Making a diagnosis Flashcards
Causes of systolic murmurs in horses
Physiological flow murmurs
Mitral insufficiency
Tricuspid insufficiency
Ventricular septal defects
Location of physiological flow murmurs
Loudest cranially on left, LIC4
Timing/intesnsity of physiological flow murmurs
Early to mid systolic
Tend to be low grade
Importance of physiological flow murmurs
None
Important DD for MR
Radiation of physiological flow murmurs
Cranio-dorsal
Mitral insufficiency in horses
Common, second commonest form of VHD
Most common cause of clinical signs of cardiac disease
Murmur of mitral insufficiency
Grade: 1-6
Timing: early, mid, holo, pan-systolic
Shape: band shaped
Loudest: left 5th intercostal space
Radiates: caudodorsally
Signalment for mitral insufficiency
All age groups
Clinical signs of mitral insufficiency in horses
Incidental findings
Poor Performance
Atrial fibrillation
Left-sided failure (Acute onset)
Right-sided failure
Collapse, fainting or sudden death
Mitral insufficiency disease progression
Diastole:
- increased ventricular filling
- loud third heart sound
Systole
- increased ventricular work will increase the regurgitant fraction
- Left atrial enlargement > AF
Can have a very loud 3rd sound as increased ventricular filling
Blood will leak back into lungs leading to pulmonary artery being at point of failure
Right sided heart failure
Prognostic indicators in mitral insufficiency
Loud murmus (grade 3 and above)
Loud 3rd heart sound
Dysrrhythmia (atrial fibrillation)
Congestive heart failure (left or biventricular)
Bacterial endocarditis
Pulmonary hypertension
Left atrial enlargement
Tricuspid insufficiency in horses
May be related to hypertrophy (training)
Generally well tolerated in TB
Less common in other breeds
§ Bacterial endocarditis - secondary to septic jugular thrombosis
§ Dental disease
§ Other causes?
Negative prognostic indicators of tricuspid insufficiency
Loud murmurs (4 and above in TB)
Loud third heart sound
Dysrrhythmia (atrial fibrillation)
Congestive heart failure (right sided)
Bacterial endocarditis
Pulmonary hypertension
Right atrial enlargement
Ventricular septal defects in horses
Common in welsh ponies
Size of defect determines significance - if small can be athletes
Murmur intensity is not a useful guide to severity
Concurrent systolic murmur on LHS (LIC 4)
§ Relative pulmonic stenosis
Often quieter in summer as pony puts on weight
Negative prognostic signs for VSD
Murmur grade not useful
Secondary diastolic murmur
Defect size
Cardiac enlargement
Usually left sided