About heart murmur,
Murmurs are extra heart sounds that are produced as a result of turbulent blood flow that is sufficient to produce audible noise. Most murmurs can only be heard with the assistance of a stethoscope ("on auscultation").
A functional murmur or "physiologic murmur" is a heart murmur that is primarily due to physiologic conditions outside the heart, as opposed to structural defects in the heart itself. Functional murmurs may be benign (an "innocent murmur"), mildly troublesome, or serious.
Murmurs may also be the result of various problems, such as narrowing or leaking of valves, or the presence of abnormal passages through which blood flows in or near the heart. Such murmurs, known as pathologic murmurs, should be evaluated by an expert.
Heart murmurs are most frequently organized by timing, into systolic heart murmurs and diastolic heart murmurs. However, continuous murmurs cannot be directly placed into either category.
Classification
Murmurs can be classified by seven different characteristics: timing, shape, location, radiation, intensity, pitch and quality.
Timing refers to whether the murmur is a systolic or diastolic murmur.
Shape refers to the intensity over time; murmurs can be crescendo, decrescendo or crescendo-decrescendo.
Location refers to where the heart murmur is usually auscultated best. There are six places on the anterior chest to listen for heart murmurs; each of the locations roughly corresponds to a specific part of the heart. The first five of the six locations are adjacent to the sternum. The six locations are:
the 2nd right intercostal space
the 2nd to 5th left intercostal spaces
the 5th mid-clavicular intercostal space.
Radiation refers to where the sound of the murmur radiates. The general rule of thumb is that the sound radiates in the direction of the blood flow.
Intensity refers to the loudness of the murmur, and is graded on a scale from 0-6/6.
Pitch can be low, medium or high and is determined by whether it can be auscultated best with the bell or diaphragm of a stethoscope.
Quality refers to unusual characteristics of a murmur, such as blowing, harsh, rumbling or musical.
Interventions that change murmur sounds
Inhalation will increase the amount of blood filling into the right ventricle, thereby prolonging ejection time. This will affect the closure of the pulmonary valve. This finding, also called Carvallo's Maneuver,has been found by studies to have a sensitivity of 100% and a specificity of 80% to 88% in detecting murmurs originating in the right heart.
abrupt standing
squatting
valsalva maneuver. One study found the valsalva maneuver to have a sensitivity of 65%, specificity of 96% in detecting Hypertrophic obstructive cardiomyopathy (HOCM).
hand grip
post ectopic potentiation
amyl nitrite
methoxamine
positioning of the patient. ie. positioning patients in the left lateral position will allow a murmur in the mitral valve area to be more pronounced.
Examples of anatomic source of murmur
Stenosis of Bicuspid aortic valve
Symptoms tend to present between 40 and 70 years of age.
Stenosis of Tricuspid Aortic Valve
Symptoms more likely to present after 80 years of age.
Hypertrophic subaortic stenosis
Symptoms are a harsh murmur in mid-systole, often accompanied by S4, Brisk Bifid Carotid upstroke. Murmur increases with standing and valsalva maneuver.
Ventral septal defect
Symptoms are holosystolic, heard best at left lower sternal border.
Showing posts with label heart. Show all posts
Showing posts with label heart. Show all posts
Wednesday, June 16, 2010
The Anatomy of Human Heart
Here are some facts about human heart.
The heart is basically a hollow muscular pump, which pushes the blood through out the body via the blood vessels. A normal sized healthy heart is roughly the same size as a fist. It is located between the lungs and slightly to the left of center. The heart is an involuntary muscle that has approximately seventy to ninety contractions per minute during a restful state. It begins to pump early in the life of a fetus and will continue unceasingly until death.
A hollow organ, the heart’s walls are made up by three distinct layers. They are as follows:
1. Endocardium (en-do-kar’de-um) this is a very smooth layer of cells that form the interior membrane of the heart. The endocardium tissue is also the type of tissue that makes up the valves of the heart.
