EKG Rhythm Strips Definitions

Study Notes

Sinus Rhythm: Normal rhythm with a heart rate (HR) of 60-100 bpm; characterized by regularity.
Sinus Bradycardia: HR < 60 bpm; complexes become closer together, potentially burying the P wave within the T wave.
Sinus Arrhythmia: Normal rhythm with minimal HR variations; resembles sinus rhythm with distinct intervals between cardiac complexes.

Sinus Arrest: Sudden electrical inactivity leading to a pause, with consistent R to R intervals before and after the pause.
Premature Atrial Complex: Occurs when an impulse arises from the atria other than the SA node; P wave alterations appear biphasic or irregular.
Wandering Atrial Pacemaker: Minimum of three different shaped P waves; rhythm may vary in regularity, potentially affecting the PR interval.

Multifocal Atrial Tachycardia: Faster variant of wandering atrial pacemaker with at least three different P wave shapes, commonly seen in COPD patients.
Atrial Flutter: Rapid depolarizations within the atria; absence of P waves replaced by F waves, displays a “saw tooth” pattern.
Atrial Fibrillation: Chaotic electrical activity leads to absent P waves and a chaotic waveform between QRS complexes.

Premature Ventricular Complexes: Occur from early impulses in ventricles; characterized by absent P waves and bizarre QRS complexes.
Agonal Rhythm: HR < 60 bpm with absent P waves and wide, bizarre QRS complexes; many patients may be unconscious and may require defibrillation.
Ventricular Fibrillation: Absence of P waves and QRS complexes; presents as a chaotic waveform with no measurable rate or effective heart function.

Asystole: Total electrical activity absence in the heart; clinical death signified by absent P waves and QRS complexes.
Ventricular Asystole: Similar to asystole but may have P waves; patient is clinically dead.
First Degree Heart Block: Normal sinus appearance but with a prolonged PR interval (>0.2s); no QRS drop occurs.
Second Degree Heart Block Type I (Wenckebach): Characterized by progressively prolonged PR intervals followed by QRS drop; regular P-P intervals, irregular R-R intervals.

Second Degree Heart Block Type II: QRS complexes appear in a stable pattern correlated with P waves (e.g., 2:1 or 3:1).
Third Degree Heart Block: Complete blockage leading to independent functioning pacemakers in the atria and ventricles; results in dissociation of P waves and QRS complexes.

Supraventricular Tachycardia: Regular rhythm with HR > 140 bpm; presents narrow QRS, ambiguous P wave identification.
Lown-Ganong Levine Syndrome and Wolf-Parkinson-White Syndrome: Pre-excitation syndrome where conduction bypasses normal AV pathways; characterized by an early R wave upstroke before the QRS and slurred QRS appearance.