THE ELECTROCARDIOGRAM

Dr. Mariano J. Rey

1. To learn the cardiac electrophysiologic processes that are the basis for the genesis of the patterns of the ECG.

2. To know the scientific and practical aspects that are involved in the generation of the ECG tracing.

3. To begin to use the ECG to evaluate cardiac electrophysiology (e.g. heart rate, mean electrical axis).

1. Historical background
• A. Einthoven - string galvanometer
2. Generation of the ECG
• A. The Heart as a Dipole
• B. EinthovenÕs Triangle
• C. Scalar Quantities
• D. The ECG Leads
• (1) Unipolar vs. Bipolar Leads
• (2) Standard Bipolar Limb Leads (I, II, and III)
• (3) Augmented Unipolar Limb Leads (aVR, aVL, and aVF)
• (4) Precordial Leads (V1 to V6)
3. Electrogenesis of the ECG
• A. Waves (P, Q, R, S, and T)
• B. QRS Complex
• C. Intervals (PR and QT)
• D. Segments (PR and ST)
4. Electrical Axis
• A. Hexagonal Reference System
• B. EinthovenÕs Law (I + III = II)
• C. Vectorial Analysis

Define or Explain
• dipole
• scalar vs. vector quantities
• unipolar vs. bipolar leads
• interval vs. segment
• isoelectric line

Computer Module

The Hippocrates Project EKG Module is a superb tool to use in an interactive auto-tutorial fashion to help you understand the electrocardiogram and its generation. The entire module should take about an hour to complete on your own. All seven sections of the module are pertinent to the material covered in this lecture. The EKG Module will also be used in the first half of this weekÕs seminar.