Cardiac diagnosis.pptx

Unit II
Diagnostic and
therapeutic
intervention
Cardiac System
Prepared by
Ms. Pooja Prakash
Lecturer
Cardio-vascular and Thoracic Nursing

Diagnostic Evaluation of Cardiac System
Chest X-ray
Coronary Angiography
Echocardiography
CVP- Monitoring
ECG

Chest X-ray
• German physicist Wilhelm Röntgen was the first person
to discoverer X-rays in 1895.
• gave them the name "X-rays", though many referred to
these as "Röntgen rays“
• X-rays are a form of ionizing electromagnetic radiation.
• Most X-rays have a wavelength in the range of 0.01 to
10 nanometers
• The voltage used for diagnostic X rays is in range of 20 –
150kV
• There are 5 basic radiographic densities
- Gas, fat, soft tissue (water), bone and metal
- Anatomic structures are recognized on x-ray by their
density differences

• There are four major views
1. Posterior-anterior (PA) View:
• Standard view for routine Chest x-rays
• Taken in full inspiration
2. Anterior-Posterior (AP) view:
• Patient is too ill to stand or non-cooperative
• Heart at a greater distance from film, appears enlarged
3. Lateral view
• Lung lobes, mediastinum & bony thoracic cavity better
visualized
• Useful for lobar pathology, mediastinal masses,
encysted pleural fluid & basal consolidation
4. Lateral decubitus view
• Specialized projection to demonstrate small pleural
effusions or pneumothorax

• A radiograph is an X-ray image obtained by placing a
part of the patient in front of an X-ray detector and
then illuminating it with a short X-ray pulse.
• X ray detectors used to collect images are
- photographic film
- scintillator
- semiconductor diode
- photostimulable phosphor plates, or PSP
• Pre and post procedure Care
• explain the procedure to patient and offer him/her
opportunity to ask any questions that patient might
have about the procedure.
• Generally, no prior preparation, such as fasting or
sedation, is required.
• Notify the radiologic technician if patient is pregnant or
suspect that patient may be pregnant.

• Patient is asked to remove any clothing, jewelry, or
other objects that may interfere with the particular
view that is ordered.
• Patient is positioned carefully so that the desired
view of the chest is obtained.
• For a standing or sitting film, patient stands or sits
in front of the X-ray plate. atientt is asked to roll his
shoulders forward, take in a deep breath, and hold
it until the X- ray exposure is made. For patients
who are unable to hold their breath, the radiologic
technician takes the picture at the appropriate time
by watching the breathing pattern.

CVP-MONITORING
• Hemodynamic monitoring refers to the
measurement of pressure, flow and oxygenation
within the cardiovascular system.
• Commonly measured values are
- Direct arterial pressure
- Pulmonary artery pressure
- Central venous pressure (CVP)
- Pulmonary artery wedge pressure (PAWP)
- Cardiac output/index
- Stroke volume/index
- Oxygen saturation of hemoglobin of arterial blood
(SaO2) and mixed venous blood (SvO2)

Central venous or right atrial pressure
monitoring
• CVP is a measurement of right ventricular preload (Blood
from the systemic veins flows into the right atrium).
• The pressure in the right atrium is the CVP.
• A catheter is passed via; the subclavian vein or jugular vein
into the superior vena cava to determine the venous return
and intravascular volume of the right atrium.
• It can be measured with a Pulmonary artery (PA) catheter
using one of the proximal lumens or with a central venous
catheter placed in the internal jugular or subclavian vein.
• CVP is measured as a mean pressure at the end of expiration.
• The normal value is 5-10cm H2O or 2-8 mmHg.

CENTRAL VENOUS PRESSURE MONITORING
PURPOSE
• To serve as a guide of fluid balance in critically ill
patients
• To estimate the circulating blood volume
• To determine the function of the right side of the
heart
• To assist in monitoring circulatory failure
• None of these variables are measured directly; they
must be interpreted.

