Certified EKG Technician (NHA) Exam Study Guide

120 minutes.

$117.

The exam has 100 scored questions.

A scaled score of 390 or higher.

About 1.2 minutes per question, since 120 minutes are split across 100 questions.

The right leg (RL) electrode serves as the ground/reference.

The T wave (atrial repolarization is hidden within the QRS complex).

Chaotic, disorganized waveforms with no identifiable P, QRS, or T waves; the ventricles quiver instead of pumping, so it requires immediate defibrillation.

Artifact is unwanted electrical interference distorting the tracing; common causes include patient movement, muscle tremor, loose electrodes, and 60-cycle (AC) interference.

The P wave represents atrial depolarization, the QRS complex represents ventricular depolarization, and the T wave represents ventricular repolarization. Together they show the electrical conduction through the heart.

The normal PR interval is 0.12 to 0.20 seconds (3 to 5 small squares on ECG paper). It represents the time from atrial depolarization through AV node conduction to the beginning of ventricular depolarization.

Normal sinus rhythm has a heart rate of 60-100 bpm, regular rhythm with consistent P waves preceding each QRS, normal PR interval (0.12-0.20 sec), and normal QRS duration (<0.12 sec).

Tachycardia is an elevated heart rate, typically defined as greater than 100 beats per minute at rest. It can result from fever, anxiety, exercise, heart disease, or other medical conditions.

Atrial fibrillation shows an irregularly irregular rhythm with no discernible P waves, replaced by chaotic baseline undulations. The QRS complexes occur at irregular intervals despite preserved QRS morphology.

A PVC is an early heartbeat originating from the ventricles. It appears as a wide (>0.12 sec), abnormally shaped QRS complex occurring before the expected beat, often followed by a compensatory pause.

ST segment elevation typically indicates acute myocardial infarction (MI) or myocarditis. It reflects injury current in the affected region and is a medical emergency requiring immediate intervention.

First-degree AV block is characterized by a prolonged PR interval (>0.20 sec) but with normal conduction of all impulses. Each P wave is followed by a QRS complex, just with delay.

The V1 electrode is placed at the 4th intercostal space at the right sternal border. It views the right ventricle and interventricular septum.

The QRS duration is normally 0.06 to 0.12 seconds (<3 small squares). It represents the time for ventricular depolarization and contraction.

Peaked T waves often indicate hyperkalemia (elevated potassium), acute myocardial ischemia, or left ventricular hypertrophy. Severe hyperkalemia is a medical emergency.

The normal QT interval is approximately 0.34 to 0.43 seconds and varies with heart rate and gender. It represents the total time from ventricular depolarization through repolarization.

WPW syndrome is a pre-excitation condition with an accessory conduction pathway. It shows a shortened PR interval (<0.12 sec) and a delta wave at the beginning of the QRS complex.

1) Check patient identification and calibration, 2) Calculate heart rate, 3) Determine rhythm regularity, 4) Measure PR interval, QRS duration, and QT interval, 5) Identify axis deviation, 6) Look for abnormalities in each wave.

Reversing the arm electrodes (swapping RA and LA) or placing chest electrodes in incorrect intercostal spaces can create false MI patterns that mimic acute coronary syndrome.

The normal ST segment is isoelectric (at the baseline) at the junction point between the S wave and T wave. It should be flat and at the same level as the baseline before the P wave.

A bundle branch block shows a widened QRS complex (>0.12 sec) with an abnormal, often notched or slurred appearance. The specific pattern (RSR' or similar) indicates which branch is blocked.

The electrical axis is the overall direction of electrical activity in the heart. The normal axis is between -30 and +90 degrees. Left axis deviation occurs with left ventricular hypertrophy or inferior MI; right axis deviation with right ventricular hypertrophy.

I, II, and III are the limb leads. Lead I views the left ventricle laterally; Lead II views the inferior wall; Lead III also views the inferior wall. They are bipolar leads using two electrodes each.

Ventricular tachycardia shows a rapid rate (>100 bpm), wide QRS complexes (>0.12 sec), and an abnormal shape. AV dissociation (independent P waves) may be present and confirms the diagnosis.

Flutter waves are rapid, regular, sawtooth-like waves seen in atrial flutter, typically at rates of 250-350 bpm. Atrial flutter shows regular atrial activity with variable AV conduction (e.g., 2:1, 3:1).

Low-amplitude QRS complexes can result from obesity, emphysema, myocarditis, dilated cardiomyopathy, pericardial effusion, or hypothermia. Obesity and emphysema are the most common causes in routine encounters.

The standard paper speed is 25 mm/sec. At this speed, each small square (1 mm) equals 0.04 seconds, and each large square (5 mm) equals 0.20 seconds. This standardization allows accurate measurement of intervals and rates.

Stop recording immediately and wait for movement to cease. Muscle artifact will distort the tracing. If the patient cannot remain still, note the reason in the ECG report and inform the physician of the artifact present.