Systolic Dysfunction Flashcards
Exam IV
Three main functions
Conduct electricity (rhythms; know the PQRST waves) - does not mean contraction Myocytes conduct electricity
Systole (contraction)
Diastole (filling)
How does blood flow?
Know chambers
From high pressure to low pressure
Systemic venous: 5 RA: 5 RV: 20/5 PA: 20/8 PCap: 6 PV: 6 LA: 6 LV: 120/6 Ao: 120/80 Systolic/Diastolic
Diastolic = low for filling Systolic = high for pushing blood out
Blood pressure equation
BP = CO x Systemic Vascular Resistance
Concentric hypertrophy
What is it?
What DfDx?
Wall thickening and lumen gets smaller
Diastolic dysfunction
Pressure overload
HCM
Eccentric hypertrophy
What is it?
What DfDx?
Wall is the same size but there is an increase in the lumen size
Systolic dysfunction (residual blood in lumen) Volume overload
Sequela to systolic dysfunction
As lumen gets bigger the mitral valve gets pulled apart -> murmur
Systolic Dysfunction
Murmur
Murmur:
Left side; Mitral valve
Timing: systolic
Quality: regurgitation/plateau
Endocardiosis can cause this
Systolic Dysfunction
Femoral Pulses
Potentially weak
Lower CO so not as strong of pulses as normal (LV not contracting properly)
Systolic Dysfunction
PE findings
Arrhythmias; pulse deficits
Hear beat but do not feel pulse
Systolic Dysfunction
DfDx (two categories)
Primary:
DCM (diagnosis of exclusion)
Arrhythmogenic Right Ventricular Cardiomyopathy
Secondary: Toxin/Drug (Doxorubicin) Dietary deficiency Tachycardia-induced cardiomyopathy Hypothyroidism Inflammation (Myocarditis; sepsis)
Systolic Dysfunction
Treatment
Treat underlying disease!
Systolic Dysfunction:
Hypothyroidism
Physiologic effects
Treatment
Physiologic effects of thyroid hormone:
Indirect cardiac effects -> increase metabolic rate; heart is responsible for delivering oxygen to body
Direct cardiac effects -> increases iontropy + chronotropy
Direct receptors on heart
Treat hypothyroidism (levothyroxine) and may cause systolic dysfunction to resolve
Systolic Dysfunction:
Tachycardia-Induced Cardiomyopathy
Arrhytmia?
Treatment?
Supraventricular arrhythmias
Atrial fibrillation
Treatment:
Stop the tachycardia
Antiarrhythmic (beta-blocker, sotalol, diltiazem, digoxin)
Catch early enough you can cure it
Systolic Dysfunction: Dietary Deficiency (Taurine)
Taurine!
Amino acid (concentrated in the heart and retina)
An essential amino acid in cats (b/c cannot make their own)
Causes:
Central retinal degeneration (blindness)
Cardiac systolid dysfunction
Grain free diets are causing this!
Systolic Dysfunction:
Dietary Deficiency
Treatment
Treat CHF:
Furosemide
Pimobedan
ACE-inhibitor
Taurine or L-carnitine supplementation
Potential diet change
Potentially curable if caught early enough
Systolic Dysfunction: Dietary Deficiency (L-carnitine)
Protein:
Concentrated in skeletal and cardiac muscles
Who?
American Cocker Spaniels
Golden Retrievers
Boxers
Systolic Dysfunction:
Doxorubicin
Chemotherapeutic agent
Free radical that damages organs that use a lot of oxygen
Cardio toxic:
Dose dependent
Arrhythmias
Severe systolic dysfunction
Prognosis:
Poor because irreversible
Systolic Dysfunction:
Primary DCM Treatment
Stage B (pre-CHF):
B1: monitor
B2: Pimobendan, +/- ACE inhibitor
Stage C (post-CHF):
Furosemide, Pimobendan, ACE-inhibitor, +/- spironolactone, +/- antiarrhythmics
Not a good prognosis overall
CHF?
Fluid in the lungs is possible! (pulmonary edema)
Systolic Dysfunction:
Arrhythmogenic Right Ventricular Cardiomyopathy
What is it?
Boxer Cardiomyopathy
Unique disease; right-sided disease that can cause syncope and/or sudden death
Idiopathic most likely genetic component
Histologically: fibro-fatty replacement of myocytes
Systolic Dysfunction:
Arrhythmogenic Right Ventricular Cardiomyopathy
Diagnosis
Holter monitor for 24 hours looking for VPCs
Echocardiogram
Systolic Dysfunction:
Arrhythmogenic Right Ventricular Cardiomyopathy
Treatment
Arrhythmias:
Antiarrhythmics (Mexiletine, Sotalol)
Systolic Dysfunction:
CHF -> furosemide, Pimobendan, ACE-inhibitor, +/- spironolactone
