Cardiac Flashcards
The sinoatrial node is located where and which cells are the main pacemaker?
Located in right atrium and P cells are the main pacemaker
Which abnormalities can lead to electrical alternans ?
Decreased calcium/K/Mg, amiodarone, HCM, CHF, TE
Which diseases can cause delayed repolarization and why is it bad?
Congenital (mutation of sodium or potassium channels) vs acquired (decreased Mg, K or Ça)
Can increase susceptibility to arrhythmia
What are the characteristics of A-fib ?
Absence of P wave, tachycardia and normal but irregular QRS
Which factors can cause vasodilation?
Adenosine, CO2, potassium, H+, histamine and NO
Which hormones are the most powerful for vasoconstriction?
Vasopressin > Angiotensin II > norepinephrine
Which ions causes vasoconstriction?
Calcium
Which nutrient does the heart consumes (as opposed to other systems)
Fatty acid instead of carbohydrates
Is calcium more present inside or outside the cell?
Extracellular
What happens at the neuromuscular junction?
Entry of calcium –> release Ach –> opens ions channels (Na,K, Ça) on post-synaptic membre –> action potential –> anticholinesterase destruct Ach –> résorbe choline
Which drugs can cause bradycardia?
Opioid, a2-agonist, B-adrenergic/calcium channel blockers (diltiazem, digoxin or sotalol)
What are the causes of sick sinus syndrome?
Mutation (in sodium channels or smooth muscles), fibrosis, dysfunction of ryanodine receptor)
What are the changes seen on ECG for atrial standstill and what is the treatment?
No P wave, only escape beats.
Ventricular pacemaker
Which treatment can be given for neurocardiogenic bradycardia mediated by cardiac C fibers?
Hyoscyamine/propantheline, theophylline (antagonist A1 adenosine receptor), terbutaline (acts on B1 receptor to increase parasympathetic tone) or isoproterenol (non selective B adrenergic receptors)
DCM is due to a mutation in which gene for which breed?
Pyruvate dehydrogenase kinase 4 in doberman
What can be heard on auscultation in DCM?
Low grade systolic left apical murmur with S3
Which disease is associated with a genetic deletion mutation in the 3’ untranslated region of striatin
ARVC
What are the 3 components of the virchow’s triad ?
Stasis, vessel wall injury and hypercoagulable state
Which change can be seen on radiographs with heartworm?
Enlarged caudal pulmonary artery
Do cats have evidence of microfilaria in HW disease?
No - 60% are not microfilaremic
What are the 2 ways to test for HW with ELISA?
Antigen that detects reproductive tract of adult female
Antibodies against L4 exposure
Which stage of the heartworm lives in mosquito?
L1-L3
How long does it take for L4 to turn into adult heartworms? And how long before it produces off springs (L1)?
2-3 months and 3-4 months
Which intracellular gram - bacteria contribute to pulmonary and renal inflammation through the protein WSP ?
Wolbachia
In which case is adulticide therapy contra-indicated in heartworm infection?
Cats
Caval syndrome
Which bacteria are the most common with endocarditis?
Staphylococcus, streptococcus and e.coli
Which valves are the most affected with endocarditis ?
Mitral (can lead to TE) and aortic (bounding pulses)
Which valve does Bartonella affects the most?
Aortic
What are the major and minor criteria to diagnose endocarditis? How many to you need for definitive diagnosis?
Major: vegetative lesion on echocardiogram, new valvular insufficiency, > 2 positive blood culture
Minor criteria : fever, > 15 kg with mitral valve disease, TE, immune mediated disease
Definitive- 2 major or 1 Major and 2 minors
What infection can lead to myocarditis in cats? dogs?
Cats - respiratory infection, toxoplasma
Dogs: parvovirus, Chagas, Lyme, Bartonella
Which electrolyte abnormality can lead to atrial standstill?
Hyperkalemia
Which ECG abnormalities are seen with tricuspid valve dysplasia?
Splintered QRS and P pulmonale
Which congenital heart disease is the most common in cats ?
Ventricular septal defect
ADH acts on V2 receptor within the kidneys to cause water retention, but also affects the cardiovascular system by which way?
Reacts with V1A receptors and causes vasoconstriction and inotropic actions
Wall stress =
Pressure x radius (/2) x wall thickness
What are the ECG characteristics for torsade de pointe, possible causes and treatment?
ECG - R on T ventricular extrasystole
Causes: hypokalemia, hypocalcemia, quinidine
Treatment: magnesium
Are right bundle branch block pathological
Not pathological
Which characteristic is seen on ECG in patient with Wolff Parkinson white syndrome?
Delta wave (mountain 🏔️)
Which abnormalities of the pulses can be seen with the following congenital disease?
- PDA
- Subaortic stenosis
- TVD/PS
- PDA : water hammer pulse
- Subaortic stenosis: weak pulse
- TVD/PS: jugular pulse
Which vessels are involved in PDA ?
Descending aorta and main pulmonary artery
Are male or female overrepresented in PDA?
Female
Where does the heart murmur from aortic stenosis can be hear?
Left base into carotid artery
Which congenital heart disease requires prophylactic antibiotics?
Aortic stenosis
Which medication can be use in case of severe subaortic stenosis?
Atenolol
Tight ventricular outflow obstruction, VSD and rightward position aorta Along with cyanosis are seen with which disease?
Tetralogy of fallot
Which radiographic change is seen with tetralogy of fallot?
Decrease pulmonary vasculature
Which cat breed is predisposed to HCM ?
Maine coons - mutation in cardiac MyBPC
Which anticoagulant can cause initial hypercoagulable state?
Warfarin because protein C levels fall prior to decrease in coagulation factors
Which hypertensive ocular lesion is the most common? Can recovery occur?
Retinal hemorrhage
Yes, if < 1 week
Dirofilaria results in which type of pneumopathy?
Restrictive
What are the possible treatment for VSD?
Pulmonary artery banding (cats: if Qp:Qs > 3 or CHF)
Percutaneous transcatheter coil embolization (dogs)
Which vascular ring abnormality is the most common in dogs ?
Type I - PRAA and left ligamentum arteriosum
Which is the most common heart disease in dogs?
Pulmonary stenosis
