Page 1 of 4: Library: Learn ecg bed side easy way

tanmay_mehta · Credits: 18350 Preparing for: AIPGE My Scrapbook

posting some useful tips to make ecg easier. hope they are helpful. plz send your inputs as per your experience.

work systematically through the ECG:
'The rate is...' To work out the rate take 300 and divide by the distance between two QRS complexes. Normal is 60 - 100 beats per minute in the average .
• 6 squares = 300/6 = 50bpm (bradycardia)
• 5 squares = 300/5 = 60bpm
• 4 squares = 300/4 = 75bpm
• 3 squares = 300/3 = 100bpm
• 2 squares = 300/2 = 150bpm (tachycardia)

tanmay_mehta · Credits: 18350 Preparing for: AIPGE My Scrapbook

'The rhythm is...' Is the rhythm regular? This can be worked out by marking the QRS distances on a piece of paper and shifting it along to see if the pattern always fits. If it is irregular, is it irregularly irregular? If there are P waves before each QRS and it is regular, the rhythm is 'sinus'.

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The axis of the heart is the average direction of impulse flow. To assess this, look at leads I, II and III. For axis, look at the overall deflection of the QRS. Is it up (positive) or down (negative)? The normal axis of the heart is from +90° to -30°, measured from 3 o'clock as 0°.

tanmay_mehta · Credits: 18350 Preparing for: AIPGE My Scrapbook

easiest way to think of this is as vectors. In the normal ECG all three leads are positive.

If lead I is negative, there is right axis deviation

If leads II and III are negative, there is left axis deviation

tanmay_mehta · Credits: 18350 Preparing for: AIPGE My Scrapbook

The P wave should be normal in shape and size (<2.5mm tall). It reflects the atrial depolarization. Abnormalities reflect changes in the atria and valves.

tanmay_mehta · Credits: 18350 Preparing for: AIPGE My Scrapbook

QRS should be less than 3 small squares wide. Wider complexes imply abnormal depolarization. Very tall R waves can reflect left ventricular hypertrophy.

tanmay_mehta · Credits: 18350 Preparing for: AIPGE My Scrapbook

'The T wave is...' Normal is <10mm tall. Abnormal T waves can be peaked or inverted.

tanmay_mehta · Credits: 18350 Preparing for: AIPGE My Scrapbook

U waves are rarely seen in normal people or hypokalaemia

sd04 · Credits: 4337 Preparing for: Canada My Scrapbook

gud work

tanmay_mehta · Credits: 18350 Preparing for: AIPGE My Scrapbook

Torsades de Pointes is a rapid ventricular rhythm caused by low potassium, medications (those that block potassium channels), or congenital abnormalities (e.g., Long QT Syndrome) that lengthen the QT interval. The rate is a variable 250 to 350 per minute, in brief episodes.

2shar · Credits: 7895 Preparing for: USMLE Step 1 My Scrapbook

What is QTc interval(corrected QT interval)?and why we do it?

sea_corel · Credits: 12021 Preparing for: DNB Part 1 My Scrapbook

The term "corrected" QT-interval may be misunderstood. It does not mean the measured QT-interval is incorrect, but adjusted for heart rate. The reason is that the QT interval is affected by the heart rate. QTc in concept is best compared to the Body Mass Index (BMI).

Diagnosis of long QT syndrome is commonly suspected or made from an ECG. The corrected QT-interval (QTc) on the ECG is checked for prolongation.

A QTc-interval above 440 milliseconds is considered prolonged.
The average QTc for someone who has QT syndrome is 490 milliseconds

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women exhibit a longer QTc interval and an increased propensity toward torsade de pointes

In familial long QT syndrome linked to either chromosome 7q or 11p, men exhibit shorter mean QTc values than both women and children

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Calculating QTc

Several formulas have been proposed to adjust the QT-interval for the heart rate. The most commonly used QT correction (QTc) formula is the one postulated by Bazett in 1920 (QTc=QT/RR1/2).

Other common formulas include the nomogram method (QTNc=QT+correcting number), the Friderica formula (QTFc=QT/RR1/3) and the linear regression equitation (QTLc=QT+0.154x[1-RR]).

The nomogram method adjusted the QT-interval most accurately over the whole range of heart rates on the basis of smallest mean-squared residual values between measured and predicted QT-intervals.

