Lead Placement Standard Leads (bipolar) I - lateral wall II - inferior wall III - inferior wall Augmented leads (unipolar) aVR - no mans land aVL - lateral wall aVF - inferior wall Chest Leads (unipolar) V1 - septal wall V2 - septal wall V3 - anterior wall V4 - anterior wall V5 - lateral wall V6 - lateral wall Lead Placement Electrical activity towards = ↑ Electrical activity away = ↓ Īxis The direction of an ECG waveform in the frontal plane measured in degrees Represents the flow of the majority of electrical activity Normally the QRS complex is measured Lead Placement V1 = 4th ICS right sternum V2 = 4th ICS left sternum V3 = midway between V2 and V4 V4 = 5th ICS midclavicular V5 = between V4 and V6 anterior auxiliary line V6 = midauxillary line lateral to V4 and V5 Overview Lead Placement Axis Common abnormalities in Critical Care Heart block Bundle branch blocks Life threatening arrhythmias QT interval = length (R-R/2 or QT c InterpretationĪbnormalities: Supraventricular arrhythmias Atrial Fibrillation Atrial Flutter Supraventricular Tachycardia (SVT) Premature Ventricular Complexes (PACs) Abnormalities: Ventricular arrhythmiasĬonduction Pathways Supraventricular Narrow QRS complex Ventricular Wide QRS complexĪbnormalities: atrial fibrillation Rhythm: Irregular Rate: A: 350 – 650 V: varies P: poorly defined P-R: N/A QRS: narrow complex S-T: normal T: normal Q-T: normalĪbnormalities: atrial flutter Rhythm: Regular / Irregular Rate: A: 220 – 430 V: Rhythm: Regular Rate: >100 P: not visible P-R: not defined QRS: narrow complex S-T: depression (sometimes) T: normal Q-T: prolonged (sometimes) Ībnormalities: premature ventricular complexes ST Segment = shape, isoelectric with PR segment Interpretationħ. QRS = duration (0.06 - 0.10 ), voltage, q or Q waves 6. P-R interval = length (0.12 - 0.2 sec = Interpretationĥ. P wave = present, 1 per QRS, shape, duration, voltage. Interpretation P rate: 8 x 10 = 80 R rate: 8 x 10 = 80ģ. Rate = Number of P’s (atrial) R’s (ventricular) per minute (6 second X 10 = minute rate).

QT Interval = This interval spans the onset of depolarisation to the completion of repolarization of the ventricles. T wave = usually same direction as QRS - ventricular repolarisation.

ST segment = isoelectric - part of repolarisation. QRS complex = ventricular depolarisation. PR Interval = impulse from atria to ventricles. Overview Conduction Pathways Systematic Interpretation Common abnormalities in Critical Care Supraventricular arrhythmias Ventricular arrhythmias ECG INTERPRETATION: the basics Jamie Ranse Critical Care Education Coordinator Staff Development Unit ACT Health

Ecg made incredibly easy pdf