Why the Doctor Uses a Stethoscope

You'll see a stethoscope wrapped around the neck of practically every physician. But you may not be aware that this wonderfully useful instrument had its origins not in science, but in modesty.

Physicians used to check the heart by simply putting an ear on the patient's chest. That was a bit embarrassing for many people, however, so in 1817 a French physician named Rene Laennec began using a hollow wooden tube for the task. The idea caught on, and by the early 1900s, the stethoscope had evolved into its present form with rubber tubes and a metal bell on the end.

Your doctor's stethoscope is a simple device that nevertheless gives him or her crucial information about your heart. First your doctor listens for two sounds -- a "lub," followed by a "dub." The "lub" is the sound of the first set of heart valves closing; the dub is the second set closing. In between the lub and dub, the heart should be quiet. If it isn't, there might be a problem.

Your doctor also listens for a whoosh or gurgle heard in between the lub and dub. This is called a murmur. Murmurs can be caused by a rough edge on a valve. A murmur may tell your doctor that some blood is leaking backward with every beat. Other times it indicates a turbulence in flow that is not necessarily dangerous. This type of murmur often appears in children. In many cases, it goes away with time.

Another heart sound is a second dub that can give the heartbeat a sort of galloping sound. This sound may indicate a serious condition called heart failure, meaning the heart is weak and can't push enough blood through the body.

One more sound is a sneaky little mini-lub heard just before the main lub. Your doctor needs a quiet room and lots of concentration to hear this quiet sound. This one may mean your heart is stiffer than normal, for example from high blood pressure or after damage from a heart attack.

Besides listening for these sounds, your doctor is also listening for how steady or regular that lub-dub is. If it skips or jumps, you have an irregular heart rate. This irregularity can indicate a problem. In many cases, however, it is disconcerting but not dangerous to you.