Heart murmurs

Outline
I. Basic Pathophysiology
II. Describing murmurs
III. Systolic murmurs
IV. Diastolic murmurs
V. Continuous murmurs
VI. Summary

Basic Pathophysiology
Murmurs = Math
Q = V*A
Q = P/R
NR = d*D*V/n
Therefore:
Inc. P => Inc. V => Inc. NR
Systolic Diastolic

Describing a heart murmur
1. Timing
murmurs are longer than heart sounds
HS can distinguished by simultaneous palpation of the carotid arterial pulse
systolic, diastolic, continuous
2. Shape
crescendo (grows louder), decrescendo, crescendo-decrescendo, plateau
3. Location of maximum intensity
is determined by the site where the murmur originates
e.g. A, P, T, M listening areas

Describing a heart murmur con’t:
4. Radiation
reflects the intensity of the murmur and the direction of blood flow
5. Intensity
graded on a 6 point scale
Grade 1 = very faint
Grade 2 = quiet but heard immediately
Grade 3 = moderately loud
Grade 4 = loud
Grade 5 = heard with stethoscope partly off the chest
Grade 6 = no stethoscope needed
*Note: Thrills are assoc. with murmurs of grades 4 - 6

Describing a heart murmur con’t:
6. Pitch
high, medium, low
7. Quality
blowing, harsh, rumbling, and musical
8. Others:
i. Variation with respiration
Right sided murmurs change more than left sided
ii. Variation with position of the patient
iii. Variation with special maneuvers
Valsalva/Standing => Murmurs decrease in length and intensity
EXCEPT: Hypertrophic cardiomyopathy and Mitral valve prolapse

Systolic Murmurs
Derived from increased turbulence associated with:
1. Increased flow across normal SL valve or into a dilated great vessel
2. Flow across an abnormal SL valve or narrowed ventricular outflow tract - e.g. aortic stenosis
3. Flow across an incompetent AV valve - e.g. mitral regurg.
4. Flow across the interventricular septum

Early Systolic murmurs
1. Acute severe mitral regurgitation
decrescendo murmur
best heard at apical impulse
Caused by:
i. Papillary muscle rupture
ii. Infective endocarditis
iii. Rupture of the chordae tendineae
iv. Blunt chest wall trauma
2. Congenital, small muscular septal defect
3. Tricuspid regurg. with normal PA pressures

Midsystolic (ejection) murmurs
Are the most common kind of heart murmur
Are usually crescendo-decrescendo
They may be:
1. Innocent
common in children and young adults
2. Physiologic
can be detected in hyperdynamic states
e.g. anemia, pregnancy, fever, and hyperthyroidism
3. Pathologic
are secondary to structural CV abnormalities
e.g. Aortic stenosis, Hypertrophic cardiomyopathy, Pulmonic stenosis

Aortic stenosis
Loudest in aortic area; radiates along the carotid arteries
Intensity varies directly with CO
A2 decreases as the stenosis worsens
Other conditions which may mimic the murmur of aortic stenosis w/o obstructing flow:
1. Aortic sclerosis
2. Bicuspid aortic valve
3. Dilated aorta
4. Increased flow across the valve during systole

Hypertrophic cardiomyopathy
Loudest b/t left sternal edge and apex; Grade 2-3/6
Does NOT radiate into neck; carotid upstrokes are brisk and may be bifid
Intensity increases w/ maneuvers that decrease LV volume

Pansystolic (Holosystolic) Murmurs
Are pathologic
Murmur begins immediately with S1 and continues up to S2
1. Mitral valve regurgitation
Loudest at the left ventricular apex
Radiation reflects the direction of the regurgitant jet
i. To the base of the heart = anterosuperior jet (flail posterior leaflet)
ii. To the axilla and back = posterior jet (flail anterior leaflet
Also usually associated with a systolic thrill, a soft S3, and a short diastolic rumbling (best heard in left lateral decubitus
2. Tricuspid valve regurgitation
3. Ventricular septal defect

Diastolic Murmurs
Almost always indicate heart disease
Two basic types:
1. Early decrescendo diastolic murmurs
signify regurgitant flow through an imcompetent semilunar valve
e.g. aortic regurgitation
2. Rumbling diastolic murmurs in mid- or late diastole
suggest stenosis of an AV valve
e.g. mitral stenosis

Aortic Regurgitation
Best heard in the 2nd ICS at the left sternal edge
High pitched, decrescendo
Blowing quality => may be mistaken for breath sounds
Radiation:
i. Left sternal border = assoc. with primary valvular pathology;
ii. Right sternal edge = assoc. w/ primary aortic root pathology
Other associated murmurs:
i. Midsystolic murmur
ii. Austin Flint murmur

Mitral Stenosis
Two components:
1. Middiastolic - during rapid ventricular filling
2. Presystolic - during atrial contraction; therefore, it disappears if atrial fibrillation develops
Is low-pitched and best heard over the apex (w/ the bell)
Little or no radiation
Murmur begins after an Opening Snap; S1 is accentuated

Continuous Murmurs
Begin in systole, peak near s2, and continue into all or part of diastole.
1. Cervical venous hum
Audible in kids; can be abolished by compression over the IJV
2. Mammary souffle
Represents augmented arterial flow through engorged breasts
Becomes audible during late 3rd trimester and lactation
3. Patent Ductus Arteriosus
Has a harsh, machinery-like quality
4. Pericardial friction rub
Has scratchy, scraping quality

Back to the Basics
1. When does it occur - systole or diastole
2. Where is it loudest - A, P, T, M
I. Systolic Murmurs:
1. Aortic stenosis - ejection type
2. Mitral regurgitation - holosystolic
3. Mitral valve prolapse - late systole
II. Diastolic Murmurs:
1. Aortic regurgitation - early diastole
2. Mitral stenosis - mid to late diastole