cvs examination of domestic animals

1. SPECIAL CLINICAL EXAMINATION
OF THE CARDIOVASCULAR SYSTEM
OF DOMESTIC ANIMALS.

2. 1
SPECIAL CLINICAL EXAMINATION OF THE CARDIOVASCULAR SYSTEM
OF CATTLE (RUMINANTS).
Introduction
Cattle are phlegmatic animals and rarely undertake strenuous exercise. As a
result, signs of cardiac disease may not be recognised until the disease is at
an advanced stage. Cardiac anomalies are not uncommon in calves. Affected
calves may show signs of poor growth and, in advanced cases, heart failure.
In mild cases there may be no external signs and the cardiovascular
abnormality is only detected during a careful clinical examination. In severe
and advanced cases of heart disease some external signs of illness, including
those of heart failure, may be seen. Animals may lose condition and may
show increased respiratory effort in an attempt to compensate for developing
hypoxia. Exercise tolerance may be reduced.
Applied anatomy
The heart lies in the anterior part of the thorax between the 3rdand 6th pair of
ribs (Fig1.). The base of the heart is situated approximately half way up the
thorax. The heart is tilted in a craniocaudal direction in the thorax. The
anterior extremity ofthe base ofthe heart where the great vessels originate is
level with the 3rd rib. The posterior extremity is higher up in the chest and is
level with the 5th rib. The apex of the heart is low down in the chest and level
with the 6th rib.
(Fig 1)
Aorta
Lt Atrium
Lt VentricleRt ventricle
Pulmonaryartery
Anteriorvenacava

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Visual inspection and physical examination of the cardiovascular system
As part of the complete clinical examination the patient is inspected to see if
there are any gross signs of cardiac disease or cardiac failure. The
cardiovascular system is then carefully and methodically examined to
determine whether any abnormalities are present. Abnormalities detected
during the examination might be contributing to physical signs already
present or which might cause signs at a later stage of the disease.
Signs of heart failure
These have been divided into those involving the right and left side of the heart
and relate to the physiological functions of that part of cardiac activity.
Right-sided heart failure
The signs of right-sided heart failure are associated with congestion of the
peripheral circulation. They include distension of the jugular veins, brisket
and submandibular oedema, and less commonly distension of the abdomen
by ascites (Fig2.). The hypovolaemia of a failing peripheral circulation may
result in reduced renal perfusion and lowered urinary output. Venous
congestion in the portal system may result in enlargement of the liver, a
reduction in hepatic activity and diarrhoea. Poor exercise tolerance may also
be observed, and the animal may appear dull and depressed. Occasionally in
cardiovascular disease cases, signs of collapse with temporary loss in
consciousness (syncope) may be seen.
Left-sided heart failure
In left-sided heart failure there is increased pulmonary venous pressure causing
oedema and decreased elasticity of the lung tissue. Breathing may appear
laborious, and the rate and depth of respira- tion may increase. The animal
may have reduced exercise tolerance, there may be cyanosis of the mucous
membranes and the animal may occasionally have a cough. In advanced
cases both sides of the heart are affected and signs of generalised congestive
heart failure including diarrhoea may be evident.
Abnormalities associated with specific cardiac diseases including endocarditis,
pericarditis and cardiomyopathy may also be observed.

4. 3
Fig 2) Bullock with right-sided heart failure. submandibular and brisket oedema,
distended jugular vein and ascites.
Abdominal
enlargement caused
by ascites
Submandibularodema
Distendedjugularvein
Brisketodema

5. 4
Examination of the cardiovascular system
Peripheral pulse
The peripheral pulse may have been taken earlier on in the clinical examination
but can be checked again. The pulse is influenced by many factors and the
significance of abnormalities in its rate, rhythm, strength and character must
be interpreted with care and in relation to the other clinical findings. If a
peripheral pulse cannot be easily and safely detected the pulse rate can be
measured during cardiac auscultation. Pulse deficits noted when the pulse rate
is slower than the heart rate – are uncommon in cattle.
Tachycardia may occur in nervous and stressed animals, and the patient should
be allowed time to settle down before the pulse is taken. The pulse rate also
rises in pyrexic animals and those which have under- gone strenuous exercise
or are experiencing pain.
It also rises when oxygen levels in the body fall or CO2 levels rise. An increase
in pulse frequently accompanies conditions such as cardiac disease,
pneumonia and anaemia.
Bradycardia may occur in terminally ill animals and in some cases of vagal
indigestion.
Rhythm, strength and character The rhythm, strength and character of the
peripheral pulse should also be assessed.
Irregularities of rhythm – dysrhythmias – are seen in some cases of chronic
cardiac disease and also in some cases of metabolic disease such as ketosis.
In the latter cases cardiac dysrhythmia returns to normal after the metabolic
disease has been resolved. Dysrhythmia is also seen in cases where blood
potassium rises, including some cases of calf diarrhoea and in downer cows
with ischaemic muscle necrosis. A hard bounding pulse is recognised by the
strength with which it pushes against the clinician’s fingers. It indicates a
greater stroke volume by the heart. It occurs in response to pain, excitement
and resistance
to blood flow.

