Convert from Fahrenheit to Celsius: 98.6

A. AV Node: The AV node is responsible for delaying electrical impulses before they pass to the ventricles, but it does not generate the P wave. It affects the PR interval rather than the P wave itself.

B. SA Node: The SA (sinoatrial) node initiates electrical impulses and is responsible for atrial depolarization, which produces the P wave on an ECG. This makes it the correct answer.

C. Purkinje Fibers: The Purkinje fibers play a role in ventricular contraction (QRS complex), not in the formation of the P wave.

D. Bundle of HIS: The Bundle of HIS transmits impulses to the ventricles and is involved in ventricular depolarization, not atrial activity. It is not responsible for the P wave.

A. Initiate a peripheral IV: While an IV line is useful for medication administration, the patient’s pain has significantly improved with nitroglycerin. An IV may be necessary later, but it is not the next step in this scenario.

B. Administer another nitroglycerin tablet: Nitroglycerin can be repeated every 5 minutes up to 3 doses if chest pain persists or does not decrease significantly. Since the pain has improved (from 6 to 2), additional nitroglycerin is unnecessary.

C. Obtain an ECG/EKG: Even though the pain improved, unstable angina can progress to myocardial infarction. An ECG helps evaluate for ischemic changes and ensures the pain is truly resolving.

D. Call the Rapid Response Team (RRT): RRT should be called for worsening chest pain, unresponsiveness, or hemodynamic instability. Since the pain has improved, calling RRT is unnecessary.