How to Read an EKG Rhythm Strip

HOW TO READ AN EKG RHYTHM STRIP

Introduction to Cardiac Arrhythmia

  • Dysrhythmia and Arrhythmia: Terms that refer to abnormal heart rhythms and/or speed, meaning when the heart is not beating at a regular rhythm or speed.

  • Example of an arrhythmia: Atrial Fibrillation (A-Fib).

Types of ECGs

  • Rhythm Strip: Typically lasts 6 seconds.

  • Best lead for reading a rhythm strip: Lead II.

  • Reason for Lead II preference: Optimal for observing electrical activity of the heart.

Steps for Reading a EKG

  1. Identify all P waves:

    • Absence or irregularity indicates an atrial rhythm.

    • Normal P wave allows progression to next step.

    • Bonus: Count the PR Interval (small boxes x 0.04 seconds).

  2. Identify all QRS complexes:

    • Assess whether complexes are narrow or wide:

      • Narrow complexes suggest tachycardia.

      • Wide complexes indicate slower ventricular contraction.

  3. Identify all T waves:

    • T waves follow QRS complexes.

    • Absence suggests potential myocardial infarction; check for ST elevation.

  4. Calculate heart rate if applicable:

    • Each strip represents 6 seconds.

    • Use the 6 second rule for calculating the heart rate.

  5. Identify the arrhythmia:

    • Determine whether it is Sinus, Atrial, or Ventricular Rhythm.

    • Example: Atrial fibrillation (named after its specific problem).

EKG Rhythm Examples

1. Normal Sinus Rhythm (NSR)

  • All parts of the heartbeat present: P waves, QRS complexes, and T waves.

  • Heart rate: 60-100 beats per minute (BPM).

  • Signifies SA Node is initiating impulses.

2. Ventricular Tachycardia (V-Tach)

  • No definable P or T waves.

  • Ventricles beat out of control (known as “Tombstones”).

  • Can lead to ventricular fibrillation (V-Fib).

  • Requires immediate defibrillation if patient has no pulse:

    • Options:

      • Asynchronized Cardioversion: Shock delivered at any time in the cardiac cycle.

      • Synchronized Cardioversion: Shock synchronized to a specific point in the cardiac cycle.

3. Ventricular Fibrillation (V-Fib)

  • No definable P, QRS, or T waves.

  • Ventricles quiver between 200-300 BPM with no coordinated activity.

  • Immediate CPR/AED required to restore blood flow.

  • After defibrillation, an implanted defibrillator may be needed.

4. Atrial Fibrillation (A-Fib)

  • No definable P or T waves.

  • Irregular ventricular rate; atrium beats chaotically around 200-300 BPM.

  • Causes blood pooling in the atria, leading to clots and potential ischemic stroke.

  • Treatment may include:

    • Antiarrhythmic medications

    • Blood thinners (anticoagulants)

    • Cardioversion

    • Ablation procedures

5. Atrial Flutter

  • No definable P or T waves.

  • More organized depolarization than A-Fib; presents a “sawtooth” pattern on EKG.

  • Risk of clotting similar to A-Fib; may require anticoagulants.

6. Sinus Tachycardia

  • All heartbeat components present; rate exceeds 100 BPM.

7. Sinus Bradycardia

  • All heartbeat components present; rate is below 60 BPM.

8. Premature Ventricular Contraction (PVC)

  • Underlying heart rate may vary.

  • No P wave preceding the PVC; QRS complexes wide and bizarre.

  • Often resolves itself; may feel like heart is “skipping” beats.

  • Causes include stress, caffeine, and electrolyte deficiencies.

9. Sinus Arrest

  • A break in the normal EKG; SA node fails to fire.

  • Significant only if symptomatic or lasts longer than 6 seconds.

10. Premature Atrial Contractions (PACs)

  • Atria contract prematurely.

  • More than 6 PACs per minute is abnormal.

  • Features an extra (premature) P wave preceding QRS.

11. Asystole

  • Complete absence of electrical activity on EKG; requires immediate assessment.

  • If patient is alert, check for disconnected electrodes.

  • If not alert, call 911 and begin CPR.

12. Sinus Dysrhythmia

  • Slight irregularities in QRS complexes; common in children and linked with breathing.

Atrial Rhythms

  • Atrial rhythms originate from tissue outside the SA node and are defined by lack of P waves.

  • Common examples include A-fib and A-flutter.

Definitions and Vocabulary

  • Ischemia: Deficient blood supply due to obstruction of arterial inflow.

  • An ectopic heartbeat: Irregular heartbeat due to early contraction.

  • Pulseless Electrical Activity (PEA): An electrocardiogram records electrical activity, but no pulse is detected; requires immediate medical intervention.

EKG Artifacts

  • Artifacts: Markings caused by improper technique or interference, complicating diagnosis.

Types of Artifacts

  1. Somatic Tremor: Caused by muscle movement or tension, leading to erratic spikes and shifting baseline.

    • Prevent by keeping the patient still.

  2. Wandering Baseline: Shift in baseline caused by poor conduction or loose electrodes.

    • Prevent by securing electrode connections.

  3. Flat Line: Break in tracing due to disconnected wires or cardiac arrest.

    • Regular cleaning and maintenance of equipment are necessary.

  4. AC Interference (60-cycle interference): Regular spikes due to nearby electrical equipment.

    • Disconnect interfering devices and ensure proper grounding.

Lead Adjustments and Patient Positioning

  • Adjust precordial leads to avoid bone placement; utilize fleshy areas.

  • Position patients appropriately depending on their respiratory condition (Semi-Fowler's for dyspnea).

Special Considerations

  • Dextrocardia: Rare condition where the heart is on the right side necessitating modified lead placements.

  • Right-sided and Posterior Leads: Used for better visualizing certain cardiac conditions or infarcts.

  • 15-lead ECG: Includes posterior leads to enhance STEMI diagnosis, particularly beneficial in emergency settings.

Acute Coronary Syndrome (ACS)

  1. Stable Angina: Pain occurs with increased myocardial demand and stable plaque.

  2. Unstable Angina: Rupture of plaque forming thrombus causes pain even at rest.

  3. NSTEMI (Non-ST Elevation Myocardial Infarction): Partial occlusion leading to subendocardial injury.

  4. STEMI (ST Elevation Myocardial Infarction): Complete occlusion causing transmural injury; requires prompt medical attention.

Learning Recap

  • The 12-lead EKG is the standard tool for evaluating heart rhythm and function.

  • Any notable arrhythmia should be reported to a physician, showcasing the necessity for accurate readings and assessments in cardiac care.

Concluding Notes

  • The axis of the heart: Indicates the average direction of electrical activity spread and helps assess cardiac function. A normal axis falls between -30° and +90° on an ECG.