Cardiac Testing

RA

right arm lead is white

LA

left arm lead is black

RL

right leg lead is green

LL

left leg lead is red

V1

Fourth intercostal space, right of sternum

V2

Fourth intercostal space, left of sternum

V3

Midway between V2 and V4

V4

Fifth intercostal space, midclavicular line

V5

Anterior axillary line, same level as V4

V6

Midaxillary line, same level as V4

Lead I

Records electrical activity from right arm to left arm

Lead II

Records electrical activity from right arm to left leg

Lead III

Records electrical activity from left arm to left leg

aVR

Records electrical activity away from midpoint between left arm and left leg to left arm (across heart to right shoulder)

aVL

Records electrical activity from midpoint between right arm and left leg to left arm (across heart to left shoulder)

aVF

Records electrical activity from midpoint between right arm and left arm to left leg (across heart toward feet)

V1

Records electrical activity between center of heart and the chest wall where V1 electrode is placed

V2

Records electrical activity between center of heart and the chest wall where V2 electrode is placed

V3

Records electrical activity between center of heart and the chest wall where V3 electrode is placed

V4

Records electrical activity between center of heart and the chest wall where V4 electrode is placed

V5

Records electrical activity between center of heart and the chest wall where V5 electrode is placed

V6

Records electrical activity between center of heart and the chest wall where V6 electrode is placed

Common placement errors

Misidentifying lead positions, placing limb leads too close to the torso, and incorrect chest lead positioning.

Quality control measures

Include reviewing the initial waveform for clarity, identifying artifacts, and repeating the test if necessary.

Preparation

Observe appropriate body substance isolation precautions and follow appropriate procedures.

Application

Explain the procedure to the patient.Clean and prep the skin, alcohol prep, shave, and use an abrasive pad.

Three Lead Placement

White: Rt upper chest inferior to clavicle Black: Lt upper chest inferior to clavicle Red: below Lt pectoral muscle

Five Lead Placement

RA: Rt upper chest inferior to clavicle LA: Lt upper chest inferior to clavicle V1: modified to Lt midaxillary LL and RL: modified to Lt midaxillary high lumbar region

Twelve Lead Placement (standard)

RA: Right Arm, shoulder area LA: Left Arm, shoulder area LL: Left Leg, left hip/ thigh area RL: Right Leg, right hip/ thigh area V1: 4th intercostal space, Rt sternal borderV2: 4th intercostal space, Lt sternal border V3: between V2 and V4 V4: 5th intercostal space, midclavicular V5: 5th intercostal anterior axillary line between V4 & V6 V6: 5th intercostal left midaxillary line

Adjustments

"Set the gain and sensitivity of the EKG machine to 1 mV to ensure accurate amplitude for the

ECG waveform. This will standardize the deflection of the waveform so that 1 mV corresponds to

a 10 mm vertical deflection on the paper. Ensure the patient's comfort, privacy, and dignity are

maintained at all times."

Inspect rhythm strip

Wandering baseline Artifact Muscle tremor artifact Disconnect or intermittent loss of signal Poor prep (contact artifact)

Documentation

Run the strip. Record the findings Document the time obtained

Completion

Remove leads Clean patient skin Remove PPE Wash hands

Electrocardiogram

graphic record or tracing of the heart's electrical activity;

Dysrhythmia

abnormal rhythm

upward deflections

Impulses that travel toward a positive electrode

downward deflection

Impulses that travel toward a negative electrode

The five steps in analyzing an ECG

heart rate,regularity, P-waves, QRS complex, and P-R interval.

P wave

Represents atrial depolarization, indicating atrial contraction

PR interval

Measures the time from atrial depolarization to ventricular depolarization, reflecting AV node conduction

QRS complex

Represents ventricular depolarization, signaling ventricular contraction

ST segment

Indicates the early phase of ventricular repolarization

T wave

Represents ventricular repolarization, or recovery

QT interval

Measures the total time for ventricular depolarization and repolarization, with prolongation potentially indicating a risk for arrhythmias

1500 method:

This method involves counting the number of small squares between two consecutive R-waves and dividing that number by 1500. This is the most accurate method of obtaining the heart rate but can only be used on regular rhythms.

Rate calculators

These are devices that measure between R-waves and give the rate.

6-second interval X 10 method

This method involves counting the number of QRS complexes on a 6 second rhythm and multiplying that number by 10. This is the only method that can be used on an irregular rhythm.

300, 150, 100, 75, 60, 50 method

This method involves locating an R-wave on a bold line on the ECG paper, then finding the next consecutive R wave and counting down from 300 on the subsequent bold lines to determine the rate.

Calipers

This is a device used to measure the intervals. This is the quickest and easiest method.

Paper and pen

This involves marking an R-wave, then marking the next R wave, and using that to judge the R waves of the rest of the rhythm.

Count the small squares between each R-R interval

This involves seeing if the small squares between each RR-interval are all the same. This method takes longer but does not require any equipment to use.

Irregularly (totally) irregular

No consistencyto the rhythm (e.g., atrial fibrillation)

Patterned irregularity

Irregularity repeats over and over (e.g., AV-heart blocks)

Very irregular

Multiple occurrences of an abnormality (e.g., PVC or PAC in one rhythm strip)

Normal QRS complexes

Indicates the impulse originated above the ventricles and traveled through the ventricles in a normal fashion.

A normal P-wave

Uupright and rounded in Leads I, II, avf, and V2 thru V6.

P-R intervals

Distance from the beginning of the P-wave to the beginning of the Q wave or R-wave.