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A weak soft pulse can be difficult to detect, especially if the animal is restless. It
indicates a reduced cardiac output or a loss of blood volume. This type of
pulse may also be seen in terminally ill animals, those with heart failure and
following severe blood loss. A weak pulse may also be found in cows
suffering from milk fever.
Cold extremities in an animal may suggest poor peripheral blood perfusion.
Colour of mucous membranes -
The colour of the mucous membranes should always be observed. Normally
salmon pink in colour, the membranes may be cyanotic in cases of
terminal heart failure or severe respiratory disease. Pale mucous
membranes indicate poor peripheral perfusion. Anaemia may be caused by
blood loss or by a failure in the production of blood. It may also develop in
some cases of endocarditis and in calves with cardiac anomalies in which red
blood cells are destroyed by a turbulence in blood flow. Primary anaemia, not
associated with cardiac disease, may also give rise to signs of exercise
intolerance, tachycardia and some- times tachypnoea.
Capillary refill time
This is a measure of effective cardiac function. Digital pressure on an area of
non-pigmented mucosa of the lips, dental pad or vulval mucosa causes
blanching of the mucous membranes. Colour should return quickly in less
than 2 seconds after pressure is released. Prolonged capillary refill time of
more than 5 seconds is indicative of a poor circulation. It can be caused by
cardiovascular disease or by other abnormalities such as dehydration.
Apex beat of the heart
The apex beat of the heart, caused by the apex or point of the heart contacting
the chest wall, may be palpable low down in the chest at the level of the 6th
rib. The apex beat can often be seen and readily palpated in the newborn calf.
Its presence in older animals may indicate a degree of cardiac enlargement

7. 6
Jugular pulse
Some pulsation of the jugular vein associated with closure of the left
atrioventricular (mitral) valve is normally visible in the lower third of the
jugular furrow on both sides of the body. It is associated with atrial systole.
Compression of the vein in normal animals should lead to the disappearance of
the jugular pulse as the vein empties. Pulsation extending up to the angle of
the jaw is abnormal and may suggest in- competence of the tricuspid valve. In
such cases compression of the vein does not result in a loss of the jugular
pulse. The pulsation may be particularly obvious when the jugular vein is
already distended by circulatory failure. If a normal animal’s head is lowered
as for example when feeding pulsation can often be seen throughout the
length of the jugular veins. This pulsation disappears when the head is raised
and is of no pathological significance. The normal jugular vein looks full when
the head is lowered and the vein is below the level of the heart. False jugular
pulsation may be observed if pulsation of the carotid artery beneath the vein is
displacing it.
Jugular filling
The filling and emptying of the jugular veins are important indicators of the
efficiency of the cardiovascular system, especially in terms of venous
drainage (return) and the ability of the heart to pump back blood from the
peripheral and pulmonary circulations. Distension of the jugular vein can be
a sign of right-sided heart failure and should not be present in normal animals.
Blocking venous return in the jugular vein by pressing on the vein near the
base of the neck causes rapid distension of the vein in a normal animal (Fig
3.). The distension should disappear as soon as pressure on the vein is
removed. Release of digital pressure on a distended jugular vein does not
result in it emptying in cases of conges- tive heart failure. Distension of the
jugular veins may also be observed in animals in which there is a space
occupying lesion at the thoracic inlet. The large external abdominal veins
(‘milk veins’) which lie below the level of the heart normally appear full of
blood. In dehydrated animals or those suffering from shock the jugular veins
may appear flat and empty. Pressure on the lower extremity of the vein may
fail to produce any degree of filling.

8. 7
(fig 3)
Auscultation ofthe heart –
This is carried out on both sides of the chest between the 3rd and 6th ribs. As
this area is covered by the triceps muscle it helps to pull the patient’s foreleg
forwards, a movement that may not be tolerated ex- cept in small or very quiet
animals.
The observations made during auscultation are now described.
Normal heart sounds
Four heart sounds have been described in cattle: S1, S2, S3 and S4. S1 and S2
are normally heard without difficulty, but S3 and S4 may not be readily
detected under noisy farm conditions. The events accompa- nying the normal
heart sounds are as follows:
S1 – ‘lub’: closure ofthe atrioventricular valves in full systole
S2 – ‘dup’: closure of the aortic and pulmonary valves at the start of diastole
S3 – a dull thud sometimes audible immediately after S2: the ventricles fill
with blood in early diastole
S4 – a soft sound, sometimes heard just before S1, which is associated with
atrial contraction
Enlarged
retropharyngeal
lymph nodes Lesions of ‘skin TB’
Distended jugular vein
Thumb occluding
jugular vein
Palpation/compression of
trachea Larynx

9. 8
Intensity of heart sounds
The bovine heart should be clearly audible through the stethoscope. In fat,
heavily muscled animals the intensity of the heart sounds may be reduced,
but in such animals there should be no other signs of heart failure. Pericardial
effusion may result in reduction of the audible intensity of the heart sounds
and may be accompanied by other signs of cardiac disease such as brisket
oedema. Pericardial effusion may occur in early cases of pericarditis and in
some cases of endocarditis. Heart sounds are usually equally intense on both
sides of the chest, but may be slightly louder on the left side. The heart sounds
may be very loud in cases of acute hypomagnesaemia when they may be
audible without a stethoscope through the chest wall.
Auscultation of the heart valves
The position of the heart valves is shown diagram- matically in Figs 4 –6. In the
living animal they can be located within the area bounded by a line drawn
horizontally back from the shoulder joint and a line drawn vertically up from
the elbow joint.
Figure 4 Position of the
pulmonary (P), aortic (A) and
bicuspid or mitral (B) heart
valves.The stethoscope is advanced
under the triceps muscle to get as
close to the valves as possible.

