This patient has a benign or innocent mitral valve murmur. Murmurs can be pathological or innocent, and it is important to be able to distinguish between the two.
History is key in helping to determine the difference. In this case, part of the clue is the introduction – the patient was examined during a routine check-up and not for symptoms. In the PACES, unlike real life, you do not have lots of information to use, and so you must use every piece of information you have.
As with all cardiac auscultation, the following features should be detected:
- The timing of the abnormal sound – at what point in the cardiac cycle does it occur?
- The location of the murmur – not only of where it is loudest, but where it radiates too, and with what degree of intensity to those areas (see later)
- The quality or pitch of the murmur – in this case it is not of a pathological quality, in that it caries with the cardiac cycles and is sometimes louder or softer (see below)
- The more it changes, the less pathological it is, especially if it changes in different positions, or disappears altogether
- The presence or absence of ejection or non-ejection systolic clicks.
A clear clinical sign are that manoeuvres, which reduce the blood flow of blood returning to the heart will reduce the flow murmur intensity, which is yet another clue that it is innocent and not pathological.
The 3rd heart sound is associated with atrial fibrillation and mitral valve regurgitation (otherwise known as incompetence). It is low-pitch in nature, and can cause what is termed a ‘gallop rhythm’.
A 3rd HS on the left is best heard, in expiration at the left lateral position with the bell rather than the diaphragm. On the right side it is best heard at the left sternal edge, in inspiration naturally, rather than expiration.
Whilst it is a normal variant in children and young adults, if found in patients over the age of 40-years it should be further investigated. It is also present in high output states.