Diseases Of The Cardiovascular System Flashcards
What is heart failure?
When the blood returning to the heart cannot be pumped out at a rate matching the body’s need, heart failure occurs.
Many causes of heart failure exists it depends on the diagnosis and regimens of the animal. The doctor has to determine if it is myocardial dysfunction(pump failure) or circulatory failure ( lack of circulating fluid volume)
What are the disease myocardial dysfunction is seen in?
Cardiomyopathy
Myocarditis
Taurine deficiency in cats
What is circulatory failure a result of?
Hypovolemia( shock,hemorrhage,dehydration)
Anemia
Valvular dysfunction
Congenital shunts or defects
What is congestive heart failure?
The failing heart allows fluid congestion and edema to accumulate in the body. Most heart failure will become congestive as the pump progressively fails. The myocardial cells are striated and involuntary.
What is Canine Dilated Cardiomyopathy?
One of the most commonly acquired cardiovascular diseases of dogs. It’s primarily a disease of older, male,large- and giant breed dogs such as Scottish Deerhounds, Dobermans, Newfoundland, boxers, Irish wolfhounds, st. Bernard’s,Afghans, and old English sheepdogs. Has been seen in cocker spaniels.Rare in dogs weighting less than 12kg
Wat is the pathology of Canine Dilated Cardiomyopathy?
Involves dilation of all chambers of the heart. Caused by weak, thin, and flabby cardiac muscle that results in a decrease in cardiac output and an increase in cardiac afterload where blood left in the heart in diastole. DCM results in impaired systolic function of the ventricles and therefore, decreased stroke volume( volume of blood ejected from the heart with each contraction). The effect on the animal is one of low output circulatory failure exhibited by weakness, exercise intolerance, syncope, or shock. Dogs may experience development of atrial fibrillation that contributes to a decrease I cardiac output.
What are the signs of AF?
Rapid irregular heart rhythms or sudden death. patients may remain normal until the atria dilate excessively. The enlarged atria are unable to contract normally,and clinical signs of heart disease become evident. Signs of this dilation appear to be breed related.
Dobermans- familial related, related to an autosomal demonstrate a genetic predisposition for this disease.
What is Taurine deficiency?
Results in DCM in Cocker spaniels. Appears to be related in cocker spaniels to diets high in lamb meat and rice and low in taurine.
What are the signs of DCM?
Giant or large breed dogs 4-10 years of age.
Right-sided heat failure: ascites, hepatomegaly, weight loss, abdominal distensión
Left-sided heart failure: coughing, pulmonary edema, syncope
Exercise intolerence
Murmur of mitral regurgitation heard best on left chest.
=/- gallop rhythm
+/- tachyrhythm
How do you diagnose DCM?
Radiographs: may be normal early in the disease. May show enlarged heart later in the disease time line; left ventricle enlargement, enlargement of both atria may be visible
Echocardiograph: test choice for examination of the heart; will demonstrate left and right atrial wall atria may be visible.
ECG: may show widened QRS and P waves, rhythm disturbances but is fairly insensitive to changes seen in DCM
Lab tests
How do you treat DCM?
No cure exists for DCM
Diuretics
Enalapril
+/- beta blockers
Pimobendan
What is feline Hypertrophic cardiomyopathy?
Similar to disease in dogs. Left ventricle being hypertrophy in predominant pathology.
Most common in cats.
35% involve HCM. Neutered male cats between 1 and 16 years of age have been found to be most at risk. Most common in Maine coons and ragdoll breeds.
What causes HCM?
May be related to abnormal myocardial myosin or calcium transport within the myocardial cells. Left ventricle becomes thickened and stiff.
As atrial dilates the endothelium lining the chambers is damaged, resulting in the release of clotting enzymes, which can result in clot formation.
Thromboembolism occurs in about 16%- 18% of feline HCM cases.
What are the signs of HCM?
A soft, systolic murmur grade2-3 or 6
Gallop rhythms or other arrhythmias
Acute onset of heart failure or systemic thromboembolism
How do you diagnose HCM?
Radiographs : may show normal size heart or mild left atrial enlargement. May see the valentine heart shape in the dorsoventral view.
ECG
Echocardiology
Biomarkers
How do you treat HCM?
ACE inhibitors
Propranolol
Diliazem
Low dose heparin
Diuretic
What is a Thromboembolism?
Thrombus formation is a common and serious complication of myocardial disease in cats. Estimated the between 10% and 20% of cats with HCM will experience development of thrombi on the left side of the heart, which may dislodge and become trapped elsewhere in the atrial system.
What are the signs of thromboembolism?
Acute onset of rear leg pain and paresis accompanied by vocalization
Cold, bluish foot pads
Lack of palpable pulses in rear limbs
Lack of palpable pulses in rear limbs
History or clinical findings of myocardial disease
How to diagnose thromboembolism?
Clinical signs
No selective angiography if available
How do you treat thromboembolism?
TPA
Heparin
Prophylaxis- low dose aspirin
What is Patent Ductus Arteriosus?
Failure of the ductus arteries is to close after birth results in blood shunting from systemic circulation to the pulmonary artery.
Th increase in oxygen tension in the blood at birth results in closure of the path in the first 12-14 hours of life
What are the signs of PDA?
Usually female dogs are most commonly affected, especially chihuahuas, collies, Maltese, Poodles, Pomeranians
, English springers, keeshonds, bichons frises, and Shetland sheepdogs.
Presence of loud murmur heard best over left thorax
Some puppies may be asymptomatic
How do you diagnose PDA?
ECG
Radiographs
How do you treat PDA?
Surgical duct ligation before 2 years of age
Coil or amplatz embolization