2shar · Credits: 7895 Preparing for: USMLE Step 1 My Scrapbook

thanx

legolassildarin · Credits: 2428 Preparing for: Maharashtra PG My Scrapbook

gr8 information.

tanmay_mehta · Credits: 18350 Preparing for: AIPGE My Scrapbook

doing great job

tanmay_mehta · Credits: 18350 Preparing for: AIPGE My Scrapbook

• normal sinus rhythm
o each P wave is followed by a QRS
o P waves normal for the subject
o P wave rate 60 - 100 bpm with <10% variation
 rate <60 = sinus bradycardia
 rate >100 = sinus tachycardia
 variation >10% = sinus arrhythmia
• normal QRS axis
• normal P waves
o height < 2.5 mm in lead II
o width < 0.11 s in lead II
 for abnormal P waves see right atrial hypertrophy, left atrial hypertrophy, atrial premature beat, hyperkalaemia
• normal PR interval
o 0.12 to 0.20 s (3 - 5 small squares)
 for short PR segment consider Wolff-Parkinson-White syndrome or Lown-Ganong-Levine syndrome (other causes - Duchenne muscular dystrophy, type II glycogen storage disease (Pompe's), HOCM)
 for long PR interval see first degree heart block and 'trifasicular' block
• normal QRS complex
o < 0.12 s duration (3 small squares)
 for abnormally wide QRS consider right or left bundle branch block, ventricular rhythm, hyperkalaemia, etc.
o no pathological Q waves
o no evidence of left or right ventricular hypertrophy
• normal QT interval
o Calculate the corrected QT interval (QTc) by dividing the QT interval by the square root of the preceeding R - R interval. Normal = 0.42 s.
o Causes of long QT interval
 myocardial infarction, myocarditis, diffuse myocardial disease
 hypocalcaemia, hypothyrodism
 subarachnoid haemorrhage, intracerebral haemorrhage
 drugs (e.g. sotalol, amiodarone)
 hereditary
 Romano Ward syndrome (autosomal dominant)
 Jervill + Lange Nielson syndrome (autosomal recessive) associated with sensorineural deafness
• normal ST segment
o no elevation or depression
 causes of elevation include acute MI (e.g. anterior, inferior), left bundle branch block, normal variants (e.g. athletic heart, Edeiken pattern, high-take off), acute pericarditis
 causes of depression include myocardial ischaemia, digoxin effect, ventricular hypertrophy, acute posterior MI, pulmonary embolus,
 left bundle branch block
• normal T wave
 causes of tall T waves include hyperkalaemia, hyperacute myocardial infarction and left bundle branch block
 causes of small, flattened or inverted T waves are numerous and include ischaemia, age, race, hyperventilation, anxiety, drinking iced water, LVH, drugs (e.g. digoxin), pericarditis, PE, intraventricular conduction delay (e.g. RBBB)and electrolyte disturbance.

tanmay_mehta · Credits: 18350 Preparing for: AIPGE My Scrapbook

now lets talk about MI

Acute inferior myocardial infarction
• ST elevation in the inferior leads II, III and aVF
• reciprocal ST depression in the anterior leads
Right Bundle Branch Block and sinus bradycardia are also present.

Acute anterior myocardial infarction
• ST elevation in the anterior leads V1 - 6, I and aVL
• reciprocal ST depression in the inferior leads

Acute posterior myocardial infarction
• (hyperacute) the mirror image of acute injury in leads V1 - 3
• (fully evolved) tall R wave, tall upright T wave in leads V1 -3
• usually associated with inferior and/or lateral wall MI

Old inferior myocardial infarction
• a Q wave in lead III wider than 1 mm (1 small square) and
• a Q wave in lead aVF wider than 0.5 mm and
• a Q wave of any size in lead II

Acute myocardial infarction in the presence of left bundle branch block
Features suggesting acute MI
• ST changes in the same direction as the QRS (as shown here)
• ST elevation more than you'd expect from LBBB alone (e.g. > 5 mm in leads V1 - 3)
• Q waves in two consecutive lateral leads (indicating anteroseptal MI)

tanmay_mehta · Credits: 18350 Preparing for: AIPGE My Scrapbook

hope this is useful . do send ur feedback

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