Diastolic Dysfunction Flashcards
Exam IV
Diastolic Dysfunction
DfDx (categories)
Primary:
Hypertrophic Obstructive Cardiomyopathy
Hypertrophic Cardiomyopathy
Restrictive Cardiomyopathy
Secondary: Pressure Overload (Hypertension, Stenosis) Pericardial Diseases (cannot relax because so stiff)
Brief pathophysiology of aortic and pulmonic stenosis
Diastolic Dysfunction
Pressure in aorta too high (due to stenosis) causing pressure overload in LV
Pressure in pulmonary artery too high (pulmonic stenosis) causing pressure overload in RV
What is Diastolic Dysfunction?
Concentric Hypertrophy; increased wall thickness and decrease lumen
Usually a disease of cats
Blood pressure importance
Blood pressure dictates perfusion (blood to vital organs; brain, kidney, heart, eyes)
Hypotension: ischemia, not enough vascular tone, perfusion is poor
Hypertension (Systolic >160 mmHg): capillary beds will rupture, too high of pressure
Systemic Hypertension
DfDx
Hyperaldosteronism Pheochromocytoma (increases production of Epinephrine and norepinephrine which act directly on heart -> vasoconstriction, also causes vasoconstriction peripherally) Acromegaly Medications Diabetes Mellitus Hyper/hypo-thyroidism Hyperadrenocorticism (Cushing's; papillary muscles will enlarged in LV) Renal Disease
Systemic Hypertension
Hypertensive Encephalopathy
Diastolic Dysfunction
Hemorrhage into brain Seizures Ataxia Stupor Blindness (especially cats)
Systemic Hypertension
Hypertensive retinopathy
Vascular distension and tortuosity
Retinal hemorrhage
Cat with acute blindness? Always check blood pressure
Fundic exam: very injected vessels
Systemic Hypertension
Hypertensive Choroidopathy
Focal necrosis: hypopigmentation
Retinal detachment: fuzzy appearance because the retinal is floating towards you
Treatable!
Systemic Hypertension
Hypertensive optic neuropathy
Optic nerve ischemia -> edema -> atrophy
Absence of retinal blood vessels
Retina is dead; not reversible
Systemic Hypertension:
Cardiac damage
Results in secondary cardiac remodeling
Concentric hypertrophy of LV; wall gets so thickened that there is ischemic damage
Muscle growing inwards but the arterial blood supply does not grow => myocardial ischemia
NOTE: Heart disease does NOT cause systemic hypertension
Actually, heart disease decreases CO resulting in hypotension
Systemic Hypertension:
Kidney Damage
Patients with kidney disease will worsen
Increased glomerular pressure
Proteinuria, glomerular ischemia
Dysregulation of autoregulatory mechanisms
Interstitial inflammation and fibrosis
Systemic Hypertension relationship to Diastolic Dysfunction
Hypertension induces compensatory thickening of ventricular wall (LV concentric hypertrophy) => decreases LV filling
Looks similar to HCM but is not HCM
Systemic Hypertension
Treatment
Treat underlying disease (DfDx)
Decrease BP:
Beta blockers (good in hyperthyroidism cats)
Decrease preload (diuretics)
SVR:
ACE inhibitors (small BP drop)
Amlodipine (Rx of choice especially in animals with renal disease; Ca2+ channel blocker)
Phenoxybenzamine (pheochromocytoma)
Systemic Hypertension
Treatment Goals
Correct BP: 100 to 160 mmHg
Alleviate clinical signs
Prevent progression of end-organ damage
What effect does severe acute arteriolar vasoconstriction have on the heart rate?
BP = CO x SVR
SVR increases therefore BP increases
BP stimulates HR to decrease (reflex bradycardia)
Brain needs perfusion!
Decrease HR means decrease CO; so brain will want to increase systemic blood pressure -> reflex bradycardia
Cushing’s Reflex
What is Hypertrophic Cardiomyopathy?
dysfunction, PE, etiology
Diastolic dysfunction, concentric hypertrophy of LV (wall grows inward)
Cats!