10. 9
(Fig 5) Position of the tricuspid (T) heart valve ( fig 6) Positions of the cardiac valves looking down
into the heart from above: P, pulmonary;A, aortic;T, tricuspid; B, bicuspid or mitral valve
Abnormal heart sounds
Adventitious sounds – cardiac murmurs – are sounds which are superimposed
over the normal heart sounds. They may be so loud that they mask normal
heart sounds or so quiet that they are overlooked in a noisy environment.
Murmurs are mostly caused by leakage of blood through closed but
incompetent valves, or through congenital orifices between the chambers of
the heart. Other murmurs are caused by the presence and movement of fluid
within the pericardium. It is important to detect, by careful auscultation over a
series of cardiac cycles, the nature and location of any cardiac abnormality
which is causing the murmur. Small defects can produce quite loud murmurs.
Murmurs are most likely to be heard in systole when blood within the heart
is under the greatest pressure. It is important to be sure that audible murmurs
are arising from the heart and not from the respiratory system. Friction rubs
caused by pleural adhesions may be mistaken for abnormal heart sounds.
Brief blockage of the nostrils will eliminate respiratory but not cardiac sounds.
Murmurs may be classified according to the part of the cardiac cycle over which
they can be heard. Apansystolic murmur extends over the whole period of
systole. Such a murmur may be heard in cases where there is incompetence
of an atrioventricular valve. Diastolic murmurs are less common but may be
audible, for example, where there is incompetence of the aortic valve: this
allows blood to leak back into the heart with a resultant murmur when the
valve is closed. In cases of patent ductus arteriosus (PDA) the murmur, which
is of varying intensity, extends over the whole cardiac cycle.

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In some cases the audible pitch of the murmur re- mains constant, in which
case it is called a plateau murmur. If the pitch rises it is known as a
crescendo murmur. If the pitch falls it is known as a decres- cendo murmur.
If it rises and falls it is known as a crescendo–decrescendo murmur.
Haemic murmurs may be heard during systole in the region of the tricuspid
valve. They are sometimes present in anaemic animals, possibly as a result of
cardiac dilation and reduced viscosity of the blood.
In some animals with cardiac defects where the pa- tient is chronically hypoxic
an increase in the number of circulating blood cells – polycythaemia – occurs
as a compensatory mechanism.
Grading of abnormal heart sounds
Murmurs can be graded from 1 to 6 according to their intensity orloudness:
Grade 1 – very quiet, heard only with difficulty
Grade 2 – quiet but easily heard
Grade 3 – equal intensity with the normal heart sounds
Grade 4 – louder than the normal heart sounds
Grade 5 – very loud with a thrill (a vibration) that is palpable through the chest
wall
Grade 6 – very loud and audible through a stetho- scope held just off the chest
wall
Point of maximum intensity (PMI) of a murmur
This point should be located by moving the stethoscope carefully around the
area of the chest wall be- tween the 3rd and 6th ribs. Murmurs may be audible
on one or both sides of the chest with a PMI on either side.

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Percussion of the heart
This test can provide a useful indication of the size of the heart and whether it is
enlarged. Pulling the fore- leg forward helps expose the area for percussion
on the chest wall. Cardiac percussion should normally be included with
general percussion of the chest, since findings can be influenced by the
presence of pulmonary abnormalities. The heart lies beneath the 3rd and 6th
ribs on the right and beneath the 3rd and 5th ribs on the left; it extends
approximately half way up the ribs on both sides. Percussion around and
across this region indicates the area of cardiac dull- ness. The area may be
more obvious on the left than on the right. Any increase in the size of the
area of cardiac dullness can be caused by compensatory enlargement of the
heart in cases of chronic cardiac disease. It is also increased by the presence
of a peri- cardial effusion. The area of cardiac dullness can be reduced by
emphysema in the lungs. In cattle with pneumonia, ventral consolidation of
the lungs can make identification of areas of cardiac dullness difficult.
Electrocardiograph
The ECG is of limited value in cattle but can be used to confirm abnormalities
of rhythm. The extensive Purkinge network of the bovine heart makes it un-
likely that changes in ventricular size can be inferred from an ECG recording.
A three-lead system is used (Fig. 7) with the right arm (RA) lead attached to
the thoracic wall over the base of the heart. The left arm (LA) lead is attached
over the cardiac apex and the neutral (N) lead is attached to the skin over the
withers. The P and T waves of the ECG trace are usually clearly visible as is
the QRS complex (Fig. 8). In cases of atrial fibrillation including some
animals with gastrointestinal disturbance, the normal P–QRS–T sequence in
the trace is not visible. A series of of abnormal F waves replace the P wave,
with QRS complexes appearing at random.

