ECG SUPPLEMENTAL TRAINING BY BRAD CHAPMAN RCT

INTRODUCTION This supplemental course is to help RN’s, LPN’s and MRT’s to do an accurate ECG in a hospital setting when a Cardiology Technologist is not available. This course is not in anyway to replace Cardiology Technologist but to give the best patient care possible. New Brunswick is currently the only province in Canada that has legislation in place regarding ECG’s, Stress Testing, Holter Monitoring and Pacemakers. An ECG can only be done by someone other then a Cardiology Technologist if a Cardiology Technologist is not available. Examples would be outer hospitals and nights at some facilities where a Cardiology Technologist is not present.

What is an ECG? An ECG is a test that measures the electrical activity of the heart from 12 different views.

There are many things assessed through an ECG Rate Rhythm Regularity Voltage Conduction (Axis)

The result from these recordings form an ECG

The waves produced from these electrical impulses are charted on graph paper.

What do all the lines mean? A typical ECG tracing of a normal heartbeat (or cardiac cycle) consists of a P wave, a QRS complex and a T wave.

The Baseline It’s the straight line in between each wave

Baseline It is important to have a clear steady baseline for interpretation of the ECG. You want a nice horizontal line. If the baseline is wandering, one can’t truly assess for S-T elevations accurately. Note the baseline wandering of this strip.

The “P” Wave Initial contraction (depolarization) of the atria. The first wave to appear in a cardiac cycle. Rounded and symmetrical. Precedes QRS complex Typically upright in all leads except AVR. There should only be one “P” wave for every QRST (1:1 RATIO).

QRS Waves Initial contraction or depolarization of the ventricle. The Q wave is located at the beginning of the complex. This is the first negative (downward) deflection. Not all ECG’s will show a “Q” wave. The R wave is the first positive (upward) deflection of the QRS. The S wave is the negative (downward) deflection following the R wave.

ST Segment Represents the beginning of ventricular repolarization (relaxation and refilling). End of the S wave to the beginning of the T wave. The ST segment is often used in diagnosing infarcts, ischemia etc. ST segment are observed for elevation, depression, T wave inversion, etc.

“T” Wave Represents ventricular repolarization (electrical recovery). Follows ST segment Usually rounded and symmetrical Upright in most leads, may be inverted in AVR and AVL.

The paper from the Electrocardiograph ECG paper is made up of small and large boxes. The small boxes measure .04 seconds while as the big boxes (5 small boxes) measure 0.04 X 5 = .20 seconds. An easy way to calculate the rate on your ECG is to count the number of large squares between R waves and count as follows:

10 Wires – 12 Angles??? How can I get 12 different angles from an ECG with only 10 wires? Only the chest leads read what is going on directly underneath them. The rest read as follows: Lead I: The electrical current moves from the Right Arm towards the Left Arm Lead II: The electrical current moves from the Right Arm towards the Left Leg Lead III: The electrical current moves from the Left Arm to the Left Leg These leads will all have a positive deflection.

The Unipolar Leads Leads AVR, AVL and AVF, they are called augmented leads. AVR: Recording are from Right arm to the midpoint of the chest. AVF: Recording are from left leg to the midpoint of the chest. AVL: Recording are from Left arm to the midpoint of the chest.

Lead Placement Find the first intercoastal space by moving a finger down the right collar bone towards the sternum. Stop a ½ “ before the sternum Rock fingers down chest counting the intercostal spaces Count down to the 4th intercostal space, this will be the V1 position Repeat process on the Left side of the sternum and place V2

Draw a vertical line from mid-clavicular to under the breast and place a sticker. This will be V4. V3 would be on a diagonal plane between v2 and v4 and on top of the breast. Visually drop a horizontal straight line down from v4 to mid-auxilla and place a sticker (v6) Place V5 between v4 and v6

Chest Lead Placement All chest leads are labelled v1, v2, v3,...v6. All leads are color coded. Chest leads are Red Yellow Green Blue Orange Purple

Easy to remember Stop Light BOP Red, Yellow, Green BLUE, ORANGE, PURPLE

A Technically Accurate ECG! LEAD I will always have a positive deflection and the R wave will be upright. The “R” wave is the first “Positive” deflection after the “P” wave. The “R” wave will be small in V1 and get larger as you go to V5. V6 will be slightly smaller then V5. Standardization will be 10 mv

What to look for on an ECG 1: Check for correct patient information, ordering physician, location, time and date. 2: Paper speed (25 mm/ms) 3: Standardization should be at (10 mm/mv) to check if this is accurate, check your squares at the end of leads V4, V5 and V6 . 4: All leads are visible and without artifact. 5: You should have a positive R wave in lead I.

What to look for on an ECG 6: You should have a good R wave progression in the chest leads V1 to V6. The R wave is small in V1 and becomes progressively larger as it continues to V6. 7: 1 P wave per QRS complex, 1:1 ratio. 8: Before removing your electrodes check to make sure all limb leads and chest leads are situated in the right position.

R WAVE PROGRESSION

R WAVE PROGRESSION Note “R” wave increases in positive deflection from leads V1 to V5 and then slightly smaller in V6. Proper lead hook-up.

POOR R WAVE PROGRESSION Note “R” wave progression from V1 to V3. It goes from tall R wave to shorter then small then to biphasic. V1 and V3 are reversed – most common mistake in lead reversal.

BIPHASIC EXAMPLES Between V3 and V4 the lead will be “Biphasic” (almost equally upward as downward)

What to look for in an ECG Electrode/lead placement is very important.  If one were to accidentally confuse the red and white lead cables (i.e. place the white one where the red one should go, vice versa), he might get an ECG that looks like below. In this ECG, we can make out a normal sinus rhythm with all of the waves upside-down. 

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