Venous return is determined by:

Venous return is determined by:

A 50-year-old man with a lengthy history of diabetes mellitus and hypertension has had pain in the left shoulder and arm for the past 12 hours. Over the next 6 hours, he develops shortness of breath, which persists for 2 days. On day 3, he visits the physician. On physical examination, his blood pressure is 160/100 mm Hg. Laboratory studies show that the total creatine kinase (CK) activity is within reference range, but the troponin I level is elevated. The patient is admitted to the hospital and continues to experience dyspnea for the next 3 days. On day 7 after the onset of shoulder pain, he has a cardiac arrest. Postmortem examination shows a large transmural infarction of the left anterior free wall with rupture and hemopericardium. Which of the following statements is best supported by these clinical and autopsy data?

Which one of the following is correct regarding alpha-adrenergic blockers?

Which of the following could cause reflex tachycardia and/or postural hypotension on initial administration?

A 58-year-old man undergoes open-heart surgery for a triple coronary bypass graft. His surgery goes smoothly, but the next day he develops chest palpitation. Metoprolol is started to keep his supraventricular tachycardia from interfering with ventricular rhythm. Under which Singh-Vaughan Williams class of antiarrhythmic does metoprolol fall?