Defining murmurs Flashcards
Factors involved in the classification of murmurs
Grade/intesity
- poor indication of severity
- Quiet murmurs less likely to be important (not necessarily)
Timing
- systole vs diastole
Radiation
- dorsal or ventral
Point of maximal intensity
- Cranial ICS 4
- Caudal ICS 5
Grade 1 murmur
Quiet murmur often difficult to identify
Grade 2 murmur
Murmur quieter than heart sounds
Grade 3 murmur
Murmur as loud as S1 and S2
Grade 4 murmur
Murmur louder than S1 and S2
Grade 5 murmur
Loud cardiac murmur with a precordial thrill
Can feel it vibrating under fingers
Grade 6 murmur
Murmur audible with stethoscope off thoracic wall
Holo-systolic murmur (or diastolic)
Between cardiac sounds
Lub-shhhhhh.dub
Pan-systolic murmur
Across heart sounds
LShhhhhh…..
Mid-systolic murmur
Lub….Shhhh….dub
What causes heart murmurs in horses?
Normal blood flow - physiological (ejection type) murmurs
Valvular regurgitation
- Valvular disease (endocarditis, endocardiosis)
- Cardiac defects (ventricular septal defects)
Further investigations for heart murmurs in horses
Echocardiography
- Doppler (confirm diagnosis, estimate size of lesion)
- Two dimensional echo (structural pathology, chamber enlargement, estimate size of lesion)
Blood pressure
ECG
- rest (confirm diagnosis)
- Exercise (exercise induced abnormalities, impact on exercise intolerance, predict safety)
Most likely cause of left sided systolic murmur in horses?
Flow murmurs
Mitral valve regurgitation
Most likely cause of right sided systolic murmur in horses?
Tricuspid regurgitation
Ventricular septal defect
Most likely cause of diastolic murmur in horses?
Aortic valve regurgitation
Physiological filling murmur
