HEART MURMURS

Are sounds produced by turbulent flow generated by the passage of blood in narrow areas (strictures) in hyperdynamic conditions (anemia, thyrotoxicosis, pregnancy, etc.) Blood reflux in incompetent valves, abnormal communications (eg.: septal defect, persistent arterial duct). There are murmurs that are heard in systole and others, in diastole. Although most murmurs represent any organic disorder, there are some, especially in children and young adults, who are considered functional, and no great importance. These are called innocent murmurs which are characterized by occurring in systole, ejection rate are not giving thrills, never occur in diastole and not associated with an organic disorder.
 
Features blows where it should be fixed:

• If it occurs in systole, in diastole, or both phases of the cardiac cycle.
• The moment occurs. Prefixes are used proto, meso and television to describe murmurs that occur mainly at the beginning, middle or end of systole and diastole, respectively (eg midsystolic, if it occurs in half of systole; protodiastolic, if it occurs at the beginning of diastole).
• His relationship with the heart sounds (eg, the murmur of mitral stenosis begins with the opening snap, and the murmur of aortic stenosis, you can start by clicking the aorta, "which is not always audible, and that occurs after the first sound).
• The intensity of sound. To evaluate this aspect, there is a scale of 6 degrees or levels. The intensity of the murmur is expressed as a ratio where the numerator is indicated which corresponds to the breath and the denominator of the full scale value (eg, murmur grade 2 / 6). These intensity levels are:
• Grade I: When it is difficult to hear in a quiet room (even, it is possible that not all reviewers will listen).
• Grade II. Weak, but all the auscultated examiners.
• Grade III. Moderately strong, clearly audible.
• Grade IV. Strong, began to be felt a thrill.
• Grade V. Very strong and thrill.
• Grade VI. Very strong, can be heard even without supporting the diaphragm of the stethoscope on the surface of the chest palpable thrill.
• The shape of the breath:  in decrescendo, holosystolic, continuous.
• The ejection murmur occurring in systole and depend on the pressure gradient generated by the contraction of the myocardium, have a diamond shape: it increases to a maximum and then decrease.
• Regurgitation murmurs of incompetence of atrioventricular valve begins with the noise, remain relatively constant throughout systole and reach the second sound, or even what encompass, are called holosystolic or pansystolic.
• Regurgitant murmurs of aortic valve incompetence or lung, occurs in diastole, beginning immediately after the second noise and decrease in intensity until it disappeared (in decrescendo).
• Murmurs due to stenosis of the mitral or tricuspid valve, occurs in diastole, after opening the valve (opening snap), and decreases in intensity until it disappeared (in decrescendo). If the patient is in sinus rhythm at the end of diastole and immediately before the first noise may be heard a brief crescendo murmur due to atrial contraction (booster presystolic).
• The focus where it listens more intense irradiation.
• If you change with respiration or with some maneuvers such as straining, exercise, push or squatting (eg: a tricuspid regurgitation murmur increases with inspiration more blood to the right cavities).
• The pitch of sound: high, medium, low. The low key blows are heard best with the bell of the stethoscope.
• The ring also may be different, with some rough character, grunts, music, etc.

 
Characteristics of blows, with particular reference to whether they occur on the systole or diastole:

Murmurs that occur in systole:

Mid-systolic murmurs or ejection type:

Murmurs are most frequently found. These are people whose intensity is greater in the middle of systole, and usually end before the second noise (R _2). Its diamond-shaped (crescendo-decrescendo) is not always obvious and the space between the end of the blow and R ₂ helps to differentiate the holosystolic (or pansystolic).

• Innocent murmurs: Are due to the ejection of blood from the left ventricle to the aorta. Occasionally may be generated by right ventricular ejection. Not associated with cardiovascular disease. Are more frequently found in children, young adults and older adults occasionally. Heard in the 2 nd, 3 rd and 4 th intercostal space between the sternum and the apex, are mild and short-irradiation.

