ACVIM key terms

Dynamic anterior displacement of the mitral leaflet toward the interventricular septum during systole, which narrows the left ventricular outflow tract and can cause obstruction in cats and dogs with hypertrophic cardiomyopathy.

Primary myocardial disease characterized by concentric left ventricular hypertrophy without an identifiable hemodynamic cause such as hypertension or aortic stenosis; common in cats and often inherited in Maine Coons and Ragdolls.

Impaired ventricular relaxation or compliance during diastole, raising filling pressures at normal volume; assessed echocardiographically by transmitral flow patterns and tissue Doppler velocities.

Increased left atrial dimension or volume, a marker of chronically elevated left-sided filling pressures; predicts congestive heart failure and thromboembolic risk in cardiomyopathies.

Migration of a clot formed in a dilated left atrium (often the auricle) into systemic arteries, most commonly the aortic trifurcation, producing acute hindlimb paresis with cold, pulseless limbs.

Persistence of the fetal ductus arteriosus connecting the descending aorta and main pulmonary artery; causes continuous left-to-right shunting with a machinery murmur and volume overload of the left heart.

Excess pulmonary blood flow from a large left-to-right shunt, which increases pulmonary venous pressure and can produce edema or, chronically, pulmonary arterial changes.

Myocardial disease with systolic dysfunction and chamber dilation in the absence of other causes; in dogs often diet- or taurine-associated or breed-related, and in cats linked to taurine deficiency.

Echocardiographic index of left ventricular systolic function calculated as (end-diastolic dimension minus end-systolic dimension) divided by end-diastolic dimension, expressed as a percentage.

Insufficient dietary taurine, an essential amino acid for cats and conditionally for some dogs, causing dilated cardiomyopathy that may reverse with supplementation.

Diastolic retrograde flow across an incompetent aortic valve, producing a decrescendo diastolic murmur and volume overload of the left ventricle.

Persistently elevated arterial blood pressure causing injury to eyes, kidneys, brain, or heart; retinal detachment, proteinuria, and left ventricular hypertrophy are common consequences in small animals.

Accumulation of fluid in the pericardial sac that can raise intrapericardial pressure and impair diastolic filling, causing cardiac tamponade with pulsus paradoxus and muffled heart sounds.

Hemodynamic compromise from elevated pericardial pressure that limits ventricular filling, producing hypotension, weak pulses, and collapse; treated by pericardiocentesis.

Foregut motility disorder in cattle with reduced abomasal outflow, leading to rumen hypomotility, distension, and chronic bloat; often secondary to vagal nerve injury or abomasal disease.

Reduced frequency or amplitude of ruminal contractions from acidosis, hypocalcemia, vagal injury, or systemic illness, causing anorexia, bloat, and altered fermentation.

Abomasum migrating dorsally and to the left between the rumen and abdominal wall, typically postpartum, producing a ping on simultaneous auscultation and percussion and reduced milk production.

Negative energy balance in early lactation causing excessive fat mobilization and ketone accumulation, with anorexia, decreased milk yield, and ketonuria.

Low blood calcium around calving causing muscle weakness, recumbency, and bloat in dairy cattle; treated with intravenous calcium and monitored for cardiac arrhythmias.

Multifactorial pneumonia of feedlot and dairy calves involving viral and bacterial pathogens plus environmental and management stressors, causing fever, cough, and increased respiratory effort.

Bedside imaging technique using the intercostal windows to detect lung consolidation, pleural effusion, and comet-tail artifacts, useful for diagnosing and monitoring bovine and equine respiratory disease.

Painful inflammation and weakening of the lamellar attachments between hoof wall and distal phalanx, often triggered by endocrine disease or sepsis, causing lameness and potential phalangeal rotation.

Age-related equine disorder with excessive pituitary hormone secretion, causing hirsutism, muscle wasting, laminitis, and insulin dysregulation; diagnosed with resting ACTH or dynamic testing.

Cluster of insulin dysregulation, regional adiposity, and laminitis risk in horses, managed with weight control, exercise, and dietary carbohydrate restriction.

The level of neuronal excitability at which a paroxysmal discharge spreads to produce a clinical seizure; lowered by metabolic derangements, toxins, and structural lesions.

Recurrent unprovoked seizures without an identifiable structural or metabolic cause, commonly diagnosed in young dogs after normal interictal examination and testing.

Continuous seizure activity lasting five minutes or more, or repeated seizures without full recovery, requiring immediate anticonvulsant therapy to prevent neuronal injury.

Barbiturate anticonvulsant that enhances GABA-mediated inhibition; requires monitoring of serum concentrations, liver enzymes, and sedation because of hepatic enzyme induction.

Pressure within the cranial vault; elevation from edema, hemorrhage, or mass causes brain herniation and is managed with hyperosmolar therapy and head elevation.

Displacement of brain tissue through the tentorial notch or foramen magnum due to raised intracranial pressure, producing altered consciousness, pupillary changes, and respiratory compromise.

Loss of conscious awareness of limb position, detected by paw placement and hopping tests, indicating spinal cord or peripheral nerve dysfunction.

Rupture of the annulus fibrosus with herniation of nucleus pulposus into the spinal canal, causing compressive myelopathy with pain, ataxia, or paralysis.

Daily energy needed by a resting animal in a thermoneutral environment, commonly estimated as 70 times body weight in kilograms raised to the 0.75 power.

Daily energy needed to maintain body weight, calculated as a life-stage and activity factor multiplied by the resting energy requirement.

Validated semiquantitative assessment of body fat based on palpation and visual inspection of ribs, spine, and waist, scored on a 1-to-9 or 1-to-5 scale.

Minimum or maximum percentages of crude protein, fat, fiber, and moisture required on pet food labels; not a measure of digestibility or adequacy.

Label statement indicating whether a pet food is complete and balanced by formulation or feeding trial according to Association of American Feed Control Officials profiles.

Most common canine hematopoietic tumor, typically affecting peripheral lymph nodes; classified by immunophenotype and grade, and treated with multiagent chemotherapy.

Minimally invasive sampling of masses or lymph nodes with a small needle to obtain cells for microscopic evaluation; useful for initial diagnosis of round cell tumors.

Elevated blood calcium caused by tumor-derived factors such as PTHrP or osteolytic metastases; lymphoma and anal sac adenocarcinoma are common causes in dogs.

Malignant tumor of the apocrine glands of the anal sacs in dogs, often causing hypercalcemia and metastasis to sublumbar lymph nodes; may present with hypercalcemia before a mass is noticed.

Systematic assessment of primary tumor size, regional lymph node involvement, and distant metastasis to guide prognosis and treatment planning.