5. Heart Sounds Flashcards

Flashcards covering normal and abnormal heart sounds, murmurs, and related cardiac conditions.

S1 Heart Sound (Lub)

Caused by AV valve closure. High frequency normal heart sound, caused by vibrations within the ventricles.

S2 Heart Sound (Dub)

Caused by Semi-lunar valve closure. High frequency normal heart sound, caused by vibrations within the ventricles.

S3 Heart Sound

Rapid diastolic filling of ventricle. Abnormal in dogs and rarely heard in normal cats. Can be heard in larger animals (gallop rhythm).

S4 Heart Sound

Atrial contraction. Abnormal in dogs and rarely heard in normal cats. Can be heard in larger animals (gallop rhythm).

Murmurs

Sounds created by turbulent blood flow which may be high velocity, caused by an obstruction, or low viscosity.

Physiologic Murmur

Ejection (flow) murmur, can be due to anemia, fever, or found in young animals. Low intensity, high frequency, early systolic murmurs.

Pathologic Murmur

Due to valvular regurgitation, stenosis, or congenital defects.

Stenosis

Narrowing of passage or opening.

Holosystolic Murmur

Occurs immediately after S1 until S2.

Pansystolic Murmur

Occurs immediately at the onset of S1 and through S2.

Diastolic Murmur

Start after S2 and continue through diastole.

Continuous Murmur

Throughout systole and diastole.

Patent Ductus Arteriosus

Continuous murmur where it is often difficult to hear the lub-dub sound. Persistent fetal circulation due to the ductus arteriosus not closing after birth - type of cardiac malformation.