Pros and cons of the different diagnostic investigations of the cardiovascular system.

1. Diagnostic Investigations
of Cardiovascular System
A presentation by Tejaswini M

2. Introduction
• Diagnostic investigations in
cardiology are methods of
identifying heart conditions
associated with unhealthy,
pathologic, heart function.

3. Types
• Many
• Invasive or Non invasive
• Mainly dealing with:
▫ Electrocardiography
▫ Echocardiography/Ultraso
und
▫ Cardiac Angiography
▫ Intravascular Ultrasound
▫ Nuclear Heart Scan
▫ Chest X Ray
▫ Sphygmomanometer
▫ CT Scan
▫ MRI

4. Electrocardiography
• The recording produced by
this procedure is termed an
electrocardiogram (ECG
or EKG from the German
Elektrokardiogramm).
Electrocardiography (ECG / EKG) is a
transthoracic interpretation of the electrical
activity of the heart over a period of time, as
detected by electrodes attached to the outer
surface of the skin and recorded by a device
external to the body(electrocardiograph).

5. Working:
• The ECG device detects and amplifies the tiny electrical
changes on the skin that are caused when the heart
muscle depolarizes [ contracts ]during each heartbeat.
• This depolarization is detected as tiny rises and falls in
the voltage between two electrodes placed on either side
of the heart which is displayed as a wavy line either on a
screen or on paper.

6. Lead System
• Consists of electrodes used in pairs
▫ Eg: LA+ and RA-, Active and indifferent
• The output from each pair is known as a lead.
• Each lead is said to look at the heart
from a different angle.
• Usually, ECG is recorded
in 12 leads:
▫ Bipolar
▫ Unipolar

7. Bipolar leads
• Electrodes are connected to two limbs one being a positive
pole and other being a negative pole
• The limb leads form the points of Einthoven's triangle
• They are:
• Limb lead I: LA+, RA-
• Limb lead II: RA-, LL+
• Limb lead III: LA-, LL+

9. Unipolar leads
• Here the electrodes have two poles, one is active and the
other inactive.
• They are:
▫ Augmented limb leads
▫ Precordial leads
• The negative pole is produced by connecting the
electrodes, RA; LA; and LL, together, via a simple
resistive network.
• Positive pole is active and negative pole inactive

10. Augmented limb leads
• They are: aVR , aVF, aVL
• Lead augmented vector right (aVR):
• +ve electrode: right arm
• -ve electrode: left arm & left foot
• Lead augmented vector left (aVL):
• +ve electrode: left arm
• -ve electrode: right arm & the left foot
• Lead augmented vector foot (aVF):
• +ve electrode: left foot.
• -ve electrode: right arm & left arm

11. Precordial leads
• Active electrode-placed directly on 6 points on
the chest.
• Electrodes do not require augmentation.
• They are:
▫ V1:4th intercostal space near right sternal margin.
▫ V2:4th intercostal space near the left sternal
margin.
▫ V4: left 5th intercostal space on midclavicular
line.
▫ V3: between V2 and V4.
▫ V5: left 5th intercostal space on anterior axillary
line.
▫ V6: left 5th intercostal space on mid axillary line.
• Vector: direction of travel of heart’s electrical
potential in an instant.

12. Procedure
• Patient lies down on his back.
• Several areas on skin of arms,
legs, and chest are cleaned and
shaved, and small patches i.e
electrodes are attached to these
areas.
• The patches are connected by
wires to the ECG machine
• The heart's electrical signals
are printed into wavy lines on
paper.
• Variations in size and length of
the different parts of the
tracing may indicate a problem
in the part of the heart
associated with that particular
lead.

13. Devices: Holter monitor, Event monitor, 12 lead
electrocardiograph

14. Cardiac Stress Test

15. Normal waves

16. Feature Description Cause
P wave Impulse travels from
the SA node towards
the AV node, and
spreads from the right
atrium to the left atrium
Atrial depolarization
[contraction]
QRS complex From beginning of Q
wave to end of S wave
Ventricular
depolarization
T wave Relaxation of ventricles Ventricular
repolarization

17. Featur
es
Descirption Cause
PR
interval
Onset of P wave to onset of Q wave
Isoelectric line
Atrial depolarization and
conduction through AV node
QT
interval
Onset of Q wave and end of T wave Electrical activity in ventricles [
depolarization and repolarization]
ST
segment
End Of S wave and onset of T wave
Isoelectric line
Ventricles already depolarized

18. Purpose:
Indications:
To measure:
• Any damage to the heart
• Heart disease
• The effects of drugs[Digitalis] or
devices (pacemaker) used to control
the heart
• The size and position of the heart
chambers
• Heart rate
• Heart rhythm
Symptoms like:
• Cardiac murmurs
• Syncope or collapse
• Seizures
• Perceived cardiac
dysrhythmias
• Angina, palpitations,
breathlesness.

