A 49-year-old man comes to the physician because of worsening fatigue and increasing difficulty performing daily tasks due to chest pain on exertion. After a positive stress test, a coronary angiography is performed and shows coronary artery stenosis. He is scheduled to undergo a coronary artery bypass graft procedure using the internal thoracic artery. Which of the following vessels will most likely continue to supply blood to the anterior part of the upper intercostal spaces after the procedure?

A 3-year-old boy is brought to the physician by his mother for a routine examination. Cardiac examination shows a loud systolic murmur and a wide, fixed, split S2 sound. An x-ray of the chest shows an enlarged right heart and the patient is diagnosed with an atrial septal defect. This condition usually results from incomplete closure of which of the following structures?

A 69-year-old woman is admitted to the hospital because of laryngeal cancer. Physical examination shows a thin-appearing woman with a hoarse voice. A CT scan examination of the chest and abdomen shows multiple masses in the lungs and liver. For nutritional needs a nasogastric tube is inserted. What is the last site at which resistance would be expected as the tube passes from the nose to the stomach? 

A 42-year-old woman is brought to the emergency department after a motor vehicle collision. She sustained blunt trauma to her sternum by the steering wheel during the crash. Her blood pressure is 75/55 mm Hg, pulse is 105/min, and respirations are 22 minutes. Physical examination shows muffled heart sounds and jugular vein distention. Ultrasound examination shows a cardiac tamponade. Which of the following cardiac structures will most likely be injured? 

A 52-year-old patient is brought to the emergency department because of severe chest pain. His blood pressure is 90/60 mm Hg, pulse is 100/min, and respirations are 22/min. Physical examination shows muffled heart sounds and jugular vein distention. ECG shows ST segment elevations and labs show elevated troponins confirming a myocardial infarction. Cardiac tamponade is suspected and an emergency pericardiocentesis is performed. At which of the following locations should the needle be inserted to relieve the tamponade?

A 42-year-old man is brought to the emergency department after a stab wound to his chest during a violent domestic dispute. His blood pressure is 70/55 mm Hg, pulse is 115/min, and respirations are 35/min. Physical examination shows cool and clammy extremities. Echocardiogram shows fluid in the pericardial space. Which of the following will most likely be found during physical examination?

A 42-year-old woman is brought to the emergency department because of shortness of breath. Physical examination shows a holosystolic murmur best heard at the left fifth intercostal space at the midclavicular line with radiation to the left axilla. Echocardiogram shows severe mitral valve regurgitation. Which of the following structures prevents regurgitation of the mitral valve cusps into the left atrium during systole?

A 35-year-old woman is brought to the emergency department because of palpitations, lightheadedness, and weakness. Her pulse is 120/min and irregular, blood pressure is 130/80 mm Hg, and respirations are 25/min. ECG examination shows absent P-waves confirming atrial fibrillation. Where is the mass of specialized conducting tissue that initiates the cardiac cycle located?

A 45-year-old woman comes to the physician because of bilateral lower extremity swelling. Physical examination shows a holosystolic murmur best heard at the left lower sternal border. Echocardiogram shows an enlarged right atrium and an incompetent tricuspid valve. Into which of the following areas would the regurgitation of blood flow in this cardiac abnormality?

An 18-year-old man is brought to the emergency department because of nosebleed, fatigue, and a headache that has worsened over several days. Physical examination shows that brachial artery pressure is markedly increased, femoral pressure is decreased, and the femoral pulses are delayed. The patient shows no external signs of inflammation. Which of the following is the most likely diagnosis?

A 34-year-old man is brought to the emergency department after being found unconscious. His temperature is 37°C (96.8°F), pulse is 90/min, and blood pressure is 120/90 mm Hg. A central venous line is placed. A subsequent x-ray of the chest shows a chylothorax. Which of the following structures was most likely accidentally damaged during the placement of the central venous line?

A 35-year-old man is brought to the emergency department with severe chest pain, dyspnea, tachycardia, cough, and fever. An x-ray of the chest shows significant pericardial effusion. When pericardiocentesis is performed, the needle is inserted up from the infrasternal angle. The needle passes too deeply, piercing the visceral pericardium and entering the heart. Which of the following chambers would be the first to be penetrated by the needle? 

A 45-year-old man is brought to the emergency department with severe chest pain radiating to his left arm and left upper jaw. An ECG shows an acute myocardial infarction of the inferior ventricular wall. Which of the following spinal cord segments would most likely receive the sensations of pain in this case?

A 42-year-old woman is brought to the emergency department after a fall from a balcony. The patient is in significant distress. Physical examination shows distant heart sounds, reduced systolic pressure, and engorged external jugular veins. Which condition is most likely characterized by these signs?

A 35-year-old woman was brought to the emergency department for a drug overdose. The patient is unresponsive and an empty bottle of acetaminophen was found in her handbag. The patient required insertion of a nasogastric tube and administration of activated charcoal. What are the three sites in the esophagus where one should anticipate resistance due to compression on the organ?

A 62-year-old man is brought to the emergency department with a complaint of severe chest pain. ECG shows an acute myocardial infarction. After the patient is stabilized, angiography is performed and the ejection fraction of the left ventricle is reduced to 30% from 60% on previous echocardiogram 3 months ago. A cardiac pacemaker is placed to prevent fatal arrhythmias (see image below). What is the location of the tip of the pacemaker?

A 68-year-old man comes to the physician for postoperative follow up after mitral valve replacement 8 weeks ago. The surgery went well without complications and the patient has been well since the surgery. The patient had a significant cardiac hypertrophy before the surgery (see image below). Which of the following structures would be most likely compressed?

A 55-year-old man is brought to the emergency department with complaints of severe chest pain radiating to his left arm and increased sweating over his chest. ECG shows an acute myocardial infarction of the posterior wall of the left ventricle. Which nerve fibers are most likely responsible for the increased sweating? 

A 42-year-old woman is brought to the emergency department after a fall from the balcony of her apartment. Vitals are within normal limits. Physical examination shows absent heart sounds, reduced systolic pressure, and engorged jugular veins. The condition that was created can be alleviated with which of the following procedures?

A 49-year-old man comes to the physician to undergo coronary artery bypass. He has a history of hypertension and diabetes. During the procedure, the left internal thoracic artery is used as the coronary artery bypass graft. The anterior intercostal arteries in the third to sixth intercostal spaces are ligated. Which of the following arteries will most likely provide collateral supply to these intercostal spaces?