Cardiovascular and Respiratory Diseases (Test 3) Flashcards
What is the flow of blood through the heart?
- Vena Cava
- Right Atrium
- Tricuspid Valve
- Right Ventricle
- Pulmonary Valve
- Pulmonary Artery
- Lungs
- Pulmonary Vein
- Left Atrium
- Mitral Valve
- Left Ventricle
- Aortic Vein
- Aorta
- Systemic Circulation
- Vena Cava
What valves can be heard on the left side of the heart?
- aortic
- pulmonic
- mitral
What valve can be heard on the right side of the heart?
-tricuspid
Do the Atria and Ventricles contract at the same time?
What happens when the Atria contract?
- Bicuspid and Tricuspid valves OPEN
- Semilunar valves CLOSE
- Ventricles RELAX
What happens during Ventricular contraction?
- Semilunar valves OPEN
- Bicuspid and Tricuspid valves CLOSE
- Atria RELAX
- blood enters Atria from Vena Cava and Pulmonary Veins
What happens during Systole?
- contraction of atria and ventricles
- blood is being EJECTED from the heart
What happens during Diastole?
- relaxtion of Atria and Ventricles
- heart is FILLING with blood
What happens during S1 (LUB)?
- beginning of systole
- increase in Intraventricular pressure during contraction exceeds the pressure within the Atria
- AV valves close (mitral first)
- contraction forces blood into semilunar valves
What happens during S2 (DUB)?
- beginning of Diastole (no pulse)
- Ventricles relax
- pressures within the heart become less than the semilunar valves
- causes semilunar valves to snap shut (Aortic first)
What 3 factors effect Stroke Volume?
- Contractility
- Preload
- Afterload
What is Contractility?
- intrinsic ability of cardiac muscle to develop force for a given muscle length
- AKA: inotropism
What is Preload?
- muscle length prior to contractility
- dependent of ventricular filling (end diastolic volume)
- value is related to Right Atrial Pressure
- most important factor for preload is Venous Return
What is Afterload?
- tension (arterial pressure) against which the ventricle must contract
- if arterial pressure increases, afterload increases
What determines the Afterload for the Left Ventricle?
Aortic Pressure
What determines the Afterload for the Right Ventricle?
Pulmonary Artery Pressure
What is the normal heart size (ribs)?
2.5-3.5 rib spaces
What is a level 1 Murmur?
- lowest intensity
- difficult to hear even by expert
What is a level 2 Murmur?
- low intensity
- usually audible by all listeners
What is a level 3 Murmur?
- medium intensity
- easy to hear even by inexperienced listeners
- without palpable thrill
What is a level 4 Murmur?
- Medium intensity
- palpable thrill
What is a level 5 Murmur?
- loud intensity
- palpable thrill
- audible with stehoscope placed on the chest with the edge of the diaphragm
What is a level 6 Murmur?
- loudest intensity
- palpable thrill
- audible even with the stethoscope raised above chest
What can cause Pump Failure?
- Myocardial Dysfunction
- Circulatory Function
What kind of Myocardial Dysfunctions can cause Pump Failure?
- Cardiomyopathy
- Myocardia
- Taurine Deficency in cats
What kind of Circulatory Failures can cause Pump Failures?
- Hypovolemia: shock, hemorrhage, dehydration
- Anemia
- Valvular Dysfunction
- Congential shunts or defects
What is the best test to determine heart disease?
- echocardiography
- including Doppler Echocardiography
- AKA: ultrasound
What types of dogs does Canine Dilated Cardiomyopathy occur in?
- 90% occurs in Doberman Pinschers, Boxers
- other breeds include: Wolfhounds, Great Danes, and Cocker Spaniels
- deep chested animals
What causes Canine Dilated Cardiomyopathy?
- decreased contractility from an unknown cause
- decreased contractility = decreased cardiac output
How do you calculate Cardiac Output?
CO (Cardiac Output)= SV (Stroke Volume) X HR (Heart Rate)
What is Cardiac Output?
amount of blood that leaves the heart
What is Stroke Volume?
amount of blood ejected with each cardiac contraction
What is Heart Rate?
how often the heart contracts
How does the body compensate with Canine Dilated Cardiomyopathy?
- increasing heart rate
- done by sympathetic nervous system
- trying to increase stroke volume by increasing preload
- done by activation of RAA system => sodium and water retention
What is the RAA system?
- R:Renin (kindeys)
- A:Angiotensin (Blood Vessels)
- A: Aldosterone (Adrenal Glands)
- kindeys tell BV which tell AG to release antidiuretic hormone. tells kidneys to reabsorb sodium, water follows
- causes more volume in preload and vessels
What are the Pathological Lesions of Canine Dilated Cardiomyopathy?