19. Abnormal ECG
Helpful in diagnosing:
• Arrhythmias
▫ Tachycardia/Bradycardia
▫ Ectopic heart beat
▫ Heart block-BBB
▫ Atrial flutter and fibrillation
▫ Extrasystole
▫ Paroxysomal tachycardia
▫ Wolff-Parkinson-White
syndrome
• Myocardial infarction
• Hypertrophy of heart chambers
• Coronary Artery Disease
• Congenital heart disease
▫ Tetralogy of Fallot
▫ PDA
• Cardiac Ischemia
• Stable and Unstable Angina
• Infective endocarditis
• Valvular heart disease.
▫ Mitral regurgitation
▫ Mitral stenosis
▫ Mitral valve prolapse
▫ Aortic stenosis
▫ Aortic insufficiency
▫ Pulmonary valve stenosis
▫ Tricuspid regurgitation
• Pericarditis
• Aortic dissection
• Coarctation of the aorta
• C ardiac failure
• Hypertensive heart disease
• Cardiomyopathy-hypertrophic
/alcoholic/dilated/idiopathic/
peripartum
• Cardiac Tamponade
• Atrial Myxoma
• Myocarditis
• Primary amyloidosis
• Stroke

20. • Myocardial Infarction:
▫ Ischaemia-Raised ST segment convex upwards.
▫ Injury-Inverted T -waves peaked and symmetrical

21. Echocardiography
• It is the diagnostic
procedure which uses
ultrasound
waves(fq>20000 Hz) to
produce 2D 0r 3D image
slices of the heart
muscle.
• It determines size, shape,
movement of valves and
heart chambers and flow
of blood through the
heart.

22. Working
• A transducer containing piezoelectric crystals converts
electrical energy into an ultrasound beam
• This beam is directed towards heart.
• The beam is reflected when it strikes the surface between
tissues of different densities.
• Reflected ultrasound/echo is converted to electrical energy by
piezoelectric crystals which constructs image based on
▫ Intensity of echos
▫ Time taken for echoes to return

23. Procedure
• Trans-thoracic echocardiogram(TTE):
▫ Echocardiogram of the heart through the thorax
external to the body.
▫ Non-invasive, painless, highly accurate and quick.

24. • Trans-esophageal echocardiogram(TEE)
▫ Echocardiogram of the heart through a catheter
placed in the esophagus which is attached to an
ultrasound transducer.

25. ▫ Invasive and must be performed
under supervision.
• Doppler echocardiography:
▫ Waves reflected from RBCs have
different frequency than that of
transmitted waves.
▫ Determines direction and
velocity of blood flow.
▫ Assessment of
 Cardiac valve areas and function
 Abnormal communications
between the left and right side of
the heart
 Valvular regurgitation
 Calculation of the cardiac output
and ejection fraction.
Heart valve defect

26. Uses and Indications
Assessment of
▫ Pericardial effusion
▫ Congenital Heart Defects
▫ Valvular heart diseases
▫ Myocardial Infarction
▫ High blood pressure/ Hypertensive heart disease
▫ Hypertrophic cardiomyopathy
▫ Intracardiac tumors [myxomas] and blood clots
▫ Aortic regurgitation/stenosis/aneurysm and dissection
▫ Calcification of valves
▫ Rheumatic mitral valve disease
▫ Cardiac failure
VSD

27. Advantages
• No known risks or
side effects.
• No radiation
involved.
• Both 2D and 3D
images can be viewed.

28. Cardiac Angiography
• Cardiac
Angiography or arteriography is
a medical imaging technique used to
visualize the lumen of the blood
vessels [ arteries, veins] and the heart
chambers.
• This is traditionally done by inserting
a catheter followed by injecting a
radio-opaque contrast agent[dye
which absorbs the x-rays] into the
blood vessel and imaging using a
camera and X-ray based techniques
such as fluoroscopy.

29. Procedure
• Cardiac Catheterization + X ray fluoroscopy
• Patient lies on his back on the X-ray table.
• Precautions
• A round cylinder or rectangular box that takes the pictures
during fluoroscopy will be moved under the patient during
the test.
• The place where the catheter is inserted is shaved and
cleaned.
• The doctor numbs the area with a local anesthetic.

