During a threshold test, what action should be taken if the pacing is not effective?

Increasing the amplitude during a threshold test is essential when pacing is not effective, as it directly enhances the electrical energy delivered to the heart. By raising the amplitude, the likelihood of successfully depolarizing the myocardial cells increases, which may lead to a capture, allowing the heart to respond accordingly. This systematic approach is grounded in the principle that the pacing output must be adequate to stimulate the heart, particularly in cases where the initial settings are insufficient to achieve effective capture.

The other approaches, such as reducing pacing duration or changing the lead position, do not address the immediate requirement of increasing the electrical stimulus being provided to the heart muscle. Monitoring for longer durations may allow for observation of the pacing effects, but it does not rectify the issue of ineffective pacing. Therefore, increasing the amplitude is the most direct and appropriate response when pacing effectiveness is lacking.