Indications Monitoring of the central
venous pressure (CVP)
• Major operative procedures involving large fluid shifts or blood loss
• Intravascular volume assessment when urine output is not reliable or
unavailable
• Temporary hemodialysis
• Surgical procedure with a high risk for air embolism, CVP catheter
may be used to aspirate intracardiac air
• Frequent venous blood sampling, inadequate peripheral intravenous
access
• Temporary pacing
• Venous access for vassoactive or irritating drugs and chronic drug
administration
• Rapid infusion of intravenous fluids (using large cannulae)
• Total parenteral nutrition

Common sites of CVP line insertion
A. Central line
- Right internal jugular
- Left internal jugular
- Right subclavian
- Left subclavian
B. Peripherally inserted central catheters (PICC)
- Antecubital veins
- Basilic vein
- Cephalic vein
- Femoral artery

• Factors affecting CVP
- Cardiac function
- Blood volume
- Capacitance of vessel
- Intrathoracic and intraperitoneal pressure
• CVP Equipments
- CVP insertion kit
- A sterile bag of fluids with attached fluid adminstration set, IV
extension set, manometer and stopcock
- Iv extension set to entry port of patient central line
- IV giving set of fluid bag
- Barrier precaution kit: surgical mask, surgical cap, full bed
drape, sterile gown
- Chlorihexidine for skin preparation
- NS for flush 10ml syringe, heparine flush 10 units per ml

• CVP position of patient during insrtion of CVP catheter
- Supine position
- Trendelenburg position (10-15 degrees to significantly helps
to increase jugular size)
- Adduct the patient’s arm
- Place small sandbag or rolled towel between the scapula to
retract the shoulders and facilitate needle insertion by
rducing the deltoid prominence
- Instruct awake patient to perform Valsalva manuever (breath
strongly through mouth while holding nose tightly closed)
• Post procedure confirmation of correct placement
- Chest x-ray, adjust scale and set appropriate alarm
parameters
- Repositioning patient into semi fowlers position if applicable
- Ensure line and insertion site free of tension

• Principles of pressure monitoring
1. Refrencing
- Positioning the transducer so that the the zero
reference point is at the level of the atria of the heart.
- The stopcock nearest transducer is usually zero
reference for the transducer
- To place level with atria, external landmark the
phlebostatic axis is used.
1. Zeroing
• Confirms that when pressure within system is zero, the
monitor reads zero.
• This is accomplished by opening of the reference
stopcock to room air (off to the patient)and observing
the monitor for reading zero
• Recommended at the initial set-up immediately after
insertion of the arterial line.

• The normal CVP-waveform consists of three upward
deflection (a,c and v) and two downward deflection (x
and y descents)
• “a-wave”: produced by right atrial contraction and
occurs just after the p wave on ECG
• “c-wave”: occurs due to isovolumic ventricular
contraction forcing the tricuspid valve to bulge upward
into the right atrium
• “x-wave”: produced due to the pressure within the RA
decrease as the tricuspid valve is pulled away from the
atrium during ventricular ejection
• “v-wave”: the RA continues to fill during late ventricular
systole
• “y-wave” occurs when the tricuspid valve opens and
blood from the RA empties rapidly into the RV during
early diastole.

Complications of CVP
• Complications of central venous access and
cannulation
- Arterial puncture with hematoma
- Arteriovenous fistula
- Hemothorax, Chylothorax or pneumothorax
- Nerve injury
- Air embolus
- Catheter or wire shearing
- Right atrial or right ventricular perforation
• Complications of catheter presence
- thrombosis, thromboembolism
- Infection, sepsis, endocarditis, arrhythmias,
hydrothorax

Nursing Consideration
• The patient should me closely monitored and the catheter site and the system
observed.
• Monitor and record the vital signs
• Handling of the line should be kept to a minimum to reduce risk of contamination
and the line should be securely fasten to the patient
• The dressing on the cv site should be transparent and changed in accordance with
hospital policy and procedure and in aseptic condition
• Observe for discharge, bleeding, redness or rashes
• Closely observe fro complications and take precautions to avoid air embolism
• Proper positioning of patient
• Before removing the catheter, the tip of catheter should be cut with sterile scissors
and placed in sterile specimen, after labeling send it for microbiological study or
culture
• CV catheter should be changed as per policy of hospital (96hrs or 7-days)
• The removal of procedure is carried out using an aseptic technique
• After removal of sutures from around the catheter, a wad of sterile gauze should be
held under pressure over the site
• After removal of catheter need to apply continues pressure to the site for upto5
minutes
• The site is sealed with an airtight dressing, and it should be left for 48 hours.

Echo-cardiography
• It is a type of ultrasound test that uses high pitched
sound waves to produce an image of the heart.
• The sound waves are sent through a device called a
transducer and are reflected off the various
structures of the heart.
• These echoes are converted into pictures of the
heart that can be seen on a video monitor.

COMPONENETS
• Pulse generator - applies high amplitude voltage to
energize the crystals.
• Transducer - converts electrical energy to
mechanical (ultrasound) energy and vice versa.
• Receiver - detects and amplifies weak signals.
• Display - displays ultrasound signals in a variety of
modes.
• Memory - stores video display .