31. • A needle is put into the femoral artery
/vein [near groin] or brachial
artery/vein[above elbow].
• A guide wire is put through the needle
into the blood vessel and the needle is
removed.
• The thin flexible catheter is placed over
the guide wire and moved into the
blood vessel.
• The catheter is then guided through
the blood vessels until it reaches the
area to be studied [aorta, coronary
arteries, left ventricle and atrium and
inferior vena cava , right atrium and
ventricles, pulmonary artery etc]----
Cardiac Catheterization

32. • The fluoroscope is used to watch
the movement of the catheter in
the blood vessels.
• When the catheter is in place,
Iodine dye is injected through it.
• Several X-ray pictures are taken
one after another which may either
be still images, displayed on
a image intensifier or film, or
motion images stored digitally on
computer.
• Duration: 1-3 hrs
• The catheter is taken out after the
angiogram, and pressure is put on
the needle site for 10 to 15 minutes
to stop any bleeding.

33. Uses
• Mainly used to detect abnormalities of blood
flow :
▫ A tear in a blood vessel (which can cause blockage or
internal bleeding)
▫ Haemorrhages
▫ Aneurysms
▫ Stenosis
▫ Pattern of blood flow to a tumor.
▫ Abnormal position of blood vessels
▫ Abnormal branching of blood vessels since birth
▫ Changes in the blood vessels of injured heart.
• Presence or absence of atherosclerosis within the
walls of the arteries cannot be clearly determined.
• Not confirmatory..

34. Intravascular Ultrasound
• Principle:
▫ Coronary catheterization+ Ultrasound
• Ultrasound transducer attached at the
tip of catheter guided through coronary
arteries from femoral/brachial artery.
• Proximal end of catheter attached to
ultrasound equipment
• Evaluates
▫ Coronary plaques—structure and
composition [not seen in angiography]
▫ Wall of blood vessel
▫ Connective tissue surrounding vessel
• Prescribed for
▫ Coronary angioplasty
▫ Stenting

35. Nuclear Heart Scan
• A nuclear heart scan is a type of medical test where a safe, radioactive
material called a tracer is injected through a vein into the bloodstream.
• The tracer travels to the heart and releases energy, which special cameras
outside of the body detect to create pictures of different parts of the heart.
• Using computer software, the images are made to appear as if the heart is
moving.

36. Procedure
Pretest
• The radioactive tracer is injected into the
bloodstream through the intravenous line.
• ECG patches are attached to the body to check
the heart's electrical activity during the test.
Exercise
• An exercise stress test maybe done as a part of
nuclear heart scan
Chemical stress
• If Patient is unable to exercise, medicine is used to
make the heart beat faster. This is called a chemical
stress test.

37. • Before the exercise or the chemical stress test stops, the
tracer is again injected through the IV line.
• The patient then lies very still on a padded table.
• The nuclear heart scan camera, called a gamma
camera,[sometimes doughnut shaped] is enclosed in a
metal housing which is put in several positions around
the body.
• The computer collects the pictures of the heart nearby
or in another room.
• Two sets of pictures is taken. One is taken right after
exercise /chemical stress test and the other is taken after
a period of rest.
• Each set of pictures takes about 15 to 30 minutes.

39. Types
Two main types:
• Single positron emission
computed tomography
(SPECT)
• Cardiac positron emission
tomography (PET)

40. Uses
Detects :
• The flow of blood throughout the heart
muscle --myocardial perfusion
scanning.
• To look for damaged heart muscle due
to a previous heart attack, injury,
infection, or medicine---myocardial
viability testing.
• Pumping action of heart to the body--
ventricular function scanning.

41. Uses
Also evaluates:
▫ Coronary Artery Disease
▫ Heart valve diseases
▫ Past heart attack (myocardial infarction)
▫ Poor pumping function and heart failure
• Decides whether coronary angiography or cardiac
catheterization will be helpful.
• Decides whether angioplasty or coronary artery
bypass grafting (CABG) will be needed
• Monitors procedures or surgeries, such as CABG or a
heart transplant

42. Indications
Conditions under which the test may be
performed:
▫ Atrial septal defect
▫ Dilated cardiomyopathy
▫ Idiopathic cardiomyopathy
▫ Peripartum cardiomyopathy
▫ Senile cardiac amyloid
▫ Heart failure

43. Chest X ray
A chest X-ray uses a very small amount of radiation to produce an
image of the heart, lungs, and chest bones on film.

