If the P wave > 0.12 sec( 3 mm) usually in any lead.

Notched P wave usually in lead I ,aVl may be lead II

Negative terminal portion of P wave in V1 , 1 mm depth and 3 mm width( most specific) Since Mitral valve stenosis is the most common

cause of LA enlargement . It is called P Mitrale

P wave > 0.12 sec , 2.5 mm (pecked) usually in Lead II III aVF and V1.

It is called P pulmonale , because chronic pulmonary disease is frequently the cause.

Slide 14

P -WAVE

P pulmonale Tall peaked P wave. Generally due to enlarged right atrium- commonly associated with congenital heart disease, tricuspid valve disease, pulmonary hypertension and diffuse lung disease. Biphasic P wave Its terminal negative deflection more than 40 ms wide and more than 1 mm deep is an ECG sign of left atrial enlargement. P mitrale Wide P wave, often bifid, may be due to mitral stenosis or left atrial enlargement.

LEFT VENTRICULAR

HYPERTROPHY RIGHT VENTRICULAR

HYPERTROPHY AND

So, we have to start looking at the S waves and R waves

Voltage criteria :

1. R Lead 1 or aVL > 20 mm

2. R V5 or V6 + S V1 > 35 mm

3. In sever LVH There will be ST segment depression and T wave inversion in Lateral leads (I aVL,V5 V6)

Prominent R in V1 ( =or > S wave) . prominent S in V 6( = or > R wave ). Usually associated with RT axis

deviation(>+110). In sever RVH ST depression & T wave

inversion V1 may be V2 V3

The impulse will be conducted from : SA node --- AV node ---- Bundle of His ---

RT & LT bundle branches. Any interference with this path way leads

to impulse delay or block Level of the block : SA block , AV block ,

Bundle branch block (BBB), Fascicular block

The most common site of block . Of three degrees : 1. 1st Deg. : all impulses from SA node will

reach the ventricle but with delay , normal P wave followed by normal QRS but the PR interval is > 0.2 sec (5mm)

Characterized by PR Interval > 0.20 seconds Delay in conduction AV Node Prolonged PR Interval constant Usually asymptomatic Least concerning of the blocks

Two types : 1. Mobitz type 1 (wenchebach phenomena): Progressive PR segment prolongation till the

beat will drop out , P wave which will not followed by QRS , the cycle will recurs again .

P wave which is not followed by QRS with out preceding PR segment prolongation.

We see P waves> than QRS complexes, if the P waves are double the no. of QRS , called 2:1 block , if every 3 Ps one QRS complexes , called 3:1 block and so on .

The more the no of P for QRS the more sever the block.

The impulse generated in the SA node will not pass at all to the ventricle , the lower pace maker in the Perkinje fibers will act to stimulate the ventricle .

There are P waves not related to QRS complexes, PP interval regular and different from RR interval also regular at other rate (30-40 b/min)

RT BBB : QRS > 0.12 , Broad S lead I and V6 rSR in V1 . T inversion in V1-V3

QRS duration ≥ 110ms rSR’ pattern or notched R wave in V1 Wide S wave in I and V6

RBBB

QRS > 0.11 RSR in lead I aVL , V5 V6. ST segment depression , T wave inversion in

the same leads. High voltage but LVH cannot be diagnosed.

Look at the ECG , regular or irregular. If it is regular irregularity or irregular

irregularity . Look for the P wave and its relation to QRS Look to the Shape of the P wave and QRS

configuration.

'supraventricular' (sinus, atrial or junctional)

produce narrow QRS complexes

ventricular produce narrow QRS complexes

There P wave for each QRS. PP or RR < 60 beat/mint . Frequently seen in : Athletes , Hypothyroidism Hypothermia, Increased intracranial pressure, inferior MI.

Hear rate > 100 b/min. P wave for each QRS . Seen in : fever , anxiety , exercise, anemia , hyperthyrodsim.

Basically the ECG is regular , some impulses are not , but there is P wave (which looks different from previous one) for each QRS (which is normal).

The PR interval is changeable in these beats ( shorter or longer).

Premature Atrial Contraction PAC

Very common dysrrhythmia. Heart rate 160-220 b/m. Usually regular rhythm .

Rapid atrial rate 250-350 b/m. Usually there is AV block (2:1, 3:1,4:1 etc.) Usually the PP rate is Faster than RR rate , the

atrial rate is regular, ventricular rate could be regular or irregular depending on the degree of block .

Because of very frequent P wave the base line in undulated , called saw teeth appearance.

Completely irregular (irregular irregularity). No P wave but there is f wave (fibrillatory

wave). Atrial rate 350-450 , ventricular rate is totally

irregular.

Generally the ECG is regular with some beats looks wide ,no preceding P wave , wide QRS and T wave in opposite direction to QRS .

Usually followed by compensatory Pause. Could be single or multiple.

Runs of wide QRS complexes fast tachycardia, no preceding P wave, regular .

Usually serious dysrrhytmia, may progress to more serious Ventricular fibrillation.

Fatal dysrhythmia , no actual QRS complexes , rather bizarre and chaotic undulation of the base line.

Unconscious patient No central pulsation No respiration

Hypokalemia : ECG can be used as guide to give clue about

serum potassium level . Hypokalemia leads to flattening of T wave ,

may be U wave . Hyprekalemia showed pecked T wave

Flat T wave

Pecked T wave