ECG Rhythms and Interference Types

60 Cycle Interference

AC power interference; regular oscillations

Somatic Tremor

Muscle contractions; rapid, irregular spikes

Wandering Baseline

Deep breathing causes the ECG baseline to drift

Lead Fault

Poor lead connection; no reading

Sinus Rhythm

Normal rhythm originating from the SA node; normal P wave and QRS complex

Sinus Bradycardia

Heart rate <60 bpm

Sinus Tachycardia

Heart rate >100 bpm

Atrial Rhythms

Originates from atrial tissue outside the SA node; no normal P wave

Atrial Flutter

Single area in the atria fires rapidly

Atrial Flutter ECG

Many flutter/fibrillatory waves between QRS complexes

Premature Atrial Contraction (PAC)

Atria contract early

Premature Ventricular Contraction (PVC)

Ventricles contract early

PACs/PVCs

Usually benign if fewer than 6 per minute

Ventricular Rhythms

Originates from ventricular tissue

Ventricular Tachycardia (VT)

Regular, fast ventricular rhythm

VT ECG Findings

Large, irregular QRS complexes; absent P waves

VT Pulse

Often presents with no pulse

Ventricular Fibrillation (VF)

Ventricles twitch/quiver instead of contracting effectively

Asystole

No electrical activity (flatline) on ECG; medical emergency