Exam template

ECG type and recording

• 12 lead vs rhythm strip, rate (normal 25 mm/s)

• Calibration (5mm wide, 10mm high = 1mV)

• Unusual leads – right, posterior, lead grouping format

Rate

• normal 60 – 100/min

• tachy/bradycardia (SA node) vs –arrhythmia (not SA node)

• method: 300/RR interval (large squares) or number of QRS complexes x 6 (if 25mm/s)

Rhythm

• Pattern – regular/ regularly irregular/ irregularly irregular

• Seven step approach to rhythm analysis

Axis

• Normal QRS axis -30 to 90/ LAD/ RAD/ NW axis

• Rotation (clockwise/ anticlockwise)

• Quick look test (Lead I and aVF)

• Three Lead Analysis (Lead I, Lead II, aVF)

• Isoelectric Lead Analysis

• Super SAM the axis Man

P wave

• Present? (esp check II and V1)

• Amplitude + duration: normal <3mm high and wide (LAE/RAE/Biatrial)

• Contour: normal — inverted aVR, biphasic V1, upright I,II, aVF, V2-V6

PR interval + PR segment

• Duration 0.12-0.2s normal/ short/ long/ varying

• Heart blocks:
• 1st Degree, Wenkebach, Mobitz 2, Fixed Ratio, High Grade, CHB

• PR depression

Q wave

• Normal: <25%R in I, aVL, AVF, V456

• Pathological: V23 > 0.02s, other >0.03s + >1mm deep

R wave

• Transition: normal V34, early: R>S in V1/2

• Poor R Wave Progression: R <3mm V3

QRS complex

• Duration: 60-110msec normal/ wide; R wave peak time

• Amplitude: normal/ large voltage/ low voltage/ alternans

• Morphology: notched/ RBBB/ LBBB

• Displacement: elevation/ depression (J point vs TP interval)

• Contour: horizontal /upsloping / downsloping

T wave

• Amplitude: normal <2/3 R/ peaked/ inversion/ alternans

• Duration: normal 390-450 or 460msec / long/ short/ QT dispersion

• Method, 3+ QRS in 3+ leads, QTc formulae, caveats

U wave

• Normal 10% T or <1.5mm/ prominent/ inversion/ alternans

Additional waves

• DOE: Delta wave, Osborn wave, Epsilon Wave

Chamber hypertrophy

• Atrial – LAE, RAE, biatrial

• Ventricular – LVH, RVH, biventricular

Lethal – do not miss!

• Ischaemia – STE criteria and DDX/ Sgarbossa/ reciprocal change/ Wellens/ aVR

• Quick BRAD Walk Home! (lethal causes of syncope: Long/ short QT, Brugada, RV infarction, ARVD, DCM, WPW, HCM)

• Pulmonary Embolus

• Electrolytes — hyperK, hypoK, hypoCa, hyperCa, hypoMg

• Toxicology — TCAs, digoxin

Other tricks and traps

• Dextrocardia, Lead reversals

• Artifacts – tremor artifact

• Pacing spikes – pacemaker malfunction: failure to sense/ capture/ output?

Synthesis

• Leave space to put this at the start of the answer

• Unifying diagnosis, DDx, life threats