P, Q, R, S, T

5 large square = 1 sec

PR interval (start of P to start of R): 3-5 small squares

Axis: Normal (I+, II+, III+); RAD (I-, II+, III+); LAD (I+, II-, III-)

Heart block: 1 deg (PR>5ss), 2 deg (Mobitz, Wenkeback), 3rd deg

Bundle branch block: RBBB (RSR in V1), LBBB (M pattern in V6)

Sinus arrhythmia, atrial escape, nodal (junctional) escape, CHB, ventricular escape, extrasystoles, atrial tachycardia, flutter, fibrillation, junctional/nodal tachycardia, ventricular tachy, VF, WPW

Atrial hypertrophy (LAH: bifid p wave; RAH: peaked p wave)

Ventricle hypertrophy

RVH: tall R in V1, deep S in V6, RAD)

LVH: R wave >25mm V5 or 6, deep S in V2, inverted T in V5/6/II/ VL;

Q wave, small = depolarisation of septum from L to R). If >0.04s & 2mm deep: myocardial infarction (changes usually permanent, i.e. no indication of when)

ST segment, should be isoelectric i.e. same level as between T and next P. Elevation: acute myocardial injury (infarction or pericarditis), horizontal depression (ischaemia)

Ischaemia: infarction (elevation>Q waves, inverted T waves), anterior, ant/lat, inferior, subendocardial i.e. not full-thickness (T wave inversion, no Q waves)

Dig effect: T wave inversion, sloping ST depression

T wave: normally inverted in V1, V2 (young people), V3 (blacks), low K (flat and increased QT), high K (peaked), inversion, often permanent (ishaemia)