Please enable JavaScript.
Coggle requires JavaScript to display documents.
Cardiology, Result of:
Ischemia, exertion--> Heart failure…
-
Result of:
- Ischemia, exertion--> Heart failure (overworked & myocytes die)
- Nutritional--> white muscle disease
- Toxic: Monensin, box elder in horses & other toxins
-
- Endocardial & Epicardial Hemorrhages
- Valvular hemocysts
- Blood clots in cardiac ventricles
- Gritty white material (euth drugs)
Disease of the heart muscle (myocardium)
Primary: either idiopathic or genetic cause
Secondary: caused by something outside myocardium: hyperthyro, nutrition, hypertension, heart failure
- Bacterial infection of heart valve
- From bacteria in blood that has colonized the heart and valve is damaged from everyday wear & tear or from turbulent flow
- Focal thickening, white, rough, dull surface bc inflammation destroyed epithelium
Sequelae:
- Heart failure due to valvular incompetence
- Thromboembolism to the lungs
- Bacteremia/septicemia --> polyarthritis, lesions/infarcts in organs --> aortic endocarditis (thrombo to aortic bifurcation)
- Degenerative Lesion
- Degeneration of heart valve over many years
- Small dogs
- Most commonly left AV valve--> myxomatous mitral valve disease
- Usually slow, but can rapidly cause death
- Nodular thickening of AV valves but with smooth, shiny surface
3 reasons for acute exacerbation with chronic heart failure:
- Chordae tendonae can rupture
- Myocardial ischemia --> reduced cardiac output--> necrosis
- Left atrial rupture due to distention --> hemopericardium
Sequelae:
- Jet Lesions: from the regurgitation of blood flow from ventricle to atrium during systole, hitting the atrial endocardium
Heart Failure:
- Decreased CO: myocardial ischemia, hypoxia, edema
- Increased venous hydrostatic pressure because cannot move venous blood forward
Left Sided CHF: Pulmonary edema, Hydrothorax (cats), hemosideran-laden alveolar macros (heart failure cells)
Right Sided CHF: Ascites, hepatomegaly, nutmeg liver (cows and dogs), Hydrothorax (cats) Compensation: inefficient, increases work for myocardium, decreases time for filling, reduces myocardial perfusionDecompensation: may lead to myocardial ischemia due to decreased contractility, dilation of ventricle, venous congestion & edema
Myocardium cannot contract--> dilates, from: unknown, volume overload (MMVD, PDA, VSD), necrosis & inflammation
Ventricle gets too much blood--> dilates --> eccentric hypertrophy --> mass and lumen dilates
-Diastole failure, cannot fill properly during diastole
- Common in cats: get left atrial dilation if developing heart failure. Some cats get turbulent flow leading to thrombosis and embolism to aortic-iliac bifurcation causing pain & paresis
Lesion: hypertrophy of ventricle (usually left!) with small lumen (looks like concentric hypertrophy) LV: RV= 4:1Histo: myocardial fibrosis, disarray of myofibres, replacement of myofibres by fatSequelae: Unpredictable
- Sudden death
- Arrhythmia
- CHF
- Syncope (reduced CO)
Eccentric: volume overload--> mass increases & lumen dilates. Caused by: VSD, leaky valves Concentric: pressure overload (NO increase in blood volume)--> increased mass & decreased lumen. Most common cause: Subaortic stenosis (SAS) b/c has to work hard to push blood past the stenotic outflow tract. Other causes: PS, Pulmonary hypertension, pheochromocytoma--> systemic hypertension, hyperthyroSequelae:
- Inadequate perfusion of myocardium
- Increased myocardial oxygen consumption
- Compromised blood flow--> inefficient tubular flow --> increased work again--> ischemic necrosis of myofibres & ventricular dilation
- Rare, occ in cats
- Myocardial fibrosis or endocardial fibrosis restrict heart from filling during diastole (like HCM but not concentric)
Systolic failure: heart cannot contract properly during systole Lesion: globular heart, dilation affects usually both atria and ventricles, walls are thinnedIf all 4 chambers dilated think extrinsic (Secondary) cause:
- Failure of myocardium to contract from myocardial necrosis (monensin tox), or infection causing myocarditis and volume overload
- Volume overload on all 4 from: endocardiosis (incompetence of AV valves)
Primary: cannot find a cause, intrinsic to myocardium (predisposed breeds). Cats are usually primary (but can get secondary from deficiency in taurine & carnitine) Predisposed dogs: Dobes, giants (wolfhound, dane, newf), english cockers
- Idiopathic- thinks Boxers!
- Sudden death to arrhythmia, syncope, or CHF
- Lesion: dilation of RV, but some may appear grossly normal!
- Histo: replacement of myocytes with adipocytes & fibrosu tissue
- Young ruminants
- Cause: nutritional deficiency of Vitamin E/ Selenium or from excessive intake of oxidized fatty acids
Lesion: Myocardial/skeletal muscle necrosis, mineralization (white and gritty)Histo: Pulmonary edema= cause of death then
-
-
-
- Common cause of myocarditis in feedlot cattle
- Acute onset of L sided heart failure from bacteremia--> vasculitis-->infarction
Lesion: focal coagulation necrosis or abscess in LV papillary muscle with pulmonary edema
Excessive clear fluid in the pericardial sac, doesn't usually impair function unless accumulates fast
Caused by: CHF, hypoproteinemia
Accumulation of blood in pericardial sac Caused by:
- Rupture of right atrial hemangio., ruptured left atrium secondary to MMVD or rupture of aorta in horses (racing)
- Anticoagulant rodenticide toxicity
- Trauma
Leads to: Cardiac tamponade and right sided CHF
Inflammation of pericardium caused by bacteria which enters by:
- Blood-borne: E.coli in neonates, streptococcus suis or Glasser's disease (hemophilus parasuis) in pigs/piglets, blackleg in cattle (Often Combined with: pleuritis, peritonitis, polyarthritis, meningitis)
- Penetrating injury --> fibrosis and tamponade
- Extension from an adjacent lesion (myocardial abscess inducing massive pericarditis)
- M1 fibronous pericarditis occurs with many blackleg cases in cattle (clostridium chauvoei)
- Serous atrophy of fat: normally the epicardium contains gat in coronary groove but chronic disease and starvation causes fat stores to be metabolized and remaining protein has gelatinous appearance
- Epicardial petechiae: a few can be normal, but many suggests sepsis (horse with colitis)