Pearls of Knowledge: Detecting Murmurs

Advanced Heart Sounds: Detecting Murmurs

Pearls of Knowledge          © BrainyNurses.com 

To elevate clinical practice, health care professionals should be listening to all four areas of the heart valves during an assessment. 

In acute conditions, listening to heart sound is very important on presentation and then with subsequent assessments. If heart sounds change, it generally signifies a deterioration in condition such as ischemia or infarction (especially with inferior wall), or rupture of a papillary muscle, or the perforation of the intraventricular septum due to scar tissue.

Four areas of the valves to listen to:

• Aortic: 2^nd ICS, right sternal border
• Pulmonic: 2^nd ICS, left sternal border
• Tricuspid: 4^th ICS, left sternal border
• Mitral: 5^th ICS, left midclavicular line under the breast

Murmurs may be innocent or benign, all of which will be systolic murmurs.

• Innocent murmurs are heard in children, adolescents, and young adults. They are best heard when lying flat and disappear when sitting or standing.
• Benign murmurs are heard in high output states such as fever, exercise, pregnancy, anemia, and thyrotoxicosis. 

Terms associated with murmurs 

Murmurs are classified and described with the following terms.

• Timing is systolic or diastolic and may be early, late, mid-cycle, or “holo” when it is heard throughout. 

• Pitch will be high, medium, or low. 

• Intensity is graded from I (barely audible) to VI (can be heard without a stethoscope). 

• Pattern can be crescendo or decrescendo. 

• Quality can be harsh, raspy, vibratory, musical, or blowing. 

• Location is the anatomical landmark(s) where the murmur is heard. 

• Radiation can be to various structures such as the axilla or neck. 

• Thrill which feels like a cat burring on the skin surface is associated with grade IV-VI murmurs.

Murmurs in valvular dysfunction 

Murmurs are often due to valvular dysfunction. In regurgitation, the valve is incompetent. In stenosis, damage to the valve results in the need for higher pressures to open them. Often a “click” will be heard as the valve snaps open. Dysfunction is frequently due to heart failure, myocardia ischemia or infarction, rheumatic fever, and congenital abnormalities. 

Murmurs can be systolic or diastolic murmurs. Review this table, which is a good way to remember the type of murmur, where it is heard, and the associated pathology.

Some medical professionals feel like they want to “listen” to audio recordings of heart murmurs. While this may be beneficial, it is difficult to translate what you heard on a demo into clinical practice. Instead, try listening for “sounds” in words to describe what the murmurs should sound like. 

• Systolic murmurs will sound like “Swish-Dub” and are heard the most frequently. 

• Diastolic murmurs will sound like “Lub-Swish-Dub”.- 

• Mitral valve prolapse will sound like “Lub-Click-Swish-Dub”.

Common types of valvular dysfunction 

Mitral regurgitation

• One of the most common murmurs heard.
• Frequently seen in left ventricular failure and left ventricular infarction.
• May be transient in myocardial ischemia, especially inferior wall involvement.
• Results in a narrow pulse pressure.
• Loud holosystolic murmur heard best in the left lateral position.
• Radiates to the axilla. 

Tricuspid regurgitation

• Frequently seen in right ventricular failure and right ventricular infarction.
• May be transient in right ventricular ischemia and cardiac contusion.
• High pitched and blowing systolic murmur which may radiate. 

Aortic regurgitation

• Results in a widened pulse pressure.
• Water--hammer pulse will be present (strong, then falls quickly).
• Heard in dissecting aortic aneurysm.
• Low pitched early diastolic murmur heard best while leaning forward. 

Aortic stenosis

• Seen the most often in the elderly.
• Loud midsystolic to late murmur heard best while leaning forward.
• Radiates to the neck.
• In hypertrophic cardiomyopathy, the murmur will decrease in a squatting position. 

Septal defects

• May be atrial or ventricular.
• Ventricular septal defect has a loud, prolonged systolic
• Atrial septal defect murmur is more difficult to hear and fixed splitting of A₂ and P₂ is present on inhalation and exhalation. 

Uncommon types of valvular dysfunction 

Mitral and tricuspid stenosis

• Associated with rheumatic fever.
• Heard best in the left lateral position.
• Low pitched diastolic murmur which is best heard with the bell of the stethoscope. 

Pulmonic stenosis and regurgitation

• Most often due to congenital disorders.
• Loud midsystolic to late murmur with stenosis.
• Low pitched, early diastolic murmur with regurgitation. 

Summary 

So, the next time you are doing an assessment, incorporate into your practice the habit of listening to all four areas of the valves. 

• Repeat the “All Providers Take Money” pneumonic to know what valves you are hearing. 

• Recognize some of the characteristics of murmurs, such as timing (which is the most important), pitch, quality, and radiation. (And no, you do not need to be a cardiologist! 😊) 

• Recognize systolic (“Swish-Dub”) murmurs
  • Mitral and tricuspid regurgitation
  • Aortic and pulmonic stenosis
  • Ventricular septal defect
  • Innocent (e.g., in children) or benign (e.g., anemia or pregnancy). 

• Recognize diastolic (“Lub-Swish-Dub”) murmurs
  • Always pathological
  • Mitral and tricuspid stenosis
  • Aortic and pulmonic regurgitation 

• Recognize mitral valve prolapse
  • Systolic murmur
  • “Lub-Click-Swish-Dub” 

• Recognize septal defects
  • Ventricular has a loud, prolonged systolic murmur and the patient will (generally) have a history of a previous myocardial infarction involving the anteroseptal wall. 
  • Atrial is more difficult to hear and is usually associated with a congenital defect unless it is surgically created in severe pulmonary hypertension in an effort offset the desaturation of the blood that bypassed the lungs.