INDICATION
• Heart Murmurs, Valvular Stenosis, Valvular
Regurgitation, Prosthetic Valve Assessment
• Infective Endocarditis, Ischaemic Heart Disease -
Known or Suspected
• Cardiomyopathy
• Pericardial Disease, Cardiac Masses, Pulmonary
Disease, Neurological Disease, Arrhythmia,
Palpitations and Syncope
• Hypertension
• Aortic and Major Arterial Disease
• Pre-Operative Echocardiography for Elective and
Semi-urgent Surgery

Standard Echo Windows
• Standard positions on the chest wall are used
for placement of the transducer called “echo
windows
• 1. Suprasternal
• 2. Right parasternal
• 3. Left parasternal
• 4. Apical
• 5. Sub costal

• Parasternal long-axis view (PLAX)
- Pt Positioning: left lateral decubitus.
- transducer positioning: placed near the sternum in
the left third or fourth intercostal space .
- Marker dot direction: points towards right shoulder.
- Closest structure to the transducer. The right
ventricular outflow tract (RVOT),in the upper site of
the image.
• Structures seen : proximal aorta, aortic valve, left
atrium, mitral valve, left ventricle, IV septum,
posterior wall , right ventricle, pericardium.
• Most echo studies begin with this view. It sets the
stage for subsequent echo views.

• Parasternal Short Axis View (PSAX)
- Transducer position: left sternal edge; 2nd–4th
space
- Marker dot direction: points towards left shoulder
(90° clockwise from PLAX).
- By tilting the transducer on an axis between the left
hip and right shoulder, short-axis cuts are obtained
at different levels, from the aorta to the LV apex .
- This angulations of the transducer from the base to
apex of the heart for short-axis views is known as
“bread-loafing”.
- Structure seen: 1. pulmonary artery 2. aortic valve
level 3. mitral valve level 4. papillary muscle 5. left
ventricle.

• Apical 4-Chamber View (A4CH View)
- Transducer position: apex of the heart.
- Marker dot direction: points towards left shoulder.
- Structures seen: – right and left ventricle – right and
left atrium – mitral, tricuspid valves – IA and IV septum
– left ventricular apex – lateral wall left ventricle – free
wall right ventricle.
• Apical 5-Chamber View (A5CH view)
- The A5CH view is obtained after the A4CH view by
slight downward tilting of the transducer. The 5th
chamber added is the left ventricular outflow tract
(LVOT).
- Transducer position: as in A4CH view.
- Marker dot direction: as in A4CH view.
- Structures seen: — LV outflow tract — aortic valve —
proximal aorta.

• Sub costal View
- Pt position: The subject lies supine with the head held
slightly low, feet planted on the couch and the knees
slightly flexed.
- Better images are obtained with the abdomen relaxed
and during the phase of inspiration.
- Transducer position: under the xiphisternum
- Marker dot position: points towards left shoulder.
- Structures seen: As in A4CH view. The subcostal view is
particularly useful when transthoracic E is technically
difficult because of the following reasons: – severe
morbid obesity – chest wall deformity – pulmonary
emphysema.
- The following structures are better seen from the
subcostal view than from the apical 4-chamber view: –
inferior vena cava – descending aorta – interatrial
septum – pericardial effusion

• Suprasternal View
- Pt Position: he subject lies supine with the neck
hyperextended by placing a pillow under the
shoulders. The head is rotated slightly towards the
left. The position of arms or legs and the phase of
respiration have no bearing on this echo window.
- Transducer position:suprasternal notch. Marker
dot direction: points towards left jaw.
- Structures seen: – ascending aorta – pulmonary
artery.

Echocardiography Types
• Transthoracic echocardiogram :
Conventional echocardiography is
performed from the anterior chest wall
(precordium) and is known as transthoracic
echo.
• Transesophageal echo:
Echocardiography can also be performed
from the esophagus which is known as
transesophageal echo.