Genetic basis:
Maine Coons
Ragdolls
PE:
+/- systolic murmur
+/- gallop sound (could be due to Hyperthyroidism as well)
+/- normal
Diagnosis of exclusion; only definitively diagnosed via echocardiogram
Asymptomatic HCM, Stage B
Treatment
B1 Mild: No treatment, monitor
B2 Moderate/Severe: \+/- ACE inhibitor \+/- Beta blocker \+/- Diltiazem \+/- Spironolactone \+/- Antithrombotic
Symptomatic HCM, Stage C
Treatment
CHF: Furosemide (pulmonary effusion) ACE-inhibitor \+/- thoracocentesis \+/- pimobendan \+/- spironolactone \+/- antiarrhythmics
Arterial thromboembolism:
Supportive care
Antithrombotics (aspirin, clopidogrel, low molecular weight heparin)
Virchow’s Triad
Blood stasis
Endothelial Injury -vasculitis-(release clot activating substances)
Hypercoagulability (inflammatory disease -IMHA-, hyperadrenocorticism, PLN)
Neoplasia can cause all
Feline Arterial Thromboembolism
Death due to? ECG?
Reperfusion injury (hyperkalemia) -> cardiac arrest
ECG changes:
Tented T waves
Decreased amplitude P waves to no P waves
Increased PR interval
Wide QRS complexes
Potentially atrial standstill (no P waves, ventricular escape complexes)
Feline Arterial Thromboembolism
Treatment
Dextrose +/- insulin
Bicarbonate
Calcium
Furosemide
IV fluids; may have to decrease if the cat has heart disease
Pain will most likely resolve within 3 days; treat pain while hospitalized (monitor potassium)
Guarded to poor prognosis (<40% survive)
Feline Arterial Thromboembolism
Regaining function
3-6 months to regain function
Complications (self mutilation, necrosis, need for amputation)
Recurrence Rate: 25-50%
Keep on Clopidigral
Hypertrophic Obstructive Cardiomyopathy
What is it?
Diagnosis
Diastolic Dysfunction
Idiopathic
Cat disease
Diagnosis; echocardiogram
Systolic anterior motion of mitral valve:
transient with stress -> no hypertrophy
obstruction -> concentric hypertrophy
Asymptomatic Hypertrophic Obstructive Cardiomyopathy, Stage B
Treatment
B1 and B2:
Slow heart rate to reduce systolic anterior motion
Beta blocker (go to)
Dilitiazem
Symptomatic Hypertrophic Obstructive Cardiomyopathy, Stage C
Treatment
CHF: Furosemide (pulmonary effusion) ACE-inhibitor \+/- slow HR \+/- thoracocentesis \+/- pimobendan \+/- spironolactone \+/- antiarrhythmics
Arterial thromboembolism
Supportive care
Slow heart rate (beta blocker)
Antithrombotics (aspirin, clopidogrel, low molecular weight heparin)
Restrictive Cardiomyopathy
What is it?
Diagnosis
Diastolic Dysfunction
Idiopathic: amyloidosis, fibrosis
Cat disease
Diagnosis:
Echocardiogram;
Normal wall thickness (not HCM)
Normal to reduced systolic dysfunction
Diagnosis of exclusion
What is pulmonary hypertension?
A secondary disease process! (left heart disease or pulmonary disease)
Increased pressure in the lungs
Normal pressures:
Systolic: 30 mmHg
Diastolic: 10 mmHg
What increases pulmonary venous/LA pressure?
Decreased pulmonary venous drainage
Left-sided heart failure (any left heart disease) - LA pressure increase can cause increase in pulmonary venous pressure (back up)
Pulmonary venous obstruction (hilar lymph nodes at bifurcation or trachea and mainstem bronchi)
CO and Pulmonary Hypertension
Increased CO can increase pulmonary hypertension
Increase volume going through lungs during exercise
Lungs reach capacity and will end up in pulmonary hypertension
What can increase pulmonary venous return?
Increase right-sided CO
Anemia, fever, exercise
Large L -> R shunts:
PDA
VSD
Atrial septal defect (ASD)
What can increase pulmonary vascular resistance?
Loss of pulmonary vessels (obstruction)
Pulmonary thromboembolism (Virchow’s Triad)
Pulmonary vasoconstriction (Hypoxemia; which will want to cause vasodilation); will vasoconstrict to shunt blood to areas that are in need of oxygen rich blood
Causes of Hypoxemia
Primary lung disease:
Chronic obstructive pulmonary disease (chronic bronchitis)
Pulmonary fibrosis
Collapsing trachea (lungs hypoventilated; pulmonary hypertension due to vasoconstriction)
High altitude
Pulmonary vasoconstriction resulting in pulmonary hypertension
How do you diagnose pulmonary hypertension
Cardiac catheterization; measures direct pressures of the PA, pulmonary capillaries, and pulmonary veins
Jugular vein –> cranial vena cava –> RA –> RV –> pulmonary artery –> lungs –> pulmonary vein
Echocardiogram; indirect measures of pulmonary pressures
Only definitive if pulmonic regurgitation is present
Pulmonary Hypertension
Treatment
Treat underlying disease (usually respiratory)
Cardiac protectants
Viagra (sildenafil)
Phosphodiesterase type V
Specifically vasodilates, pulmonary vasculature; pulmonary vasodilation
What is Cardiac tamponade?