44. Procedure
• Patient has to remove all clothes and metallic jewelry from the waist
up and put on a hospital gown for the test.
• Patient then stands very still with his chest against the cassette that
contains the film.
• The X-ray machine sends a beam of ionizing radiation through an
X-ray tube.
• This energy passes through the chest and is absorbed on film to
create a picture.
• Bones and other dense areas show up as lighter shades of
gray
• Areas that don't absorb the radiation appear as dark gray.
• The entire test takes no more than 10 to 15 minutes.

45. Views
PA or postero-anterior view:
• Patient stands with his chest
against the container of the film
• The X-ray beam from the
machine comes from the
posterior/back and moves
through the chest to the
anterior/front.
Lateral view:
• Patient stands sideways in front
of the film with arms raised up.
• The X rays penetrate the chest
from the sides.

46. Uses
• Helps to diagnose heart diseases such as
▫ Cardiomegaly
▫ Aneurysm and Coarctation of aorta
▫ Acute Myocardial Infarction
▫ Heart failure
▫ Pericardial effusion with Tamponade
▫ ASD, VSD, PDA
• Evaluates placement of devices (pacemakers,
defibrillators) or catheters, chest tubes placed
during hospitalization.

47. Cardiomegaly
Heart failure

48. Sphygmomanometry
• A sphygmomanometer is a
device used to measure blood
pressure. It is always used in
conjunction with a
stethoscope.
• A manual
sphygmomanometer consists
of an inflatable cuff to
restrict blood flow, a
measuring unit -the
mercury manometer or
aneroid gauge, and
inflation bulb and valve.

50. Procedure
• Patient lies in supine or sitting position
with the Sphygmomanometer at level of
the heart
• The arm cuff is tied around the upper arm
above the cubital fossa
• Size of cuff should be appropriate for arm
• Cuff is attached to the mercury
manometer.
• 3 methods:
▫ Palpatory method:
 Radial artery is palpated
 Cuff is inflated until radial pulse disappears
 Pressure is increased further by 20 mm Hg

51.  Pressure is then released
slowly through opening of
valve
 Mercury column is noted when
the pulse reappears and is felt
 Systolic pressure is obtained
▫ Auscultatory Method:
 Stethoscope placed over the
brachial artery in cubital fossa
 Pressure is raised by 20 mm
Hg after pulse disappears to
occlude the Brachial artery
 Pressure is released from cuff
through opening of the valve

52. • A series of sounds—Korotkoff’s sounds are heard
▫ 1st phase:
 Sudden clear tapping sound
 Louder on releasing pressure
 Appearance-Systolic pressure
▫ 2nd phase:
 Murmuring sound
▫ 3rd phase:
 Clear louder GONG type of sound
▫ 4th phase
 Mild muffled sound
▫ 5th phase
 Disappearance of sound
 Diastolic Blood pressure

53. ▫ Oscillatory method:
 Pressure is increased above systolic
pressure –mercury column remains
still
 When pressure is decreased—some
oscillations occur
 When pressure is reduced
further--
 Amplitude and duration of
oscillations suddenly increase--
Systolic BP
 When further deflated – amplitude
and duration of oscillations is
reduced--- Diastolic BP
 Inaccurate

54. Uses
Diagnosing
• Hypotension
• Hypertension
▫ Can be indicative of
 Congestive Heart failure
 Stroke
 Myocardial Infarction

55. Cardiac CT Scan (CCT)
• Computerised Tomography (CT) is a
medical imaging method employing
tomography, created by computer
processing.
• Tomography refers to imaging by sections or
sectioning, through the use of any kind of
penetrating wave [radiation].
• A three-dimensional image of the inside of
the heart is generated from a large series of
two-dimensional X-ray picture taken around a
single axis of rotation.
• In simpler terms, it is an imaging method that
uses x-rays to create cross-sectional pictures of
the heart.

56. Procedure
• The patient will be asked to lie on a
narrow table that slides into the center of
the CT scanner.
• Once he is inside the scanner, the
machine's x-ray beam rotates around him.
• A computer creates separate images of the
body area, called slices.
• Three-dimensional models of the body
area can be created by stacking the slices
together.
• Sometimes an iodine-based dye (contrast
dye) is injected intravenously during the
scan. The contrast dye travels through the
blood vessels, which helps highlight them
on the x-ray pictures.

57. • These images can be stored/ viewed on a
monitor, or printed on film.
• Patient must be still during the exam, because
movement causes blurred images.

