THE 12 LEADS STNDARD ECG
NORMAL ECGABNORMAL ECG
THE 12 LEADS STNDARD ECG*6 STANDARD LIMB LEADS (ORIANTED ON THE FRONTAL PLANE OF THE HEART) -BIPOLAR LIMB LEADS LEAD1:RA(-)TO LA(+) LEADII:RA(-)TO LF(+) LEADIII:LA(-)TO LF(+) -AUGMENTED UNIPOLAR LIMB LEADS LEAD aVR:RA(+)TO(LA&LF) (-) LEAD aVL:LA(+)TO(RA&LF) (-) LEAD aVF : LF(+)TO(LA&RA) (-)
*6 UNIPOLAR (+) CHEST LEADS ORIANTED ON THE HORIZENTAL PLANE OF THE HEART) -LEADS V1,V2,V3,V4,V5,V6
LEAD PLACEMENT
V1: right 4th intercostal space V2: left 4th intercostal space V3: halfway between V2 and V4 V4: left 5th intercostal space, mid-clavicular line V5: horizontal to V4, anterior axillary line V6: horizontal to V5, mid-axillary's line.*LEADS II,III,aVF: RECORD CHANGES FROM INF. BORDER OF THE HEART. *V1-V2 : RECORD CHANGES FROM THE RV *V3-V4 : RECORD CHANGES FROM THE INTERVENT. SEPTUM. *V5-V6 -I-aVL: RECORD CHANGES FROM LV
ECG Waves and Intervals
P wave: the sequential activation (depolarization) of the right and left atria. QRS complex: right and left ventricular depolarization (normally the ventricles are activated simultaneously). ST-T wave: ventricular repolarization. U wave: origin for this wave is not clear - but probably represents "afterdepolarizations" in the ventriclesPR interval: time interval from onset of atrial depolarization (P wave) to onset of ventricular depolarization (QRS complex) QRS duration: duration of ventricular muscle depolarization QT interval: duration of ventricular depolarization and repolarization RR interval: duration of ventricular cardiac cycle (an indicator of ventricular rate) PP interval: duration of atrial cycle (an indicator of atrial rate)
MEASUREMENTS
SENSIVITY :10mm = 1mv =2 large sq vertically PAPER SPEED :25mm/sec EACH LARGE 5mm SQ=0,2s EACH SMALL 1mm SQ=0,04 H.R =1500/R-R interv.in 1mm Ssq =300/R-R interv. In 5mm L sq P-R INTERV.=0,12-0,2 sec QRS DURATION=0,06-0,10 sec QT INTERV.=/< 0,4 secREADING & INTERPRITING ECG
METHODS OF READING &INTERPRETING THE ECG1.DETERMINE THE CARDIAC RATE 2.DETERMINE THE CARDIAC RHYTHEM 3.DETERMINE THE AXIS OF THE HEART 4.EXAMINE THE P WAVE 5.ASSES THE PR INTERVAL 6.EXAMINE THE QRS COMPLEX 7.EXAMINE THE ST SEGMENT 8.EXAMINE THE T WAVE 9.EXAMINE THE U WAVE
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EXAMINATION OF P WAVE
*REPRESENT SEQUENCIAL RIGHT &LEFT ATRIA ACTIVATION *DURATION >0,12 S. *AMPLITUDE >2,5 mm *BEST STUDIED IN LEAD IIABNORMALITIES OF P WAVE
1.P MITRAL (L A. HYPERTROPHY) *BROADENING OF P WAVE *M SHAPE CONFIGERATION 2. P PULMONAL (R ATR. HYPERTROPHY) *PEAKED P WAVE 3. INVERTED P WAVE(NODAL RHYTHEM) 4. ABSENT P WAVE (A.F,VT,SA BLOCK) 5.INVERTED P IN L I (WRONG CONNECTION, DEXTROCARDIA)