Cardio 2 Flashcards
Cardiovascular history keys
-appetite/ weight changes
-activity levels/exercise tolerance
-weakness, syncope
-previous history of murmur
-cough (timing; dry, productive, severity)- associated with weakness or syncope
Physical exam for cardiovascular
- observe 1st (breathing rate and pattern; weakness/willingness to move)
- Physical
-abdominal palpation
-retinal exam (hypertensive retinopathy)
-mucous membranes
-CRT
-jugular vein
-palpate trachea
-cardiac auscultation
Mucous membranes and CRT for cardiac exam
MM: cyanosis, pale, icteric
CRT: prolonged=poor perfusion but normal does not rule out heart disease
Jugular vein
Reflects status of R atrium
*look for pulses and distension
Trachea palpation
-can induce cough and check for thyroid slip in cats
Apex beat
Location= shifts if heart shifts
Strength= reduced with effusion, pneumothorax, obesity, DCM
Pulses
-palpate while auscultating
-check symmetry, strength, dorsal pedal
Auscultation
-listen to heart and lungs
Cardiac auscultation
-check rhythm and dropped beats
*murmurs
Murmurs
- Physiologic: anemia, flow murmurs in athletes (sled dogs), young animals
- Pathologic: everything else
Murmur characterization
-timing
-intensity
-PMI
ECG
A way to measure the hearts electrical activity on body surface
*important part of complete cardiac exam
How to record ECG?
Cables and alligator clips
-6 standard leads (I, II, III, aVR, aVL, aVF)
-animal in right recumbency
What can only an ECG do?
-diagnose rhythm
-diagnose conduction defects
-detect adverse effects of anesthesia on cardiac impulse generation and conduction
-drug monitoring for meds that influence the heart rhythm and conduction
What can an ECG do reasonably well?
-detect cardiomegaly (better for cats)
-combined with radiographs, can indicate congenital defects
-emergency test for suspected hyperkalemia
-helpful with pericardial effusion
What does an ECG not provide?
-definitive diagnosis on heart size
-determine mechanical strength of contraction induced by electrical impulses
-determine if congestive heart failure is present
Indications for an ECG
- arrhythmia on auscultation
-heart disease present
-dyspnea
-cough
-weakness, syncope
-peri-operative after GDVs and splenic disease
-trauma patients
-certain meds (tricyclics, cardiac drugs)
-monitoring during pericardiocentesis
-shock
-bradycardias
ECG screening tests
1.Certain breeds (doberman, boxers)
- Geriatric program
- Pre-operative
Normal ECG wave
Importance of imaging studies in cardio
-allows you to determine that issue is actually cardiac in origin
-radiographs can be used to check lungs, and to determine heart failure but not myocardial disease
Indications for thoracic radiographs
-cough (heart, lung)
-heart murmurs or abnormal lung sounds
-neoplasia
-exercise intolerance
-dyspnea, tachypnea (edema, effusions, tumour, fungus)
-arrhythmias (heart or tumour)
Value of thoracic radiographs
-helps determine cardiomegaly, vascular status, heart failure, lung changes
*more diagnostic in dogs than cats; can be fatal in compromised patients
Components of good quality radiographs
-Right lateral, VD or DV (avoid VD if breathing is an issue)
-fully inspiratory
*artifacts: anesthesia (breathing different/atelectasis)
Expiratory
Inspiratory
Indications for echocardiography
-cardiac disease in cats
-congenital disease
-endocarditis suspects
-early detection of DCM
-pericardial effusion
-arrhythmias without obvious cause
Components of echocardiography
- 2D
- M-mode
- Doppler
2D of echocardiography
-90degree fan shaped beam
-used to assess structural morphology (thick valves, shunts, tumours, effusion)
M-mode of echocardiography
-1D technique which uses a very narrow beam to image a small portion of the hart
-used to detect only axial motion
Doppler
Used to assess velocity and character of blood flow
-used to find valvular stenoses/insufficiencies and shunts
Treatment for heart failure
-avoid stressful situations
-often need oxygen therapy
What are goals of diagnosing and treating cardiac issues?
- prolong length of life (influencing neurohumoral mechanism prolongs life)
- improve quality of life (which also increases length of life)
Factors affecting CO
-preload=increase preload, increase stroke volume, then results in congestion
-afterload= reduce afterload, improve CO
-contractility= improved contraction results in increased CO
-heart rate- increased=increased CO
Preload reduction
Reduce preload=reduce congestion
0use diuretics, venodilators, low salt diet
Furosemide
Loop diuretic (potassium wasting)
-can lead to arrhythmias and digoxin toxicity
-quick drop in volume= decreased preload and CO= activates RAAS
**powerful enough to cause low output failure
Spironolactone
Potassium sparing diuretic
-can result in hyperkalemia
-not potent
-usually add on diuretic
-likely blocks aldosterone escape
*prolongs life- the “in” drug right now
Other diuretics
-chlorthiazides
-thiazide and spironolactone combos
-ACE inhibitors (cuts thirst, aldosterone and ADH = reduces preload)
Nitroglycerine
-Venodilator
-works in dogs
-pools blood into abdomen, away from lungs
-anti-thrombotic effect
-ointment or patch applied to skin; oral not effective
-good for emergency, but tolerance can develop
How do you reduce afterload?
Need to decreased systemic vascular resistance
*not by decreasing the chamber diameter or hypertrophying the wall
ACE inhibitors
-includes enalapril and benazapril
-decrease ATII to reduce vasoconstriction, reduce myocardial oxygen demand, and counteract compensatory cardiac hypertrophy
-proven to prolong life in dogs, and cats with refractory heart failure
Mechanism of ACE inhibitors
1.Decrease vasoconstriction
2. decrease systemic vascular resistance= decrease BP
3. But since Afterload is decreased, CO is increased therefore counteracting drop in BP
Side effects of ACE inhibitors
-renal compromise
-rare cough
Hydralazine
Arterial dilator
-does not prolong life
-can cause significant hypotension
Amlodipine
Ca channel blocker
-mainly used for hypertension in cats
-can improve exercise intolerance
Inotropic support
Increases contractility
-adrenergic agent drugs: Dobutamine (CRI only), or dopamine (cheap but arrythmias and vasoconstriction can occur)
Pimobendan
-inodilator; positive ionotrope
-great for dobermans and most DCMs
-for use in all dogs and cats in heart failure and for DCM, and asymptomatic endocardiosis +left atrial enlargement
Heart Rate
-increased HR increases CO
but at high rates=ventricular filling and output drops
What is commonly see with heart failure?
Sinus tachycardia
What does treating heart failure result in?
Reduction in heart rate
*important for arrhythmias and severe bradycardias