58. Uses:
Helps in evaluating:
• Calcium buildup in the walls of
the coronary arteries-
coronary calcium scan
• Coronary Artery Disease
• Problems with heart function
and heart valves.
• Aneurysm and Dissection of
Aorta
• Atrial Fibrillation
• Pericardial Disease
• Wall motion and Ejection
fraction
• Cardiac masses and post-
operative abnormalities
• Congenital Heart Diseases

59. Indications:
The Patient is Asymptomatic
• Family history of coronary artery disease
• Persistent high triglyceride levels
• Other high risk factors such as smoking, diabetes,
etc.
• ECG abnormalities
• Abnormalities on a routine stress test
• Moderate to severe hypertension
• Earlier to non-coronary surgery in the adult
population such as
a. Pre-ASD repair
b. Pre-valvular repair
c. Pre-tumor surgery

60. Indications
The Patient is Symptomatic :
• Atypical chest pain (right side,
shoulder tip, etc.)
• Suspected dilated cardiomyopathy
• Anomalous coronary arteries, ectasia
or aneurysms
Other:
• Post-bypass: assessing the status of
bypass grafts.
• Post-stent: for assessing in-stent
lumen.
• Tumors and cardiac neoplasms

61. Cardiac Magnetic Resonance Imaging
• Cardiovascular magnetic
resonance imaging (CMR) /
cardiac MRI, is a medical imaging
technology that uses powerful magnets
and radio waves to create pictures of
the body.
• Single MRI images produced are called
slices.
• One exam produces dozens or
sometimes hundreds of images which
can be combined to produce 3D models.
• The images can be stored on a
computer or printed on film.

62. Principle
• The single proton of the nucleus of a hydrogen atom vibrates ,
or "resonates," when exposed to bursts of magnetic energy.
• When many hydrogen nuclei resonate in response to changes
in a magnetic field, they emit radiofrequency energy.
• The MRI machine detects this emitted energy, and converts it
to an image.
• Hydrogen nuclei are used because hydrogen atoms are
present in water molecules (H2O), and therefore are present
in every tissue in the body.
• Subtle differences in the hydrogen atoms between various
parts of a tissue - emit different amounts of energy.
• These energy differences show up as different shades of gray
on the MRI which is helpful in detecting areas of cardiac
tissue that have poor blood flow (coronary artery disease) or
that has been damaged (heart attack).

64. Procedure
• Patient is asked to wear a hospital gown or clothing without
metal items or ornaments
• Patient will lie on a narrow table, which slides into a large
tunnel-shaped scanner.
• Sometimes a dye is usually injected before the test
intravenously in the hand or forearm to see images more
clearly
• Small devices, called coils, may be placed around the head,
arm, or leg, or other areas to be studied. These devices help
send and receive the radio waves, and improve the quality of
the images.
• During the MRI, the person who operates the machine will
watch you from another room.
• An intercom in the room allows patient to speak to the
monitoring person at any time.
• The test most often lasts 30-60 minutes, but may take longer.

65. Closed MRI
Open MRI

66. Uses
• Helps in visualising
▫ Heart muscle scar or fat without using a contrast agent
▫ Heart function using cine imaging
▫ Infarct imaging using contrast
▫ Perfusion defects
▫ Congenital Heart Defects
▫ Aortic Dissection
▫ Cardiac tumor
▫ Cardiomyopathies
▫ Thrombus
▫ Pericarditis
▫ Stenosis of valves

67. ▫ Assessing
 Volume of blood flow and
Ejection fraction
 Damage caused by Heart
attack
 Heart Failure
 Coronary Artery Disease
▫ Distinguishing between
"stable
atherosclerotic plaques and
"vulnerable" plaques.
▫ Visualising blood vessels and
the flow of blood through
them -- magnetic resonance
angiography (MRA).

68. Advantages
• Safe, non-invasive test
• MRI uses radio waves, without ionizing radiation or X
rays
• Unlike CT does not carry any risk of causing cancer.
• The images generated remarkably complete, detailed
and precise
• MRI has the potential of replacing other cardiac tests
like:
▫ Echocardiogram,
▫ NH scan,
▫ Thallium scan
▫ Diagnostic cardiac catheterization.

69. References:
Books:
• Essentials of Medical Physiology - Sembulingam
• Hutchinson’s Clinical Methods – Michael Swash
• Practical Medicine – P. J Mehta
• Macleod’s Clinical Examination – Douglas,
Nicol, Robertson
Internet:
• www.google.com
• www.wikipedia.org