A patient with chest pain tells you that he feels the same now as when he had a heart attack 2 years ago. He is diaphoretic, nauseated, and vomiting; he has a pulse of 84, respirations of 16 breaths/min, and a blood pressure of 78/50 mmHg. The patient is allergic to aspirin. He asks you to assist him in taking one of his nitroglycerin pills because his arthritis makes it too hard for him to open the medication bottle. Which of the assessment findings represents a contraindication to the nitroglycerin?