- Sinus rhythm: The default heart rhythm, characterized by regular P waves, QRS complexes, and T waves with consistent PR intervals and a rate between 60–100 bpm.
- Atrial flutter: Tachycardic atrial activity (~300 bpm) with a characteristic “sawtooth” baseline due to re-entry circuit in the right atrium; AV conduction often results in 2:1 or 4:1 block.
- Shockable rhythms: Includes ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT); both require immediate defibrillation and CPR.
- Paced rhythm: Regulated by an artificial pacemaker; shows characteristic pacing spikes preceding QRS complexes, indicating electrical stimulation of the heart.
- Third-degree/complete heart block: No relationship between P waves and QRS complexes due to complete failure of AV conduction; requires pacemaker.
- Ventricular tachycardia: Broad QRS complexes (>120 ms), often monomorphic or polymorphic, with AV dissociation; may degenerate into VF.
- Second-degree heart block, Mobitz Type I (Wenckebach): Progressive prolongation of the PR interval until a QRS complex is dropped; usually benign, associated with AV node dysfunction.
- Wolff-Parkinson-White syndrome: Congenital accessory pathway causing pre-excitation; ECG shows short PR interval and delta wave; predisposes to paroxysmal tachyarrhythmias.
- Supraventricular tachycardia: Narrow complex tachycardia due to re-entry circuit involving the AV node or accessory pathway; often sudden onset and termination.
- Normal ECG: P wave (atrial depolarization), QRS complex (ventricular depolarization), T wave (ventricular repolarization); normal intervals and morphology.
- Atrial fibrillation: Irregularly irregular rhythm with absent P waves, variable RR intervals, and narrow QRS complexes; caused by disorganized atrial activity; risk of stroke.
- Second-degree heart block, Mobitz Type II: Intermittent non-conducted P waves without PR prolongation; indicates His-Purkinje system disease; higher risk of progressing to complete heart block.
- Ventricular fibrillation: Chaotic, disorganized electrical activity with no discernible P waves, QRS complexes, or T waves; no pulse; requires immediate defibrillation.
- First-degree heart block: Consistently prolonged PR interval (>200 ms) due to slowed conduction through the AV node; usually asymptomatic and incidental.
Parent Tip: Review the logic above to help your child master the concept of printable ekg rhythm flashcards.