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Fig 7 Recording a bovine electrocardiograph.The right arm (RA) lead is placed on the neck, the left arm (LA) lead
is placed on the chest wall just above the sternum, and the neutral (N) lead is placed on the withers
fig 8 ECGfrom a normal animal recorded using the
lead configuration shown in Fig. 7 . Note the
positive P and T waves and the negative QRS
complex
Ultrasonographic (US) evaluation
This is useful to detect abnormalities around the heart and some details of its
internal structure. Evidence of fluid within the pericardial sac may be seen as
a black nonechogenic area surrounding the heart. If the contents of the
pericardial sac are purulent, flecks of hyperechogenic material may be seen.
The B-mode scanner can also be used to guide a needle into the pericardial
sac to collect a sample of fluid for analysis. A 3.5 or 5MHz probe is suitable
for examin- ing the heart in calves. For larger cattle, a 2.25 or 3.0 MHz
probe, which gives greater penetration, is needed. Access for
ultrasonography to the bovine heart may be difficult since in the lower thorax
the ribs are wide and the space between them is very narrow. Quite good
LA lead
Neutral
RA lead

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visualisation of the cardiac chambers can be achieved in calves using a basic
linear array scanner. Such scanners can also be used to detect the presence
and character of pericardial fluid (Fig.9). Sophisticated but expensive
scanners such as the Doppler flow sector scanner produce more information,
including the direction and pressure of blood flow. This information is
particularly helpful in cases of congenital cardiac abnormality.
Radiography
This is of limited value in assessing bovine cardiac morphology. The size and
mass of the bovine heart prevent clear demonstration of the internal divisions
of the heart. An outline of the heart can be delineatedradiographically giving
an approximate measure of size. Radioopaque foreign bodies (such as wires)
may be detected as they pass through the diaphragm from the reticulum to the
pericardium.
Tricuspidvalve
Bodywall
Pericardial effusion
Wall of ltventricles
Fig 9 Diagram of an ultrasonographic scan of an animal suffering from pericarditis showing the
presence of a pericardial effusion.

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Pericardiocentesis
This technique is used to collect and assess peri- cardial fluid. A 12 cm spinal
needle of size 16 BWG (1.65 mm) is used. The needle is inserted through the
chest wall into the pericardial sac and fluid is allowed to flow or is aspirated
using a syringe. Local anaes- thetic is injected into the skin and muscle
layers of the space between the 5th and 6th ribs. The area is prepared
aseptically and the needle with syringe attached is advanced carefully
towards the heart. Fluid, which may be very foul smelling if infection is
present, is aspirated for cytology, culture and drainage purposes. If
ultrasonographic equipment is available the needle may be directed visually. If
such equipment is not available care must be taken to avoid penetrating the
myocardium with the needle .(fig 10)
Fig 10 Pericardiocentesis from an animal suffering from pericarditis.
Blood culture
Blood for culture may be taken aseptically from the jugular vein. This can be
useful in cases of endocarditis, but repeated samples may needed as bacterial
release from valve lesions may be intermittent.
5th rib
Chest drain

16. 15
Pain test
It is a specific test for confirmation the diagnosis of traumatic pericarditis
Walking on down hill
Upward give no signs, Downward the animal show the signs of pain or
reluctant to walk.
Pinching of weather
the animal show the signs of pain.
Turning the animal in acute angle
it shows the signs of pain.
Side stick method
by raising the animal and suddenly release of the animal we found the grunting
sound.
Angiocardiography-
Angiocardiography is contrast radiography of the heart and great vessels. A
liquid radiocontrast agent, typically containing iodine, is injected into
the bloodstream, then the tissues are examined using X-rays.
To avoid dilution, the radiopaque material is typically introduced with
a catheter, a process known as selective angiocardiography. Normally, rather
than just a single image, hundreds of X-ray images are rapidly captured on
high-speed serial media, such as 35mm film or, a digital imaging counterpart
thus allowing the motion to be observed. The process requires fasting before
the test, with a sedative and an antihistamine being administered before the
test.
Phonocardiography –
Phonocardiography,diagnostic technique that creates a graphic record, or
phonocardiogram, of the sounds and murmurs produced by the
contracting heart, including its valves and associated great vessels. The
phonocardiogram is obtained either with a chest microphone or with a
miniature sensor in the tip of a small tubular instrument that is introduced via
the blood vessels into one of the heart chambers. The phonocardiogram
usually supplements the information obtained by listening to body sounds
with a stethoscope (auscultation) and is of special diagnostic value when
performed simultaneously with measurement of the electrical properties of
the heart (electrocardiography) and pulse rate.

17. 16
SPECIAL CLINICAL EXAMINATION OF CARDIOVASCULAR SYSTEM OF
DOG AND CAT .
INTRODUCTION
The CV examination and medical history can reveal evidence of previously
unsuspected heart abnormalities as well as provide important information in
animals with known CV disease. The patient’s signalment should be noted
because some congenital and acquired heart abnormalities are more
prevalent in certain breeds or age ranges, and some conditions have a
gender predisposition.
SIGNS OF HEART DISEASE AND FAILURE
Cardiac disease can exist without the animal being in ‘heart failure’. Signs
consistent with heart disease include cardiac murmurs, rhythm disturbances,
jugular vein pulsations, and cardiomegaly. Other clinical signs can also
suggest cardiac disease or failure, but they may occur with noncardiac
disease as well. These include cough, respiratory difficulty, exercise
intolerance, weakness, syncope, abdominal distension, tissue edema,
excessively weak or strong arterial pulses, and cyanosis.
Most clinical signs of heart failure relate to high venous pressure behind the
heart (congestive signs) or inadequate blood flow out of the heart (low
output signs). Congestive signs related to right-sided heart failure stem from
systemic venous hypertension and the elevated systemic capillary
hydrostatic pressure that results. Pulmonary venous hypertension and
subsequent lung edema result from elevated left heart filling pressure.
Chronic elevation of pulmonary venous pressure may increase pulmonary
arterial pressure and facilitate the development of right-sided heart failure in
patients with chronic left-sided heart failure. Signs of low cardiac output are
similar regardless of which ventricle is primarily diseased, because output
from the left heart is coupled to that from the right heart.

