Heart Murmurs: Characteristics, Diagnosis, and Clinical Implications

 

Efficacy

In a quiet room, a murmur can be difficult to hear (grade I) or detectable (grade VI) without a stethoscope. Grade III is a loud murmur without a thrill, whereas grade IV is a similar murmur with a thrill.

Description of Grade

Grade I: In a quiet space, a murmur that may be heard very hard
Grade II: A faint but clearly discernible murmur
Grade III: Loud murmur devoid of excitement
Grade IV: Exuberant, loud murmur
Grade V: Extremely loud murmur that can be heard over the precordium.
Grade VI: Stethoscope-free audible murmur

Location of Highest Intensity

With a few exceptions, a murmur's intensity is highest where it is produced. For example, a murmur of mitral regurgitation is loudest at the apex, while a murmur of tricuspid regurgitation is strongest at the tricuspid area. A murmur's loudness can vary throughout the precordium.

Radiation

Depending on the direction in which blood flows, a murmur may be more audible in one direction outside the precordium. This is known as radiation; for example, aortic stenosis radiates to the neck, pulmonary stenosis radiates to the left shoulder, and mitral regurgitation radiates to the axilla.

Character

While murmurs of regurgitation are typically blowing in character, murmurs of stenosis are typically harsh or coarse.

Pitch

While most murmurs are high pitched, the mitral stenosis murmur is low pitched and best audible with the bell.

The Impact of Breathing

During inspiration, the volume of the right-sided stroke increases, while the left-sided stroke increases during expiration. Right heart murmurs, such as those caused by tricuspid regurgitation or pulmonary stenosis, intensify during inspiration, whereas left heart murmurs, such as those caused by mitral regurgitation, aortic stenosis, or ventricular septal defect, intensify during expiration. Compared to left-sided murmurs, the effect of breathing is more noticeable on right-sided murmurs.

The Impact of Position

While murmurs of pulmonary and aortic regurgitation are best audible when the patient sits up and leans forward, murmurs of mitral stenosis are best heard in the left lateral position.

Rub the Pericardium

Due to the pericardium's two surfaces rubbing against one another as a result of pericarditis, there is a surface scratchy sound that can be heard during both diastole and systole. When the patient leans forward or presses the stethoscope, the sound is most discernible in the left lower sternum and gets louder. When pericardial effusion develops, rub typically goes away.
You should practice focusing on one aspect of the heart cycle at a time in order to develop auscultation. Pleural rub, audible along the left parasternal border, is created if the pleura near the heart becomes inflamed.

When both rubs occur together, the condition is known as a pleuropericardial rub. The pericardial component is induced by the movement of pleural surfaces that have become roughened by heart pulsation, not by pericarditis. Asking the patient to hold their breath allows you to distinguish between these three types of rubs:

• It is pleural if the rub goes away.
• Pericardial rub is when there is no change in the nature of the rub.
• It is pleuropericardial if the rub continues but the character changes.

The Mediastinal Crunch

Air in the mediastinum, such as after heart surgery, is the cause of it. Once heard, the crunching sound with systolic and diastolic components is unforgettably memorable.

Bruit

This sounds like a murmur made outside of the heart (technically, bruit should be used to describe the chronic ductus arteriosus murmur). This could be the result of an artery constricting or an organ receiving an excessive amount of blood flow. Excessive blood flow can manifest as thyroid bruit in hyperthyroidism or hepatic bruit in hepatocellular cancer. Examples of vascular narrowing include renal bruit and carotid bruit in atherosclerosis. Ask the patient to hold their breath as you place the stethoscope's bell along the anterior edge of the sternomastoid in order to check for carotid bruit. While the patient is holding his breath, place the stethoscope's bell on the thyroid enlargement to check for thyroid bruit.

Thyroid bruit

Thyroid bruit is limited to the thyroid enlargement (it may also have a diastolic component), whereas carotid bruit extends along the anterior boundary of the sternomastoid and may even be audible over the orbit. Move the stethoscope gradually towards the collarbone to distinguish between carotid bruit and murmurs emanating from the heart. A bruit will sound less intensely than a murmur, which will also be audible below the clavicle.

