Radiology2- Acquired Heart Disease

• degenerative valvular disease/ endocardiosis/ myxomatous degenerative disease
• mitral valve most commonly affected
• most common cause of heart failure in dogs (ESP SMALL BREEDS)
• gradual malformation of valves and retrograde flow of blood

• proportion of flow directed to aorta from LV is regurgitated into the LA
• slowly progressive over months to years, eccentric myocardial hypertrophy to accommodate blood volume
• dilation of valvular annulus
• LA may get giant before heart failure
• once heart failure, pulmonary edema d/t vascular congestion with increased hydrostatic pressure and decreased lymphatic drainage

• LA enlargement (soft tissue opacity at 12-2 on lateral; increased soft tissue opacity caudal to tracheal bifurcation on VD)
• LV enlargement (increased length from base to apex; dorsal deviation of trachea)
• +/- left auricular enlargement (on VD, soft tissue bulge at 2-3 position)

• heart can no longer keep up with metabolic demand or only able to when pressures are elevated
• high cardiac filling--> venous congestion and fluid accumulation (congestive heart failure)

systole (poor pumping); diastole (inadequate filling)

• initiating insult (occult heart disease)
• compensation (clinically silent)
• onset of clinical CHF

structural changes: elongated chordae tendineae, enlarged/ thickened leaflets--> poor apposition of leaflets (insufficient)--> decreased forward flow (stroke volume)--> compensates by increased preload--> atrial regurgitant volume complies for volume--> pulmonary vascular congestion--> increased hydrostatic pressures--> interstitial pulmonary edema +/- pleural effusion

• myocardial remodeling--> eccentric and/or concentric hypertrophy--> eventual inflammation/ fibrosis
• myocardial oxygen demands change and signals from remodeling initiate cascade of signaling for water homeostasis
• increased sympathetic tone, attenuated vagal tone, activated RAAS, and release of ADH--> overcome initial hypotension/ hypovolemia--> long term, MAL-ADAPTIVE
• sympathetic tone--> NE release
• Ang II generated by RAAS--> vasoconstriction and sodium/ water retention

• retention of fluid with ventricular failure--> back flow resulting in accumulation of fluid in inappropriate locations
• left sided failure: pulmonary venous congestion and pulmonary edema
• right sided failure (or bi-ventricular): pleural effusion and/ or peritoneal effusion

• dogs: pleural effusion is a manifestation of right-sided heart failure
• cats: pleural effusion may be due to left- or right-sded hear failure

accumulation of fluid in the interstitium and alveoli, disrupting diffusion of oxygen--> hypoxemia

unstructured interstitial pattern or alveolar pattern

mitral valve disease,cardiomyopathy, left-to-right shunting

• pulmonary edema (unstructured interstitial or alveolar pattern)
• pulmonary veins are larger than pulmonary arteries, blurring of vessels
• +/- enlarged left heart (increased base-apex length on lateral; D shape)

• Endocardiosis: peri-hilar regions most affected, peripheral lungs may be unaffected
• DCM: variable, peri-hilar or patchy lobar or peripheral
• Cats: inconsistent pattern, may also include pleural effusion

• decreased venous return to the heart with systemic accumulation of fluid
• distension of CVC (CVC: aorta ratio of 1.5 is very suggestive)
• hepatomegaly d/t increased central venous pressure--> passive venous congestion
• ascites- loss of serosal detail
• +/- pleural effusion (more common in cats)
• eventually peripheral pitting edema

• heartworm disease
• pulmonic stenosis
• tricuspid dysplasia

• heartworm disease
• enlargement and failure of the right ventricle as a response to increased vascular resistance or high blood pressure in the lungs

• pulmonary artery/ trunk
• right ventricle

space occupying, obstructive disease--> non-laminar, turbulent blood flow--> vascular intima layer roughened and hypertrophies--> more non-lmainar flow

• RV enlargement (reverse D)
• dilation of pulmonary trunk (1-2 o'clock on VD)
• large tortuous pulmonary arteries
• interstitial (structured to unstructured) to alveolar pattern (eosinophilic pneumonitis)
• hepatomegaly, ascites, caval dilation (caval syndrome, later consequence)

• Dogs: DCM most common, ARVC, hypertrophic CM
• Cats: HCM, restrictive CM, unclassified CM, DCM (acquired- taurine deficiency)

• Doberman
• Boxer
• American Cocker Spaniel
• Labs
• [genetic correlation]

• impaired cardiac contractility
• eccentric myocardial hypertrophy
• dilation of LA and LV +/- right chambers
• progression to left-sided and/or right-sided CHF

systolic dysfunction and atrial fibrillation

• left atrial and ventricular enlargement
• generalized cardiomegaly
• enlarged pulmonary veins
• interstitial to alveolar pulmonary pattern
• pleural effusion +/- peritoneal effusion

• myofiber atrophy, fibrosis, and fatty infiltration
• focal areas od myocytolysis, necrosis, hemorrhage, and monocellular infiltrate
• ventricular tachyarrhythmias, syncope or weakened states, poor myocardial function and CHF

• radiographs are frequently normal
• ventricular ectopy detected with 24-hr holter monitor

• Doxorubicin- chemo, induces acute and chronic cardiotoxicity
• L-carnitine-linked defects
• Taurine deficiency

• large amount causes rounded, "globoid" appearance to cardiac silhouette
• generalized cardiomegaly with no specific chamber dilation
• cardiac tamponade and right-sided heart failure (b/c RV is thinner walled and more easily compressed)

• Neoplasia- RA and heart base tumors
• Inflammation- pericarditis
• Traumatic- ruptured cardiac chamber
• Congenital- peritoneal-pericardial diaphragmatic hernia
• Idiopathic

• failure of closure of the septum transversum (persistent dorsal mesothelial remnant on rads)
• communication b/w the cranioventral peritoneum and pericardial sac
• may or may not develop clinical signs

• persistant dorsal mesothelial remnant
• space-occupying mass within pericardium
• cardiac tamponade

• falciform fat in cats
• liver in dogs
• also stomach, intestine, spleen

• chemodectoma (brachy breeds)
• ectopic thyroid/ parathyroid carcinoma
• thymoma
• hemangiosarcoma
• abscess
• granuloma

• bacteremia is a pre-requisite
• infections of skin, mouth, urinary tract, prostate, lungs

• endothelial damage, non-laminar turbulent blood flow, immune response, bacterial virulence
• established pathology sites of infection
• non-bacterial thromboembolic endocarditis, accumulation of fibrin and platelets

• no specific radiographic changes, may be normal
• Dx with blood cultures and echo

• absolute or relative
• relative= hyperinflation of the lungs, emphysema or hyperventilation
• absolute= hypovolemia (blood loss, shock, severe dehydration), atrophic myopathy, enocrinopathy (cushings)