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OBSERVATION OF THE PATIENT
Prior to the CV examination, the patient’s attitude, posture, body condition,
level of anxiety, and respiratory pattern should be observed. The animal’s
appearance depends on the severity of underlying disease and
hemodynamic or respiratory compromise, as well as other factors. The body
condition of patients with CV disorders is variable; some animals are thin,
some are obese. However, weight loss is common in advanced disease and
cardiac cachexia may occur with chronic heart failure.
THE CARDIOVASCULAR EXAMINATION
EVALUATION OF MUCOUS MEMBRANES
Adequacy of peripheral perfusion is estimated by mucous membrane color
and capillary refill time (CRT). Oral membranes are usually assessed, but
caudal (prepucial or vaginal) membranes also can be used. The ocular
conjunctiva can be used if the oral membranes are pigmented. When
polycythemia is present, caudal mucous membrane color should be
compared with that of the oral membranes, regardless of whether a cardiac
murmur is detected.
The CRT is assessed by applying digital pressure to blanch the membrane;
color should return within 2 seconds. Dehydration and other causes of
decreased cardiac output cause slowed CRT because of high peripheral
sympathetic tone and vasoconstriction. Mucous membrane pallor results
from anemia or peripheral vasoconstriction. Anemic animals have a normal
CRT unless hypoperfusion is also present, although the CRT can be
difficult to assess in severely anemic animals because of the lack of color
contrast.

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EVALUATION OF JUGULAR VEINS
Systemic venous and right heart filling pressures are reflected at the jugular
veins. When the animal is standing with its head in a normal position (jaw
parallel to the floor), these veins should not be distended. Persistent jugular
vein distension occurs when central venous pressure is high, and suggests
either high right heart filling pressure or obstruction to cranial vena cava
flow. Jugular pulsations extending higher than the point of the shoulder in a
standing animal are also abnormal.
Testing for hepatojugular reflux can uncover impaired RV filling, reduced
pulmonary blood flow, or tricuspid regurgitation, even in the absence of
jugular distension or pulsations at rest. To test for this reflux, apply firm
pressure to the cranial abdomen while the animal is standing quietly . This
will transiently increase venous return. Jugular distension that persists while
abdominal pressure is applied constitutes a positive (abnormal) test. Normal
animals have little to no change in jugular vein appearance.
PRECORDIALPALPATION
Normally, the strongest systolic impulse occurs over the area of the left
cardiac apex, located at approximately the 5th intercostal space near the
costochondral junction. To detect this, the precordium is palpated by
placing the palm and fingers of each hand on the corresponding side of the
animal’s chest wall over the heart. Cardiomegaly or a space-occupying
mass within the chest can shift the precordial impulse to an abnormal
location. Reduced intensity of the precordial impulse can be caused by
obesity, weak cardiac contractions, pericardial effusion, intrathoracic

20. 19
masses, pleural effusion, or pneumothorax. A stronger precordial impulse
on the right chest wall compared with the left can occur with RV
hypertrophy or displacement of the heart into the right hemithorax (e.g. by a
mass lesion, lung atelectasis, or chest deformity).
The term precordial thrill refers to palpable chest wall vibrations caused by
very loud cardiac murmurs. These feel like a focal ‘buzzing’ sensation on
the hand. A precordial thrill is usually localized over the area where the
murmur is loudest.
CARDIAC AUSCULTATION
Approximate locations of cardiac valve areas in the dog and cat.

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The normal heart sounds (S1 and S2), along with most pathologic murmurs,
are high-frequency heart sounds and are heard best with the diaphragm of
the stethoscope. The abnormal "gallop" sounds are low-frequency sounds,
and their detection is accentuated with the bell of the stethoscope. The most
common type of murmur by far is that occurring during systole; continuous
murmurs (those occurring during both systole and diastole) are a distant
second Isolated diastolic murmurs are relatively rare. Cats often present
with soft systolic murmurs along the parasternal region. These murmurs can
be very focal and quite dynamic; the intensity (or loudness) of the murmur
can vary considerably or even be absent at times (intermittent murmur).
When the timing of the murmur is combined with the anatomic location
where the murmur is loudest, the cause of the murmur can be accurately
diagnosed . The gallop sounds can be heard with abnormal ventricular
filling. The third heart sound (S3) is due to the rapid cessation of ventricular
filling associated with a dilated ventricular chamber and occurs in early
diastole. The fourth heart sound (S4) occurs when atrial contraction pushes
blood into an already stiff ventricle (and occurs during late diastole). The
presence of an S3 or S4 is always considered abnormal in the dog and cat.
Phonocardiograms illustrating murmurs and gallop sounds of common
cardiac diseases