• Physiological murmurs: Are due to turbulent flows that originate on a temporary basis and are in anemia, pregnancy, fever, and hyperthyroidism. Closely resemble innocent murmurs. Are identified by the basic condition to which they are associated.

• Aortic ejection murmur: Heard best at the base, especially in the second space parasternal right, but also in the left sternal border and apex. Radiate to the base of the neck. Could hear better with the patient sitting and leaning forward. May be preceded by a click of the valve opening, which is not always heard. Found in aortic stenosis (congenital, rheumatic, degenerative), narrowing the outflow tract (eg hypertrophic cardiomyopathy), dilated distal aorta, or increased flow in systole as in aortic insufficiency. Most murmurs are innocent and physiological aortic ejection rate but try not to associate separate cardiovascular disease. When the murmur is heard best at the apex, you should be careful not to be confused with a murmur of mitral regurgitation.

 

• Pulmonary ejection murmur: Heard best in the 2 nd and 3 ^rd left parasternal space. If it is strong, it can radiate to the left neck. Found in pulmonary valve stenosis (more common in children and cause congenital) and pulmonary hypertension. An increase in flow can also cause this breath, as in an atrial septal defect (in this condition, the mid-systolic murmur is due to increased flow through the pulmonary valve and not the flow through the atrial septal defect).

• Pansystolic or holosystolic murmurs: These are people dealing with the systole, beginning immediately after the first sound (S ₁₎ and continue until the second sound (S _2), maintaining a fairly uniform intensity.

• Murmurs of mitral regurgitation:  Are due to an incompetent valve (mitral regurgitation). Heard best at the apex and radiated to the axilla, occasionally radiating to the left sternal border. Can be heard better in the left semi-lateral decubitus. Not increase with inspiration. On occasions, such as mitral regurgitation due to ruptured chordae, irradiation can occur around the base of the heart and tend to be confused with murmurs of aortic stenosis. The first sound is diminished.

• Murmurs of tricuspid regurgitation: Are heard when the valve is incompetent (tricuspid regurgitation). The most common cause is failure and dilated right ventricle, which may be secondary to pulmonary hypertension, which in turn can lead to left ventricular failure. Are holosystolic murmur that increases with deep inspiration. Are best heard in left lower sternal border. Radiating to the right of the sternum, and perhaps somewhat to the left, but did not radiate to the axilla. Unlike mitral regurgitation in tricuspid regurgitation following occurs:
• The murmur increases with inspiration.
• there is a wave "v" giant in the jugular venous pulse.
• liver could be a heartbeat it's like to feel the bottom edge of the liver (not to be confused with a hepato-jugular reflux is increased jugular venous distension to apply pressure to the edge of the liver that can be seen in congestive pictures) 

• Holosystolic murmur due to a ventricular septal defect (VSD): The manifestations depend on the size of the communication. Whereas an injury that is not associated with other abnormalities, with a short left to right, you can sound out a holosystolic murmur that is high intensity and produces a thrill. The second sound may be obscured by the intensity of the murmur. Heard best in the 3, 4 and 5 left parasternal area, but has extensive irradiation. In diastole, you can hear a third sound or murmur decrescendo.

Murmurs by a prolapse of the mitral valve: Are end-systolic (occurring in the second half of systole) and may be preceded by a mid-systolic click. They are difficult to auscultate. Sometimes found in patients with pectum excavatum.

Murmurs that occur during diastole:

• Murmurs of aortic valve insufficiency: Begin after the second sound and its intensity is in decrescendo and disappear. Are heard at the base, left sternal border and even at the apex. Are best heard with the patient sitting, leaning forward and exhalation, without breathing for a few seconds. Are heard with the stethoscope diaphragm. To recognize it should be noted other manifestations that can occur:
  • pulse speed or water hammer, is a comprehensive and hyperdynamic pulse.
  • other characteristic of water hammer pulse is that if the examiner takes the patient's forearm using surface feel of his fingers over radial pulse area, near the wrist and forearm up from the horizontal position, you will feel the pulse more widely.
  • in the nail bed may notice a beat when you apply light pressure from the edge of nail.
  • head may have a slight oscillation following the pulse rate.
  • noticeable in the neck large beats (dance arterial).
  • arterial pulse pressure is increased (difference between systolic and diastolic) pressure is slightly increased systolic and diastolic presents a significant decline.
  • in the groin area could hear a double blow femoral (systole - diastole).