Venous Hum

This is a persistent, murmur-like sound that the patient may hear in their neck whether they are sitting, standing, or lying down on pillows. It results from hyperkinetic jugular venous flow or kinking of the major neck veins. By placing the neck above the stethoscope or putting the patient in a horizontal or head-down position, it goes away. It frequently occurs in kids. It is not to be mistaken for a persistent ductus arteriosus murmur.

Symptoms of congenital and rheumatoid heart diseases

The common illness signs are covered in brief below.

• Mitral Stenosis
• Mid-diastolic murmur at apex
• Loud S-wave
• Tapping apex beat
• Diastolic thrill at apex

Opening snap

1. The pulse is low loudness or normal. In the event that atrial fibrillation supervenes, it could be abnormally irregular.
2. Normal blood pressure exists.
3. Apex beat is tapping in character.
4. In the event that pulmonary hypertension has emerged, right ventricular heave is prevalent.
5. The diastolic thrill might be felt at the peak.
6. The first heartbeat is loud.

Mitral Stenosis: Signs and Symptoms Analysis

P₂ that is loud suggests pulmonary hypertension. After S₂, there can be a high-pitched snap that peaks medially to the apex, suggesting that the valve cusps are moving. When the bell is positioned in the left lateral position, the mid-diastolic murmur is most audible. It is confined to the apex and has a low-pitched, gritty, rumbling quality. It might be noisy when it expires. Presystolic accentuation, which is often absent in atrial fibrillation and arises from atrial contraction at the end of diastole, may be audible.

Level of Mitral Stenosis Severity

The more severe the stenosis, the shorter the delay between the opening snap and the second cardiac sound. The stenosis is more severe the longer the mid-diastolic murmur lasts.

Stenosis Tricuspid

• The pulse is regular.
• The tricuspid region may feel the diastolic thrill.
• S₁ (T) tricuspid component is loud.
• You might be able to hear the opening snap.
• The tricuspid region has a mid-diastolic murmur. In comparison to the mitral stenosis murmur, it is rougher and higher pitched. When creativity strikes, it is noisy.
• The 'a' wave is clearly seen in neck veins.

Mitral regurgitation

1. Soft S₁ contraction, heaving apex beat, systolic thrill, and pansystolic murmur spreading to the axilla
2. The pulse is loud or normal.
3. The pressure pulse is broad.
4. It is possible for the apex beat to migrate outward and downward. A poorly sustained heave is audible.
5. At the peak, there could be a noticeable systolic thrill.
6. If there is developed pulmonary hypertension, there is left parasternal heave.
7. The first heartbeat is quiet.
8. P₂ that is loud suggests pulmonary hypertension.
9. At the peak, there is a pansystolic murmur that is at its strongest. It has a high-pitched, blowing characteristic that intensifies with expiration and radiates to the axilla.
10. S₃ might be audible.

Tricuspid regurgitation

1. Loud inspiratory sound; left parasternal heave
2. Systolic thrill at the tricuspid area
3. Normal S₁; Pansystolic murmur at the tricuspid area
4. Systolic wave in neck veins; pulsatile liver
5. If the right ventricle is excessively dilated, the apex beat may move outward.
6. There is right ventricular heave.
7. There could be a noticeable systolic thrill at the tricuspid region.
8. Usually, the first heart sound is normal.
9. If functional tricuspid regurgitation is caused by pulmonary hypertension, then P₃ is loud.
10. At the tricuspid region, there is a pansystolic murmur that is at its strongest. 
11. During inspiration, it is loud, high-pitched, and perfectly in character.
12. S₃ might be audible.
13. Along with pulsatile liver, other symptoms include a significant systolic wave in the neck veins right before the real 'v' wave, which may be felt.

Aortic Stenosis symptoms include

1. Slow rising pulse, heart palpitations, ejection systolic murmur in the aortic area, soft A₂, and ejection systolic murmur radiating to the neck.
2. The pulse is gradual in its rise and loudness.
3. The pulse pressure is limited.
4. There is often well-sustained heave and no movement in the apex beat.
5. There may be a perceptible systolic thrill at the aortic region that travels up the neck (carotid shudder).
6. A₂ is not hard.
7. The aortic region has the highest strength of an ejection systolic murmur. When the patient sits up and leans forward, it is easiest to hear. During expiration, it is loud, harsh, and high pitched, and it radiates to the neck.
8. Maximum intensity of an ejection systolic click may be heard at the aortic region and apex. It is not affected by breathing. It suggests that there is valvular stenosis.