Final answer:
The characteristics evaluated in heart sounds include S1 and S2 as the normal sounds, S3 which may indicate congestive heart failure, and S4 which indicates a left ventricular failure.
Step-by-step explanation:
In a normal, healthy heart, there are only two audible heart sounds: S1 and S2. S1 is the sound created by the closing of the atrioventricular valves during ventricular contraction and is normally described as a "lub," or first heart sound. The second heart sound, S2, is the sound of the closing of the semilunar valves during ventricular diastole and is described as a "dub."
There is a third heart sound, S3, which is rarely heard in healthy individuals. It may indicate congestive heart failure if heard later in life. The fourth heart sound, S4, is a sign of failure of the left ventricle, and it occurs prior to S1. Some cardiologists refer to the combined sounds of S3, S4, S1, and S2 as the "Tennessee gallop."