2. Myocardium (mi-o-kar’de-um) is the actual muscle tissue of the heart and is by far the thickest layer.
3. Pericardium (per-I-kar’de-um) is the outermost layer of the heart and is also the tissue that serves as the lining of the pericardial sac.
The main portion of the heart is split into two different sides with an actual partition called the septum. Each side of the heart works as a separate pump and have two chambers apiece or as a whole, the heart has four distinct chambers.
1. Right atrium is the thin-walled area that receives the venous or “used” blood returning to the body by the veins.
2. Right ventricle is the “pump” area of the heart’s right side. The atrium dumps the blood into the ventricle where it is then pumped out the pulmonary arteries and to the lungs.
3. Left atrium receives the oxygenated blood returning from the lungs.
4. Left ventricle has the thickest walls of all. It is from this chamber the blood is pumped out of the heart, into the aorta and out to the rest of the body.
Since blood flow needs to be a one-way affair, there are valves at the entrance and exit of each ventricle. The entrance valves are called atrioventricular (a-tre-o-ven-trik’u-lar) and the exit valves are semilunar (sem-e-lu’nar). Each of the actual valves has it’s own specific name though.
1. Tricuspid valve is the one located at the entrance of the right ventricle. It prevents the blood from washing back into the right atrium. It gets its name from the three “cusps” or flaps that make up the valve.
2. Pulmonary semilunar valve is located between the right ventricle and the pulmonary artery.
3. Mitral valve is made of very heavy cusps and is located at the entrance of the left ventricle. This is a powerful valve that closes as the left ventricle begins each of its contractions to ensure the oxygenated blood doesn’t re-enter the left atrium.
4. Aortic valve is located, as its name would imply, between the left ventricle’s exit and the aorta itself.
Even though the heart is split up into two distinct halves, these two must work together to function properly.
When the heart starts to contract, it begins in the upper (atrium), thin-walled chambers and causes the blood to be squeezed out into the lower (ventricle) chambers. As the upper chamber finishes its squeeze, the lower chamber begins its work. The active action of these two chambers working together is called systole (sis’to-le). Each of these active periods will be followed by a short resting period known as diastole (di-as’to-le) although the heart never actually stops.
As the walls of the atrium complete their contraction, the ventricle begins its active stage. As the ventricle has been contracting the atrium has been filling up with blood so the entire process begins anew.
The sound of a normal heartbeat has often been described as “lubb” and “dupp”. The “lubb” period is the longer and deeper sounding of the two and is made as the ventricle is in its systole period. It is thought the sound is a result of the thick muscled walls of the ventricle contracting and the atrioventricular valves slamming shut. The “dupp” sound is shorter and has a distinctively sharper pitch. It occurs during the ventricle’s diastole period and is made as the semilunar valves close.
When these valves are not functioning normally there is a “swooshing” sound that can be heard. These are caused by the blood backwashing into the various chambers of the heart and are one of the possibilities when health care professionals are speaking of “murmurs.”
If a spinal or some other type of injury occurs and the nerves to voluntary muscles are cut, that muscle ceases to work and the area becomes paralyzed. Amazingly, if the nerves to the heart are cut it will continue to beat. The reason for this is that even though the heart is controlled by the nervous system, the heart’s muscles can actually contract rhythmically on its own. Unfortunately the nervous system is required for the heart to beat rapidly enough to maintain proper blood flow. If the nerves were to be cut, the heart’s rate could drop below 40 beats per minute and even if activity is increased, the heart’s rate would not.
The human heart is a fascinating organ that many, if given the chance, would love to exam. For most this possibility will never become a reality but for the really curious, there is an adequate substitute. This substitute is the heart of the common cow and can usually be obtained by visiting a local meat market and asking for one.
The heart is basically a hollow muscular pump, which pushes the blood through out the body via the blood vessels. A normal sized healthy heart is roughly the same size as a fist. It is located between the lungs and slightly to the left of center. The heart is an involuntary muscle that has approximately seventy to ninety contractions per minute during a restful state. It begins to pump early in the life of a fetus and will continue unceasingly until death.
