Cardiovascular Pathology Flashcards
What is syncope?
Acute drop in blood pressure
Describe cardiac preload.
- Volume of blood in ventricle at the end of diastole
- Stretching of the ventricles or atria while filling with blood
- Stress on myocardial cells at the end of diastole
- Cells will stretch as pre-load goes up
- Ability of ventricle to distend
- Excess pre-load leads to eccentric hypertrophy
Describe cardiac afterload.
- Resistance left ventricle must overcome to circulate blood (Ventricular wall stress during systole)
- Affected by pressure, radius and wall thicknes
- Proportional to pressure
- Impedance to flow that the ventricle has to overcome
- Greater afterload will create a decreased stroke volume
- Volume of blood in the heart after contraction
- Force that opposes ventricular contraction
- Radius of systemic arterioles are most important factor
- Compensatory response is concentric hypertrophy
- hypertrophic growth of a hollow organ without overall enlargement, in which the walls of the organ are thickened and its capacity or volume is diminished
Describe persistent foramen ovale.
- Causes blood to be shunted from the left atrium to the right atrium
- leads to right atrial dilation and increased right ventricular (RV) preload
- Leads to pulmonary over-perfusion and increased left atrium (LA) dilation
Describe Tetralogy of Fallot
- Ventricular septum defect with turbulence surrounding the right semi-lunar valve
- Pulmonic stenosis and increased RV afterload
- Causes systemic hypoxia because of the reduction in pulmonary diffusion and shunting of deoxygenated right ventricular blood to the left ventricle
- RV hypertrophy
- Dextro-rotated aorta
Describe the changes that occur in the body when blood is shunted from the left of the heart to the right of the heart.
- Leads to pulmonary hyperperfusion
- Can lead to sustained pulmonary hypertension causing vascular changes in the lung and increased resistance leading to shunt reversal and cyanosis (due to lack of oxygenated blood from the LV reaching the systemic circulation)
What does chronic hypertrophy of the heart cause?
Myofibre degeneration and interstitial fibrosis
What is myxomatous degeneration?
Mucopolysaccharide accumulation causing pathological weakening of connective tissue. Common on the mitral valve.
What cardiac condition can occur with Vitamin E/Selenium deficiency?
- White muscle disease
How does feline hyperthyroidism present in the heart?
Concentric left ventricular hypertrophy
How does Hypertrophic cardiomyopathy (HCM) present histilogically?
Myofibre disarray/loss and fibrosis
Describe valvular endocardiosis.
- Epidemiology
- Mostly a canine disease
- Commonly found in Cavalier King Charles Spaniels
- Matrix protein polysaccharides will accumulate on the valve
- Can be evaluated using the Witney Grading System
What is cor pulmonale?
- Primary chronic pulmonary disease
- Pulmonary thromboembolism
- Mechanical vascular obstruction
- Repiratory movement impairment
- Altitude disease
- Pulmonary hypertension due to lack of oxygen in the atmosphere
- Pulmonary oedema occurs as blood gets backed up in the cranial and caudal vena cava so that the fluid moves out into the peripheral tissues
Give some causes of non-infectious inflammation of the heart.
- Type III hypersensitivity
- Purpura haemorrhagica (in horses)
- Mediated by antibody/antigen complexes
- Idiopathic
- Polyarteritis nodosa
- Beagle pain syndrome
What condition can copper deficiency cause in the vascular system?
Aneurysm: an excessive localized swelling of the wall of an artery
