Characteristics of Heart Murmurs: Nursing Evaluation

Characteristics of Heart Murmurs

 Heart murmurs are defined in terms of location, intensity timing, quality pitch and radiation. These components give the information needed to determine the cause of the murmur and its clinical significance.

Location

Pinpointing the murmur's location helps determine the underlying structures involved in generating the abnormal sounds. The locations are used to identify where the laudest sounds are detected. It is helpful to include in the description the exact location from which the sound emanates, such as the location of the intercostal space and other important landmarks (right or left sternal border: midsternal, anterior axillary, midclavicular or mid-axillary lines). For example, a ventricular septal defect can be located at the left sternal border in the third and fourth intercostal spaces.

Timing

A murmur is defined in terms of when it occurs during the cardiac cycle (systole or diastole). Murmurs are further differentiated by identifying exactly when during systole or diastole they are heard. A skilled clinician can detect that the murmur is occurring during, early, mid, or late systole or diastole. Some murmurs have sounds that occur in both systole and diastole.

Intensity

A grading system is used to describe a murmur's intensity or loudness. 

• Grade 1: very faint and difficult for the inexperienced clinical to hear
• Grade 2: quiet, but readily perceived by the experienced clinician.
• Grade 3: moderately loud.
• Grade 4: loud and may be associated with a thrill.
• Grade 5: very loud; heard when the stethoscope is partially off the chest; associated with a thrill.
• Grade 6: extremely loud; detected with the stethoscope off the chest; associated with a thrill.

Pitch 

Pitch is used to define the sound frequency, identified as high, medium, or low pitched. High-pitched murmurs are heard best with the stethoscope's diaphragm, whereas low-pitched sounds are detecting using the bell of the stethoscope placed lightly on the chest wall.

Quality

Quality is the term used to define the sound that the murmur resembles. Murmurs can produce rumbling, blowing, whistling, harsh, or musical sound. For example, murmurs caused by mitral or tricuspid regurgitation have a blowing quality, whereas mitral stenosis generates a rumbling sound.

Radiation

Radiation indicates the transmission of the murmur from maximal intensity to other areas in the upper chest. The examiner determines if radiation is present by listening carefully to areas of the heart adjacent to the point where the murmur is the loudest. If radiation is present, the exact location is described. A murmur associated with aortic stenosis, for example, can radiate into the neck, down the left sternal border, and into the apical area.