ECG Flashcards
P Wave
Atrial Depolarisation
Contraction of Atria
Single hump=Simultaneous contraction
QRS Complex
Ventricular Depolarisation-Contraction of Ventricles
T Wave
Ventricular Repolarisation-Ventricles return to rest state
PR Interval
Start of P wave to QRS
0.12-0.20 secs
Time taken for signal to travel from SA Node in Atria to Ventricles
Heart Blocks occur in which ECG segment??
PR Interval
Atria and Ventricles not synced
ST Segment
End of S wave to beginning of T wave
Depressed = Myocardial Ischaemia
Elevated = Myocardial Infarction
QRS Complex
How long signal takes to spread through Ventricles
Depolarisation of Septum to Left Ventricle
Heart Rate on ECG
300/Large boxes between R-R intervals
ECG Intervals
RR= To determine HR
PR= Diagnose Heart Block
ST= Diagnose MI
Interpret ECG
Rate
Rhythm
P waves?? Any abnormal?
Heart Blocks??
Wide QRS??
1st Degree Heart Block
Prolonged PR Interval
2nd Degree Mobitz I Heart Block
Progressively increasing PR interval leading to dropped beat
2nd Degree Mobitz II Heart Block
Intermittent dropped beats
3rd Degree Heart Block
Complete Dissociation between Atria and Ventricles
Cardiac Symptoms
Chest Pain Dizziness
Leg Swelling SOB
Nausea Pallor/Cyanosis
Sweating Dyspnoea
Palpatations Syncope
Causes of ST Elevation
Limb Leads- >1mm at J Point
V Leads >2mm at J Point
ST segment elevated MI
Pericarditis
Printzmetal Angina
Causes of ST Depression
Myocardial Ischaemia
Ventricular Hypertrophy with Strain
Drugs-Digoxin
ST elevation is defined as?
Limb Leads- >1mm at J Point
V Leads >2mm at J Point
Causes of Right Bundle Branch Block
Normal
Ischaemic heart disease
Cardiomyopathy
Massive PE
What is a pathological Q wave?
-Any negative deflection that precedes an R wave
-Usually indicate current or prior myocardial infarction
-Seen in leads V1-3
Causes of small T waves
Hypokalaemia
Hypothyroidism
Pericardial Effusion
Causes of large T waves
Early Stage Myocardial Infarction
Hyperkalaemia
What are the Inferior Leads and what Coronary Vessel???
II, III, aVF
Right Coronary Artery
What are the Lateral Leads and what Coronary Vessel???
I, aVL, V5, V6
Left Coronary Artery
What are the Anterior/Septal Leads and what Coronary Vessel???
V1-V4
Left Anterior Descending
