and CPR might be necessary.

Bradycardia and Tachycardia

• Bradycardia and tachycardia are not significant unless the patient has indications of cardiovascular or respiratory compromise.
• Alert the provider, ensure emergency equipment is available, and continuously monitor the patient.
• In atrial fibrillation, there is no organized contraction of the atria. They are in a quivering state where blood clot formation due to stagnation of the blood in the ventricles is possible, resulting in a stroke or a myocardial infarction.

Heart Rhythms

• A five-step method can be used to systematically interpret an EKG for dysrhythmias:
  1. Rhythm regularity and rate
  2. P wave morphology
  3. QRS duration morphology
• First, calculate both the atrial and ventricular rates, using calipers to measure waveform regularity.
• Irregular P-P intervals indicate atrial dysfunction (P wave represents atrial depolarization).
• Irregular Q-Q intervals indicate ventricular dysfunction (QRS represents ventricular depolarization).
• A 6-10 second tracing is needed to determine P and QRS waveform regularity.
• Check the shape and location of the P wave, appearing before each QRS waveform, with a consistent shape and positive deflection.
• Measure the PR interval and QRS duration, then document the rhythm using descriptive terminology:
  • Regular: QRS complexes are the exact same distance apart.
  • Irregular: Notable differences in waveform spacing.
  • Regularly Irregular: Consistent irregular pattern (e.g., two QRS complexes close, then a delay).
  • Irregularly Irregular: No consistency throughout the tracing.
• Normal P waves have a positive deflection. Variances in the shape of the P wave or missing P waves could indicate electrical conduction pathway abnormalities.

Intervals and Waveforms

• Each waveform, interval, and segment on an EKG tracing has significant meaning.
• The cardiac cycle starts at the beginning of the P wave and ends at the end of the T wave.
• P Wave: Represents atrial depolarization, starting when the SA node fires, leading to atrial contraction. Observe shape consistency and whether it precedes each QRS waveform.
• QRS Complex/Interval: Represents ventricular depolarization, leading to ventricular contraction. Atrial repolarization happens during this phase but is not visible. Evaluate the height of each complex for uniformity, measuring from the end of the PR interval (Q wave start) to the J point. The normal range is 0.04 to 0.10 seconds. Abnormalities indicate ventricular dysfunction.
• J Point: Represents the end of ventricular depolarization and the beginning of ventricular repolarization. It's the EKG landmark for measuring the end of the QRS complex. Myocardial ischemia can cause J point elevation or depression below the baseline.
• T Wave: Represents ventricular repolarization and should follow each QRS complex, appearing uniform in configuration.
• U Wave: Represents repolarization of the bundle of His and Purkinje fibers (not always visible). Electrolyte imbalances can cause U waves to appear.
• PR Interval: Represents the time it takes for the SA node to fire, the atria to depolarize, and electricity to travel through the AV node (the time from the beginning of atrial depolarization to the beginning of ventricular depolarization). It ranges from 0.12 to 0.20 seconds.
• P-P Interval: Represents the time between atrial depolarization cycles (between P waves), useful for analyzing rate and rhythm.
• R-R Interval: Represents the time between ventricular depolarization cycles (between R waves), valuable in analyzing rate and rhythm.
• QT Interval: Represents one complete ventricular cycle (depolarization and repolarization), measured from the beginning of the Q wave to the end of the T wave.
• PR Segment: Represents the time between the end of atrial contraction and the beginning of ventricular contraction. The AV node slows the impulse to allow ventricular filling.
• ST Segment: Represents the early phase of ventricular repolarization, its shape is important for detecting ischemia. It's the time from the end of ventricular depolarization to the beginning of ventricular repolarization.
• The J point represents the point in time where ventricular depolarization stops and ventricular repolarization starts. The J point is at the end of the QRS complex, or where the ST segment begins, and is the EKG landmark to use when measuring the end of the QRS complex.