• TRANSESOPHAGEAL ECHO
• Principle : Anatomically speaking, the esophagus in its mid-course is strategically
located posterior to the heart and anterior to the descending aorta. This provides
an opportunity to interrogate the heart and related mediastinal structures with a
high frequency transducer positioned in the esophagus for better image resolution.
• Technique : A miniature transducer is mounted onto a probe or gastroscope similar
to the one employed for upper gastrointestinal endoscopy. The scope is advanced
to various depths in the esophagus to examine cardiac and related structures. By
maneuvering the transducer and the angle of beam from controls on the handle,
different views of the heart are obtained
• Advantages: Useful for patient with obesity, chest wall deformity, emphysema or
pulmonary fibrosis, better image quality and resolution due to two reasons: –
absence of acoustic barrier between the ultrasound beam and the rib cage, chest
wall and lung tissue
• Disadvantages : The transesophageal echo (TEE) views are significantly different
from standard transthoracic echo views, requires short-term sedation, oxygen
administration and ECG monitoring since, there are chances of hypoxia, arrhythmia
and angina.
• Complications : Esophageal rupture or perforation , Laryngospasm or
bronchopasm, Sustained ventricular tachycardia , vomiting , sore-throat and
hoarseness
• Contraindications : Uncooperative patient, Poor cardiorespiratory status ,
Esophageal obstruction

• Stress Echocardiography
- also called an echocardiography stress test or stress echo or
tread mill test
- Technique:The echocardiogram is performed just prior and
just after the exercise.
- NPO for four hours before the test.
- instruct not to drink or eat caffeine products (cola,
chocolate, coffee, tea) for 24 hours before the test.
- Instruct not to take cardiac medications for 24 hour before
the test :Beta-blockers , Isosorbide dinitrate ,Isosorbide
mononitrate Nitroglycerin

• Dobutamine stress echocardiogram
- A form of stress echocardiogram.
- Instead of exercising to stress the heart, the stress is obtained by giving a
drug that stimulates the heart an makes it "think" it is exercising.
- The test is used to evaluate heart and valve function when unable to
exercise on a treadmill
- It is also used to determine how well heart tolerate activity and likelihood of
having coronary artery disease, as well as evaluating the effectiveness of
cardiac treatment plan.
- Most dobutamine stress protocols start at an infusion rate of
5microgram/kg/mt and increase to a peak dose of 40 or 50 ug / kg / min
- To further increase heart rate, a bolus injection of 0.25—1 .0 mg atropine is
added
- PREPARATION
- Wear comfortable clothing, instruct for do not eat for a minimum of 4
hours before the test, Drinking water is allowed before the test, If diabetic,
juice is allowed in the morning with insulin (1/2 dose). If on antiglycemic
agent ,do not take medication until after the test is complete. ECG
electrodes will be placed to monitor electrocardiogram

• The Modalities of Echo
1. Conventional echo
- Two-Dimensional echo (2-D echo)
- Motion- mode echo (M-mode echo)
2. Doppler Echo
- Continuous wave (CW) Doppler
- Pulsed wave (PW) Doppler
- Colour flow(CF) Doppler
[All modalities follow the same principle of ultrasound. Differ
in how reflected sound waves are collected and analyzed]

• TWO-DIMENSIONAL (2- D) ECHO: is used to "see“ the actual
structures and motion of the heart structures at work.
Ultrasound is transmitted along several scan lines(90-120), over a
wide arc(about 900) and many times per second. The
combination of reflected ultrasound signals builds up an image
on the display screen
• MOTION-MODE (M- MODE) ECHO: ultrasound is transmitted and
received along only one scan line. obtained by applying the
cursor to the 2-D image and aligning it perpendicular to the
structure being studied. The transducer is finely angulated until
the cursor line is exactly perpendicular to the image. M-mode is
displayed as a continuous tracing with two axes.
• Doppler echocardiography: method for detecting the direction
and velocity of moving blood within the heart. Pulsed Wave (PW).
useful for low velocity flow . PW Doppler transmits ultrasound in
pulses and waits to receive the returning ultrasound after each
pulse. PW Doppler modality is used to localize velocity signals
and abnormal flow patterns picked up by CW Doppler and color
flow mapping, respectively.

• Continuous Wave (CW):Useful for high velocity
flow e.g aortic stenosis .it transmits and receives
ultrasound continuously. It can measure high
velocities without any upper limit and is not
hindered by the phenomenon of aliasing.
• Color Flow Doppler: Color Doppler provides a
visual display of blood flow within the heart, in the
form of a color flow map. Different colors are used
to designate the direction of blood flow. Red is
flow toward, and Blue is flow away from the
transducer with turbulent flow shown as a mosaic
pattern

Cardiac Catheterization
• is widely used for diagnostic evaluation and
therapeutic intervention in the management of
patient with cardiac disorder.
• Indications: unstable angina, Acute coronary
syndrome, Congestive heart disease, Cardiogenic
shock, myocardial infraction
• Contraindications: Acute gastrointestinal bleeding,
severe hypokalemia, digitalis toxicity, history of
anaphylactoid reaction to contrast media, severe
anemia.

