Cardiology (SA) Flashcards
What is #1?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/394/456/q_image_thumb.jpg?1579435584)
SAN
What is #2?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/394/509/q_image_thumb.jpg?1579435633)
AVN
What is #3?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/394/514/q_image_thumb.jpg?1579435658)
Bundle of His (AV bundle)
What is #4?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/394/548/q_image_thumb.jpg?1579435672)
Left Limb
What is #5?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/394/567/q_image_thumb.jpg?1579435693)
Right Limb
What is #6?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/394/574/q_image_thumb.jpg?1579435723)
Septomarginal Band
What is #7?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/394/589/q_image_thumb.jpg?1579435745)
Left Bundle Branch
What is #8?
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/394/598/q_image_thumb.jpg?1579435766)
Right Bundle Branch
Label 1-9.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/394/704/q_image_thumb.png?1579436253)
- Cranial VC
- Caudal VC
- Aorta
- Right Auricle
- Right Atrium
- Pulmonary Artery
- Right Ventricle
- Left Auricle
- Left Ventricle
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/394/704/a_image_thumb.png?1579436167)
Label 1-9.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/395/099/q_image_thumb.png?1579436919)
- Cranial Vena Cava
- Caudal Vena Cava
- Aortic Arch
- Right Atrium
- Pulmonary Artery
- Left Atrium
- Left Ventricle
- Left Auricle
Label 1-7
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/396/013/q_image_thumb.png?1579437062)
- Right Cranial Lobe
- Right Middle Lobe
- Right Caudal Lobe
- Accessory Lobe
- Left Caudal Lobe
- Caudal portion of Left Cranial Lobe
- Cranial Portion of Left Cranial Lobe
Label 1-4. (Right Lung Lobes as L Lateral)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/396/144/q_image_thumb.png?1579437156)
- Cranial Lobe
- Caudal Lobe
- Middle Lobe
- Accessory Lobe (need orthogonal views)
Label 1-3
![](https://s3.amazonaws.com/brainscape-prod/system/cm/299/396/197/q_image_thumb.png?1579437909)
- Cranial Portion of Left Cranial Lobe
- Caudal Portion of Left Cranial Lobe
- Left Caudal Lobe
Describe Starlings Law.
Hydrostatic pressure across the vessel wall and oncotic (protein) pressure within and outside the vessel balance to determine movement of fluid.
What is the Equation for Starlings Law?
Net pressure = (Pcapillary– Pinterstitium) – (Ocapillary– Ointerstitium)
P = Hydrostatic Pressure, O = Oncotic Pressure
What occurs if the result of a starlings equation is positive?
What about if it is negative?
+ = water moves out of capillary
- = water moves into capillary
What is the equation for Cardiac Output?
CO = SV x HR
What is the equation for stroke volume?
EDVV - ESVV = SV
What causes an increased preload?
Increased EDVV
What causes an increased afterload?
Increased vascular presure
What is vascular resistance inversely proportional to?
What is the significance of this?
Radius4
Increased Radius = Decreased Vascular Resistance & vice-versa.
How is mean Aortic Pressure Calculated?
Total Peripheral Resistance x CO
What is the systolic pressure of the RV?
25mmHg
What is the systolic pressure of the LV?
120mmHg
What is the normal systolic pressure of the pulmonary arteries?
25mmHg
What is the normal systolic pressure of the systemic arteries?
120mmHg
How can we increase Cardiac Output?
Increase SV (Contractility or EDVV)
Increase HR
Sympathetic Drive increases HR but maintains CO - how?
Offsets severely reduced diastole with increase in:
Contractility
Lusitropy
(can also shorten systole to slightly inc diastole)
What is the adult remnant of the umbilical vein?
The round ligament of the liver
What is the adult remnant of the umbilical artery?
The round ligament of the bladder
Which 3 breeds of dog are predisposed to aortic stenosis?
Boxer
Newfoundland
Rottweiler
What structural change(s) may be caused by Aortic Stenosis?
LV dilation/hypertrophy
What are the clinical signs of Aortic stenosis?
