A 40-year-old man comes to the physician for an insurance physical. He has no current complaints. His medical problems include borderline hypertension and seasonal allergies. He takes fexofenadine. He does not smoke and drinks 1-2 alcoholic beverages per weekend. His family history is remarkable for an uncle who died suddenly in his 30s while playing basketball. His older brother had two unexplained syncopes.
His blood pressure is 120/70 mm Hg, pulse is 88 /min, and respirations are 12 /min. The patient's pulse oximetry showed 98% on room air. His BMI is 23 kg/m². There is a 3/6 systolic murmur heard at the mid and upper sternum bilaterally. Carotid upstrokes are delayed. The intensity of the murmur decreases when the patient assumes a standing position from a sitting position.
Which of the following is the most likely diagnosis?

Question

Quizplus · Accepted Answer

11ec193a_9739_6050_853d_79c8253fcf36_MD0002_00 This patient's physical examination is consistent with aortic stenosis. Systolic ejection murmurs at the right upper sternal border imply turbulence in the left ventricular (LV) outflow tract due to aortic stenosis (AS), hypertrophic cardiomyopathy (HCM), or supravalvular AS. Maneuvers that decrease LV cavity size (i.e., Valsalva, standing) cause the hypertrophied septum in HCM to obstruct further and make the murmur louder. Fixed obstructions, as seen in AS, get slightly quieter as the decreased venous return results in less flow across the fixed obstruction. Delayed pulses ("parvus et tardus") are characteristic of aortic stenosis, while patients with HCM have a "bifid" pulse (two systolic impulses collapsed in between due to ejection→obstruction→ejection during systole). Aortic stenosis is due to either "senile" (bicuspid valve) or fibrocalcific aortic stenosis, which results from calcification of a normal aortic valve (presents around age 70). Bicuspid aortic valves are a congenital anomaly which undergo accelerated fibrocalcification and cause symptoms around age 40. Rarer causes of aortic stenosis include endocarditis, connective tissue diseases, and prior radiation. Bicuspid aortic valves (Choice A) Ebstein's anomaly is due to abnormalities of the tricuspid leaflet structure and location. The murmur is usually due to tricuspid regurgitation (holosystolic at the left lower sternal border) that does not change with standing. (Choice B) Hypertrophic cardiomyopathy is a genetic disorder with significant hypertrophy of the LV septum or the entire left heart with outflow obstruction (about 30% of patients). Maneuvers that decrease LV volume (i.e., Valsalva, standing) will increase the gradient and the murmur; while maneuvers that increase LV volume or increase afterload will decrease the murmur (i.e., squatting, handgrip, leg lift). (Choice C) The murmur produced by mitral valve prolapse is preceded by a click and heard best at the apex. Maneuvers that decrease LV filling (i.e., Valsalva, standing) make the murmur louder. Maneuvers that increase LV filling (i.e., squatting, leg raise) will improve the closure of the mitral leaflets, delay the click, and soften the murmur. (Choice E) Ventricular septal defects produce a holosystolic, harsh murmur with a thrill along the left sternal border. The murmur does not typically change with standing. Educational objective: Maneuvers that decrease left ventricular cavity size (i.e., Valsalva, standing) cause the hypertrophied septum in hypertrophic cardiomyopathy to obstruct further and make the murmur louder. Fixed obstructions, such as aortic stenosis, get slightly quieter as the decreased venous return results in less flow across the fixed obstruction. __________ References: Valvular heart disease: the influence of changing etiology on nosology. (http://www.ncbi.nlm.nih.gov/pubmed/8000586) Clinical characteristics of bicuspid aortic valves in surgical patients. (http://www.ncbi.nlm.nih.gov/pubmed/16714697) Bicuspid aortic valves are associated with aortic dilatation out of proportion to coexistent valvular lesions. (http://www.ncbi.nlm.nih.gov/pubmed/11082359)

A 40-Year-Old Man Comes to the Physician for an Insurance