• Patient preparation
 NPO for 6-12 hours before the catheterization and will be asked to void before
leaving the unit.
 Instruct the patient in deep breathing or stopping the breath without bearing down
and in coughing on request
 With deep inspiration, the diaphragm descends, preventing it from obstructing the
view of the coronary arteries in some radiographic projection.
 Valsalva maneuver increases intra abdominal pressure and may raise the
diaphragm, obstructing the view
 After injecting the contrast medium, coughing will be requested, the rapid
movement of diaphragm also acts as a mechanical stimulant to heart and helps to
prevent the bradycardia
 The appearance of the laboratory should be explained to the patient, including the
general function of the equipment
 Prepare the patient giving them gown to wear, catheter insertion site will be
washed, and remove the hair
 Explain the procedure, about equipments, expected length of procedure to the
patient
 ECG electrode placement
 The patient will be given a local anesthesia at catheter site
 The patient may have hot flashes or experience nausea while administering
contrast
 Instruct patient to report angina or other chest pain immediately to staff
 Patient should be told the expected length of bed rest after catheterization

• PROCEDURE
- A fluoroscope with image intensifier
- Fluoroscope is the continuous presentation of an X-ray image on a
fluorescent screen
- This allows the viewing of structures in motion
- Traditional fluoroscopy presents a dim image that cannot be filmed and
must be viewed in a dark room
- The image intensifier receives the fluoroscopic image and increases its
brightness, permitting filming or digital acquisition of motion pictures
- Single or biplane cameras linked to the image intensifier for filming of cine
or digital angiograms
- An X-ray table, the image intensifier for filming of C-arm that rotates around
the patient
- Pressure transducers and multichannel physiology recorder
- Equipment for CO-determination
- Advanced cardiac life support drugs and equipments
- A cardioverter-defibrillator
- An ECG with continuous monitor display
- A standby pacemaker, either a temporary transvenous electrode and pulse
generator system or an external transthoracic pacemaker

• Catheterization Approach
1. Percutaneous method (the Seldinger technique)
- Used for femoral artery and vein
- The vessels are located and local anesthesia is given
- Percutaneous with sharp inner obturator is used
- Small incision is made in the skin over the vein or artery
and needle is passed through both walls of the vessels
- The needle and obturator are pulled back into the
vessels lumen and obturator is removed
- A guidewire is placed through the neddle into the
vessel
- Catheters are exchanged by inserting a guidewire into
the catheter and inserting the catheter with guide wire
through the introducer sheath, into the vessels
- The guidewire is removed from the catheter completely
before the catheter placement

• Direct approach (Sons technique)
- Brachial artery and basilic vein
- Local anesthesia is used and the brachial pulse is identified
- An incision is made over the medial vein for right heart
catheterization or over both the brachial vein and the brachial
artery if right or left heart catheterization is planned
- The vein and artery are approached by blunt dissection and
are brought to surface and tagged with surgical tape
- Venotomy or arteriotomy are performed using scissors or
scalpel
- The distal segment of the artery is flushed with heparinized
saline to prevent clotting from distal arteries stasis
- The catheterization is performed
- After catheterization, the distal brachial artery is aspirated
until a forceful backflow is achieved, and heparinized saline is
injected
- The arterial incision is then sutured

• Post procedure care
- Observe the catheter site for bleeding or hematoma
formation and assess the peripheral pulsesin the affected
extremity (dorsalis pedis and posterior tibial pulses in the
lower extremeties, radial pulse in upper extremetis) every 15
min for 1 hr and then every 1-2 hrs until pulses are stable
- Evaluate temperature and colour of the affected extremities
and any patient complaint of pain, numbness or tingling
sensations to determine signs of arterial insufficiency
- monitor for dysrhythmias
- Inform the patient for bed rest for 2-6hrs with affected leg
straight and the head is elevated to 30 degree
- Instruct the patient to report chest pain and bleeding or
sudden discomfort from the catheter insertion site
immediately
- Encourage fluids to increase urinary output and flush out the
dye

• Complications
- Arrhythmias
- Thrombosis
- Embolism
- Stroke
- Myocardial infraction
- Hemorrhage
- Contrast reaction

Coronary Angiography
• is a procedure that uses a contrast material/dye and
x-ray to see how contrast material filled blood flows
through the coronary arteries of the heart
• Is the gold standard for the evaluation of coronary
artery disease
Indication:
- Acute MI, unstable angina, chronic stable angina,
abnormal stress test, vetricular arrythmias, valvular
disorders
Contraindication:
- Coagulopathy, active bleeding, malignant
hypertension, renal failure

