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Small Animal Medicine > Diastolic Dysfunction > Flashcards

Diastolic Dysfunction Flashcards

Exam IV

1
Q

Diastolic Dysfunction

DfDx (categories)

A

Primary:
Hypertrophic Obstructive Cardiomyopathy
Hypertrophic Cardiomyopathy
Restrictive Cardiomyopathy

Secondary:
Pressure Overload (Hypertension, Stenosis)
Pericardial Diseases (cannot relax because so stiff)
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2
Q

Brief pathophysiology of aortic and pulmonic stenosis

A

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

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3
Q

What is Diastolic Dysfunction?

A

Concentric Hypertrophy; increased wall thickness and decrease lumen

Usually a disease of cats

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4
Q

Blood pressure importance

A

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

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5
Q

Systemic Hypertension

DfDx

A 
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
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6
Q

Systemic Hypertension

Hypertensive Encephalopathy

A

Diastolic Dysfunction

Hemorrhage into brain
Seizures
Ataxia
Stupor
Blindness (especially cats)
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7
Q

Systemic Hypertension

Hypertensive retinopathy

A

Vascular distension and tortuosity
Retinal hemorrhage

Cat with acute blindness? Always check blood pressure

Fundic exam: very injected vessels

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8
Q

Systemic Hypertension

Hypertensive Choroidopathy

A

Focal necrosis: hypopigmentation

Retinal detachment: fuzzy appearance because the retinal is floating towards you

Treatable!

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9
Q

Systemic Hypertension

Hypertensive optic neuropathy

A

Optic nerve ischemia -> edema -> atrophy

Absence of retinal blood vessels

Retina is dead; not reversible

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10
Q

Systemic Hypertension:

Cardiac damage

A

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

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11
Q

Systemic Hypertension:

Kidney Damage

A

Patients with kidney disease will worsen

Increased glomerular pressure
Proteinuria, glomerular ischemia
Dysregulation of autoregulatory mechanisms
Interstitial inflammation and fibrosis

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12
Q

Systemic Hypertension relationship to Diastolic Dysfunction

A

Hypertension induces compensatory thickening of ventricular wall (LV concentric hypertrophy) => decreases LV filling

Looks similar to HCM but is not HCM

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13
Q

Systemic Hypertension

Treatment

A

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)

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14
Q

Systemic Hypertension

Treatment Goals

A

Correct BP: 100 to 160 mmHg

Alleviate clinical signs

Prevent progression of end-organ damage

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15
Q

What effect does severe acute arteriolar vasoconstriction have on the heart rate?

A

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

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16
Q

What is Hypertrophic Cardiomyopathy?

dysfunction, PE, etiology

A

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

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17
Q

Asymptomatic HCM, Stage B

Treatment

A

B1 Mild: No treatment, monitor

B2 Moderate/Severe:
\+/- ACE inhibitor
\+/- Beta blocker
\+/- Diltiazem 
\+/- Spironolactone 
\+/- Antithrombotic
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18
Q

Symptomatic HCM, Stage C

Treatment

A 
CHF:
Furosemide (pulmonary effusion) 
ACE-inhibitor
\+/- thoracocentesis 
\+/- pimobendan 
\+/- spironolactone 
\+/- antiarrhythmics

Arterial thromboembolism:
Supportive care
Antithrombotics (aspirin, clopidogrel, low molecular weight heparin)

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19
Q

Virchow’s Triad

A

Blood stasis

Endothelial Injury -vasculitis-(release clot activating substances)

Hypercoagulability (inflammatory disease -IMHA-, hyperadrenocorticism, PLN)

Neoplasia can cause all

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20
Q

Feline Arterial Thromboembolism

Death due to? ECG?

