Which of the following best describes the fourth heart sound (S4) in neonates?

The fourth heart sound (S4) is considered a low-pitched sound that occurs during late diastole. It is produced by the atrial contraction as blood is forced into a stiff or hypertrophied ventricle. In neonates, this sound may be indicative of a physiological condition as their hearts are still developing and adapting postnatally. S4 is not typically viewed as abnormal in this population when it is isolated and not associated with any other signs of cardiovascular stress or pathology.

A low-pitched sound is best detected using the bell of the stethoscope, highlighting its nature during that specific phase of the cardiac cycle. This discernment is essential when auscultating the heart sounds in neonates. Understanding that S4 can be a normal finding in certain circumstances allows healthcare providers to assess the neonate's heart function more accurately and effectively.