A very loud auscultatory sign can attract our particular interest.  Especially when this sign is palpable.  Especially when this sign is visible.   

Third heart sound (S3) is one of the most common pathological auscultatory sign.  S3 is a very useful symptom in heart failure's diagnosis in adults.   In most cases, however, S3 if faint and could be detectable by an attentive examiner only.  Rarely S3  could be loud, and even most prominent between others heart sounds.  Sometimes in such cases S3 is palpable.  

The male patient in his fifties had a long history of heart failure caused by dilated cardiomyopathy.  At the moment of described here examination, he had symptoms of moderate heart decompensation: shortness of breath, jugular veins' distention, oedema, rales and S3-gallop.  But what gallop!  At the time of S3, there was a palpable and visible impulse of the left chest.  It could be seen on the video below.  S3 alternates in intensity and sometimes disappears.  

In my experience, most adult patients with very loud S3 have dilated hearts with low ejection fraction.  In most cases, loud S3 quickly becomes soft or even disappears after few days of treatment with diuretics and dyspnoea's regression.