Cardiac Pathology Flashcards
(38 cards)
What may heart disease be clinically apparent as?
Clinical signs which are predominantly cardiac eg exercise intolerance, syncope.Clinical signs may be related to changes in other organs e.g respiratory distress.
What is the difference between primary and secondary heart disease?
Primary heart disease may have effects on other body organ systems e.g pulmonary oedema. Conversely, in secondary heart failure, systemic organ or peripheral diseases may result in secondary effects on the circulatory system.
Describe what causes increased preload
Conditions which result in an increased volume of blood entering the heart during diastole.
what causes increased afterload?
caused by conditions which increase the resistance against which the heart must pump blood during systole.
What is concentric hypertrophy?
There is an increase in the mass of the ventricle. The walls of which become thicker. There is either no change or a decrease in the end diastolic volume. (chamber volume remains the same) Conditions causing increased after load typically result in concentric hypertrophy.
What is eccentric hypertrophy?
In eccentric hypertrophy there is also an increase in the mass of the ventricle but the wall becomes longer and the chamber dilates resulting in an increase in end diastolic volume. Conditions resulting in increased preload (volume overload) usually result in eccentric hypertrophy.
Describe atrial septal defects of the heart.
This is the result of persistent foramen ovale between the atria. Blood will flow from left atrium to the right atrium and there will be increased preload on the Right heart. There will be RA dilation and increased RV preload - eccentric RV hypertrophy. Increased pulmonary return - LA dilation.
Describe ventricular septal defects of the heart.
Majority of defects situated high up in septum. There are large defects resulting in shunting of blood, usually from left to right with mixing of oxygenated and deoxygenated blood and increased right ventricular preload. RV hypertrophy, pulmonary return increased, LA dilation and increased LV preload, eccentric hypertrophy.
Describe transposition defects of the roots of the great vessels?
Usually the root of the aorta is affected, leading to displacement of the normal position. The commonest scenario is where the aorta is misplaced to lie over the right ventricle.
What is a persistent truncus arteriosus?
failure of normal spiral partitioning of the truncus arteriosus into aorta and pulmonary artery. As a result, a single large artery leaves the base of the heart into which both left and right ventricles empty.
what is semi lunar valve stenosis?
maldevelopment of semi lunar valve endocardial primordia leads to valve cusp distortion and stenosis or formation of a band of muscular or fibrous tissue in the outflow tract beneath the valve. The associated ventricle has marked concentric hypertrophy.
What is a patent ductus arteriosus?
If small, PDAs may be subclinical and cause clinical signs only when the animal is forced to exert itself. Blood flows from the aorta through the PDA to the pulmonary artery. There is increased Right ventricle afterload, > concentric hypertrophy. Pulmonary overperfusion causes increased pulmonary return, LA dilation and LV preload - eccentric hypertrophy.
What is a persistent aortic/branchial arch/ vascular ring anomalie?
Of the six pairs of branchial arches present in the early embryo, normally only the left fourth arch persists as the aortic arch. Constriction of the oesophagus may occur as a result of anomalous vascular rings or associated structures. This results in megaoesophagus.
What is atrioventricular valvular dysplasia?
In this condition the atrio ventricular valves fail to form properly leading to A-V valve regurgitation with cardiac dilation and failure. Left AV valve most commonly affected. There may be web-like valve formations with no clear leaflets. Short chordae tendinae with small papillary muscle masses.
What is hydropericardium?
True serous transudate usually the result of congestive heart failure, commensurate with degree of compensation. May also be seen with neoplasms, anaemia, uraemia, hypoproteinaemia.
What is haemopericardium?
Accumulation of whole blood in the pericardium. Usually associated with rupture of large vessels, or dilated atria due to AV valve regurgitation in dogs. Also seen in RTA, puncture wounds. Death results from cardiac tamponade.
What is pericarditis?
An inflammatory accumulation of fluid within the inelastic pericardium which causes a compressive effect affecting preferentially the thinner walled right side of the heart.
What are the possible sequelae to pericarditis?
Resolution, adhesion - organisation of fibrin following serofibrinous pericarditis, constriction/atrophy - gradual tamponade and cardiac atrophy may occur (constrictive pericarditis), myocarditis - associated with traumatic reticulitis/pericarditis (rare).
What is myocardial dilation?
May occur where the disease process is too rapid to allow cardiac compensation. More commonly it may herald the onset of failure in a previously compensating heart.
What is mulberry heart disease?
Lack of selenium/vitamin E. May be the result of low dietary vit E/se, high levels of polyunsaturated fats in diet or genetic derrangements. Causes necrosis and myocardial haemorrhages resulting from arteriolar fibrinoid necrosis.
What is Malignant Hyperthermia?
A genetic disease due to a point mutation in the skeletal muscle receptor ryr1. Triggered by stress and halothane anaesthesia, results in necrosis of cardiac and skeletal muscle.
What is feline hyperthyroidism?
More common in older cats and is associated with uni /bilateral enlargement of thyroids with accompanying hyperfunction of these. Left ventricular hypertrophy is usual and often striking.
What is dilated cardiomyopathy?
Affected hearts are enlarged with uni or more often bi ventricular dilation - they are pale and flabby.
What is restrictive cardiomyopathy?
Marked myocardial fibrosis or endomyocardial fibrosis of the left ventricular endocardium. There is marked left atrial dilation with a left ventricle of normal dimensions.
