MCQ of the day

A  60 years old patient with a known history of Myocardial infarction became gradually increasing breathless over a period of one month. Pulse=90/min regular. Blood pressure 110/70.  On auscultation an abnormal heart sound was detected.  The ejection fraction was low on echocardiography. Which phase of the cardiac cycle that abnormal heart sound is associated?

 

1. Atrial Systole
2. End of diastasis
3. Isovolumetric contration
4. Isovolumetric relaxation
5. Beginning of the middle third of diastole

 

 

 

 

 

 

 

 

 

 

 

Answer:e

Explanation:

The abnormal heart sound detected in this patient is the 3^rd heart sound associated with cardiac failure.  It is present at the beginng of the middle third of diastole. The sound of S₃ is lower in pitch than the normal sounds, usually faint, and best heard with the bell of the stethoscope.  It may be a normal finding in trained athletes. It has also been called a ventricular gallop.

(Choice a) Atrial Systole is associated with fourth heart sound.

(Choice b) It is the early part of diastasis that may have the third heart sound.

(Choice c) Isovolumetric contration is related to the 1^st heart sound.

(Choice d) Isovolumetric relaxation is related to the 2^nd  heart sound.

 

Educational Objective:

Third heart sound when present in a child or young adult implies the presence of a supple ventricle that can undergo rapid filling. Conversely, when heard in a middle-aged or older adult, an S₃ is often a sign of disease, indicating increased ventricular filling due to congestive heart failure or severe mitral or tricuspid regurgitation.  It can be a normal finding in trained athletes.