22 - PE, ECG, Imaging, Treatment Flashcards
1
Q
CV history
A
- Appetite, weight changes
- Activity level, exercise tolerance
- Weakness, syncope
- Previous history of murmur
- Cough
o Character: dry, productive, severity
o Timing
o Associated with weakness or syncope
2
Q
What are some aspects of your PE for cardiac?
A
- Retinal exam: hypersensitive retinopathy
- Mucous membranes
- CRT
o Prolonged with poor perfusion
o Normal does not rule out significant heart disease - Jugular vein: reflects status of right atrium, look for pulses and distension
- Palpate trachea: inducible cough, thyroid slip
- Apex beat: shifts if heart shifts, strength
- Pulses: symmetry, strength, dorsal pedal
- Auscultation: heart and lungs
3
Q
When is the apex beat reduced?
A
- Effusion
- Pneumothorax
- Obesity
- DCM
4
Q
Cardiac auscultation
A
- Rhythm, dropped beats
- Murmurs: physiologic vs. pathologic
o Characterization: timing, intensity, PMI - Lungs
5
Q
What are some reasons for physiologic murmurs?
A
- Anemia
- Flow murmurs in athletes (ex. sled dogs)
- Young animals
6
Q
ECG in CV medicine
A
- A way to measure the heart’s electrical activity on the body surface
- An important part of a complete cardiac exam
- Clinically relevant tool if you know what it can and cannot do
7
Q
How can I record an ECG?
A
- With cables and alligator clips
- 6 standard leads
- Standard ECG: animal in right lateral recumbency
- Direct chest lead recording
8
Q
What can only an ECG do?
A
- Diagnose a 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
9
Q
What can an ECG do reasonably well?
A
- Detect cardiomegaly (better in cats)
- Combined with radiographs can offer info on congenital defects (PS for instance)
- Emergency test for suspected hyperkalemia
- Helpful with pericardial effusion
10
Q
What can an ECG not do?
A
- Give a definitive diagnosis of heart size
- Determine the mechanical strength of the contraction induced by electrical impulses
- Determine if congestive heart failure is present
11
Q
What are some indications for an ECG?
A
- Arrhythmia on auscultation
- Heart disease present
- Dyspnea
- Cough
- Weakness, syncope
- Peri-operative especially with GDVs and splenic disease
- Trauma patients
- With certain meds (cardiac drugs, tricyclics)
- Monitoring during pericardiocentesis
- Shock
- Bradycardias
- Screening test
12
Q
When might you do ECG as a screening test?
A
- Certain breeds (Ex. Doberman, Boxer)
o Doberman: 60% with DCM - Geriatric program
- Pre-operative
13
Q
P-wave
A
- Atrial depolarization
- P-R: mostly AV node
14
Q
Q-wave
A
- Septum
- First negative before R
- Don’t always need to have a Q
15
Q
R-wave
A
- First positive deflection after P
16
Q
S-wave
A
- First negative deflection after R
- Don’t always need to have a S
17
Q
T-wave
A
- Repolarization
18
Q
Imaging studies in CV medicine
A
- Vital to determine if problems noted are actually cardiac in origin
- ECG cannot replace imaging studies
- Radiography: easily determine if failure is present
o ONLY way to look at lungs as well
19
Q
What are some indications for thoracic radiographs?
A
- Cough (heart or lung?)
- Heart murmurs, abnormal lung sounds
- Exercise intolerance (heart or lung?)
- Neoplasia (met check)
- Dyspnea, tachypnea (edema, effusion, tumor, fungus?)
- Arrhythmias (heart, tumor?)
20
Q
What is the value of thoracic radiographs for cardiology?
A
- Vital to determine
o Cardiomegaly
o Vascular status
o Heart failure
o Lung changes - *more diagnostic in dogs than cats with cardiac disease
- Can be a fatal diagnostic technique in the compromised patient (don’t do VD=more stress)
21
Q
How can you make sure the radiograph is good quality?
A
- Standard positioning
o Right later
o VD or DV - Fully inspiratory (if expiratory=thoracic cavity smaller, diaphragm more ‘up and down’ and makes heart look bigger)
- Watch out for artifacts!
o Anesthesia (not breathing the way it is supposed to)
o Not correctly positioned
o Patient related problems (obese, breed, etc.)
o *often over diagnose heart problems
22
Q
What are the indications for echocardiography?
