Anatomy and physiology of the ekg INDIAN RIVER STATE COLLEGE WEEK 5

Conduction System Step 1: SA node stimulated by either the sympathetic or parasympathetic system. Step 2: depolarization is spread throughout the atria by various pathways. Step 3: AV delays the impulse, this is essential for the atria to have time to contract and force the remaining blood into the ventricles. Step 4 & 5: depolarization spreads down the septum (bundle branches) then back up to the entirety of the ventricles.

EKG or ECG P wave: Depolarization of the atria PR segment: delay (AV node) QRS waves: Ventricular depolarization ST segment: Delay between ventricular depolarization and repolarization T wave: Ventricular repolarization

EKG with Conduction

Measuring EKG Limb Leads Chest Leads

Limb Lead Measurement

Chest Lead Measurement V1 & V2: Septum V3 & V4: Anterior V5 & V6: Lateral Notice progression from inverted QRS to Upright QRS, V1 to V6 Variations in these leads helps identify which part of the myocardium is or has been damaged Ischemia vs. Infarct ST segment Elevation Possible infarction ST segment Depression Possible ischemia

Normal 12 Lead EKG

Coronary Artery Review

Abnormal 12 Lead EKG Look at ST segment: Where is it elevated? What part of the heart does this correspond to? What coronary artery or arteries is likely blocked?

IWORX EKG SETUP Equipment should be set up ready to go (if not there should be a document that goes through setup steps if needed) Follow lead placement as shown above, with the iWorx system we will only be doing limb leads. Use an alcohol swab to clean and scrub a region where you are going to place electrodes allow to dry. Snap the lead wires onto the electrodes Remove a disposable ECG electrode from its plastic shield, and apply the electrode to the scrubbed area red (+1) lead is attached to the right wrist, could also go on edge of chest black (-1) lead is connected to the left wrist, could also go on edge of chest green (C or ground) lead is connected to the right leg, could also go above the leg.

Recording an ECG Click on the Record button, located on the upper right side of the LabScribe Main window. The signal should begin scrolling across the screen. Click on the AutoScale buttons at the upper margins of the ECG and Heart Rate channels. The ECG and heart rate recording should expand to fill the channel windows. Click Stop to halt recording