ECG final

ABNORMALITIES OF P WAVE, QRS COMPLEX AND T WAVE : 

ABNORMALITIES OF P WAVE, QRS COMPLEX AND T WAVE

REMEMBER : 

REMEMBER The P wave can only be normal, unusually tall or unusually broad. The QRS complex can only have three abnormalities. It can be too broad, too tall or it may contain an abnormal Q wave. The ST segments can only be normal, elevated or depressed. The T wave can only be right way up or the wrong way up.

ABNORMALITIES OF P WAVES : 

ABNORMALITIES OF P WAVES P-pulmonale: Anything that cause right atrium to become hypertrophied causes the P wave to become peaked.

Slide 4: 

P-mitrale: Left atrial hypertrophy causes the P wave to become broad. Inverted P waves: When pacemaker shifts from SA node to AV node.

ABNORMALITIES QRS COMPLEX : 

ABNORMALITIES QRS COMPLEX Right ventricular hypertrophy is best seen in right ventricular lead. The height of the R exceeds the depth S wave. In severe cases by the inversion of T wave in the leads V1 and V2.

Slide 6: 

Left ventricular hypertrophy: Tall R wave in leads V5 and V6 and deep S wave in the leads V1-V2.

ACUTE ANTERIOR MYOCARDIAL INfARCTION AND OLD INFERIOR INfARCTION : 

ACUTE ANTERIOR MYOCARDIAL INfARCTION AND OLD INFERIOR INfARCTION Inverted T wave indicates old interior infarction. Small Q wave in leads II, III. Small Q wave in leads V3 – V4 associated with wave ST segments, indicate acute interior infarction. The presence of Q wave does not give any indication of age of infarction because once a Q wave has developed it is usually permanent.

CURRENT OF INJURY : 

CURRENT OF INJURY The current flow from pathologically injured area to normally uninjured area is called current of injury. Causing Factors: Mechanical trauma Infectious process Ischemia of some areas of heart muscle.

EFFECT ON ECG : 

EFFECT ON ECG Current of injury causes an initial record before QRS complex.

J POINT : 

J POINT Point at which potential of ECG is exactly zero is called J point. USES: J point is used to locate injured area of heart.

ABNORMALITIES OF ST SEGMENT : 

ABNORMALITIES OF ST SEGMENT The ST lies between QRS complex and the T wave. It should be isoelectric that is at the same level between T wave and P wave. Elevation of ST segment is an indication of myocardial injury.

Slide 12: 

depression of ST segment associated with an a bright T wave is a sign of ischemia. When the ECG test is normal ST segment depression may appear during exercise.

ABNORMALITIES OF T WAVE : 

ABNORMALITIES OF T WAVE Ischemia Ventricular hypertrophy Bundle branch block

ELECTROLYTE ABNORMOLITIES : 

ELECTROLYTE ABNORMOLITIES Abnormalities of plasma level of potassium, calcium and magnesium affect the ECG. The changes in plasma sodium level do not affect ECG. The T wave and QT interval are mostly affected.

Slide 15: 

A low potassium level the appearance of a hump on the ends of T wave called “U wave”. A high potassium level causes the peaked T waves with the disappearance of ST segment. QRS complex may widened. Effects of abnormal magnesium level are similar. A low plasma calcium level causes the prolongation of QT interval and a high calcium level shortens it.

NON-SPECIFIC CHANGES : 

NON-SPECIFIC CHANGES Minor decrease of ST segments and T wave abnormalities are usually of no great significance.