A 46-year-old man comes to the office with chest pain and dyspnea on exertion. He has no known medical problems and leads a sedentary lifestyle. He is a lifetime nonsmoker. Noninvasive cardiac testing is nondiagnostic. Left and right heart catheterization is planned. During the procedure, the catheter records periodic pressure changes with a maximum of 25 mm Hg and minimum of 2 mm Hg. The catheter is advanced further, and then shows periodic pressure changes with a maximum of 25 mm Hg and a minimum of 10 mm Hg. Assuming the results of the procedure are normal, the first set of readings was most likely obtained from which of the following locations?

Question

A 46-year-old man comes to the office with chest pain and dyspnea on exertion.  He has no known medical problems and leads a sedentary lifestyle.  He is a lifetime nonsmoker.  Noninvasive cardiac testing is nondiagnostic.  Left and right heart catheterization is planned.  During the procedure, the catheter records periodic pressure changes with a maximum of 25 mm Hg and minimum of 2 mm Hg.  The catheter is advanced further, and then shows periodic pressure changes with a maximum of 25 mm Hg and a minimum of 10 mm Hg.  Assuming the results of the procedure are normal, the first set of readings was most likely obtained from which of the following locations?

Quizplus · Accepted Answer

11ec160b_3c8a_bfa7_9249_9738c981b705_MD0001_00 Cardiac catheterization is performed to evaluate for cardiac etiologies and obtain direct measurements of intracardiac pressures in patients with unexplained symptoms. In general, right-sided pressures are much lower than those of the left side as the right ventricle is pumping blood into a much lower resistance pulmonary vasculature. A balloon-tipped pulmonary artery (PA) catheter (attached distally to a pressure transducer) is inserted into the subclavian or internal jugular vein. When the PA catheter enters the superior vena cava (SVC), a venous waveform appears, and the balloon is inflated with air and the catheter is advanced. The location of the catheter tip is determined by the pressure readings as follows: The venous pressure waveform of the SVC appears as small-amplitude oscillations. The pressure remains unchanged as the catheter is advanced into the right atrium (RA). Normal pressure in the SVC and RA is 1-6 mm Hg (Choice D). As the catheter is advanced across the tricuspid valve into the right ventricle (RV), a pulsatile waveform appears. The peak (systolic) pressure is the strength of right ventricular contraction, and the lowest (diastolic) pressure is just below the RA pressure. RV systolic pressure is normally 15-30 mm Hg. As the catheter advances across the pulmonic valve into a main pulmonary artery, the pressure waveform shows a sudden increase in diastolic pressure with no change in systolic pressure. This rise in diastolic pressure is due to pulmonary capillary resistance and backward transmission of left atrial pressure. The PA diastolic pressure is normally 6-12 mm Hg (Choice C). When the catheter is advanced into the distal PA branches, a venous type waveform appears; this is called the PA occlusion pressure or pulmonary capillary wedge pressure (PCWP). This pressure is reflective of venous pressure in the left heart (left atrial pressure and left ventricular diastolic pressure) (Choice A). PCWP is usually equal to PA diastolic pressure (6-12 mm Hg). (Choice B) Left-sided pressures are much higher than right heart pressures in order to maintain systemic perfusion. The normal left ventricular systolic pressure is approximately 90-140 mm Hg with a left ventricular end-diastolic pressure of 6-12 mm Hg. Educational objective: Right-sided pressures in the heart are lower than left-sided pressures due to lower resistance in the pulmonary vasculature. Right ventricular diastolic pressure is similar to right atrial/central venous pressure (1-6 mm Hg), whereas pulmonary artery diastolic pressure is slightly higher (6-12 mm Hg) due to resistance to flow in the pulmonary circulation.

A 46-Year-Old Man Comes to the Office with Chest Pain