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STETHOSCOPE PLACEMENT FOR CARDIAC EXAMINATION
Valve Point of Maximal Intensity
Mitral Left 5th intercostal spaceat costochondraljunction
Tricuspi
d
Between right intercostal spaces 3-5 just above costochondraljunction
Pulmonic Between left intercostal spaces 2-4 just above sternum
Aortic Within left intercostal space4-5 just above costrochondraljunction
EVALUATION FOR ABNORMAL FLUID ACCUMULATION
Elevated right heart filling pressure promotes abnormal fluid accumulation
within body cavities or, usually less noticeably, in the subcutis of dependent
areas. Palpation and ballottement of the abdomen, palpation of dependent
areas, and percussion of the chest in the standing animal are used to detect
effusions and subcutaneous edema. Fluid accumulation secondary to right-
sided heart failure is usually accompanied by abnormal jugular vein
distension and/or pulsations, unless the animal’s circulating blood volume
has been reduced (e.g. by diuretic use). Hepatomegaly and/or splenomegaly
may also be palpable in cats and dogs with right-sided heart failure.

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RADIOGRAPHY
Good quality thoracic radiographs can provide vital information about
overall cardiac size and shape in dogs and cats with heart disease.
Radiographs are the best means of evaluating pulmonary blood vessels,
examining the lungs for evidence of edema or other abnormalities, and
assessing the pleural space, mediastinum, and diaphragm. However, a major
limitation of radiography is that fluid has the same opacity as soft tissue.
Because the heart appears as a single fluid/tissue opacity, internal structures
cannot be discerned and pericardial effusion cannot be differentiated from
cardiomegaly.
RADIOGRAPHIC VIEWS
At least two views should be evaluated: lateral and dorsoventral (DV) or
ventrodorsal (VD). Slight changes in cardiac appearance occur with
different patient positions; therefore, it is best to be consistent in the views
used to evaluate the heart. The right lateral view is generally preferred for
cardiac evaluation in dogs and cats. The upper (nondependent) lung fields
are accentuated on lateral view. Unilateral pulmonary disease can be better
delineated using both right and left lateral views. In general a DV view
provides better definition of the hilar area and caudal pulmonary vessels
than a VD view. Furthermore, a DV position is better tolerated when
respiration is compromised. The heart tends to look more elongated on a
VD view compared with a DV view, but a VD view is often better for
detecting lung disease and small volume pleural effusion.
Generalized cardiomegaly
that resulted from a large
congenital atrial septal
defect,tricuspid
insuffiency, and mitral
insufficiency.

24. 23
ELECTROCARDIOGRAPHY-
An electrocardiogram (ECG) is a test that records the electrical activity of the heart as
a graphic display on graph paper, known as a trace. The electrical impulses are
recorded as waves or deflections and one heartbeat is usually recorded as a grouping of
waves known as the P-QRS-T complex. Clip-on electrodes attached to the limbs and
various points on the thorax pick up the electrical impulses produced by a beating
heart, which can be detected in the heart itself and in the body surrounding it.
Electrocardiography has now been standardised to enable traces to be compared.
Interpreting an ECG -A cardiac cycle is a full sequence of events in the heart and
includes one complete heartbeat. It includes systole (the period when the heart
contracts and pumps out blood, ‘lub’), diastole (the period when the heart relaxes and
fills with blood, ‘dub’) and the intervals between. The heart beat is triggered by
electrical impulses. Cardiac depolarisation is the loss of difference in electrical charge
between the inside and the outside of the plasma membrane of a cardiac muscle cell,
and occurs when the heart muscle cells contract. Cardiac repolarisation is the
restoration of the difference in electrical charge between the inside and outside of the
plasma membrane of a cardiac muscle cell and occurs when the heart muscle cells
relax. To identify whether an ECG is normal or not you need to examine each of the
wave components in one complete cardiac cycle. • P wave – atrial depolarisation • PR
interval – delayed conduction through the AV node • QRS complex – ventricular or
depolarisation • ST segment – period between ventricular depolarisation and
repolarisation • T wave – ventricular repolarisation .
ECG parameters measured from lead II –
• Heart rate (adult dogs 70-160 beats per minute (bpm), giant breeds 60-140 bpm, toy
breeds 70-180bpm, puppies 70-220 bpm)
• Heart rate is calculated as cycles per minute (atrial rate is estimated by the number of
P waves, ventricular rate is estimated by the number of R waves)
• Are P waves visible and is there a P wave for every QRS complex?
• P wave duration (≤0.04 seconds (s))
• P wave amplitude (≤0.4 mV)
• PR interval (0.06-0.13 s)

25. 24
• Is the difference between the P wave and QRS complex constant? (small differences
are normal but they should not exceed 0.01-0.02 s)
• Are all the P waves and QRS complexes similar?
• QRS complexes, are they narrow (normal) or wide (abnormal, known as bizarre)?
• QRS complex duration (large breeds ≤0.06 s, small breeds ≤0.05 s)
• ST segments, are they normal, depressed or elevated? (≤0.2 mV depression and
≤0.15 mV elevation)
• R wave amplitude (large breeds ≤3.0 mV, small breeds ≤2.5 mV)
• T waves (≤ ¼ of R wave height)
• QT interval (0.15 - 0.25 s at normal heart rate)
• Mean electrical axis +40° - +100°
To calculate heart rate on an ECG trace:
 Paper speed 50 mm/sec: 3000 divided by measured distance between 2
complexes
 Paper speed 25 mm/sec: 1500 divided by measured distance between 2
complexes.
ECHOCARDIOGRAPHY –
An ultrasound (echocardiogram) is a non-invasive procedure used to
evaluate the internal organs of dogs and other animals. An
echocardiogram is commonly referred as an “Echo”. Ultrasound
examinations can be used to examine the heart, abdominal organs, eyes
and reproductive organs in dogs. Ultrasound applied to the heart is called
an “echocardiogram”.
For many problems, both ultrasound and X-rays are recommended for
optimal evaluation. The X-ray shows the size, shape and position of the
heart and chest contents, and also permits the veterinarian to examine the
lungs. In contrast, the echocardiogram cannot be used to examine the
lungs, but this ultrasound exam allows the veterinarian to see inside the
heart. For moving organs such as the heart, the size, tissue character, and

