The heartbeat is composed of two sounds, commonly referred to as the lub-dup. These sounds can be heard when the thorax is listened to or auscultated. The heart sounds are closely associated with the closing action of the valves of the heart.
When one listens closely to the sound the heart makes, there is a rhythmic pattern that can be observed. Often times, the rhythm goes as lub-dup, a short pause, lub-dup. The rhythm goes on and on in a normal, healthy heart. The pause in the heart sounds indicate quiescent period.
The Lub-dup sound
The lub sound or the first sound happens when the atroiventricular valve of the heart closes. It also signifies a point in which the pressure in the atria is much less compared to the pressure in the ventricle or to simply put, the beginning of the ventricular systole. The lub sound appears to be longer, more resonant and louder than the dup sound. The second sound or the dup sound is much sharper, shorter in duration than the first sound.
The dup sound happens when the semilunar valve or the SL valve of the heart closes. The sound furthermore signifies that ventricular diastole or relaxation occurs. There is a possibility to distinguish the sounds that the four valves make. The mitral valve or the bicuspid valve closes slightly before the tricuspid does and the semilunar valve at the base of the left ventricle closes before the semilunar valve at the base of the right ventricle, then the possibility is present to distinguish the sounds that individual valves make.
Abnormal Heart Sounds
Many names are synonymous with abnormal heart sounds, one relatively common term is heart murmur. When a healthy heart is auscultated, the rushing of blood can be heard. The blood typically travels smoothly and uninterruptedly. It is normally silent or sometimes like a peaceful gush of wind. Once the flow of blood encounters an obstruction, the smooth flow is suddenly interrupted and it becomes turbulent. The labored travel of the blood generates heart murmurs which can easily be recognized when using a stethoscope.
However, heart murmurs heard from children are completely normal since the walls of the heart are relatively thin and can vibrate with the sudden rush of blood. When it comes to adults, heart murmurs usually signify an abnormality or problem with the heart valves.
An incompetent heart valve creates a swishing sound. The sound is made as the blood flows back to the previous valve since the valve that’s supposed to be closed is not capable of performing its task.
Another type of obstruction that blood flow may encounter is with a stenotic valve. The opening in the valve is narrowed thereby restricting the smooth sailing flow of blood through the respective valves.
Knowing the location and normal height size of the heart is important for one to recognize an abnormal or enlarged heart. Often, when sounds are not heard where they’re supposed to be heard or when additional sounds are heard, it often indicates a diseased heart.