VTS: Cardiac emergencies and ECGs

• 1. Epicardium - outside layer over myocardium
• 2. Myocardium - cardiac muscle
• 3. Endocardium - lines atrial/ventricular cavities

Systemic

pulmonary

Cranial/caudal vena cava ⇾ R atrium ⇾ Tricuspid valve ⇾ R ventricle ⇾ pulmonary arteries ⇾ lungs ⇾ pulmonary vein ⇾ L atrium ⇾ mitral valve ⇾ Left ventricle ⇾ aorta

interatrial septum

interventricular septum

• L ventricle
• thick walled

fibromuscular strands that help secure cardiac valves

• 1. thick walled
• 2. have associated pulse
• 3. carry oxygenated blood from heart to body

• 1. small exchange vessels
• 2. fluid passes from capillaries to tissue interstitium
• 3. some fluid moves back into capillaries

• 1. thin walled
• 2. little to no pressure
• 3. carry deoxygenated blood back to heart

volume of blood in L ventricle just before it contracts

systemic venous constriction or dilation

decreased blood in L ventricle, decreased preload

increased blood in L ventricle, increased preload

stiff/fibrotic myocardium causes decreased ventricular filling

resistance to L ventricular ejection of blood at the point of peak tension in wall of ventricle

• Dilated vein = decreased resistance
• Constricted vein = increased resistance

• 1. volume loss
• 2. pain
• 3. hypoxemia
• 4. hypocapnia
• 5. sepsis
• 6. decreased SVR

HR 2 times normal rate

• 1. high vagal tone
• 2. atrioventricular conduction disturbances
• 3. hyperkalemia
• 4. severe hypothermia
• 5. drugs
• 6. increased intracranial pressure

60 - 70 mm Hg

40 mm Hg

difference between systolic & diastolic pressure

rate and rhythm of heart

• CO
• Vascular capacity
• Blood volume

• Other 2 compensate
• Stimulated by adrenomedullary and neurohormonal stress reactions:
• Catecholamines, renin-angiotensin system
• Temporary

• Oscillometric
• Ultrasonic (doppler)
• Direct (arterial)

Sphygmomanometer

• First pulse sound = systolic
• Change to "swishing" sound is diastolic

• Dorsal metatarsal
• Ventral coccygeal
• Palmar metacarpal

• Hypotension
• Tachycardia

• 100-160
• 60-110
• 80-120
• mmHg

difference between systolic and diastolic

• hypovolemia
• poor cardiac output
• systemic vasodilation

• extracellular fluid deficits
• vascular volume deficits

• myocardial failure
• valvular dz
• pericardial tamponade
• severe brady/tachycardia
• arrhythmias

• Sepsis
• anaphylaxis
• vasodilatory drugs

• Systolic <80
• MAP <60

MAP >140

• retinal detachment
• hemorrhage
• increased ICP
• excessive afterload

MAP = [ (2 x diastolic) + systolic] / 3

MAP = diastolic + (systolic - diastolic)

central venous pressure

• Intravascular volume
• venous tone and compliance
• intrathoracic pressure
• cardiac function

• Assessing fluid therapy w/
• renal dz
• pulmonary dz
• cardiac dz
• septic shock

• 0-5 ccH20
• OR
• 0-3 mmHg

Trends

• 1. volume overload
• 2. pleural/pericardial effusion
• 3. pulmonary edema
• 4. pulmonary thromboembolism
• 5. pneumothorax
• 6. pulmonary hypertension

• Long jugular cath
• tip just cranial to heart

• colloid oncotic pressure
• measures holding pattern of fluids in vascular compartment

third spacing

• hypoproteinemia
• increased capillary permeability

Refractometer - TP

<3.5 mg/dl

• Refractometer/TP can be skewed
• Colloid osmometer better assessment

18-25 mmHg

<15 mmgh

single digits

inadequate tissue oxygenation associated with impaired perfusion

• skeletal muscle
• GI tract

<1.0 mmol/L

• hypovolemia
• thromboembolism

• K
• Ca
• Mg
• Na

• Ca
• Mg
• Na

• heart that pumps inadequate volume of blood to all tissues of body 
• Causes inadequate tissue perfusion
• NOT a diagnostic indicator of underlying cause

• +/-
• congestion
• poor peripheral perfusion
• systemic hypotension

• congestive heart failure
• more specific than heart failure
• impaired cardiac function resulting in increased venous and capillary pressures

organs congested with blood or edematous fluid

• R ventricular failure
• L ventricular failure
• Biventricular failure

result of decreased CO and systemic hypertension

• weakness
• exercise intolerance
• syncope

• pallor
• jugular venous distension and pulsation
• enlargement of liver or spleen (congestion)
• tachypnea
• peritoneal or pleural effusion

• CVP (increase)
• Rads - 
• +/- 
• ascites
• cardiomegally
• pleural effusion

• similar hx to R CHF
• +/- 
• cough
• orthopnea
• hemoptysis
• oliguria

coughing up blood

• +/-
• abnormal cardiac rhythm
• heart murmur
• auscultable lung crackles
• cyanosis

• ekg
• rads
• arterial BP
• general blood profile

=/- arrythmias due to myocardial ischemia or atrial enlargment

• often pulmonary edema
• or pleural effusion in cats
• +- cardiomegally

often decreased

• pre-renal azotemia
• hypoproteinemia
• mild-mod increased LES

• combination of L/R CHF signs
• along with +/- arterial thromboembolism
• cachexia