26. 25
muscle function can be assessed in what is called a “real time”
examination that resembles a motion picture. Components of the
echocardiogram can include the two-dimensional exam (to see lesions and
overall cardiac structure), the M-mode study (used to measure heart size
and function), and the Doppler examination (used to evaluate blood flow).
These examinations are complementary.
An echocardiogram is indicated to evaluate pets with a suspicion of
congenital or acquired heart disease. An echocardiogram may be
performed when indicated by the results of an X-ray, when there is a
suspicion of heart disease based on physical examination. For example,
detection of a heart murmur or irregular heart rhythm could be an
indication for an echocardiogram.
BloodTests
 Laboratory tests are used to detect the risk factors for heart diseases.
These include detection of the fats, cholesterol and lipid components of
blood including LDL, HDL, Triglycerides.
 Blood sugar and Glycosylated hemoglobin is measured for detection of
diabetes. C-reactive protein (CRP) and other protein markers like
Apolipo protein A1 and B are used to detect inflammation that may
lead to heart diseases.During a heart attack, heart muscle cells die and
release proteins into the bloodstream.
 Blood tests can measure the amount of these proteins in the
bloodstream. High levels of these proteins are a sign of a recent heart
attack.One of the markers of heart attack is the Cardiac Troponin-T.
Other biomarkers include fibrinogen and PAI-1, high levels of
homocysteine, elevated asymmetric dimethylarginine and elevated
brain natriuretic peptide (also known as B-type) (BNP).

27. 26
Stress Testing
For this test, the patient is made to work hard e.g. run on a treadmill or
exercise while the leads of EKG/ECG are placed over their body. Those
who cannot exercise are given pills to raise their heart rate. The test detects
the effects of the exercise on the heart.
In patients with atheroisclerosis and coronary heart diseases the arteries
that are narrowed by plaques cannot supply adequate blood to the heart
muscles while it is beating faster. This may lead to shortness of breath and
chest pain. The EKG/ECG pattern, arrhythmias etc. also show the
possibility of a coronary artery disease.
CoronaryAngiography and Cardiac Catheterization
This test is an invasive test. A dye is injected into the veins to reach the
coronary arteries. This is done via coronary catheterization. Thereafter
detailed pictures of the blood vessels of the heart are taken using special
imaging methods. This is called coronary angiography.
Cardiac catheterization involves threading of a thin, flexible tube called a
catheter via a blood vessels in the arm, groin (upper thigh), or neck. The
tube is inserted under imagin guidance till it reaches the heart. Coronary
angiography detects blockages in the large coronary arteries.
Electron-BeamComputed Tomographyor EBCT
EBCT helps to detect the calcium deposits or calcifications in the walls of
the coronary arteries.These are early markers of atherosclerosis and
coronary heart disease. This is not a routine test in coronary heart disease.
Cardiac MRI
Cardiac MRI (magnetic resonance imaging) that uses radio waves,
magnets, and a computer to create pictures of the heart. This gives a 3D
image of the moving as well as still pictures of the heart.
Phonocardiography
It allows the recording and measurement of heart sounds. A special
microphone is placed directly over the various ares of the thorax used for
heart auscultation and heart sound is recorded graphically on moving
paper or on a oscilloscope

28. 27
SPECIAL CLINICAL EXAMINATION OF CARDIOVASCULAR SYSTEM OF
HORSE.
INTRODUCTION-
The physical examination is still the most important portion of the
diagnostic work-up in the sick horse. Defining which system(s) is affected is
essential, although not always easy, when clinical signs are subtle.
HISTORY
 Signalment – age, breed and sex are very useful !!
 contact with other horses
 herd health – are the other paddock mates clinically normal ?
 vaccination status
 performance changes – “grumpy”, decreased function, collapse
 trauma – fractured ribs & myocardial damage, fractures ribs and lung
parenchymal damage, diaphragmatic hernia
 other illness – is it related ? (eg. Mild respiratory signs, a few weeks
later febrile and cardiac murmur and high fibrinogen and very high
WCC, then it might be due to endocarditis)
 feed changes, feed source (cattle feed preparation before equine –
ionophores in feed by mistake)
 changes in appetite and water intake – does the client really know ? (i.e.
paddock situation)
 toxic plants in your area
 urinating – does the owner/trainer really know – i.e. paddock versus
stabled •medications by the owner – eg. NSAIDS – how many different
ones have been administered? [eg. Phenylbutasone & Finadyne®
(Flunixin meglumine)]