• Requisite for coronary angiogram:
- Cardiac cath laboratory
- Puncture needle
- Introducer
- Short guide wire
- Cordis sheath with dilator
- Left/right judkins catheter
- Contrast media
#High osmolar ionic agents
- Sodium diatrizoate
- Sodium meglumine diatrizoate
# nonionic or low osmolar agents
- Ioxaglate, Iohexol, Iopamidol, Iodixanol

• Steps of Coronary angiogram
• Step I
- Written consent
- Fasting for at least 4 hrs
- Pre-cath investigations
- Selection of arterial access point
- Shaving of the area
- Opening the I/V line
- Connect with cardiac monitor
- Oral or I/V sedatives
• Step II
- Radiation protection for health care personnel
- An area of arm or groin is cleaned and numbed with local anesthesia
- Draping the patient
- Puncturing and introducing the short guide wear through the puncture
needle
- The process may follow using percutaneous approach or direct approach
- Introducing the cordis sheath and removal of dilator along with short guide
wire
- Flush the channel with heparinized solution

• Step III
- Catheter is inserted up into the heart, x-ray images
help to positioning the catheter
- Once the cather is placed, dye is injected into the
catheter
- X-ray images are taken, the dye helps to highlight any
blockage in blood flow.
* Drugs used during coronary angiography are:
- Analgesics : diazepam, 2.5 to 10 mg orally, and
diphenhydramine , 25-50 mg orally , 1 hr before the
procedure. Intravenous midazolam 0.5-2mg and
fentanyl 25-50 mg are useful agents to provide
sedation during the procedure
- Anticoagulants: IV unfractioned heparin, 2000 to 5000
units. If heparine overdose occurred then protamine,
1mg for every 1oo units of heparine can be
administered

ECG/ Electrocardiography
• ECG is a three letter acronym for Electro-Cardio-Graphy.
• The word is derived from Greek word
‘electro(electricity),cardio(heart) and graph("to write“)
• It is a transthoracic interpretation of the electrical
activity of the heart over time captured and externally
recorded by skin electrodes.
• The device used to produce this non invasive record is
called the electrocardiograph.
• ECG is the gold standard for the noninvasive diagnosis
of cardiac diseases and may occasionally be the only
marker for the presence of heart disease.

INDICATIONS OF ECG
• Gold standard for diagnosis of cardiac
arrhythmias
• Helps to detect electrolyte disturbances (hyper-
& hypokalemia)
• Allows for detection of conduction
abnormalities
• Screening tool for ischemic heart disease during
stresstests
• Helpful with non-cardiac diseases (e.g.
pulmonaryembolism or hypothermia
• An ECG is a diagnostic tool, NOT a treatment No
one is ever cured by an ECG

ELECTROCARDIOGRAPHY TIMELINE
• 1872:Alexander Muirhead attached wires to a feverish patient’s wrist to
obtain a record of the patients heart beat at St Bartholomews Hospital.
• 1887:British physiologist Augustus D. Waller of St Marys Medical School,
London publishes the first human electrocardiogram. The trace from the
heartbeat was projected onto a photographic plate which was itself fixed
to a toy train
• 1893: Dutch physiologist Willem Einthoven introduces the term
electrocardiogram at a meeting of the Dutch Medical Association.
• 1895: Willem Einthoven distinguishes five deflections which he names P,
Q, R, S and T4
• 1902: Einthoven publishes the first electro -cardiogram recorded on a
string galvanometer.
• 1912: Einthoven addresses the Chelsea Clinical Society in London and
describes an equilateral triangle formed by his standard leads I, II and III
later called Einthovens triangle.
• 1924: Willem Einthoven wins the Nobel prize for inventing the
electrocardiograph.
• Einthoven recording his first ECG in 1902 by placing limbs in buckets of
conducting solution

Basic electrophysiologyphysiological properties of
myocardial cell
• Automaticity: ability to initiate an impulse
• Excitability: ability to respond to a stimulus
• Conductivity: ability to transmit an impulse
• Contractility: ability to respond with pumping
action Depolarization and repolarization of a cardiac
cell generates action potential
• ECG is the composite representation of action
potential of all cardiac cell.

