Introduction: In this problem, you will examine the consequences of a single specific cardiac abnormality on the function of the total cardiovascular system using information

Introduction: In this problem, you will examine the consequences of a single specific cardiac abnormality on the function of the total cardiovascular system using information from a cardiac catheterization procedure. Cardiac Catheterization Procedure: Although some information about the function of an abnormal cardiovascular system can be obtained “from the outside” (systolic and diastolic pressures with a sphygmomanometer, heart sounds, with a stethoscope), much of the information needed to characterize the system is available only from within it. Such information has been gained from experimental studies on animal preparations in which lesions to the cardiovascular system have been produced. Now, however, information about cardiovascular abnormalities is also routinely available from medical diagnostic procedures carried out on the human patients where nature has performed the “experiment.” Cardiac catheterization is a common procedure use to diagnose cardiac disease. This invasive procedure us used only when serious disease is suspected, and the risks associated with the procedure are minimal. A cardiologist obtains information about the state of a patient’s heart by introducing a catheter (a thin plastic tube) into the circulation and from there into the heart. The patient is awake but sedated; the electrocardiogram is monitored continuously (yielding the heart rate), as is the rate of oxygen consumption. The catheter is inserted into a vein, usually the femoral in the groin, and is slowly “wedged” in a small pulmonary artery. A second catheter is threaded through the femoral artery and aorta into the left ventricle. It may be passed still further into the left atrium. As the catheters are advanced, blood samples are taken and analyzed for their O2 content, and pressure measurements are made at different locations within the circulation of the heart. A radio-opaque dye may be injected to permit x-ray visualization of the silhouette of the lumina of the blood vessels or the chambers of the heart. Problem: Mr. A.B., a 56-year-old, was admitted to the hospital complaining that head recently begun to tire on exertion (a round of golf) and that he had occasional heart palpitations. He did not appear to be in acute distress at the time of examination. Physical examination revealed a moderate systolic ejection murmur. Mr. A.B. was referred for cardiac catheterization, and the following data was obtained. Measurement V alue Heart Rate 76 / min Ventilation O2 Consumption Hemoglobin O2 content: mixed venous blood O2 content: Pulmonary Artery O2 content: Pulmonary Vein O2 content: Aorta 5.16 L / min 219 ml / min 13.6 gm / 100 ml blood 13.1 ml O2 / 100 ml blood (Vol %) 13.1 Vol % 17.4 Vol % 17.4 Vol %