In the case of a severe leak can cause a rise of anterior leaflet of the mitral valve and cause a functional stenosis able to take a breath and rolled mitral (Austin Flint murmur), which is heard at the apex and towards the armpit, left semi-lateral decubitus. On the effect of aortic reflux on the mitral valve leaflets, preventing maximum aperture, the first noise could be decreased. Another blow that can be generated secondarily by the increased flow rate is for mid-systolic aortic ejection.

• Murmurs and insufficiency of the pulmonary valve: Begin after the second sound and are in decrescendo. Occur in conditions associated with pulmonary hypertension (Graham Steell breath).

• Murmurs of mitral stenosis: Begin with the opening snap. It has two components: an initial decrescendo murmur (mitral shot), which corresponds to the rapid filling phase, and a presystolic reinforcement in crescendo, which is due to atrial contraction, and that is lost when there is atrial fibrillation. Are heard at the apex, especially in the left semi-lateral decubitus with the patient during expiration. Could be heard best with bell of stethoscope. The first sound is more intense . For the congestion that occurs toward the back of the valve, P ₂ is more intense and the split second sound is heard, the right ventricle can become palpable. The arterial pulse is of low amplitude. When the mitral murmur is caused by inflammation of the valve leaflets by an active rheumatic disease called Carey-Coombs.

• Tricuspid stenosis murmurs: Have characteristics similar to what happens in mitral stenosis, but are unlikely to be found. It is better to auscultate tricuspid focus. In an atrial septal defect murmur can be heard with these features by increasing flow through the valve.

Other heart murmurs:

• In a persistent arterial duct: It is a communication between the aorta and pulmonary artery flow increases at the lungs and left heart. You hear a continuous murmur, which covers the systole and most of diastole (machinery murmur). Is more intense toward the second sound, coming to hide. Is heard in the left second intercostal space, below the collarbone, and may be accompanied by a thrill.

• In an atrial septal defect (ASD): Is associated with a left to right shunt. In systole can be listening to a pulmonary ejection systolic murmur and the diastolic one shot by increased flow through the tricuspid valve.

 
 Tricuspid stenosis: Is usually rheumatic in origin and is associated with mitral stenosis is most evident when listening. What would be more characteristic of tricuspid stenosis is an engorgement of the jugular veins, wave "a" giant. The opening snap and diastolic ferries tend to be obscured by the noise equivalent due to mitral stenosis. 




Pulmonary stenosis: Is the heartbeat of the right ventricle is heard sustained a pulmonary ejection systolic murmur. There could be a wave "to" increased in the jugular venous pulse. Could also be listening to a pulmonary ejection click and a splitting of second sound.




Coarctation of the aorta: Is characterized by stenosis usually is after the origin of the subclavian vein. To proximal collateral circulation develops that tends to compensate for the lower distal flow exists. Hypertension was found in the upper extremities and hypotension in the lower, is also perceived difference in pulse amplitude (the small palpable femoral). In the interscapular region can be listening to a late systolic murmur.

Some special maneuvers:
To differentiate the murmur of aortic stenosis with a hypertrophic cardiomyopathy patient is asked to bear down (Valsalva maneuver) so that the amount of blood reaching the left ventricle decreases, the murmur of aortic stenosis and decreases of cardiomyopathy hypertrophic increases. For the same purpose, if the patient is placed in a squatting position, venous return and blood flow to the ventricles increases, the murmur of aortic stenosis increases and decreases of hypertrophic cardiomyopathy.