Can You Hear S3 In Afib

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Can You Hear S3 in Atrial Fibrillation?

As someone who has experienced atrial fibrillation (AFib) firsthand, I know how concerning it can be to notice new or unusual sounds coming from your heart. One sound that often causes worry is the S3 sound. But can you actually hear S3 in AFib? Let’s dive deeper into this topic and explore what S3 is and its relationship to AFib.

To understand S3, we first need to understand the normal heart sounds. The heart typically produces two main sounds, often referred to as “lub-dub.” These sounds are caused by the closing of the heart valves during each heartbeat. The first sound, “lub,” is created by the closure of the mitral and tricuspid valves, while the second sound, “dub,” is caused by the closure of the aortic and pulmonic valves.

What is S3?

S3 is an additional sound that can be heard during a heartbeat. It occurs when blood enters the ventricles of the heart during the early filling phase, known as diastole. The S3 sound is often described as a low-pitched, rumbling sound, similar to the sound produced when the word “Kentucky” is pronounced quickly.

In individuals with a healthy heart, the presence of an S3 sound is often a sign of a normal, compliant heart. In other words, it indicates that the heart is filling properly and efficiently. However, in certain situations, such as AFib, the presence of an S3 sound can be a cause for concern.

Can You Hear S3 in AFib?

In AFib, the heart’s electrical signals become chaotic, causing the atria to fibrillate or quiver instead of contracting effectively. This irregular heart rhythm can disrupt the normal filling and emptying of the ventricles. As a result, the S3 sound may not be as prominent or even audible in individuals with AFib.

It’s important to note that the absence or diminished presence of an S3 sound does not necessarily indicate a problem. In fact, in individuals with AFib, the absence of an S3 sound can be a normal finding due to the abnormal heart rhythm. However, it’s always best to consult with a healthcare professional if you have any concerns about the sounds you are hearing from your heart.


In conclusion, while S3 is a sound that can be heard in individuals with a healthy heart, its presence may not be as noticeable or even detectable in those with AFib. The irregular heart rhythm associated with AFib can disrupt the normal filling and emptying of the ventricles, potentially affecting the audibility of the S3 sound.

If you are experiencing any unusual or concerning sounds from your heart, it’s essential to seek medical advice. A healthcare professional can assess your symptoms, perform an examination, and order any necessary tests to determine the cause and appropriate treatment.