- heart walls are flabby, weak and dilated
- may cause separation of mitral valve leaflets leading to mitral reguritation
What are the Clinical Signs of Canine Dilated Cardiomyophathy?
- lethargy
- exercise intollerance
- coughing
- weight loss
- tachypnea
- syncope (fainting)
- soft murmur in mitral valve (L)
What Drugs are used to treat Canine Dilated Cardiomyopathy?
- Enalapril (reduces fluid retention)
- Furosemide (diuretic)
- Digoxin (increases contractility)
- Pimobendan ( Diruetic, eliminates excess fluids)
What OTC Drugs are used to treat Canine Dilated Cardiomyopathy?
- Coenzyme Q10 (antioxidant for cardiac muscle)
- Taurine (used in Cockers and cats, A.A.)
- L-Carnitine (amino acid)
What is Feline Dilated Cardiomyopathy?
- globular shaped heart
- severe dilation of all 4 chambers
- depressed ventricle contractions
- distorted atrioventrical valves
- leads to mitral reguritation and atrial enlargement
- atrophied papillary muscles
- thin ventricular walls
What is the Signalment for Feline Hypertrophic Cardiomyopathy?
- neutered male cats
- between 1-6yrs
What is the predominant pathology of Feline Hypertrophic Cardiomyopathy?
left ventricular hypertrophy
What are the causes of Feline Hypertrophic Cardiomyopathy?
- genetics
- abnormal myocardial myosin or calcium transport in muscles of heart
What are the 3 problems (pathophysiology) of Feline Hypertrophic Cardiomyopathy?
- diastolic failure
- pulmonary edema
- thromboembolism
What are the clinical signs of Feline Hypertrophic Cardiomyopathy?
- soft, systolic murmur (grade 2-3 /6)
- Gallop Rhythms
- echo shows increased ventricular wall thickness, dilated left atrium
- Acute onset of heart failure
- acute onset of systemic thromboembolism
- hindlimb paresis
- cold rear legs
- painful rear legs
What drugs are used in treatment of Feline Hypertrophic Cardiomyopathy?
- furosemide (diuretic)
- asprin (anticoagulant)
- Propanolol (B-Blocker, slows HR)
- Diltiazem (calcium channel blocker, inhibits contractility, low BP and cardiac afterload)
Is there a cure for Feline Hypertrophic Cardiomyopathy?
- NO
- cats may experience heart failure, arterial embolism, or sudden death
- cats whose HR stay below 200 have a better survival chance
What are the clinical signs of Canine Hypertrophic Cardiomyopathy?
- fatigue
- sudden death
- tachypnea
- syncope
- cough
What breeds are affected by Canine Hypertrophic Cardiomyopathy?
- german shepherds
- rottweilers
- cocker spaniels
What breeds does Patent Ductus Arteriosus affect?
- chihuahuas
- maltese
- poodle
- pomeranian
- shelties
- puppies are more commonly affected
When should the Ductus Arteriosus close?
12-24 hours after birth
What happens if the Ductus Arteriosus doesn’t close?
- blood begins to shut from the aorta into the pulmonary artery
- hyperfuses into the lungs
- L side of heart will have an increase in blood return and become volume overloaded
What side of the heart fails in Patent Ductus Arteriosus?
Left sided heart failure
What are the clinical signs of Patent Ductus Arteriosus?
- lound murmur (left base)
- “machinery” murmur
- may be asymptomatic
ECG: wide range of arythmias (APC’s and VPC’s)
-Radiographs: left atrial and ventricular enlargement
How do you treat Patent Ductus Arteriosus?
ligation of the ductus arteriosus
What is the Client Info for Patent Ductus Arteriosus?
- 64% of animals will die within 1 year without surgery
- should not be bred
What are clinical signs of Atrial Septal Defects?
- dilation and hypertrophy of right sided chambers
- systolic murmur
- right sided heart failure
- radiographs: right ventricular enlargement
- echo: right ventricular dilation
What are the clinical signs of Ventricular Septal Defects?
- may have no signs
- acute left sided heart failure
- harsh holosystolic murmur
What is the treatment for Ventricular Septal Defects?
- open heart surgery
- cardiopulmonary bypass
What are the 2 surgical options for Ventricular Septal Defects?
- pulmonary artery banding (before LtoR shunt has developed)
- repair of defect (open heart surgery, high risk)
What type of dogs does Pulmonic Stenosis affect?
- beagles
- bulldogs
- boxers
- mastiffs
- miniature schnauzers
- terrier breeds
What age does Pulmonic Stenosis affect?
less than 1 year old
What is the cause of Pulmonic Stenosis?
polygenic inheritance
What is Pulmonic Stenosis?
right ventricular outflow tract is narrowed
