Diagnostic tests in cardiology

1. Diagnostic tests in
Cardiology

2. • Diagnostic tests and procedures are used to
confirm the data obtained by history and physical
assessment. Some tests are easy to
interpret, but others must be interpreted by
expert clinicians. All tests should be explained
to the patient

3. • BLOOD STUDIES
• IMAGING STUDIES
Chest X-ray
Echocardiogram
C T Scan
Magnetic Resonance Imaging
• Cardiac catheterization
• ECG
• Cardiac stress tesing
• Holter monitoring
• Electrophysiologic study

4. BLOOD STUDIES
• Cardiac biomarkers
When cells are injured they release their contents into blood
stream including enzymes and other proteins
It includes
Troponin
Creatine kinase (CK-MB)
Myoglobin

5. Myoglobin
• Myoglobin, an early marker of MI, is a heme protein with
a small molecular weight. This allows it to be rapidly
released from damaged myocardial tissue and accounts
for its early rise,
• within 1 to 3 hours after the onset of an acute MI.
Myoglobin peaks in 4 to 12 hours and returns to normal
in 24 hours.

6. CREATINE KINASE( CK)
• Creatine kinase enzymes are found in variety of
organs ,occur as three isoenzymes
CK-MM, CK-BB, CK-MB
CK-MB begin to rise 3-6 hours after S/S
PEAK-12-24 HOURS
RETURN TO NORMAL-48-72 HRS

7. Troponin
• Myocardial muscle protein
• Two subtypes
Troponin T (cTnT)
Troponin I (cTnI)
• Rise – 4-6 hours
• Peak- 10-24 hours
• Returned to normal after 10-14 days

8. Other blood investigations
• C-reactive protein (CRP)- Marker of inflammation that can predict
cardiac events, even normal lipid values.
Normal-<1mg/ml
• Homocysteine- amino acids produced during protein catabolism.
Normal-<12 nmol/ml
• serum lipids
cholesterol- <200mg/dl
Triglycerides- <150 mg/dl
Lipoprotiens-
HDL , Male > 40mg/dl, Female> 50mg/dl
LDL- <100mg/dl

9. Electrocardiography
• 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

10. Lead System
• Usually, ECG is recorded
in 12 leads:
oBipolar
oUnipolar

11. 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+

12. 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

13. 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

14. 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.

15. 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.

16. 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.

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

18. 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.

19. 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

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

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

22. ▫ 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

23. 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

24. 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.

25. 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.

26. 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).

27. CARDIAC CATHETERIZATION
• Cardiac catheterization is an invasive diagnostic
procedure in which radiopaque arterial and venous
catheters are introduced into selected blood vessels of
the right and left
sides of the heart.
• Catheter advancement is guided by fluoroscopy

28. ANGIOGRAPHY
• Cardiac catheterization is usually performed with angiography, a
technique of injecting a contrast agent into the vascular system
to outline the heart and blood vessels

30. ELECTROPHYSIOLOGIC
TESTING
• The electrophysiology study (EPS) is an invasive procedure that
plays a major role in the diagnosis and management of serious
dysrhythmias and is used
• (1) to distinguish atrial from ventricular
tachycardias when the determination cannot be made from
the 12-lead ECG,
• (2) to evaluate how readily a life-threatening dysrhythmia (eg, ventricular
tachycardia, ventricular fibrillation)
• (3) to evaluate AV node function
• (4) to determine the need for other therapeutic interventions, such as a
pacemaker, implantable cardioverter defibrillator,

31. CARDIAC STRESS TESTING
• Normally, the coronary arteries dilate to four times their
usual diameter in response to increased metabolic
demands for oxygen and nutrients. Coronary arteries with
atherosclerosis, however, dilate much less, compromising
blood flow to the myocardium and causing ischemia.
• Exercise stress test, the pharmacologic stress test, and
more recently, the mental or emotional stress test

32. • (1) CAD,
• (2) cause of chest pain,
• (3) functional capacity of the heart after an MI or heart surgery,
• (4) effectiveness of antianginal or antiarrhythmic medications,
• (5) dysrhythmias that occur during physical exercise,
• (6) specific goals for a physical fitness program.

33. Exercise Stress Testing
• In an exercise stress test, the patient walks on a treadmill
(most common) or pedals a stationary bicycle or arm crank.
Exercise intensity progresses according to established
protocols. The Bruce protocol, for example, is a common
treadmill protocol in which the speed and grade of the
treadmill are increased every
3 minutes.

34. Cardiac Stress Test

35. • During the test, the following are monitored: two or
more ECG leads for heart rate, rhythm, and ischemic
changes; BP; skin temperature; physical
appearance; perceived exertion; and symptoms
including chest pain, dyspnea, dizziness, leg
cramping, and fatigue.

36. Pharmacologic Stress Testing
• Two vasodilating agents, dipyridamole (Persantin) and
adenosine (Adenocard), administered intravenously, are
used to mimic the effects of exercise by maximally dilating
the coronary arteries. The effects of dipyridamole last about
15 to 30 minutes.
The side effects are related to its vasodilating action and
include chest discomfort, dizziness, headache, flushing, and
nausea.Adenosine has similar side effects, although patients
report these symptoms as more severe

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