Waveform Characteristics

• When analyzing EKG waveforms, note deflection direction, symmetry, configuration, and presence/absence of cardiac cycle components.
• P Wave: Demonstrates coordination and sequencing of electrical activities from the atria to the ventricles. There electrical activities originate when the SA node sends the impulse through the electrical conduction system of the heart. Waveform shapes should be consistent and of the same voltage. Examine P wave symmetry; a symmetrical P wave has right and left sides that form mirror images on the Y axis. A QRS complex should follow each P wave.
  Variations indicate a deviation from the normal conduction pathway.
  Positive deflection, rising above the baseline, is normal; negative deflection is not.
• T Wave: Look for symmetry and configuration consistency. Each T wave should follow a QRS complex and typically peak toward the end, showing deflection in the same direction as the QRS complex.
• Electrical pathway concerns happen when waves are not symmetrical or do not occur during the cardiac cycle when expected.
• Shortened or extended segments/intervals indicate interferences in the normal conduction process from the SA node to the AV node through the bundle of His, the bundle branches, and to the Purkinje fibers.
• P wave and PR interval abnormalities demonstrate atrial dysfunction, whereas QRS and T wave abnormalities demonstrate ventricular dysfunction.
• Conditions external to the electrical conduction system, along with patient factors, can alter the EKG tracing.
  The body's response to threatening situations and electrolyte levels in the blood affect the heart's electrical conduction.
  High potassium slows the heart rate, while excessive potassium causes an abnormal rate/rhythm.
  Low calcium slows the heart rate, while high calcium causes longer contractions, which are identifiable in the EKG tracing.
• Medications, metabolic disorders, and medical conditions (e.g., osteoporosis) affect potassium and calcium levels.
• Artificial devices like pacemakers alter waveforms and segments.
• Gather a complete medical and medication history before obtaining and attempting to analyze the EKG.

Dysrhythmias

• The heart has three pacemakers; specific dysrhythmias result from each:
  • SA Node: The natural, primary pacemaker, located within the wall of the right atrium. It sends impulses through the heart's electrical conduction pathway.
  • Junctional Pacemaker: In the atrioventricular tissue or AV node, at the junction between the atria and ventricles. It fires impulses at a rate of 40 to 60/min.
  • Purkinje Fibers: Stimulate the ventricles slowly, firing impulses at 20 to 40/min. This backup pacemaker is not very effective and only fires when the other two fail.

SA Node Dysrhythmias

• Dysrhythmias originating from the SA node are detected when the P wave is the focal point when analyzing the EKG tracing.
  • Normal Sinus Rhythm Characteristics:
    • P wave present, upright, and rounded.
    • P wave amplitude less than 2.5 mm.
    • P wave duration less than 110 milliseconds.
    • QRS complex usually narrow.
• Dysrhythmias that originate in the sinus node include the following.
  • Sinus bradycardia: produces a normal EKG tracing, but the heart rate is less than 60/min. Sinus bradycardia is not necessarily abnormal. For some athletes, patients with medical conditions such as hypothyroidism, and older adults who live a sedentary lifestyle, this rate might be normal. However, it can be serious for patients who have symptoms of a low cardiac output, such as dizziness.
  • Sinus tachycardia produces a normal EKG, but the heart rate is greater than 100/min. Tachycardia is normal during exercise or could be present with medical conditions such as hyperthyroidism, so is not necessarily abnormal for some patients or under some circumstances. However, it can be serious for a patient who recently had a myocardial infarction (heart attack).
• Sinus dysrhythmia is a slight irregularity in the rhythm, often resulting from breathing patterns and variations in vagal tone (the vagus nerve transmits information between the brain and various organs, including the heart). It can be problematic, especially if the patient reports palpitations or dizziness, so notify the provider if you identify this dysrhythmia.
• Sinus arrest is a break in the normal EKG pattern. When this occurs, the SA node fails to fire, but it is not significant unless the arrest lasts longer than 6 seconds. If it is, initiate code blue (resuscitative) procedures.

Atrial Dysrhythmias

• Dysrhythmias that originate in the atria include the following.
  • Atrial flutter is more severe than the sinus dysrhythmias. The atria are contracting at a rapid rate, between 250 and 350/min—much faster than the ventricles are contracting. No P waves appear, only flutter (F) waves with a normal QRS duration and morphology. Notify the provider, because the patient might need oxygen and other therapies.
  • Atrial fibrillation is even more severe because there is no organized contraction of the atria. It will appear with no identifiable P waves, only fibrillatory waves with a normal QRS duration. The atria are in a quivering state where blood-clot formation (due to stagnation of the blood in the ventricles) is possible, resulting in a stroke or a myocardial infarction. Unless this dysrhythmia is chronic and the patient is already receiving treatment for it, notify the provider immediately.

