Causes of Heart Failure Flashcards
What differentials should you think about if the point of maximal intensity is at the base of the heart (dorsal and cranial)?
Physiological flow murmurs
Aortic/Pulmonic stenosis
PDAs
What differentials should you think about if the point of maximal intensity is at the the apex of the heart (sternum - caudal and ventral)?
Mitral Regurgitation
What differentials should you think about if the point of maximal intensity is at the level of the right ventricle (cranial to left)?
Tricuspid Regurgitation
VSDs
What differentials should you think about in small breed dogs with a left apical murmur?
Mitral Valve Disease
What differentials should you think about in large breed dogs with a left apical murmur?
Dilated Cardiomyopathy but some breeds can also regularly have MMVD (particularly Cocker Spaniel, Labradors, Collies)
In practice, what can you do about a murmur in a puppy or a kitten?
- If loud (grade 3+) more likely to be a congenital anomaly, but loud does not necessarily mean bad (think small VSD)
- If < grade 2 could be innocent – re-assess at 3 and 6 months
- Return to breeder and get money back (rarely done, bond formed)
- Ultimately one can only assess nature and severity of lesion with a full Doppler echocardiogram
How can we identify stage B2 MMVD dogs?
- Likely to be largely asymptomatic – sometimes a degree of exercise intolerance is present; coughing
- Murmur grade correlates well with severity of disease; Patients with grade 1-2 murmurs unlikely to have atrial enlargement
- Presence of sinus arrhythmia also good indicator atrial enlargement is unlikely to be present
- Therefore if murmur grade 3+ in a small breed dog then further investigation warranted to confirm if B2 or not;
- If breed suggests DCM also a possibility (discussed later) then regardless of murmur grade investigation warranted
What are clues to feline heart disease?
- Murmur: unreliable, can be present in healthy cats and not present in cats with severe heart disease – challenging conversation to have with owners
- Gallop rhythm: more reliable indicator
- Arrhythmia: reliable indicator, less common but majority of arrhythmias in cats caused by feline cardiomyopathy
- May be no clues to identify an asymptomatic cat as having heart disease; will often present in heart failure or even as sudden death
- Breed – Maine Coon/Ragdolls, other pedigrees?
- History – exercise intolerance, intermittent dyspnoea, syncope
- Tachycardia – far less reliable in cats than dogs
- Tachypnoea/dyspnoea
What is dilated cardiomyopathy?
- Most common form of myocardial disease in the dog
- Characterised by impaired myocardial contractility with dilation of LV (+/- RV)
- Secondary arrhythmias are common
- DCM is an end stage of many cardiac diseases – primary DCM is a diagnosis of exclusion
What are potential underlying causes of DCM?
- Inherited
- Taurine Deficiency
- Carnitine Deficiency
- Toxic/drugs – eg doxorubicin
- Endocrine – hypothyroidism
- Infectious causes leading to myocarditis - possibly under-recognised
- Persistent tachycardia
- Diet? – gluten free diets
What are the 2 stages of DCM? What clinical signs are associated to the second?
- Occult/Asymptomatic phase: Can be prolonged, difficult to detect – limited clues, early arrhythmia clues – intermittent VPCs etc
- Symptomatic phase: Usually present in CHF◦ Soft left/right apical murmur – enlarged ventricle pulls mitral/tricuspid valve leaflets apart
◦ Weight loss
◦ Sudden death
◦ Lethargy
◦ Exercise Intolerance
◦ Dyspnoea
◦ Symptomatic Arrhythmias
◦ Forward failure: pale mucous membranes, sluggish CRT, cool extremities (bad news)
What are the 2 common presentations of pericardial disease? What history is associated with each?
- Acute cases
◦ Sudden onset exercise intolerance, weakness, collapse, shock, rapid death if untreated - Chronic cases – more common
◦ 2 week history of ascites, progressive exercise intolerance, lethargy, GIT signs, collapse
What clinical signs are associated with pericardial disease?
- Jugular distension
- Positive hepatojugular reflex
- Ascites
- Tachycardia
- Muffled heart sounds
- Weak femoral pulses
- Pale mucous membranes
- Tachypnoea/dyspnoea
- GIT signs
What causes pericardial effusion in dogs and cats?
Pericardial effusion in dogs
* Cardiac neoplasia (most common)
* Haemangiosarcomas
* Heart base tumors
* Mesotheliomas
* Lymphosarcoma
* Idiopathic (haemorrhagic)
* Left atrial rupture
* Coagulopathies, uremic, infection (bacterial and fungal)
Pericardial effusion in cats
* Congestive heart failure, FIP
