Electrocardiogram (ECG)
1 Basic principles
See ECGpedia for reliable and good information with videoclips etc.
You need to be able to recognize dangerous abnormalities on ECG and telemetry, contra-indications
to training and ischemia.
Telemetry: used in cardiac rehabilitation in hospitals and it is less complex than a normal ECG and
also less full. You can see the morphology, but you can’t see as easy as on an ECG how big it is etc.
1.1 Registration
In a normal situation, the electrical sign goes in the direction of the arrow on
the picture.
The sign starts at the sinus node (right atrium, but depolarisation of both atria
happens together) AV-node bundle of His Purkinje fibres. It starts on
the top and goes downwards to the left and to the front.
1.2 Clinical: placement of electrodes
There are 6 extremity/limb leads and 6 chest leads:
In the end, we have 12 lines in 1 patient. Every line represents a certain part of the heart.
The extremity leads:
Lead I: from right arm to left arm
Lead II: right arm to left leg
Lead III: left arm from left leg
In the FRONTAL PLANE
Lead aVR: towards the right side
Lead aVL: towards the left side
Lead aVF: towards the feet
Also in FRONTAL PLANE
We need to have 4 electrodes for the frontal plane. Most of the time, we place the electrodes on the
shoulders and lower back during exercise instead of wrists and ankles because there is less
movement there.
1
, The chest leads: 6 precordial electrodes are placed resulting in V1-V6
TRANSVERSAL PLANE
The leads are like camera points: when the wave of depolarisation is
coming towards the “camera” positive on ECG (TOWARDS ME),
perpendicular on the wave of depolarisation iso-electric on ECG, wave
of depolarisation goes away from the “camera” negative on ECG.
IT IS IMPORTANT ON THE EXAM TO GET THIS CONCEPT!!!!! See examples on the ppt + interpretation
NORMAL:
Lead 1-3 and aVF are positive
V1 and aVR are negative (V1 sometimes iso-electric)
AVL is iso-electric
When it doesn’t follow these rules there is necrosis of a
part of the heart current won’t go trough that part of the
heart because it’s dead.
The different leads represent different parts of the heart:
aVR is normally not looked at because it is almost always negative.
2
1 Basic principles
See ECGpedia for reliable and good information with videoclips etc.
You need to be able to recognize dangerous abnormalities on ECG and telemetry, contra-indications
to training and ischemia.
Telemetry: used in cardiac rehabilitation in hospitals and it is less complex than a normal ECG and
also less full. You can see the morphology, but you can’t see as easy as on an ECG how big it is etc.
1.1 Registration
In a normal situation, the electrical sign goes in the direction of the arrow on
the picture.
The sign starts at the sinus node (right atrium, but depolarisation of both atria
happens together) AV-node bundle of His Purkinje fibres. It starts on
the top and goes downwards to the left and to the front.
1.2 Clinical: placement of electrodes
There are 6 extremity/limb leads and 6 chest leads:
In the end, we have 12 lines in 1 patient. Every line represents a certain part of the heart.
The extremity leads:
Lead I: from right arm to left arm
Lead II: right arm to left leg
Lead III: left arm from left leg
In the FRONTAL PLANE
Lead aVR: towards the right side
Lead aVL: towards the left side
Lead aVF: towards the feet
Also in FRONTAL PLANE
We need to have 4 electrodes for the frontal plane. Most of the time, we place the electrodes on the
shoulders and lower back during exercise instead of wrists and ankles because there is less
movement there.
1
, The chest leads: 6 precordial electrodes are placed resulting in V1-V6
TRANSVERSAL PLANE
The leads are like camera points: when the wave of depolarisation is
coming towards the “camera” positive on ECG (TOWARDS ME),
perpendicular on the wave of depolarisation iso-electric on ECG, wave
of depolarisation goes away from the “camera” negative on ECG.
IT IS IMPORTANT ON THE EXAM TO GET THIS CONCEPT!!!!! See examples on the ppt + interpretation
NORMAL:
Lead 1-3 and aVF are positive
V1 and aVR are negative (V1 sometimes iso-electric)
AVL is iso-electric
When it doesn’t follow these rules there is necrosis of a
part of the heart current won’t go trough that part of the
heart because it’s dead.
The different leads represent different parts of the heart:
aVR is normally not looked at because it is almost always negative.
2