Junctional Dysrhythmias

• Junctional dysrhythmias occur at the AV node or tissue. Since the impulses generate at the AV junction, the flow of electrical activity to the atria is backward, which results in an inverted P wave configuration. The AV node is unlikely to initiate the impulses unless there has been injury or damage to the SA node.
• Dysrhythmias that originate in the AV junction (the area around the AV node and the bundle of His) include the following.
  • Premature junctional complex (PJC) is an early impulse that occurs before the next expected beat. The P wave could occur before, after, or even be buried within the QRS complex, causing an irregularity in the rhythm.
  • Junctional escape rhythm reflects an impulse originating from the AV junction that is acting as the backup pacemaker. The atria and ventricles receive the impulse simultaneously, which can result in an absent or inverted P wave. The heart rate does not exceed 60/min. The patient might show signs of a decrease in cardiac output due to the slower heart rate and the lack of atrial kick causes in the conduction of the electrical impulse to allow the atria to fill with blood.
  • Accelerated junctional rhythm is the same as the escape rhythm except that the rate is 60 to 100/min. However, it is unlikely that the patient will show signs of a decrease in cardiac output.
  • Junctional tachycardia rhythm is the same as the escape and accelerated rhythm, but the heart rate is 100 to 150/min. The faster the rate, the more likely the patient is to feel palpitations or fluttering.
  • Supraventricular tachycardia (SVT) or narrow complex tachycardia is not necessarily a junctional dysrhythmia, but the impulse does come from any area above the ventricles. In this situation, the impulse is not following the normal electrical conduction pathway. The heart rate is above 150/min. Due to the rapid heart rate, P waves are usually not visible.

Ventricular dysrhythmias

• Ventricular dysrhythmias tend to be more emergent and life-threatening, especially without medical intervention.
• Dysrhythmias that originate in the ventricles include the following.
  • Premature ventricular complexes (PVCs) occur when the ventricles contract out of the normal sequence, due to initiation by an ectopic focal point within the ventricles. A P wave is not visible prior to a typically wide and bizarre QRS complex. Many people have occasional benign PVCs during which they feel some form of palpitation or fluttering in their throat or chest. The severity of PVCs depends on their frequency as well as any accompanying reduction in cardiac output. PVCs are occasional if there are one to five per minute and frequent if there are six or more per minute.
  • Possible PVCs patterns include the following:
    • Unifocal: Single early PVC indicates one irritable area.
    • Multifocal: PVCs with multiple shapes indicate more than one irritable area.
    • Interpolated PVC: PVC occurs with no interruption in the normal rhythm.
    • Bigeminy: PVCs occur every second beat.
    • Trigeminy: PVCs occur every third beat.
    • Quadgeminy: PVCs occur every fourth beat.
    • Coupling: Two PVCs occur back to back.
  • Ventricular tachycardia Ventricular tachycardia is three or more PVCs in a row with a ventricular rate greater than 100/min. There is a continuous state of contraction and relaxation of the ventricles, resulting in a poor cardiac output. There are no noticeable P waves in the tracing and the QRS complexes are wide and bizarre, with the T wave deflected in the opposite direction. Patients might initially have a pulse and remain conscious, but this dysrhythmia can progress quickly to cardiac and respiratory arrest.
  • Ventricular fibrillation is an emergency state in which the ventricles are not contracting but quivering, and there is no cardiac output. There are no discernible waves throughout the tracing, except for fibrillatory waves. This dysrhythmia is not compatible with life. If the heart stops, the patient has no rhythm and the EKG shows asystole (a flat line). Activate the facility’s emergency system and begin CPR.

