Electrocardiogram Flashcards
What is an EKG
Representation of the electrical events of the cardiac cycle
What is an arrythmia
Tachycardia, Bradycardia or fibrillation
What are the electrodes attached to the surface detecting
Depolarisation in the heart chambers
SA Node rate
60-100 bpm
AV Node rate
40-60 bpm
Ventricular cell rate
20-45bpm
Pacemaker cells of the heart
SA
AV
Ventricular
What is the standard calibration of the ECG
- 25 mm/s
2. 0.1 mV/mm
What do we see if the electrical impulse travels towards the electrode
A positive deflection
Describe the physiological process happening from the p-wave through the QRD complex
- SA Node
- AV Node
- Bundle of His
- Bundle Branches
- Purkyne fibres
What does the P wave show
atrial depolarisation
What is the PR interval
Atrial depolarisation AND delay in AV Node
What does each small box on ECG paper represent horizontally
0.04 s
What does each large box represent on an ECG paper
0.20 s
What does each large box on ECG paper represent vertically
0.5 mV
What are EKG leads needed for
Measure the difference in electrical potential between two points
What are bipolar leads
Two different points on th body
What are unipolar leads
One point on the body and a virtual reference point with 0 mV, located in the centre of the heart
How many leads does an EKG have
12
What are the 12 leads of a EKG
- Standard Limb
- Augmented Limb
- Precordial leads
How are the precordial leads subdivided
Septal - V1 +2
Anterior - V3 + 4
Lateral - V5 + 6
Describe the placing of the four precordial leads
- Fourth Intercostal Space right of the sternum - V1
- Fourth Intercostal space to the left of the sternum - V2
- Directly between leads V2 + V4 - V3
- Fifth intercostal space at left midclavicular line - V4
- Level with Lead V4 at left anterior axillary line - V5
- Level with lead V5 at left midaxillary line - V6
What are the four lateral leads
V5, V6, aVL, I
What are the three inferior leads
III, II, aVF