Examination of the cardio-respiratory system in dogs & cats

What respiratory/cardiac conditions are associated with certain breeds?

• Myxomatous degenerative valvular disease (= Mitral valve disease) in CKCS or small breed dogs

• Tracheal collapse in Yorkshire terriers

• Dilated cardiomyopathy (DCM) in Dobermanns & giant breeds of dogs

• Cats —> hypertrophic cardiomyopathy

What history questions do you need to ask?

• Vaccination & worming status

• Travel outside the UK

• Indoor vs outdoor

• Environment (urban vs rural)

• Other pets or animals in the environment (foxes, slugs etc.)

• Diet / appetite / thirst / V+ / D+ / PUPD

• Access to toxins

• Any change in weight / condition etc.

What questions would you ask about a dogs cough?

• When is the dog coughing - at night before bed? when excited?

• Dry cough or productive (retch/ swallow)

• Are they coughing anything up

What questions would you ask about a dogs breathing?

Laboured breathing —> Dyspnoea

• When first noticed? episodic / continuous / getting worse?

• Orthopnoea (posture to optimise breathing)

• Any change in Bark / Meow?

• Nasal discharge? Blocked?

Tachypnoea

What questions would you ask about exercise?

• How much normally? changes?

• Reluctant to exercise?

• Slowing down?

What questions would you ask about collapse?

• When?

• Describe, loss of consciousness?

• Colour of tongue / gums?

• Flaccid / rigid? Any muscle movement?

What would the first steps be with a respiratory patient?

• Observe behaviour

• Assess respiratory rate before handling (normal 20 – 30 breaths a minute)

• Assess respiratory effort (hyperpnoea if increased, orthopnoea)

• Record respiratory rate (not possible if panting, panting = probably NOT dyspnoeic)

What are the signs of orthopnoea?

• standing /sitting to breathe

• air-hunger stance

• elbows abducted

What are the different types of dyspnoea?

• Inspiratory / Expiratory or Both

• Obstructive versus Restrictive

• Upper vs Lower Airway

  • If airway noise (stridor, stertor etc. will be upper airway problem)

What would you check for in a cardio patient?

• Peripheral perfusion

• Colour of mucus membranes (if cyanotic, assess response to O2 & do not stress)

• Capillary refill (CRT) (normal <2 seconds)

• Warmth of extremities

What are the signs of forward heart failure?

What is a ddx for these clinical signs?

• Lethargy, exercise intolerance

• Weak femoral pulses, unable to detect distal pulses (metatarsal)

• Pale MM, slow CRT

• Cold extremities

• Possibly hypothermia

• Weak precordial impulse on palpation

• Heart sounds “quiet” or “distant” on auscultation

“Cardiogenic shock” (obstruction)

What is forward heart failure more likely in?

Dilated cardiomyopathy

What are the signs of left sided CHF (pulmonary oedema)?

• Tachypnoea, both inspiratory and expiratory, restrictive breathing pattern

• Cough in dogs due to left atrial enlargement

• +/- soft inspiratory crackles on auscultation (don't rely on this - not present with bad oedema)

What are the signs of right sided CHF?

• Ascites (positive fluid wave on ballottment)

• Distended jugular veins

• Positive hepatojugular reflux —> putting gentle pressure on the caudle abdomen will lead to distention of the jugular veins —> sign of increased R sided filling pressure

  

• +/- pleural effusion (could be left in cat)

• Rarely sub-cutaneous oedema in SA (horses and cattle)

How do you check the hepatojugular reflex?

• Gentle pressure on the caudal abdomen causes increased distention / pulsation of the jugular veins

• Signs of increased right sided filling pressure

What will you auscultate on the heart?

What are the normal paramotors for cats and dogs?

• Record heart rate and rhythm

  • Sinus arrhythmia is normal in dogs

  • Normal heart rate in dogs: 80 – 140

  • Normal heart rate in cats: 120 – 200

• If abnormal rhythm check femoral pulse at same time as checking HR for deficits

• Listen for murmurs & gallop sounds

How do you further define a murmur?

• Location (point of maximal intensity) —> Left vs Right; Apex vs Base

• Timing —> Systolic vs Diastolic vs Continuous

• Grade

• Character, Radiation?

How do you grade a heart murmur?

• I/VI —> very quiet murmur, only detected in optimal conditions

• II/VI —> less loud than the heart sounds

• III/VI —> as loud as the heart sounds

• IV/VI —> louder than the heart sounds

• V/VI —> loud heart murmur with a precordial thrill

• VI/VI —> very loud murmur with a precordial thrill, which can be still detected after lifting the stethoscope off the chest wall (feel with fingers on the chest)

How do you locate heart murmurs?

• Left Apex —> Mitral valve

• Left Base —> Pulmonic valve/ aortic

• Left Cranio-Dorsal —> Patent ductus arteriosus (PDA)

• Right side of chest —> Tricuspid valve (apex) = soft murmur/ ventricular septal defect = loud murmur (cranio-sternal)

What do you need to not forget to auscultate in the heart with cats?

Sternal borders (pick them up)

How do you figure out the timing of the heart murmur and what other characteristics could you identify?

• Systole —> between S1 (closure of AV valves) and S2 (closure of pulmonic & aortic valves i.e. semilunar valves)

• Plateau

• Blowing, Decrescendo

• Crescendo-Decrescendo

• Brief-mid systolic

When are heart murmurs detected?

When turbulent vs laminar flow is present in heart / great vessels

What is the equation to determine if blood is turbulent?

If Reynolds number is more than 2000 = turbulent

Describe murmurs in puppies & kittens

• Innocent murmurs

• Usually < grade 3/6

• Usually apical

• Diminish with growth

• Disappear by 16 – 20 weeks old

• Due to change in foetal to adult haemoglobin

• Hard to distinguish from congenital heart disease

How do you listen for diastolic gallops?

• S3 and S4 (not audible in SA)

• Use bell of stethoscope with very little pressure over left apex

• Will hear Lup-Dup-Te

What would be the cause of S3 and S4?

• S4 is detected in animals which depend on atrial contraction to achieve ventricular filling e.g. with abnormal LV relaxation, in feline hypertrophic cardiomyopathy

• S3 is heard when early diastolic filling is abruptly decelerated in a stiff, poorly compliant LV, and filling pressures are high e.g. dilated cardiomyopathy

What do you need to be aware of with respiratory auscultaton?

• Be aware of referred sounds from the URT (especially in brachys)

• Check larynx and trachea (palpation & auscultation)

• Bronchovesicular lung sounds —> normal respiratory sounds (harsher when faster respiratory rate / panting)

What abnormal lung sounds do you need to identify?

• Crackles (inspiratory) —> smaller airways opening

• Wheezes (expiratory) —> narrowed airways

What can you identify when you percuss the thorax?

• (percuss both sides of chest)

• Identify any asymmetry / areas of increased / decreased percussion resonance

• Pleural effusion —> increased dullness

• Pneumothorax —> increased resonance

What can thoracic compressibility be useful for?

• More useful in cats than dogs

• Useful to detect cranial mediastinal masses

• Also less compressible with significant pleural effusion

How you distinguish between cardiac and respiratory disease when a patient has a cough?

What is the commonly used classification of severity of heart disease?

ABCD classification

(heart dx DOES NOT equal heart failure)

Describe the ABCD classification

*for mitral regurgitation (MMVD = myxamatous mitral valve dx)

What is the ABCD classification for feline cardiopyopathies?