Other dysrhythmias

• Other rhythms reflecting a “dying” heart and causing unconsciousness due to extremely poor cardiac output and tissue oxygenation are the following:
  • Idioventricular rhythm occurs when only the ventricular pacemaker is functioning. The ventricular rate ranges between 20 and 40/min and there are no discernible P waves. The QRS complex is wide and bizarre. If the heart rate ranges between 40 and 100/min but all other aspects of the idioventricular rhythm are present, this is an accelerated idioventricular rhythm.
  • Agonal rhythm results when all the pacemakers of the heat (SA node, AV node, Purkinje fibers) have failed. The EKG shows a very wide, bizarre QRS complex with no P or T wave. The ventricular rate is less than 20/ min. This rhythm will more than likely result in cardiac arrest. Have all emergency equipment available.

Heart blocks

• Heart blocks occur when there is a difficulty somewhere in the electrical conduction pathway, which results in delayed or absent ventricular depolarization. The severity varies with the location and the cause of the block.
  • Bundle branch block occurs when there is interference somewhere in one of the bundle branches.
    • Left bundle branch block. The current moves through the right bundle branch for right ventricular contraction, but the current that would normally go down the left bundle moves to the left ventricle via the septum. This results in an abnormal right-to-left stimulation.
    • Right bundle branch block. The current travels normally down the conduction pathway until after the bundle of His. Then, because the right side of the pathway is blocked, it travels down the left bundle branch to initiate contraction of the ventricles. A widened QRS duration is a key indicator of a bundle branch block.
  • First-degree atrioventricular block is a delay in conduction from the SA node to the AV node. The impulse still travels through the normal pathway but is delayed. As a result, the PR interval is longer than the usual 0.20 seconds. Patients do not have symptoms from this type of block.
  • Second-degree atrioventricular block, type I : This is also known as Mobitz I or Wenckebach. In this type of block, there are nonconducted or blocked impulses from the AV node to the ventricles. As a result, there are some missing QRS complexes. The PR interval lengthens progressively until a QRS is dropped, and then the pattern repeats itself. Some patients who have this dysrhythmia have symptoms of low cardiac output.
  • Second-degree atrioventricular block, type II : Also known as Mobitz II, this is the classic form of heart block. The PR interval remains constant, but during the tracing, a P wave is present with no QRS complex or T wave. In this situation, the AV node has selectively blocked specific impulses. This type of heart block tends to progress quickly to complete heart block. Patients who have this dysrhythmia have symptoms of low cardiac output. When you identify this dysrhythmia, notify the nurse or the provider, monitor the patient, and prepare to initiate a code blue to summon the rapid response team. If the patient becomes unresponsive, begin CPR.
  • Third-degree atrioventricular block : Also known as complete heart block (CHP), this block occurs when all electrical impulses that originate above the ventricles are blocked. The atria and ventricles contract independently. The atria contract at a normal rate but the ventricles contract at 20 to 40/min, depending on where the pacemaker site originates. When you identify this dysrhythmia, watch for indications of low cardiac output, notify the nurse or the provider, monitor the patient, and prepare to initiate a code blue to summon the rapid response team. If the patient becomes unresponsive, begin CPR.

EKG Acquisition

• The electrocardiograph machine measures electrical energy traveling across the body's surface and the heart's electrical activity.
• Muscle tissue releases electrical energy when it depolarizes, creating an electrical potential change across the skin.
• Electrodes record these potential changes on graph paper or digitally as an electrocardiogram (EKG).
• The EKG is a graphic representation of energy changes over time; heart diseases result in specific EKG changes.

Standard Grid

• EKG paper measures voltage and time. Small boxes are 1 mm tall and wide; larger boxes (made of five small boxes) have thicker gridlines 5 mm apart.
  Each millimeter on the Y-axis (vertical) represents 0.1 millivolt (mV).
  Each millimeter on the X-axis (horizontal) represents 40 milliseconds or 0.04 seconds.
  Whether to count in seconds or milliseconds varies by facility.
  Familiarity with measurements helps spot abnormalities.
  At standard speed, 1 second equals 25 mm or five heavy-line boxes; 1 cm equals 1 mV (two large vertical boxes).

Standard Speed

• The standard paper speed is 25 mm/second. Providers might adjust the speed to facilitate interpretation for excessively slow or fast heart rates (e.g., increasing to 50 mm/second for rapid rates).
• Ensure standard speed; improper speed misinterprets dysrhythmias.