Presence of pericardial effusion pressure is greater than RA pressure (5 mmHg).
RA will collapse on itself; cannot open and fill
Reduction of CO
Will see clinical signs!
Physical Exam findings of pericardial effusion and cardiac tamponade
Muffled heart sounds (lung sounds should be normal)
Tachycardia (less blood getting to heart less getting pumped out)
Reduced/absent/shifted precordium (cannot feel heart beat when hand placed on chest)
Jugular venous distension/pulses
Weak femoral pulses (hypotension, pulsdes paradoxus)
Right sided CHF (ascites)
Exercise intolerance, lethargy
What is Pulsus Parodoxus?
Pulse change during inspiration and expiration due to the movement of the ventricular septum
Pulses are weak during inspiration (right ventricle fills better and left fills poorly; septum moves left)
Pulses are stronger during expiration (right ventricle fills poorly while left fills better; septum moves right)
Pericardial Effusion
Radiographic findings
Enlargement of cardiac silhouette (+/- globoid; not pathopneumonic)
Sharp well demarcated edges of heart
Distension of caudal vena cava (RA squished so blood is stuck in the vena cava; high pressure)
Small pulmonary vessels
Mass effects
Abdominal effusion
Pericardial Effusion
ECG Findings
Decreased QRS amplitude (short) -> heart surrounded by fluid and electricity cannot travel well through fluid to the leads
Electrical alternans; QRS short then tall then short then tall
Sinus rhythm
Irritation can be noted; ventricular arrhythmias (VPCs, supraventricular tachycardia)
Emergency treatment of Pericardial effusion
Short term
Goal: increase preload to force blood into the heart
Fluids! = treatment of choice
This will increase blood volume therefore increasing BP
More fluid going to heart which will increase RA pressure
Be aggressive with administration (take weight in pounds and add a zero; that is how much fluids should be given -over an hour?-)
Monitor with ECG
Want to expand the heart so you can perform a pericardiocentesis
Pericardial effusion
Diuretics?
NO do NOT use
Will decrease volume and decrease BP
Less blood going to CO
Will cause RA to collapse more -> kills patient
Emergency Treatment
Pericardial Effusion
Long term
Goal: relieve tamponade and determine etiology
Pericardiocentesis
Collect samples for culture and cytology (2 red tops and 2 purple top)
Pericardial Effusion
Transudate DfDx
Hernias Cysts CHF Hypoporteinemia Heart based mass (chemodectoma)
Pericardial Effusion
Exudates DfDx
Foregin body (TRP, porcupine quills, grass awn) Nocardia Fungal FIP Idiopathic inflammation
Pericardial Effusion
Hemorrhagic
Most common type
Neoplasia: HAS (#1; mass on right auricle tip), Chemodectoma (base of heart, around aortic base), Ectopic thyroid, lymphoma
Coagulopathy: Rodenticide
Idiopathic
Pericardocentesis
Risks
VPCs
Coronary artery laceration
Lung laceration and resultant pneumothorax, hemorrhage
Dissemination of infection/neoplastic cells to pleural space
NOTE: tamponade will kill them first therefore this must be done
Pericardocentesis
Procedure
Sterile with long (equine) catheter, 3 way stop cock, 2 red top tubes, 1 purple top tube, IV extension set
Sternal or right lateral approach, cranial to rib (intercostal space 3 to 6)
Attach ECG; if VPCs noted during procedure pull needle back
Have lidocaine ready for any arrhythmias that may occur
Sample should not clot; otherwise might have sampled from vessel or heart
Should resolve tachycardia (heart will fill better)
Peritoneal-Pericardial Diaphragmatic Hernia (PPDH)
Congenital pericardial disease in animals
Retention of abdominal contents in the pericardium (failure of embryologic separation); diaphragm and pericardium communicate
Cats can present at older ages
Peritoneal-Pericardial Diaphragmatic Hernia (PPDH)
Findings
Signalment:
Young, no trauma history, common in cats
Clinical Signs:
Variable, respiratory, GI (if intestines get impacted)
Omentum is most common organ
PE:
Muffled heart sounds
PPDH
Treatment
If symptomatic than surgery
No symptoms? Leave be.
PPDH
Diagnosis
Radiographs
Wide base connection between heart and diaphragm
Pericardium and diaphragm connected
Ultrasound
See abdominal organs near/around heart
