CPR ECG Rhythm Interpretation 5

Question 1

A patient has a regular rhythm at 42 bpm with narrow QRS complexes and no visible P waves. What is the most likely escape pacemaker site?

Accepted Answer

AV junction (junctional escape)

Answer

A junctional escape rhythm presents as a narrow QRS at 40-60 bpm with absent, retrograde, or buried P waves when the SA node fails to pace.

Question 2

Which ECG change is the earliest and most sensitive indicator of acute myocardial ischemia before ST elevation develops?

Accepted Answer

Hyperacute (peaked) T waves

Answer

Hyperacute T waves (tall, broad, symmetric) are often the earliest ECG change seen in acute coronary occlusion, appearing before ST elevation.

Question 3

On a rhythm strip, you notice the QRS complex occurring regularly at 32 bpm with wide, bizarre-looking complexes and no associated P waves. What is this rhythm?

Accepted Answer

Ventricular escape rhythm

Answer

A ventricular escape rhythm has a rate of 20-40 bpm, wide and bizarre QRS complexes, and represents the last resort pacemaker when higher pacemakers fail.

Question 4

In lead II, a normal P wave should be upright and less than how many mm tall and less than how many ms wide?

Accepted Answer

2.5 mm tall, 80 ms wide

Answer

A normal P wave in lead II should be no taller than 2.5 mm and no wider than 80 ms (0.08 seconds); exceeding these limits suggests atrial enlargement.

Question 5

A patient with a cardiac pacemaker presents to your unit. The ECG shows a pacemaker spike followed by a QRS complex in some beats but not others. What does this indicate?

Accepted Answer

Failure to capture

Answer

Failure to capture occurs when a pacemaker spike is present but fails to depolarize the myocardium, resulting in pacing spikes not followed by QRS complexes.

(CPR) Certified Paramedic Response Practice Test

(CPR) Certified Paramedic Response Practice Test

CPR ECG Rhythm Interpretation 5