A

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)

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21
Q

Feline Arterial Thromboembolism

Treatment

A

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)

22
Q

Feline Arterial Thromboembolism

Regaining function

A

3-6 months to regain function

Complications (self mutilation, necrosis, need for amputation)

Recurrence Rate: 25-50%
Keep on Clopidigral

23
Q

Hypertrophic Obstructive Cardiomyopathy
What is it?
Diagnosis

A

Diastolic Dysfunction

Idiopathic

Cat disease

Diagnosis; echocardiogram
Systolic anterior motion of mitral valve:
transient with stress -> no hypertrophy
obstruction -> concentric hypertrophy

24
Q

Asymptomatic Hypertrophic Obstructive Cardiomyopathy, Stage B
Treatment

A

B1 and B2:
Slow heart rate to reduce systolic anterior motion
Beta blocker (go to)
Dilitiazem

25
Q

Symptomatic Hypertrophic Obstructive Cardiomyopathy, Stage C

Treatment

A 
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)

26
Q

Restrictive Cardiomyopathy
What is it?
Diagnosis

A

Diastolic Dysfunction

Idiopathic: amyloidosis, fibrosis

Cat disease

Diagnosis:
Echocardiogram;
Normal wall thickness (not HCM)
Normal to reduced systolic dysfunction

Diagnosis of exclusion

27
Q

What is pulmonary hypertension?

A

A secondary disease process! (left heart disease or pulmonary disease)

Increased pressure in the lungs

Normal pressures:
Systolic: 30 mmHg
Diastolic: 10 mmHg

28
Q

What increases pulmonary venous/LA pressure?

A

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)

29
Q

CO and Pulmonary Hypertension

A

Increased CO can increase pulmonary hypertension

Increase volume going through lungs during exercise
Lungs reach capacity and will end up in pulmonary hypertension

30
Q

What can increase pulmonary venous return?

A

Increase right-sided CO
Anemia, fever, exercise

Large L -> R shunts:
PDA
VSD
Atrial septal defect (ASD)

31
Q

What can increase pulmonary vascular resistance?

A

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

32
Q

Causes of Hypoxemia

A

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

33
Q

How do you diagnose pulmonary hypertension

A

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

34
Q

Pulmonary Hypertension

Treatment

A

Treat underlying disease (usually respiratory)

Cardiac protectants

Viagra (sildenafil)
Phosphodiesterase type V

Specifically vasodilates, pulmonary vasculature; pulmonary vasodilation

35
Q

What is Cardiac tamponade?

A

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!

36
Q

Physical Exam findings of pericardial effusion and cardiac tamponade

A

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

37
Q

What is Pulsus Parodoxus?

A

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)

38
Q

Pericardial Effusion

Radiographic findings

A

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

39
Q

Pericardial Effusion

ECG Findings

A

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)

40
Q

Emergency treatment of Pericardial effusion

Short term

A

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

41
Q

Pericardial effusion

Diuretics?

A

NO do NOT use

Will decrease volume and decrease BP
Less blood going to CO
Will cause RA to collapse more -> kills patient

42
Q

Emergency Treatment
Pericardial Effusion
Long term

A

Goal: relieve tamponade and determine etiology

Pericardiocentesis
Collect samples for culture and cytology (2 red tops and 2 purple top)

43
Q

Pericardial Effusion

Transudate DfDx

A 
Hernias
Cysts
CHF
Hypoporteinemia
Heart based mass (chemodectoma)
44
Q

Pericardial Effusion

Exudates DfDx

A 
Foregin body (TRP, porcupine quills, grass awn)
Nocardia
Fungal
FIP
Idiopathic inflammation
45
Q

Pericardial Effusion

Hemorrhagic

A

Most common type

Neoplasia: HAS (#1; mass on right auricle tip), Chemodectoma (base of heart, around aortic base), Ectopic thyroid, lymphoma

Coagulopathy: Rodenticide

Idiopathic

46
Q

Pericardocentesis

Risks

A

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

47
Q

Pericardocentesis

Procedure

A

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)

48
Q

Peritoneal-Pericardial Diaphragmatic Hernia (PPDH)

A

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

49
Q

Peritoneal-Pericardial Diaphragmatic Hernia (PPDH)

Findings

A

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

50
Q

PPDH

Treatment

A

If symptomatic than surgery

No symptoms? Leave be.

51
Q

PPDH

Diagnosis

A

Radiographs
Wide base connection between heart and diaphragm
Pericardium and diaphragm connected

Ultrasound
See abdominal organs near/around heart

Small Animal Medicine (8 decks)

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