Lesson 1.3 Basic EKG Rhythm Interpretation

EKG Rhythm Strip Evaluation Steps

Determine heart rate, assess rhythm regularity, evaluate P waves, measure PR interval, evaluate QRS width, interpret overall rhythm with nursing implications

Heart Rate Determination

Count R waves in 6-second strip and multiply by 10, or count large squares between R waves and divide into 300

Rhythm Assessment Method

Measure R-R intervals using calipers or paper edge to determine regular versus irregular patterns

P Wave Evaluation Criteria

Check for presence, upright orientation in lead II, and one P wave preceding each QRS complex

PR Interval Normal Range

0.12 to 0.20 seconds representing AV conduction time from atria to ventricles

QRS Complex Width Classification

Narrow if less than 0.12 seconds indicating ventricular origin; wide if greater than 0.12 seconds indicating aberrant conduction

Normal Sinus Rhythm Parameters

Rate 60-100 bpm, regular rhythm, upright P waves before each QRS, PR interval 0.12-0.20 seconds, QRS less than 0.12 seconds

Sinus Bradycardia Characteristics

Rate less than 60 bpm with regular rhythm and normal P waves, PR interval, and QRS complexes

Bradycardia Nursing Assessment

Monitor for dizziness, hypotension, altered mental status, and decreased cardiac output requiring provider notification if symptomatic

Sinus Tachycardia Features

Rate greater than 100 bpm with regular rhythm and normal P waves, PR interval, and QRS complexes

Tachycardia Underlying Causes

Pain, fever, anxiety, hypovolemia, hypoxia, or stimulant medications requiring treatment of root cause

Atrial Fibrillation Recognition

Irregularly irregular rhythm with absent P waves replaced by fibrillatory waves and unmeasurable PR interval

Atrial Fibrillation Complications

Risk of thrombus formation and embolic stroke requiring anticoagulation and rate control medications

Atrial Flutter Pattern

Sawtooth P waves at 250-400 bpm with variable AV conduction creating regular or irregular ventricular response

Flutter Nursing Priorities

Monitor ventricular rate response and prepare for possible cardioversion or rate control interventions

Ventricular Tachycardia Criteria

Rate 100-250 bpm with wide QRS complexes greater than 0.12 seconds and absent or dissociated P waves

VT Emergency Response

Check pulse immediately; if pulseless begin CPR and defibrillate; if pulse present prepare for synchronized cardioversion

Ventricular Fibrillation Appearance

Chaotic baseline with no identifiable P waves, QRS complexes, or T waves indicating no cardiac output

VF Treatment Protocol

Immediate CPR with defibrillation as primary intervention following ACLS algorithms

Asystole Recognition

Flat line with no electrical activity, no P waves, QRS complexes, or measurable rate

Asystole Management

Confirm in two leads, begin CPR without defibrillation, administer epinephrine per ACLS protocol

Irregularly Irregular Definition

R-R intervals vary with no predictable pattern characteristic of atrial fibrillation

Fibrillatory Waves

Fine or coarse undulating baseline replacing P waves in atrial fibrillation

Sawtooth Pattern

Flutter waves appearing as regular saw-like deflections best seen in inferior leads

Wide QRS Significance

Indicates ventricular origin or aberrant conduction requiring immediate assessment for hemodynamic stability

Pulseless Rhythms

Ventricular fibrillation, pulseless ventricular tachycardia, asystole, and PEA requiring immediate CPR

Patient Versus Monitor Assessment

Always evaluate patient symptoms and hemodynamic status not just EKG appearance for clinical decisions

Systematic Rhythm Analysis

Consistent step-by-step approach prevents missed abnormalities and ensures accurate interpretation

Documentation Requirements

Record rate, rhythm, intervals, comparison to previous strips, patient symptoms, and interventions performed

Rapid Ventricular Response

Ventricular rate over 100 bpm in atrial fibrillation or flutter requiring rate control

Hemodynamic Compromise Signs

Hypotension, altered consciousness, chest pain, or dyspnea indicating urgent intervention needed

EKG Grid Measurements

Small square equals 0.04 seconds and 1mm; large square equals 0.20 seconds and 5mm

Six-Second Method

Count QRS complexes in 30 large squares (6 seconds) and multiply by 10 for heart rate

Regular Rhythm Verification

Equal R-R intervals throughout strip with less than 0.04 second variation

Absent P Waves Differential

Consider atrial fibrillation, junctional rhythm, or ventricular rhythms when P waves not visible

Treatment Priority Principle

Treat unstable patient first then identify rhythm; stable patients allow time for detailed analysis