12 Lead ECG Practical PDF

ELECTROCARDIOGRAPHY Practical AIMS AND LEARNING OUTCOMES Aim to achieve consistent high-quality diagnostic ECGs to permit accurate interpretation LO Recall the clinical indications to perform a 12-lead diagnostic ECG Describe electrode positioning List equipment configuration Re...

ELECTROCARDIOGRAPHY Practical AIMS AND LEARNING OUTCOMES Aim to achieve consistent high-quality diagnostic ECGs to permit accurate interpretation LO Recall the clinical indications to perform a 12-lead diagnostic ECG Describe electrode positioning List equipment configuration Record a 12 lead ECG of diagnostic quality Identify causes of artefact HISTORICALLY A.D Waller 1887 Einthoven 1908 P QRS and T ELECTROCARDIOGRAPHY INDICATIONS Chest Pain Acute myocardial infarction Pulmonary Embolism Dizziness/syncope Arrhythmias Drug efficacy Pre-op WHAT IS AN ECG? The standard 12-lead electrocardiogram is a representation of the summation of the heart's electrical activity recorded from electrodes on the body surface. PREPARING THE PATIENT Equipment safety Patient Explanation Relaxation Details Skin Prep Clean Abrade no oils EQUIPMENT PREPARATION Settings Operator dependent Paper speed Calibration Frequency response Paper Speed = 25mm/s CALIBRATION Sensitivity is 10 mm/mV The standard calibration signal measures 1 mV over 10mm: FREQUENCY RESPONSE Frequency response 0.05 -150Hz LEAD SYSTEMS Bipolar Unipolar Limb leads Chest Leads  LIMB LEADS Lead I – left arm to right arm Lead II – left leg to right arm Lead III – left leg to left arm aVR – Right arm aVL – Left arm aVF - Foot LEAD PLACEMENTS - LIMBS Bipolar Leads Unipolar Leads Lead I Lead aVR Lead II Lead aVL Lead III Lead aVF The correct placement of the electrodes when recording an ECG is vital for accurate interpretation.  CHEST LEADS (PRECORDIAL) V1-4th intercostal RSE V2-4th intercostal LSE V3-Midway V2-V4 V4-5th intercostal Mid-clavicular V5-left ant axilla at the level of V4 V6-mid axilla at the level of V4  CHEST LEADS – COLOUR CODE V1 - Red V2 - Yellow V3 - Green V4 - Brown V5 - Black V6 - Purple ANATOMICAL LANDMARKS ANATOMICAL VIEWS The limb leads look at the heart in a frontal plane The chest leads look at the heart in a horizontal plane. Leads II,III & aVF – inferior surface I & aVL – high lateral surface V1-V3 – anteroseptal surface V4- V6 – anterolateral surface Hexaxial reference system A 12 Lead Resting ECG SQUIGGLY LINES THE PQRS SEQUENCE P waves: atrial depolarisation QRS complex: ventricular depolarisation T waves: ventricular repolarisation HEART RATE Look at the R- R interval: 1 large square = 300 bpm 2 large squares = 150 bpm 3 large squares = 100 bpm 4 large squares = 75 bpm 5 large squares = 60 bpm 6 large squares = 50 bpm  TROUBLESHOOTING Gain Sensitivity and Paper Speed Artefact Baseline wander Muscle tremor AC interference Comments AC MAINS Baseline wander SOMATIC ANY QUESTIONS PLEASE…………………… ????????  CAN YOU? Recall the clinical indications to perform a 12-lead diagnostic ECG Describe electrode positioning List equipment configuration Record a 12 lead ECG of diagnostic quality Identify causes of artefact