An 18-year-old soccer player is seen in the office for an abnormal electrocardiogram that demonstrates normal sinus rhythm with T-wave inversion in leads V1 and V2. Listen to the auscultation findings at the cardiac apex (Click on media exhibit). Which of the following is the most likely explanation for the auscultation findings in this patient?

Question

An 18-year-old soccer player is seen in the office for an abnormal electrocardiogram that demonstrates normal sinus rhythm with T-wave inversion in leads V1 and V2.  Listen to the auscultation findings at the cardiac apex (Click on media exhibit).  Which of the following is the most likely explanation for the auscultation findings in this patient?

Quizplus · Accepted Answer

The auscultation of heart sounds over the cardiac apex shows a low-frequency diastolic sound due to the presence of the third heart sound (S3). S3 occurs during diastole, usually 0.14-0.16 seconds after the second heart sound (S2), and is heard best with the bell of the stethoscope over the cardiac apex in the left lateral decubitus position. The precise mechanism of S3 is unclear. However, it is thought to occur as a result of sudden limitation of ventricular movement during rapid passive ventricular filling. S3 can be heard as a normal finding in healthy young adults and does not signify an underlying abnormality in asymptomatic patients. In contrast, the fourth heart sound (S4) can be heard in healthy older adults and is due to decreased ventricular compliance with age. However, S4 presence in young adults usually signifies an underlying abnormality. The presence of S3 in patients age >40 is considered abnormal and suggests enlargement of the ventricular chambers (Choice B). S3 can be heard in patients with chronic severe mitral regurgitation, chronic aortic regurgitation, heart failure associated with dilated cardiomyopathy, and occasionally in patients with high cardiac output states such as pregnancy or thyrotoxicosis. (Choice A) Hypertrophic cardiomyopathy leads to decreased ventricular compliance and can cause S4 due to atrial contraction against the stiff and noncompliant left ventricle. It is also accompanied by the typical harsh crescendo-decrescendo systolic murmur heard best at the apex and lower left sternal border. (Choice C) Patients with mitral valve prolapse and chronic severe mitral regurgitation can develop S3 due to enlargement of the left ventricle. These patients also typically have early systolic clicks, along with systolic murmur of mitral regurgitation. (Choice E) Patients with pulmonic stenosis and right ventricular hypertrophy can have right-sided S4 over the left sternal border. Other accompanying findings include an ejection click followed by an ejection systolic murmur heard best over the left upper sternal border. Educational objective: The third heart sound can be a normal finding in healthy young adults and does not signify an underlying abnormality in asymptomatic patients. In contrast, the fourth heart sound can be heard in healthy older adults and its presence in young adults usually signifies an underlying abnormality. __________

An 18-Year-Old Soccer Player Is Seen in the Office for an Abnormal