EKG certification Certification Pacemakers & Cardiac Devices 3

Question 1

What is cardiac resynchronization therapy (CRT) and which patients typically benefit from it?

Accepted Answer

Biventricular pacing to synchronize ventricular contraction in patients with heart failure and wide QRS

Answer

CRT uses a biventricular pacemaker to simultaneously pace both ventricles, correcting dyssynchrony in heart failure patients with a wide QRS (usually LBBB ≥150 ms) and reduced ejection fraction.

Question 2

What EKG finding is expected in a patient with a functioning biventricular pacemaker (CRT)?

Accepted Answer

Pacemaker spikes followed by a narrow or narrower QRS than the baseline LBBB

Answer

Successful CRT results in a narrower paced QRS compared to the patient's native wide LBBB, as simultaneous biventricular activation resynchronizes ventricular contraction.

Question 3

What is the AOO pacemaker mode?

Accepted Answer

Atrium paced, no sensing, asynchronous (fixed-rate) pacing

Answer

AOO is asynchronous atrial pacing: the atrium is paced at a fixed rate with no sensing function; this mode ignores any native cardiac activity and paces regardless.

Question 4

Which measurement on the EKG represents the pacemaker's AV delay (or programmed AV interval) in a dual-chamber device?

Accepted Answer

The interval from the atrial pacing spike to the ventricular pacing spike

Answer

The AV delay in a dual-chamber pacemaker is measured from the atrial pacing spike to the subsequent ventricular pacing spike, mimicking the natural PR interval.

Question 5

What is pacemaker-mediated tachycardia (PMT)?

Accepted Answer

An endless-loop tachycardia where retrograde P waves trigger repetitive ventricular pacing in a DDD pacemaker

Answer

PMT is an endless-loop tachycardia unique to dual-chamber pacemakers where retrograde conduction from a ventricular beat creates a retrograde P wave that is sensed by the atrial channel, triggering repeated ventricular pacing at the upper rate limit.

EKG certification Practice Test

EKG certification Practice Test

EKG certification Certification Pacemakers & Cardiac Devices 3