Cardiovascular Pathology Flashcards
pericardium Function
maintains hert position
Anchors Heart in mediastinum
Protect against acute ventricular dilation
Facilitation of ventrical interdependence
NOT essential for normal cardiac function
coronary ateries
originate form left and right semilunar valvula of the aortic valve
Valves
aortic and mitral left and right coronary arteries.
Heart:
Epicardial Hemorrhage
Frequently seen in large animals and often considered an agonal or perimortem finding
If other portions are affected by hemorrhage, it may reflect an underlying coagulation problem
Heart:
Epicardial Lymphatic Dilation, Tortuosity
variable-sized, tortuous dilated lymphatics filled with serous to yellow fluid.
Considered an incidental finding typically affecting horses
Concentric Hypertrophy
- Increased Afterload
- aortic and pulmonary stenosis
- Pulmonary hypertension
- Primary (Genentic) hyperthryroid
- increase in mass without an increases in chamber volume
- chambers pumping against increased pressure
Eccentric Hypertrophy
- Initially physiologic (exercise, pregnancy) increased preload
- valvular insufficiencies
- Increased return from shunts
- Increased in mass accompanied by an increased in end diastolic volume
- chambers pumping more blood
Dilation
End stage disease
Primary (genetic) nutritional
taurine deficiency
- A response to increased workload in both physiologic and pathologic states
- acute volume overload leads to physiologic dilation, while chronic overload will stimulate hypertrophy
- Chamber dilation is the endstage of a variety of heart disease
- In disease where fibrosis replaces normal myocardium, the chronic pressure will result in stretching of abnormal fibrous tissue
Right Sided Heart Failure
- Back-up of blood in systemic and protal circulation
- ruminant and horse tend to develop edema
- Dogs tend to ascites
- Cats tend to hydrothorax
- Enlarged liver with “nutmeg” pattern
Left Sided Heart Failure
- Back up of blood in the lungs and reduced cardiac output
- pulmonary congestion
- Leads to alveolar and interstitial edema
- Persenting complaints
- dyspnea
- Wheezing
- Paroxymal nocturnal cough
Congenital:
Ductus Arteriosus
- Fetal vascular structure connecting the Pulmonary artery and the aorta that closes soon after birth
- forms the ligamentum arteriosum
- Fetal blood flow uses the DA to bypass the lungs and shunt right-sided blood into systemic circulation
- Smooth muscle in the wall of this vessel responds to altered oxygen pressure and other vascular mediators to constrict postnatally, becoming functionally closed within hours of birth.
- A ductus that remains patent beyond 5 days is considered abnormal
- If the ductus persists, blood from the high pressure aorta moves across the PDA into the pulmonary artery (Left → right shunting) → increased pressure in the pulmonary circulation causes right heart hypertrophy, while the increased volume returning to the left side of the heart causes left atrial dilation and LV hypertrophy
Congenital:
Foramen ovale
Atrial Septal Defect
- In fetal circulation, allows movement of blood form Right → left allowing blood to bypass the pulmonary circulation
- Normally the flap of the left atrial wall is functionally closed postnatally by pressure differences established at birth
- Failure to close an lead to atrial septal defect, allowing communication between the right and left sides of the circulating throught a patent opening
- Blood then flows form Left → right causing volume overload of the right side of the heart
- One of the most common defects in cattle
Congenital:
Ventricular Septal Defect
- Typically located near the base and in the membranous portion of the interventricular septum and referred to as a high VSD
- When located in the muscular portion of the interventricular septum, VSDs are referred to as ‘low’
- VSD can occur as a single defect or as part of a more complex anomaly
- Leads to Left → Right Shunting
- Clinical signs depend upon the size of the VSD, spontaneous closure of small VSDs is reportedly common in dogs
- One of the most common cardiac defects, most commonly affecting horses and cattle
Aortic valve:
Subvalvular Stenosis
- narrowing can be supravalvular, valvular, or subvalvular
- Subvalvular lesions may be subtle and represent a restrictive band
- The restrictive band increases resistance to outflow, resulting in ventricular hypertrophy. Turbulence and pressure cause a post stenotic dilation of the vessels
- Interventricular septum hypertrophy may be more pronounced resulting in degeneration, altered electroconduction, arrhythmia, and sudden death
- Typically observed in dogs and pigs
Congenital:
Truncus arteriosus
- A single large arterial vessel exits the heart above a large VSD
- Coronary arteries and pulmonary artery and aorta arise from the large vessel
- Most commonly diagnosed in calves and foals