A
- Cardiac disease in cats
- Congenital disease
- Endocarditis suspects
- Early detection of DCM
- Pericardial effusion
- Arrhythmias w/o obvious cause
23
Q
What are the basics of echocardiography?
A
- 2D: assess structural morphology (thickened valves, shunts, tumors, effusion)
- M-mode (motion mode)
o 1D technique: to detect ONLY axial motion and to measure - Doppler: assess velocity and character of blood flow
o Valvular stenoses/insufficiencies and shunts
24
Q
What are some general concepts for treating heart failure?
A
- Know status of patient, IV may be too stressful in some (especially cats)
- Know if you can diagnose or need to treat first
- Oxygen therapy: often helpful
- Quiet often helps in stressed patients
25
What are your goals for treating heart failure?
- Prolong length of life
o Just improving function does NOT guarantee survival
o *influencing neurohumoral mechanism DOES prolong life
- Improve quality of life
26
Preload reduction
- To reduce congestion
- Can be achieved with diuretics, vasodilators or LOW salt diet
o Furosemide
o Spironolactone
o Chlorthiazides
o Thiazide and spironolactone combos
o ACE inhibitors: cut thirst, aldosterone and ADH also reduces preload
27
Furosemide
- Powerful loop diuretic
o K wasting can predispose to arrhythmias and digoxin toxicity
- Activates RAAS by dropping volume
- Powerful enough to cause LOW output failure
o Be cautious in cases with low output failure
- Almost “too good” it doesn’t work well
28
Spironolactone
- K sparing diuretic (can result in hyperkalemia)
- Not especially potent
- Usually an “add-on” diuretic
- Can prolong life in humans with chronic heart failure
- Probably blocks aldosterone escape
- *reduced risk of death or euthanasia by 69% (flawed study?)
29
Nitroglycerine
- Venodilator, proven efficacy in dogs
- Pools blood into abdomen, away from lungs
- Anti-thrombotic effect
- Ointment or patch, apply to skin
- Good for emergency work, tolerance develops
- Oral products: isosorbibe dinitrate (NOT effective)
30
Afterload reduction
- CANNOT do it by hypertrophying the wall or by directly decreasing chamber diameter
- NEED to decrease it by decreasing systemic vascular resistance
o Since decreasing SVR=can have BP drop, but CO is increased (due to decreased afterload) it counteracts drop in BP
- Ex. ACE inhibitors, hydralazine, amlodipine
31
ACE inhibitors
- Enalapril and benazepril
- Proven to prolong life in humans and dogs (also cats with refractory heart failure)
- By decreasing ATII= vasoconstriction is counteracted
- Myocardial oxygen demand is reduced
- Compensatory cardiac hypertrophy is counteracted
- Can see renal compromise
- Rare: cough (common in humans)
*he doesn't use them (or used when they have failure)
32
Hydralazine
- Arterial dilatory
- Does NOT prolong lifespan
- Can cause significant hypotension (need to monitor)
33
Amlodipine
- Calcium channel blocker
- Mainly used for hypertension in cats
- **Can improve exercise tolerance (sometimes he adds it in to help improve QOL, ex. owner wants it to go around the block)
34
Inotropic support (increasing contractility)
- Can be helpful in emergency situations
- Most agents are adrenergic:
o Dobutamine: CRI only, preferred drug (forward failure)
o Dopamine: cheaper, can cause arrhythmias and at higher doses vasoconstriction
- Most other oral drugs significantly decrease survival time
35
Pimobendan: 'miracle drug'
- Inodilator
- Positive inotrope
- Great efficacy in Dobermans, (most DCMS)
- Indicated in all cats and dogs in heart failure (not totally sure if it works in cats)
- Indicated with occult DCM and asymptomatic endocardiosis with left atrial enlargement
>owners want: assymptomatic
36
Heart and treatment (case example in slides)
- Increased HR increases CO
- At high rates, ventricular filling is inadequate and output drops
- Sinus tachycardia is a normal response to failure
- Treating failure often REDUCES HR
o Becomes important with arrhythmias and sever bradycardias
