A 32-year-old man comes to the office due to progressive dyspnea, dizziness, and chest discomfort. He has no prior medical problems but had a mild respiratory illness 2 weeks earlier that resolved spontaneously. His father has a history of myocardial infarction. Echocardiography shows pericardial fluid accumulation with late diastolic collapse of the right atrium. Which of the following physical examination findings is most likely to be seen in this patient?

Question

A 32-year-old man comes to the office due to progressive dyspnea, dizziness, and chest discomfort.  He has no prior medical problems but had a mild respiratory illness 2 weeks earlier that resolved spontaneously.  His father has a history of myocardial infarction.  Echocardiography shows pericardial fluid accumulation with late diastolic collapse of the right atrium.  Which of the following physical examination findings is most likely to be seen in this patient?

Quizplus · Accepted Answer

This patient has a pericardial effusion with associated cardiac tamponade. Echocardiography showing pericardial fluid accumulation with late diastolic collapse of the right atrium (due to excessive pericardial fluid compressing the right atrium) is diagnostic. Pulsus paradoxus is an important physical finding in cardiac tamponade and refers to an exaggerated drop in systolic blood pressure (>10 mm Hg) during inspiration. Fluid accumulation in the pericardium limits the ability of the right ventricular free wall to expand outward; during inspiration, the increase in venous return is instead accommodated by bowing of the interventricular septum toward the left ventricle (LV), decreasing LV end-diastolic volume and stroke volume. The result is decreased systolic pulse pressure during inspiration. Less common causes of pulsus paradoxus include severe asthma and chronic obstructive pulmonary disease (due to excessive swings in intrathoracic pressure with breathing), as well as the restriction of right ventricular filling that occurs with constrictive pericarditis. (Choice A) Pulsus alternans refers to beat-to-beat variation in pulse amplitude (ie, systolic blood pressure); it is most commonly seen in patients with severe LV systolic dysfunction (possibly related to the effect of the Frank-Starling mechanism on the failing ventricle) and is not expected with cardiac tamponade. Electrical alternans is sometimes seen with cardiac tamponade and refers to a beat-to-beat variation in the QRS complex amplitude on ECG (ie, variation in electrical signal rather than pulse) due to the swinging motion of the heart in the pericardial fluid. (Choice C) A dicrotic pulse has 2 distinct peaks (one during systole and the other during diastole) due to an accentuated diastolic dicrotic wave after the dicrotic notch. This finding typically occurs in patients with severe systolic dysfunction and high systemic vascular resistance. (Choice D) A hyperkinetic pulse has a rapidly rising amplitude due to the rapid ejection of a large stroke volume against a decreased afterload. This can occur with aortic regurgitation and high-output heart failure (eg, thyrotoxicosis, arteriovenous fistula). (Choice E) Fixed LV outflow tract obstruction (eg, valvular aortic stenosis) can cause pulsus parvus et tardus, or a slow-rising, low-amplitude pulse resulting from diminished stroke volume (pulsus parvus) and prolonged LV ejection time (pulsus tardus). Educational objective: Pulsus paradoxus refers to an exaggerated drop (>10 mm Hg) in systolic blood pressure during inspiration. It is most commonly seen in patients with cardiac tamponade but can also occur in severe asthma, chronic obstructive pulmonary disease, or constrictive pericarditis.

A 32-Year-Old Man Comes to the Office Due to Progressive