29. 28
Inspection - Initially includes: general attitude, movement in stall. Prominent
jugular pulse with distended vein alerts the clinician.
MUCOUS MEMBRANE COLOUR:
Give guide to approximate tissue oxidation & perfusion of capillary bed to
assessed area.
NORMAL: pale pink(mouth & eye), pink (nasal septum), Bluish/cyanotic
(hypoxygenation ) ,dark red(deydration & endotoxemia) .
CAPILLARY REFILTIME:
Pressing index finger on MM on gum & above corner incisor tooth.
Blanching of MM after which blood will refill-1-2 sec. Prolonged CRT-
decreased peripheral perfusions.
Palpation –
 Its important to palpate all four legs,ventral chest & abdomen for any
swelling signs.
 Palpation of apex beat –indication of heart in thorax.
 Apex beat felt on left ventral chest wall about 10cm dorsal to
sternum in5-6 ICS.
 If thrill detected on cardiac palpation-severe flow disorder.
Auscultation :
 Examine with stethoscope.
 Examination starts over area of apex beat, caudal to triceps muscle &
about area 10cm ventral to level of point of shoulder.
 25-40 beats/min.
Heart sounds –
FIRST HEART SOUND:
Generated by closure of left(mitral) & right (tricuspid) artrioventricular
valves. Maximum audibility of mitral valve –on left 5th ICS.
Maximum audibility of tricuspid valve –on right side at 4th ICS.
SECOND HEART SOUND:
Sound generated by closure of aortic & pulmonary valve & is synchronous
with end of systole & beginning of of cardiac diastole.
Aortic component is audible-just ventral to horizontal line drawn drawn

30. 29
through point of shoulder in left 4thICS.
Pulmonic component is audible –ventral & anterior to aortic valve at in
left 3rd ICS.
THIRD HEART SOUND:
Low frequency sound produced with rapid filling of ventricles.Occurs
immediately afer 2nd sound.Common n horses.
FOURTH HEART SOUND:
Associated with atrial contraction.
Murmurs are audible successive sounds with distinct duration as opposed to
heart sound which are short & transient.
 Prolonged audible vibrations occuring during normal silent period of
cardiac cycle.
 Problems resulting in heart murmurs are:
 Decreased viscosity.
 Condition producing increased cardiac output.
 Abnormal blood flow.
 Temporary mumurs can be heard in colic also.
ELECTROCARDIOGRAPHY-
An electrocardiogram (ECG) is a test that records the electrical activity of
the heart as a graphic display on graph paper, known as a trace. The
electrical impulses are recorded as waves or deflections and one heartbeat
is usually recorded as a grouping of waves known as the P-QRS-T
complex. Clip-on electrodes attached to the limbs and various points on
the thorax pick up the electrical impulses produced by a beating heart,
which can be detected in the heart itself and in the body surrounding it.
Electrocardiography has now been standardised to enable traces to be
compared.
METAL ELECTRODE THAT
ARE CONNECTED TO LEG
BY RUBBER STRAP:
 Electrodes are applied on
forelimb caudal aspect of
distal radius just proximal
to carpal bone.

31. 30
 Electrodes are applied on hindlimb at cranial aspect of of distal tibia
above point of hock.
 Chest electrode -5cm behind point of elbow on left ventral thorax.
BIPOLAR LEAD SYSTEM USING Y LEAD:
 Positive lead attached over xiphisternum.
 Negative lead attached over manurium.
 Earth lead can be attached over point of shoulder.
ECHOCARDIOGRAPHY –
An ultrasound (echocardiogram) is a non-invasive procedure used to
evaluate the internal organs of horse and other animals. An
echocardiogram is commonly referred as an “Echo”. Ultrasound
examinations can be used to examine the heart, abdominal organs, eyes
and reproductive organs in horses. Ultrasound applied to the heart is
called an “echocardiogram”.
For many problems, both ultrasound and X-rays are recommended for
optimal evaluation. The X-ray shows the size, shape and position of the
heart and chest contents, and also permits the veterinarian to examine the
lungs. In contrast, the echocardiogram cannot be used to examine the
lungs, but this ultrasound exam allows the veterinarian to see inside the
heart. For moving organs such as the heart, the size, tissue character, and
muscle function can be assessed in what is called a “real time”
examination that resembles a motion picture. Components of the
echocardiogram can include the two-dimensional exam (to see lesions and
overall cardiac structure), the M-mode study (used to measure heart size
and function), and the Doppler examination (used to evaluate blood flow).
These examinations are complementary.
An echocardiogram is indicated to evaluate pets with a suspicion of
congenital or acquired heart disease. An echocardiogram may be
performed when indicated by the results of an X-ray, when there is a
suspicion of heart disease based on physical examination. For example,
detection of a heart murmur or irregular heart rhythm could be an
indication for an echocardiogram.

32. 31
Radiography
This is of limited value in assessing equine cardiac morphology. The size and
mass of the equine heart prevent clear demonstration of the internal divisions
of the heart. An outline of the heart can be delineatedradiographically giving
an approximate measure of size. Radioopaque foreign bodies (such as wires)
may be detected as they pass through the diaphragm from the reticulum to the
pericardium.
Reference-
1) Cardiovascular diseases in small animal medicine by wendy A ware
2) Clinical examination of farm animals by peter G.G jackson
Peter D.cockcroft .
3) Cardiology of horse by cella M. marr
I.mark bowen