Standard Amplitude (Gain)

• Acquire EKGs at a standard amplitude (gain) of 10 mm per 1 mV unless directed otherwise.
  Document any requested amplitude changes to avoid misinterpretations.

Standard Calibration

• Calibration marks (rectangular waveforms) at the beginning of each lead indicate paper speed and amplitude. A positively deflected, rectangular standard marking should measure 10 mm tall by 5 mm wide, indicating the standard speed (25 mm/second) and amplitude (10 mm/mV).

Lead Placement

• Limb lead placement measures the heart’s electrical axis and is the reference point for the unipolar leads. Limb lead placement can be distal (wrists/ankles) or proximal (upper arms/thighs/shoulders) because the placement is a conductor originating from a particular point. Uniformity in placement is important for forming Einthoven’s triangle.

Unipolar Leads

• Unipolar leads measure in one direction (e.g., precordial or chest leads V1-V6).

Augmented Leads

• Augmented leads are also unipolar. The angle of measurement makes the voltage low in these leads, so the machine must make the waveforms larger for them to be readable. Augmented leads (aVr, aVl, aVf)record activity along the frontal plane; the combination of the three augmented leads and the bipolar leads constitute the six limb leads of the EKG.

Bipolar Leads

• Bipolar leads have positive and negative poles. Standard limb leads are bipolar and the EKG tracing that measures and records the potential difference between the poles create Einthoven's triangle.

EKG Acquisition

• The electrocardiograph machine measures electrical energy traveling across the body's surface and the heart's electrical activity.
• Muscle tissue releases electrical energy when it depolarizes, creating an electrical potential change across the skin.
• Electrodes record these potential changes on graph paper or digitally as an electrocardiogram (EKG).
• The EKG is a graphic representation of energy changes over time; heart diseases result in specific EKG changes.

Standard Grid

• EKG paper measures voltage and time. Small boxes are 1 mm tall and wide; larger boxes (made of five small boxes) have thicker gridlines 5 mm apart.
  Each millimeter on the Y-axis (vertical) represents 0.1 millivolt (mV).
  Each millimeter on the X-axis (horizontal) represents 40 milliseconds or 0.04 seconds.
  Whether to count in seconds or milliseconds varies by facility.
  Familiarity with measurements helps spot abnormalities.
  At standard speed, 1 second equals 25 mm or five heavy-line boxes; 1 cm equals 1 mV (two large vertical boxes).

Standard Speed

• The standard paper speed is 25 mm/second. Providers might adjust the speed to facilitate interpretation for excessively slow or fast heart rates (e.g., increasing to 50 mm/second for rapid rates).
• Ensure standard speed; improper speed misinterprets dysrhythmias.

Standard Amplitude (Gain)

• Acquire EKGs at a standard amplitude (gain) of 10 mm per 1 mV unless directed otherwise.
  Document any requested amplitude changes to avoid misinterpretations.

Standard Calibration

• Calibration marks (rectangular waveforms) at the beginning of each lead indicate paper speed and amplitude. A positively deflected, rectangular standard marking should measure 10 mm tall by 5 mm wide, indicating the standard speed (25 mm/second) and amplitude (10 mm/mV).

Lead Placement

• Limb lead placement measures the heart’s electrical axis and is the reference point for the unipolar leads. Limb lead placement can be distal (wrists/ankles) or proximal (upper arms/thighs/shoulders) because the placement is a conductor originating from a particular point. Uniformity in placement is important for forming Einthoven’s triangle.

Unipolar Leads

• Unipolar leads measure in one direction (e.g., precordial or chest leads V1-V6).

Augmented Leads

• Augmented leads are also unipolar. The angle of measurement makes the voltage low in these leads, so the machine must make the waveforms larger for them to be readable. Augmented leads (aVr, aVl, aVf)record activity along the frontal plane; the combination of the three augmented leads and the bipolar leads constitute the six limb leads of the EKG.

Bipolar Leads

• Bipolar leads have positive and negative poles. Standard limb leads are bipolar and the EKG tracing that measures and records the potential difference between the poles create Einthoven's triangle.