What is failure to capture on a heart rhythm?

What is failure to capture on a heart rhythm?

• A. Pacemaker spikes that are not followed by QRS complexes
• B. QRS complexes without preceding pacer spikes
• C. A normal rhythm
• D. A continuous rhythm

Answer: (A)

Failure to capture happens when the pacemaker delivers an electrical impulse, but the heart muscle does not respond with depolarization. On an ECG, you’ll see a pacing spike that is not followed by a QRS complex. That means the device is trying to pace, but the impulse fails to trigger contraction. This indicates the pacing threshold is not being met and needs attention. Management focuses on ensuring the lead is properly positioned and connected, and increasing the pacemaker’s output (or reprogramming the device) to a level that achieves capture. Lead problems, battery issues, or tissue changes at the lead tip can cause this, so device interrogation and possible lead adjustments are often required. If the patient is symptomatic or the capture loss is persistent, urgent evaluation is warranted. (Notes: this differs from failure to sense, where the device fails to detect intrinsic activity and paces at inappropriate times; a normal rhythm or continuous rhythm is not describing a loss of capture.)

Failure to capture happens when the pacemaker delivers an electrical impulse, but the heart muscle does not respond with depolarization. On an ECG, you’ll see a pacing spike that is not followed by a QRS complex. That means the device is trying to pace, but the impulse fails to trigger contraction.

This indicates the pacing threshold is not being met and needs attention. Management focuses on ensuring the lead is properly positioned and connected, and increasing the pacemaker’s output (or reprogramming the device) to a level that achieves capture. Lead problems, battery issues, or tissue changes at the lead tip can cause this, so device interrogation and possible lead adjustments are often required. If the patient is symptomatic or the capture loss is persistent, urgent evaluation is warranted.

(Notes: this differs from failure to sense, where the device fails to detect intrinsic activity and paces at inappropriate times; a normal rhythm or continuous rhythm is not describing a loss of capture.)