ECG And Rhythm Disorders Flashcards
What does each wave in the cardiac cycle represent?
P-wave: atrial systole
QRS: ventricular contraction
T-wave: ventricular repolarisation
Describe the electric journey in the heart and what part each corresponds to in an ECG
Sinoatrial node: P wave
Av node and bundle of his: PR segment
Bundle branches: Q wave
Purkinje fibres: R wave and S wave
Ventricles: T wave
Describe the lead placements on the body:
Lead I: Left arm to right arm
Lead II: Right arm to left leg
Lead III: Left arm to left leg
What are the 6 electrodes on an ECG? Where are they each placed?
V1-V6
V1: right sternal border on 4th intercostal space
V2: left sternal border on 4th intercostal space
V4: mid-clavicule line on 5th intercostal space
V3: halfway between v2-v4
V5: anterior axillary line at V4 level
V6: mid axillary line at V4 level
What are the main arteries of the heart?
What part of the heart do they each refer to?
What leads do each of these coronary arteries correspond to?
How can we use an abnomality in a part of an ECG to know what part of the heart is wrong?
Left circumflex artery - I, aVL, V5-V6 Lateral side of heart
Right coronary artery - II, III, aVF Inferior side of heart
Left anterior descending - V1-V4 Anterior/Septal side of heart
Use ecg to tell you what side of the heart it is depending on what Artery supplies it
What does the width and height of a big box on the ECG show?
Width- 0.2 secs
Height- 0.5mv
What is the normal range of the cardiac axis?
How does this differ in longer and shorter individuals?
90 to -30
Taller slim people have smaller cardiac axis as his heart is more elongated- they should have something close to 90
Short stubby people’s hearts are wider as his chest cavity is shorter- they should have something closer to 0
What heart rate defines en ECG as tachycardia and bradycardia?
Tachycardia > 100bpm
Bradycardia < 65bpm
What is atrial fibrillation and what is its shape described as?
What kind of heart rate can you expect?
What are you at risk of?
Irregular contraction of the aorta
Oscillating baseline
Slow heart rate
Clotting
What is atrial flutter? What is it described as on an ECG?
Atrial contracting abnormally fast
Saw tooth patterns
Describe the 3 types of heart block
Describe their regularities
1st degree- prolonged P-R segment caused by the AV node, but still regular
2nd degree Mobitz T1- P-R segment gets longer every beat until one is missed, but regularly irregular
2nd degree Mobitz T2- P-R segment isn’t long but occasionally a QRS complex will be missed. Regularly irregular
3rd degree- P-waves and QRS complexes happening but there is not relationship between them
What is happening in ventricular tachycardia?
What waves can sometimes be hidden?
Fast ventricular contraction
Fast heart rate > 100bpm
P-waves can be hidden
What is happening in ventricular fibrillation?
Extremely fast ventricular contraction- cardiac arrest
Heart rate over 250bpm
How do you treat ventricular arrhythmias (tachycardia and fibrillation) vs flat lining?
Ventricular arrhythmias- shock
Flat lining- inject adrenaline
What is happening to the heart in ST-segment elevation and depression?
How much do either need to be increased or decreased to count as such?
Elevation- tissue death due to infarction
Depression-tissue death due to myocardial ischaemia
Has to be over or under 2mm (4 tiny boxes)