• ELECTRICAL CONDUCTION SYSTEM OF THE HEART
• The electrical discharge for each cardiac cycle normally
starts in a special area of the right atrium called
the‘sinoatrial (SA) node’.
• Depolarization then spreads through the atrial
musclefibres.
• There is a delay while the depolarization spreads
through another special area in the atrium, the
‘atrioventricular(AV) node’.
• Thereafter, the electrical discharge travels very rapidly,
down specialized conduction tissue: first a single
pathway, the ‘bundle of His’, which then divides in the
septum between the ventricles into right and left
bundle branches.
• Within the ventricular mass, conduction spreads some
what more slowly, through specialized tissue called
‘Purkinje fibres’.

• CONDUCTION OF THE IMPULSE:
# Rapid Depolarization
- Due to rapid opening of Na Channels
- Duration: 2 miliseconds
- Amplitude: + 20mv
# Plataeu
- phase when membrane potential becomes almost constant,
membranes slowly begins to repolarize
- Due to slow and prolonged opening of calcium channels
- Duration 200 and 300 m/s atrial and ventricle respectively
# Slow repolarization
- Due to closure of calcium channels and opening of potassium
channels
- Last for 50m/s
• Depolarization is followed by muscle contraction and
repolarisation is followed by muscle relaxation.

Velocity conduction of impulses (m/s)
• Arterial muscle fibers = 0.3 m/s
• Internodal fibers = 1m/s
• Av nodes = 0.05 m/s
• Bundle of His = 0.12 m/s
• Purkinje fibers = 4 m/s
• Ventricular muscle fibers = 0.5m/s

• P wave: first seen wave, small, upright (positive) wave indicating atrial
depolarization (0.1 s) (SA node towards the AV node)
• Q wave: first negative wave
• R wave: first positive wave
• S wave: first negative after positive R wave
• T wave: rounded upright (positive) wave following QRS complex indicating
ventricular repolarization (0.2s)
• U wave: small rounded, upright (positive) wave following T wave
repolarization of purkinje muscle
• QRS complex: represents ventricular depolarization as well as repolarization
of atrium
• Q-T interval: measured from beginning of QRS complex to end of T wave it
represents the total ventricular activity and the duration is 0.4-0.42s
• P-R interval: Distance beginning of P-wave and beginning of QRS complex
indicating the duration of depolarization wave travelling from the atria to
ventricles its duration is 0.12-0.2s
• S-T segment: Measured as a distance between S wave and beginning of T
wave and represents the time between the ventricular depolarization and
beginning of ventricular repolarization its duration is 0.08 s.

Basic Electrocardiography
• The ECG is the graphical record of the electrical activity of the heart.
• The spread of the electrical impulse through the heart produces weak
electrical currents through the entire body
• which can be detected and amplified by the ECG machine and recorded on
calibrated graph paper.
• The electrocardiograph uses thermal paper, which is a graph paper & runs
normally at a speed of 25mm/sec
• The grid on the paper consists of a series of small and large boxes.
• Horizontal boxes measures time and vertical measures voltages. OR Time is
plotted on the X axis & voltage is plotted on the Y axis.
• In X axis, 1 second is divided into 5 large squares each of which represents
0.2 sec. Each large square is further divided into 5 small squares which
represents 0.04 sec.
• The ECG machine is calibrated in such a way that an increase of voltage by 1
mVolt should move the stylus vertically by 1cms.
• Each small box horizontal is equal to 0.04 sec and each large box horizontal
is equal to 0.20sec.
• On vertical axis, small box measures 1mm is equal to 0.1 mV and large box
measures 5mm i.e. 0.5mV.

The 12-lead Electrocardiogram
• The standard 12-lead ECG consists of 4-standard limb leads that record
electrical activity in the frontal plane-traveling up/down and right/left in the
heart.
• 6-precordial leads that record electrical activity in the horizontal plane-
traveling anterior/posterior and right/left.
• Limb leads are recorded by electrodes placed on the arms and legs,
whereas precordial leads are recorded by electrodes placed on the chest.
• Bipolar leads: has a positive pole and negative pole, with each contributing
equally to the recording lead I,II,III are bipolar limb leads.
• Unipolar leads: A unipolar lead has one positive pole and a reference pole in
the centre of the chest that is algebraically determined by the ECG machine.
The reference pole represents the centre of the electrical field of the heart
and has a zero potential, so only the positive pole of a unipolar lead
contributes to the tracing. Unipolar leads are aVR, aVL, aVF these are also
called as augmented limb leads. These augmented leads are produced
when the current flows from right arm (aVR), left arm (aVL), and left leg
(aVF) respectively to the centre of heart. The chest leads V1 to V6 are also
called unipolar leads.
• Right Chest and Posterior Leads: additional leads can be recorded on the
chest or posterior thorax to gain additional information about right
ventricular or posterior infraction or right ventricular hypertrophy

