7. Interpreting ECG
Rate-
<60 bradycardia, >100 tachycardia
Rhythm- relation of P & QRS
Regular or irregular
Axis- use QRS in leads I & aVF
0-90 normal, <0 LAD, >90 RAD
P wave- best seen in lead II
Peaked P- P pulmonale- RAH, wide bifid P- P mitrale- LAH
PR interval- normal ~0.2 sec.
Short- WPW syndrome, long- AV blocks
8. Interpretation- continued
QRS complex- normal <0.12 sec
Broad- ectopic, BBB-RSR’ in V1 RBBB, ‘M’ in V1 LBBB
Q wave >2 mm is pathological, suggesting old MI
ST segment- difficult to interpret with BBB
Depressed- ischemia, elevated- infarction
Saddle shaped across the leads- pericarditis
QT interval- normal ~0.4 sec
Prolongation predisposes to ventricular arrythmias
T wave- upright in all, except III & V1
Tall tented- hyperkalemia
Inverted- ischemia, previous infarction, hypokalemia