You have performed an ECG on a patient who has a pacemaker. A portion of the ECG tracing is shown here. What type of pacemaker is indicated, and at what rate is the pacemaker set?
A)Atrial pacemaker set at 64 bpm
B)Atrial pacemaker set at 71 bpm
C)Ventricular pacemaker set at 78 bpm
D)Ventricular pacemaker set at 83 bpm

Question

You have performed an ECG on a patient who has a pacemaker. A portion of the ECG tracing is shown here. What type of pacemaker is indicated, and at what rate is the pacemaker set? 
A)Atrial pacemaker set at 64 bpm 
B)Atrial pacemaker set at 71 bpm 
C)Ventricular pacemaker set at 78 bpm 
D)Ventricular pacemaker set at 83 bpm

Quizplus · Accepted Answer

The ECG tracing shows regular P waves with a narrow QRS complex, indicating atrial pacing with intact conduction to the ventricles. The rate can be calculated by measuring the distance (in mm) between the P waves and dividing into 1500 (since each small box represents 0.04 seconds and 60,000/40=1500). In this case, the P-P interval is approximately 17 small boxes, or 0.68 seconds (68/100), resulting in a pacemaker rate of approximately 88 bpm. However, since this patient has a pacemaker, the actual pacemaker rate will be the programmed rate, which is closest to 71 bpm (choice B).

You Have Performed an ECG on a Patient Who Has