ECG In Ischemic Heart Disease
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Transcript of ECG In Ischemic Heart Disease
ECG in IHD
Topics will be covered• ECG basics• How to identify normal ECG• How to identify abnormal findings in ECG
– Atrial hypertrophy - Hyperkalaemia– Atrial fibrillation - Hypokalaemia– Atrial flutter- Pericarditis– Heart blocks– Chambers enlargement– IHD– AMI
Topics will not be covered• Signs and symptoms of the diseases with
abnormal ECG • Treatments of those diseases
What is ECG?• ECG is a medical device capable of
recording the electrical activity of the heart from electrodes placed on the skin in specific locations.
Standard ECG leads• Limb leads
Bipolar limb leads – I, II, IIIUnipolar limb leads – aVL, aVR, aVF
• Chest leadsV1 - V6
Right Arm
Right Leg
Left Leg
Left Arm
• Limb leads are typically placed on the inside of the wrists and ankles
• To help reduce artifacts you can use the upper arms and thighs
• Do not place limb leads on the torso
Limb leads
Chest Leads look at the heart in Chest Leads look at the heart in a horizontal plane.a horizontal plane.
• V1: right sternal edge (4th)V1: right sternal edge (4th)• V2: Left sternal edge (4th)V2: Left sternal edge (4th)• V4: the patient’s apex V4: the patient’s apex
beatbeat• V3: half-way b/t V2 and V4V3: half-way b/t V2 and V4• V5: anterior axillary lineV5: anterior axillary line• V6: mid-axillary lineV6: mid-axillary lineV5 and V6 are in the same V5 and V6 are in the same
horizontal plane as V4horizontal plane as V4ChestLeads
Interpretation of an ECGPatient identificationStandardization1.Rate2.Rhythm3.Axis4.P wave5.PR interval6.QRS complex7.ST segment8.T wave9.U wave10.QT interval
Conduction system of heart
Wave. Interval. Complex.• One letter = wave
– Eg = P, T• Need to check height and width
• Two letters = interval– PR interval
• Need to check length
• 3 letters = complex– QRS complex
• Need to check height, width and shape
• Name• Age • ID number• DOB• Father’s name
Patient identification and standardization
• Regular RhythmRate = 300÷numbers of large square
• Irregular RhythmNumbers of R in 6 sec x 10 (6s method)
Rate determination
Regular Rhythm
Irregular Rhythm
Using 6-sec ECG rhythm strip to calculate heart rate: 7×10 = 70 bpm.
P wave• Atrial depolarization• Best seen at Lead II• Normal Height <2 ⅟2 small square Width <2 ⅟2 small square
Causes of ST depression• Angina
• NSTEMI
• LVH
ST depression
• A – upward may be normal• B – down sloping strain / digoxin effect• C – planar ischaemia***
Angina Pectoris• Imbalance between myocardial oxygen
demand and supply• ST depression and/or T inversion
Causes of ST elevation
• AMI
• Pericarditis
Acute Myocardial Infarction• Hyper acute T • ST elevation – myocardial injury• T inversion – myocardial injury• Q wave – myocardial necrosis
Q wave• NormalLateral leads (I,aVL,V5,V6)III alone mb present1:1:4 =Physiological Q(height <1 ssq, width < 1ssq,Q <1/4 R)
-Old MI
Standard ECG leads• Limb leads
Bipolar limb leads – I, II, IIIUnipolar limb leads – aVL, aVR, aVF
• Chest leadsV1 - V6
Infarction Leads
Inferior II,III,aVF
Lateral I,aVL,V5,V6
Septal V1,V2
Anterior V1-V4
Localizing the Infarct
Inferior Infarction
• Right coronary artery
• Leads II, III, aVF
Inferior Infarction
I II III aVR aVL aVF V1 V2 V3 V4 V5 V6
Right coronary artery
Lateral Infarction
• Left circumflex artery
• I, aVL, V5, V6
• Usually associated with another infarction
Lateral Infarction
I II III aVR aVL aVF V1 V2 V3 V4 V5 V6
Left circumflex artery
Anterior Infarction
• Left anterior descending artery
• V2-V4
• V1-V4 = antero-septal infarction
• V1-V6 = extensive anterior infarction
Anterior Infarction
I II III aVR aVL aVF V1 V2 V3 V4 V5 V6
LADA
Pericarditis
T wave• Normal1/8 R < T < 2/3 R
• Tall T– Peak T wave (> 50% of preceding R)– Hyperkalaemia(Tall T , Small P, Wide QRS)
U wave• Slow repolarization of papillary muscle
• Normal – V1, V2
• Prominent U wave – hypokalaemia
Interpretation of an ECGPatient identificationStandardization1.Rate2.Rhythm3.Axis4.P wave5.PR interval6.QRS complex7.ST segment8.T wave9.U wave10.QT interval
P wave : Duration: 0.08 sec ( 2 small squares ) Height: < 2.5 mm ( 2 small squares )
PR interval: Duration: 0.12 - 0.20 sec (3-5 small squares)
QRS Complex : Duration: 0.07–0.10 sec(2 – 2½ small squares)
ST segment : Isoelectric
T wave : 1/8 previous R < T < 2/3 previous R
Important intervals and durations
Thank You