A hollow organ, the heart’s walls are made up by three distinct layers. They are as follows:
1. Endocardium (en-do-kar’de-um) this is a very smooth layer of cells that form the interior membrane of the heart. The endocardium tissue is also the type of tissue that makes up the valves of the heart.
2. Myocardium (mi-o-kar’de-um) is the actual muscle tissue of the heart and is by far the thickest layer.
3. Pericardium (per-I-kar’de-um) is the outermost layer of the heart and is also the tissue that serves as the lining of the pericardial sac.
The main portion of the heart is split into two different sides with an actual partition called the septum. Each side of the heart works as a separate pump and have two chambers apiece or as a whole, the heart has four distinct chambers.
1. Right atrium is the thin-walled area that receives the venous or “used” blood returning to the body by the veins.
2. Right ventricle is the “pump” area of the heart’s right side. The atrium dumps the blood into the ventricle where it is then pumped out the pulmonary arteries and to the lungs.
3. Left atrium receives the oxygenated blood returning from the lungs.
4. Left ventricle has the thickest walls of all. It is from this chamber the blood is pumped out of the heart, into the aorta and out to the rest of the body.
Since blood flow needs to be a one-way affair, there are valves at the entrance and exit of each ventricle. The entrance valves are called atrioventricular (a-tre-o-ven-trik’u-lar) and the exit valves are semilunar (sem-e-lu’nar). Each of the actual valves has it’s own specific name though.
1. Tricuspid valve is the one located at the entrance of the right ventricle. It prevents the blood from washing back into the right atrium. It gets its name from the three “cusps” or flaps that make up the valve.
2. Pulmonary semilunar valve is located between the right ventricle and the pulmonary artery.
3. Mitral valve is made of very heavy cusps and is located at the entrance of the left ventricle. This is a powerful valve that closes as the left ventricle begins each of its contractions to ensure the oxygenated blood doesn’t re-enter the left atrium.
4. Aortic valve is located, as its name would imply, between the left ventricle’s exit and the aorta itself.
Even though the heart is split up into two distinct halves, these two must work together to function properly.
When the heart starts to contract, it begins in the upper (atrium), thin-walled chambers and causes the blood to be squeezed out into the lower (ventricle) chambers. As the upper chamber finishes its squeeze, the lower chamber begins its work. The active action of these two chambers working together is called systole (sis’to-le). Each of these active periods will be followed by a short resting period known as diastole (di-as’to-le) although the heart never actually stops.
As the walls of the atrium complete their contraction, the ventricle begins its active stage. As the ventricle has been contracting the atrium has been filling up with blood so the entire process begins anew.
The sound of a normal heartbeat has often been described as “lubb” and “dupp”. The “lubb” period is the longer and deeper sounding of the two and is made as the ventricle is in its systole period. It is thought the sound is a result of the thick muscled walls of the ventricle contracting and the atrioventricular valves slamming shut. The “dupp” sound is shorter and has a distinctively sharper pitch. It occurs during the ventricle’s diastole period and is made as the semilunar valves close.
When these valves are not functioning normally there is a “swooshing” sound that can be heard. These are caused by the blood backwashing into the various chambers of the heart and are one of the possibilities when health care professionals are speaking of “murmurs.”
If a spinal or some other type of injury occurs and the nerves to voluntary muscles are cut, that muscle ceases to work and the area becomes paralyzed. Amazingly, if the nerves to the heart are cut it will continue to beat. The reason for this is that even though the heart is controlled by the nervous system, the heart’s muscles can actually contract rhythmically on its own. Unfortunately the nervous system is required for the heart to beat rapidly enough to maintain proper blood flow. If the nerves were to be cut, the heart’s rate could drop below 40 beats per minute and even if activity is increased, the heart’s rate would not.
The human heart is a fascinating organ that many, if given the chance, would love to exam. For most this possibility will never become a reality but for the really curious, there is an adequate substitute. This substitute is the heart of the common cow and can usually be obtained by visiting a local meat market and asking for one.
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