It’s been years since you’ve thought about heart sounds and in all honesty, they were kind of confusing to begin with. There was all that “lub” and “dub” and diastole and systole. It was enough to make a nursing student’s head spin round, but heart sounds can actually tell you a great deal about a patient if you take the time to listen to them
(Also read how to perform a chest pain assessment).
Instead of settling for good old “lub-dub,” put that stethoscope to greater use and reacquaint yourself with the sound of the heart.
Okay, let’s make this simple. We are going to listen to the heart over the valves, and nothing more. No Erb’s point or anything esoteric. It just doesn’t matter in your everyday assessment. Now, if you hear a murmur over the valve… we are getting somewhere.
You know there are four valves in your heart: aortic, pulmonic, tricuspid, and mitral. It helps to think of them in this order. They make a sort of elongated “z” on the chest, with the aortic valve starting at the top right, two intercostal spaces down at the sternal border.
The pulmonic valve is easy enough to find. It’s right across the sternum at the left sternal border.
To find the tricuspid valve area, stay on the left side and count down four intercostal spaces.
The mitral valve is relatively easy to find if you are used to taking an apical pulse. If not, go to the fifth intercostal space at the mid-clavicular line.
Now that you know where to put your stethoscope, you have to make sense of what you are listening to. The first sound you hear in the cardiac cycle is the “lub,” and it is a sound full of meaning.
“Lub” means that the heart is in systole, or the ejection phase of the heart. It is the sound of the mitral and tricuspid valves closing as the body empties the ventricles into the lungs (see lung sounds) and body. It is also known as S1.
“Dub,” or S2, is the beginning of diastole, or the relaxation phase of the heart. It is the sound of the aortic and pulmonic valves closing. During this time, the ventricles fill and the atria contract.
Occasionally, you may hear a “split” S2 that sounds like “du-dub.” This is the aortic valve closing slightly before the pulmonic valve and is often a normal sound heard on inspiration. You can have a split S1, too, which is when the mitral valve closes before the pulmonic valve, and it can sometime indicate a bundle branch block. It is important to listen closely to hear when the sounds split.
This is where most people’s eyes start to glaze over, but it is where you can learn something useful to your patient. You will need to listen to the heart with the bell of your stethoscope to hear the abnormal heart sounds.
To hear a ventricular gallop, or S3, you should listen over the mitral valve with the bell. It will sound like a weird plopping noise right after you hear the “dub.” The whole heart beat will sound like the beats in the word ‘Kentucky’. This heart sound can indicate heart ischaemia or heart failure. The ventricles are stiffening and resisting the influx of blood in diastole. However, it is a normal sound in young adults under 30.
S4 is the heart sound for atrial gallop, and the heart beat will sound like the beats in the word ‘Tennessee’. Listen over the mitral valve with the bell of the stethoscope. You will hear the plopping noise just before the “lub” starts, which means it happens right before systole starts. This heart sound can tell you quite a bit. It is heard after heart attacks, and can indicate aortic stenosis, ischemia, heart failure, and hypertension.
Heart murmurs are the other heart sounds you will hear if you listen to enough hearts. They will often sound like the words “rush” or “hush” and can last throughout the heartbeat.
The above sample is of a ventricular septal defect (VSD) holosystolic heart murmur, caused by a opening in the dividing walls of the left and right heart ventricles.
Other murmurs can be caused by stiff and narrowed valves that cannot tolerate the rapid flow of blood through them. Many people walk around with a murmur and have no problems with it, but it can indicate something serious if it starts suddenly. A sudden onset murmur can indicate heart failure, shock, or a ruptured papillary muscle. Murmurs can also indicate ischaemia, infection, medicine toxicity, and genetic disease, in some cases.
Many cardiologists and cardiac nurses can pinpoint which valve the murmur comes from, when in the heart cycle it starts, and what grade the murmur rates. For those who are not so specialised, identifying that a murmur is present and calling it to the attention of the physician is likely all you need.