This document provides an overview of Module I of an ECG Rhythm Interpretation course. The module introduces ECG basics, including normal impulse conduction through the heart, the components of the PQRST waveform, pacemakers of the heart, and how to read the graph paper used to plot ECG rhythms. The objectives are to recognize normal sinus rhythm and 13 common rhythm disturbances, and identify myocardial infarctions on ECGs. Future modules will cover analyzing rhythms, specific arrhythmias, and advanced 12-lead interpretation.

1. ECG Rhythm Interpretation
Module I
ECG Basics
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2. INDIAN DENTAL ACADEMY
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3. Course Objectives
• To recognize the normal rhythm of the
heart - “Normal Sinus Rhythm.”
• To recognize the 13 most common
rhythm disturbances.
• To recognize an acute myocardial
infarction on a 12-lead ECG.
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4. Learning Modules
• ECG Basics
• How to Analyze a Rhythm
• Normal Sinus Rhythm
• Heart Arrhythmias
• Diagnosing a Myocardial Infarction
• Advanced 12-Lead Interpretation
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5. Normal Impulse Conduction
Sinoatrial node
AV node
Bundle of His
Bundle Branches
Purkinje fibers
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6. Impulse Conduction & the ECG
Sinoatrial node
AV node
Bundle of His
Bundle Branches
Purkinje fibers
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7. The “PQRST”
• P wave - Atrial
depolarization
• T wave - Ventricular
repolarization
• QRS - Ventricular
depolarization
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8. The PR Interval
Atrial depolarization
+
delay in AV junction
(AV node/Bundle of His)
(delay allows time for
the atria to contract
before the ventricles
contract) www.indiandentalacademy.com

9. Pacemakers of the Heart
• SA Node - Dominant pacemaker with an
intrinsic rate of 60 - 100 beats/minute.
• AV Node - Back-up pacemaker with an
intrinsic rate of 40 - 60 beats/minute.
• Ventricular cells - Back-up pacemaker
with an intrinsic rate of 20 - 45 bpm.
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10. The ECG Paper
• Horizontally
– One small box - 0.04 s
– One large box - 0.20 s
• Vertically
– One large box - 0.5 mV
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11. The ECG Paper (cont)
• Every 3 seconds (15 large boxes) is
marked by a vertical line.
• This helps when calculating the heart
rate.
NOTE: the following strips are not marked
but all are 6 seconds long.
3 sec 3 sec
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12. End of Module I
ECG Basics
Proceed to Module I Practice Quiz
on WebCT
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13. Thank you
For more details please visit
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