ECG Webinar Series · 2020-05-12 · ECG Webinar Series Episode 1: ECG Basics 11th May 2020 at...

ECG Webinar SeriesEpisode 1: ECG Basics

11th May 2020 at 19:00

Presented by:

Mr Innes Eaton

Paramedic Practitioner

STC Training SolutionsAsk us about our BLS and ILS refresher training for

healthcare professionals!

01895 730020 | [email protected]

Session Plan

• Basic anatomy

• Electrophysiology

• How ECG machines work

• Indications for requesting an ECG

• Lead placement & ‘views’ of the heart

• Layout of the printed ECG

• Introduction to the individual waves

• Q&A Session

www.stctrainingsolutions.co.uk | 01895 730020 | [email protected]

ECG Webinar Series | Episode 1 | ECG Basics

1. Grab your smart phone

2. Go to: www.menti.com

3. Enter the code

4. Answer the question

Basic Anatomy & Coronary Arteries



Electrophysiology



B ’ B • The atria and ventricles are electrically isolated

from one another and all electrical signals pass

through the AV node (in a normal, healthy heart)

• The SA node is the main pacemaker of the heart –

if uncontrolled it will generate a HR of 100bpm

• Sympathetic and parasympathetic nerve fibres

innervate the SA node to control heart rate

• If the SA node were to fail, pacemaker cells in the

AV node and His-Purkinje system take over (at a

much slower rate)

Fast Cell Action Potentials



Slow Cell Action Potentials



Introduction to Cardiac Axis



• Individual myocytes

create electrical

activity that results in a

VECTOR

• If you were to take the

‘average’ direction of

all of these vectors,

you can calculate the

AXIS

• Imagine the ECG leads

as cameras

• How the wave appears

will depend on the

angle of the ‘camera’

in relation to the axis

• An axis travelling

directly towards an

ECG lead will give a

positive wave

Turning Vectors into Waves



ECG Indications

• Chest pain and/or dyspnoea that is not readily explained

• Unstable patients, where the cause is not immediately known

• TLoC or first presentation seizure

• Unexplained falls in the elderly

• Palpitations

• Abnormal pulse (<40, >150, newly irregular)

• Drug overdoses & recreational drug use

• Diabetics with unexplained symptoms

A normal ECG does not rule out acute coronary syndrome!



Further Investigations

• Serial ECGs

• Serial Bloods

• Imaging – CXR, CT/MRI, Echo

• Angiography



Lead Placement



Lead Views



Imagine you are standing

on the arrow head

looking back at the heart

Augmented views

(aVR/aVL/aVF) are just

views that are calculated

by the machine, as

opposes to ‘true’ views

ECG Views



ECG Layout



Print Speed:

• 25mm/s

Small Square:

• 40ms

• 1mV

Large Square:

• 200ms

To estimate rate:

300 ÷ LARGE

squares

between the R

waves

(or 1500 ÷

SMALL squares

between the R

waves)

ECG Waves Introduction



Question Time



[email protected]

ECG Webinar Series · 2020-05-12 · ECG Webinar Series Episode 1: ECG Basics 11th May 2020 at...

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