Normally Asymptomatic - occasionally syncope.
Possibly also arrhythmia and sudden death.
Which dog breeds are commonly predisposed to pulmonic stenosis?
Bulldogs and Fox Terriers
What structural CV changes are caused by pulmonic stenosis?
dilation +/- hypertrophy of the RV
What are the clinical signs of pulmonic stenosis?
RHS heart failure
Which species most commonly suffers from PDA?
Dogs
Where does the blood travel in a PDA?
Aorta to Pulmonary Artery (L –> R)
What are the clinical signs of PDA?
LHS CHF - Pulmonary Oedema
Pulmoanry hypertension & shift to R > L flow = Differential Cyanosis (blue caudal MMs)
Desribe a PDA murmur.
Systolic + Diastolic
Rib Space 3/4
“Machinery Murmur”
Describe the murmur caused by Aortic Stenosis.
Sytolic.
4th ICS.
High-Pitched.
Describe the murmur caused by Pulmonic Stenosis.
Systolic
3rd ICS
Describe the murmur caused by a Small VSD.
Systolic
RHS - ICS 5
Loud, High-pitched.
Describe the murmur caused by a large VSD
Systolic
ICS 5 RHS.
Low, soft murmur.
Which 4 conditions encompass the Tetralogy of Fallot?
VSD
Dextraposed Aorta
Pulmonary Stenosis
RV Hypertrophy
Which cardiac defect may cause megaoesophagus?
Persistent right 4th Aortic Arch & L ductus arteriosus.
Which Cardiac Glycoside is used in Veterinary Medicine?
Digoxin
How do Cardiac Glycosides work?
Inhibit Na removal from cardiac myocytes.
Increases intracellular Ca & therefore SR Ca.
+ Inotrope
ALSO -ve Chronotrope via inhibition of Na Removal
Which receptors are present on cardiac myocytes?
ß1
Which ß1 agonist do we use in anaesthesia and why?
Dobutamine - to induce tachycardia.
What is the role of phosphodiesterase?
Degardes intracellular cAMP
What do PDE III inhibtors do to the heart? How?
Increase contractility.
Increased cAMP –> inc Ca channel opening –> increase Ca in myocyte.
Apart from increased contractility, what CV effects do PDE inhibitors have on?
Vasodilation
Tachycardia
What is the most common PDE III inhibitor used in veterinary practice and what are its major CV effects?
Pimobendan
+ inotrope, vasodilator
What are the potential adverse effects of PDE III inhibitors?
Inappetance
Lethargy
Dyspnoea
Azotaemia
What is the most appropriate treatment for a Bradyarrhythmia?
Pacemaker implantation
What can you use during anaesthesia to combat Bradycardia?
Anticholinergic - Atropine
What are the 4 classes of Vaughn-Williams?
I - Na blocker
II - Beta blockers
III - K blocker
IV - Ca blocker
How do Class I Vaughn-Williams drugs work?
Block fast Na channels and reduce heart rate.
K+ dependent: hypoK decreases fct, hyperK increases it.
Describe the Na blockade and effect on refractory period of VW class Ia drugs.
Na Blockade: Moderate
ERP: Increased
Describe the Na blockade and effect on refractory period of VW class Ib drugs.
Na Blockade: Weak
ERP: decreased
Describe the Na blockade and effect on refractory period of VW class Ic drugs.
Na Blockade: Strong
ERP = no change
Give an example of a VW class 1a drug.
Quinidine
Give an example of a VW class Ib drug.
Lidocaine
Give an example of a VW class Ic drug.
Flecainide
What is the route of administration for quinidine?
Oral
What are the 2 effects of quinidine?
Na blocking
Vagolytic (inc HR/conduction)
What is quinidine used to treat?
Atrial Fibrillation in horses
What are 4 possible side effects of quinidine?
Arrhythmia
GI signs
Behavioural - nervous/depression
Negative inotrope/vasodilation –> CHF
What is the route of administration for lidocaine when treating dysrhythmia?
SLOW IV!