Which of the following is a vagal maneuver included in the treatment for stable atrial tachycardia?

The correct choice is associated with the Valsalva maneuver, which involves the "bear down" action. This technique increases intrathoracic pressure, stimulating the vagus nerve and potentially leading to a decrease in heart rate by facilitating a change in the heart's electrical conduction.

In the context of stable atrial tachycardia, vagal maneuvers are employed to increase parasympathetic tone and may help convert the arrhythmia to a normal rhythm or slow the heart rate. The "bear down" technique effectively leverages this principle by promoting increased pressure in the chest that can impact the heart's conduction system.

The other options presented do not align with established vagal maneuvers in this clinical scenario. Holding breath, turning the head, and applying cold water to the face are commonly discussed but are not universally recognized in the same way as the Valsalva maneuver or "bear down" technique for treating stable atrial tachycardia. Understanding the specific maneuver that effectively influences vagal tone is vital in clinical practice and reflects the significance of choosing the correct method for management in arrhythmic conditions.