Technique is everything. The best stethoscope is between your ears, and is called your brain. Using internet databases of heart sounds is a good way to get a general idea of what the murmur should sound like.
e.g lub shhhhh dub. or lushhhh dub or lub dush or lub dubsh
Sit the patient appropriately for cardiovascular examination. Usually 45 deg is good enough. Make sure you find where that apex beat is located, and then ausculate all the areas Mitral (apex), Tricuspid, Pulmonary and Aortic. Then roll the patient into the left lateral position and auscultate in the mitral region (some say use the bell to pick up mitral stenosis, but i've heard it easily with the diaphragm too so your choice really). Roll the patient back on their back and sit them well forward. Auscultate for aortic regurgitation in the aortic area.
If you hear murmurs - you should always do two things. 1) check for radiation 2) accentuating manoeuvres
When you're starting out you should probably go through the accentuating maneouvres anyway, because some murmurs will only become audible when using such tricks. Its probably enough to use the inspiration/expiration manoeuvre, and if you hear anything else, then try some of the other ones.
Always check to see if murmurs radiate to the carotids, to the L axilla, to the back, to the liver, or to the femoral a.
i've often heard loud aortic stenosis radiating into the abdomen. perhaps i just have sensitive ears!
As for timing a murmur. Put your finger on the pulse (carotid, brachial, radial etc.). As a general rule, the felt beat of the pulse coincides with systole.
i.e. it will occur between S1 and S2
for this reason, systolic murmurs or sounds will always be 'in-time' with the felt pulse, and diastolic murmurs or sounds will always be 'off-beat'. Having a musical ear probably helps for this.
It's probably a fair comment that distinguishing murmurs from their sounds is unreliable, especially at fast heart rates (ie children). However, with a lot of experience, it does come much easier.
practise practise practise. once youve heard lots of murmurs youll become confident. however beware. after getting more comfortable with murmurs - i think you go through a phase where you think EVERYONE has a murmur. this is simply not true. so dont be overconfident either.