• 12 conventional leads, physiologically divided into two groups
1. Bipolar leads- 3 Standard limb leads
2. Unipolar leads-3 Augmented limb leads and 6 precordialc hest leads.
• Bipolar leads : These record the actual difference in potential across the two
electrodes. There are three standard limb lead:
- Lead I Left arm Right arm
- Lead II Left foot Right arm
- Lead III Left foot Left arm
• These lead axes form the sides of an equilateral triangle with the heart at the
center ( Einthovens triangle)
• The sum total of the potential in the three leads equals zero and mathematically it
could be demonstrated that the potential in L II equals sum of the potentials in L I
and L III i.e. Einthovens law.
• Unipolar limb leads: Constituted by the indifferent electrode which forms the
negative electrode and the exploring electrode which forms the positive electrode.
• The indifferent electrode is constituted by connecting all limb lead electrodes
together through an electrical resistance there by maintaining the zero potential.
• The positive electrode records the true potential at a given point.
• Here the cord is of low voltage.
• Goldberger augmented these leads for proper recording, came to be known as
augmented unipolar limb leads, represented by aVR, aVF, aVL leads.

lead Positive input Negative input View of the heart
Standard limb leads
Lead I Left arm Right arm lateral
Lead II Left leg Right arm inferior
Lead III Left leg Left arm inferior
Augmented limb leads
aVR Right arm Centre of the heart none
aVL Left arm Centre of the heart Lateral
aVF Left leg Centre of the heart Inferior

Lead positive input Negative input view

Axis determination
• The electrical axis of the heart is the mean direction of
the action potentials traveling through the ventricles
during ventricular depolarization.
• The QRS complex, which represents ventricular
depolarization, is used for the determination of the
electrical heart axis.
• Generally perpendicular leads are taken account
a. Lead I and aVF are perpendicular leads
b. Lead II and aVL are perpendicular leads
c. Lead III and aVR are perpendicular leads
• Methods of Axis determination
1. Simple method
2. Classic method
3. Equiphasic method

• The normal electrical axis of the heart is situated
between -300 and +900 with respect to the horizontal
line
• Left axis deviation: the electrical heart axis is between -
300 and -900 with respect to the horizontal line. Causes:
Qwaves of inferior MI, emphysema, tricuspid atresia
• Right axis deviation: between +900 and 1800 with
respect to horizontal line. Causes are: normal in
children, rt ventricular hypertrophy, chronic lung
disease, anterolateral MI, atrial septal defect.
• Extreme axis deviation /northwest axis : between +1800
and -900 with respect to horizontal line. Causes:
emphysema, hyperkalaemia, artificial cardiac pacing,
ventricular tachycardia

Classic method for axis determination

Laboratory Studies
Test description Normal value
CK-MB >5% of total creatine kinase are highly
indicative of MI. serum level increases
within 4-6 hrs after MI
0-9 u/L
Cardiac specific
troponins
Contractile myocardial muscle proteins
released after injury. Detectable within
1hr after injury. High at 3-6 hrs following
symptoms and reach peak within 12 hrs
Normally there is no
circulating troponin
- cTnT (Troponin T) <0.1ng /mL
- cTnI (Troponin I) <0.4ng/mL
myoglobin Low molecular weight heme protein
found in cardiac and skeletal muscle. 99-
100% sensitive for MI. Serum elevation
occurs within 30-60 mins of injury
<92ng/mL (men)
<76 ng/mL (women)
C-reactive protein Marks of inflammation. Can predict risk of
cardiac events,
Normal <1mg/L
Moderate risk 1-3 mg/L
High risk >3mg/L

Homocysteine Amino acid produced during
protein catabolism that is risk
for CV disorder. Causes
damage to endothelium and
formation of thrombi
Optimal <12umol/L
Moderate risk 12-15 umol/L
High risk >15 umol/L
Beta-type natriuretic peptide Peptide that causes
natriuresis. Elevation indicates
presence of heart failure and
distinguishes cardiac vs
respiratory cause of dyspnea
Normal <100pg/mL
Cholesterol Normal 140-200 mg/dL
(3.62-5.17 mmol/L)
Triglycerides Normal 40-190 mg/dL
(0.45-2.15 mmol/L
Lipoproteins
Lipoproteins-associated
phospholipase A2
Normal 131-136 ng/mL (men)
120-342 ng/mL (women)

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