CCT Pacemaker Rhythm Interpretation 2

Question 1

On an ECG, what is the characteristic appearance of a pacemaker spike followed by a wide QRS complex?

Accepted Answer

A thin vertical spike immediately followed by a broad, LBBB-morphology QRS greater than 0.12 seconds

Answer

A narrow P wave followed by a normal-width QRS

Answer

A tall peaked T wave without a preceding spike

Answer

A broad, notched P wave before a narrow QRS

Question 2

What is pacemaker failure to capture?

Accepted Answer

The pacemaker fires (spike visible) but does not depolarize the myocardium (no QRS follows)

Answer

The pacemaker does not fire at all, producing no spikes

Answer

The pacemaker fires too slowly, below the programmed rate

Answer

The pacemaker senses intrinsic beats correctly but does not pace

Question 3

What does the middle letter in a three-letter pacemaker code represent? (e.g., DDD, VVI, VDD)

Accepted Answer

The chamber sensed by the pacemaker

Answer

The chamber paced

Answer

The response to sensing

Answer

The programmability level

Question 4

A patient with a DDD pacemaker shows pacing spikes before both P waves and QRS complexes on the ECG. What pacemaker mode is currently functioning?

Accepted Answer

AV sequential (DDD) pacing — both atrium and ventricle are being paced

Answer

VVI pacing — only the ventricle is being paced

Answer

AAI pacing — only the atrium is being paced

Answer

The pacemaker is malfunctioning

Question 5

What is undersensing in a pacemaker, and what ECG pattern does it produce?

Accepted Answer

The pacemaker fails to detect intrinsic cardiac activity and fires at inappropriate times, producing spikes that may fall on T waves

Answer

The pacemaker fires too rapidly, exceeding the programmed rate

Answer

The pacemaker cannot capture the myocardium despite sensing correctly

Answer

The pacemaker fires at a rate slower than programmed

Question 6

Which pacemaker code indicates rate-responsive pacing?

Accepted Answer

A fifth letter 'R' added after the standard three-letter code, as in DDDR or VVIR

Answer

A capital 'S' after the first letter

Answer

A number after the three-letter code indicating the sensor type

Answer

The letter 'P' added as a prefix before the standard code