Electrocardiography Technician Fundamentals Flashcards

Which ECG finding indicates first-degree AV block?

Answer: PR interval > 0.20 seconds with all P waves conducted

First-degree AV block is characterized by a consistently prolonged PR interval (>0.20 seconds) with all P waves followed by a QRS.

Ventricular fibrillation on ECG appears as:

Answer: Chaotic irregular waveform with no identifiable complexes

Ventricular fibrillation produces a chaotic, irregular waveform with no identifiable P waves, QRS complexes, or T waves.

Lead II is the most commonly used rhythm monitoring lead because it:

Answer: Produces the tallest P wave and QRS in most patients

Lead II runs nearly parallel to the heart's electrical axis, producing tall, clear P waves and QRS complexes ideal for rhythm analysis.

The QT interval represents:

Answer: Total ventricular depolarization and repolarization

The QT interval spans from the start of the QRS to the end of the T wave, encompassing total ventricular electrical activity.

Which condition can cause a prolonged QT interval on ECG?

Answer: Hypokalemia and hypomagnesemia

Hypokalemia and hypomagnesemia are common electrolyte causes of QT prolongation, increasing risk of torsades de pointes.

When attaching limb leads, the right leg (RL) electrode serves as the:

Answer: Ground electrode

The right leg electrode is the ground (neutral) reference in standard ECG recordings, used to reduce electrical interference.