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What causes Heart Sound 1 and Tumor Plop Sound?

Mar 17, 2023

Heart Sound

Ist Stage - First heart sound (S1) is heard at the end of the atrial systole (Mitral and Tricuspid valve closure). 

2nd stage is isovolumetric contraction, the ventricles begins to contract, at this point no blood is coming in and going out. 

3rd stage -Ejection click sound is heard at the opening of the  aortic and pulmonic valve.As the pressure in the ventricles increase, there is opening of the aortic and pulmonic valve  and slight bulge in the mitral and tricuspid valve.  If due to any reason less amount of blood goes through ventricle , more amount of blood will accumulate in ventricles , that will cause pulmonary edema. In 

4th stage- second heart sound (S2) is heard at the end of ventricular systole i.e closure of the aortic and pulmonic valve. After that the heart begins to relax and is called isovolumetric relaxation. 

5th stage is rapid ventricular filling . 70% of the atrial blood goes into the ventricle. Opening of the mitral and triscuspid valve is refer to as opening snap. Opening snap is heard at the end of the volumetric relaxation 

This is a high-yield topic for Medicine subject and it is highly important for NEET PG exam Preparation.

Heart sound 1

Q.During which phase of cardiac activity , the heart literally stand still (least cardiac motion)?

  • Least cardiac motion will be in the phase of diastatsis

Q.Protodiastole starts from? 

  • It starts from end of systole and ends up at aortic valve closure
Heart sounds

Abnormal Heart Sounds

  • Third heart sound (S3)- heard at the phase of rapid heart filling, also referred as ventricular gallop rhythm 
  • Fourth heart sound (S4), also called  atrial gallop rhythm, present right after S1 

Heart sound heard at which side of stethoscope ?

  • Third and Fourth heart sounds are low pitched heart sounds, heard from the bell side of stethoscope
  • High pitched heart sounds heard from the diaphragm side of stethoscope 

All heart sounds are high pitched except 

  • S3
  • S4
  • Tumor plop
  • Murmur of mitral stenosis

These are low pitched sounds

Tumor Plop Sound

Atrial myxoma (benign tumor of the heart) is a pedunculated tumor , orginate from inter atrial septum, which  being suspended in the left atria. While filling of blood, the movement the blood hit the tumor, it  will swing . The tumor will strike the mitral valve leaflet and the sound produced due to tumor impacting is called as tumor plop sound. It is a diastolic finding because tumor impacts on already open mitral valve. This sound will be heard after the opening snap. It is a low pitched heart sound heard with the bell. 

Tumor Plop Sound

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Effort intolerance, dyspnea on exertion, breathlessness while sitting (platypnea) because while sitting,due to gravity the tumor will block the mitral valve , which obstructs the passage of blood and more pressure will build up in left atria

On Examination

Tumor plop sound, mid or late diastolic murmur, repeated impact of the tumor on mitral valve leaflet contribute to valve endothelium damage, and platelet plug formation which cause transient ischemic attacks


Transthoracic echocardiography


Cardiothoracic vascular surgery, surgically resection of the tumor

Papillary elastoma

Tumor originating directly from mitral valve leaflet.

Papillary elastoma


Embolic manifestations, Transient ischemic attacks, mimics mitral stenosis

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Most Common

  • Most common tumor of the heart-metastatic (Oat cell carcinoma lung, breast cancer, malignant melanoma)
  • Most common primary malignant tumor of the heart- Angiosarcoma
  • Most common benign tumor of the heart - A. myxoma

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