Cardiology Notes

Inherent Rates

  • Three major areas of the conduction system have built-in rates:
    • SA node: 60-100 bpm
    • AV junction: 40-60 bpm
    • Ventricles: 20-40 bpm
  • Irritability: A site discharges impulses faster than normal, overriding the SA node.
  • Escape: The normal pacemaker slows or fails, and the next highest inherent rate takes over.

Autonomic Nervous System

  • Sympathetic
  • Parasympathetic
  • Vagus Nerve

12 Lead ECG: Step 1 - General Impressions

  • QRS Complexes in every lead
  • Paper Speed
  • Regularity
  • Rate
  • Date & Time
  • Patient Demographics
  • Calibration Spike
  • Cleanliness of the ECG

Key Components

  • P wave
  • QRS complex
  • T wave
  • PR segment
  • ST segment
  • PR interval