Cardiac Rhythm Interpretation for NCLEX: ECG Basics, Arrhythmias & Nursing Actions
Learn cardiac rhythm interpretation for the NCLEX. Covers normal sinus rhythm, common arrhythmias, ECG strip analysis, and nursing interventions.
Cardiac Rhythm Interpretation for NCLEX
Cardiac rhythm interpretation is a fundamental nursing skill tested on the NCLEX. You must be able to identify common arrhythmias, understand their clinical significance, and determine appropriate nursing actions.
ECG Basics
The P wave represents atrial depolarization. The QRS complex represents ventricular depolarization (normal is 0.06-0.12 seconds). The T wave represents ventricular repolarization. The PR interval measures conduction through the AV node (normal is 0.12-0.20 seconds). The QT interval represents total ventricular activity. A systematic approach to rhythm analysis includes: determine rate, determine regularity, identify P waves, measure PR interval, and measure QRS duration.
Common Arrhythmias
Sinus bradycardia: rate below 60 bpm with normal P waves and QRS. May be normal in athletes. Treat with atropine if symptomatic. Sinus tachycardia: rate above 100 bpm with normal P waves and QRS. Identify and treat the underlying cause (pain, fever, anxiety, hypovolemia). Atrial fibrillation: irregularly irregular rhythm with no discernible P waves. Risk of thrombus formation increases stroke risk. Treatment includes rate control (beta-blockers, calcium channel blockers) and anticoagulation. Atrial flutter: sawtooth pattern of flutter waves. Ventricular rate depends on the conduction ratio.
Life-Threatening Arrhythmias
Ventricular tachycardia: wide QRS complexes at a rate above 150 bpm. If pulseless, treat as cardiac arrest with defibrillation. If stable with a pulse, administer amiodarone. Ventricular fibrillation: chaotic, disorganized electrical activity with no cardiac output. Immediate defibrillation is the priority intervention. Asystole: flat line with no electrical activity. Do not defibrillate asystole. Initiate CPR, administer epinephrine, and identify reversible causes (Hs and Ts).
Heart Blocks
First-degree: prolonged PR interval (greater than 0.20 seconds), usually benign. Second-degree Type I (Wenckebach): progressive PR prolongation until a QRS is dropped. Second-degree Type II: constant PR interval with sudden dropped QRS, more dangerous. Third-degree (complete): atria and ventricles beat independently, requires pacemaker. Practice with our clinical nursing mini-exams and review cardiac rhythm cheat sheets.