What is a contraindication for performing a myocardial perfusion resting study?

A contraindication for performing a myocardial perfusion resting study includes being on a nitroglycerin drip. This is because nitroglycerin can affect myocardial blood flow and alter the study's results. The primary goal of a myocardial perfusion study is to assess the coronary blood flow at rest and identify areas of ischemia or inadequate perfusion. When a patient is receiving nitroglycerin, it can induce vasodilation, potentially masking or mimicking ischemic conditions and complicating the interpretation of the results.

In contrast, fasting for a specific duration, drinking cold water, or being NPO does not inherently alter coronary blood flow and are not contraindications for the study, provided that any other protocols or individual patient circumstances allow for these actions. The focus on maintaining the integrity of the myocardial perfusion assessment makes the presence of a nitroglycerin drip a significant concern.