Purvi shah ecg ppt
- 3. Electrocardiogram An ECG is a permanent record of the electrical impulses generated in the heart by the depolarization & repolarization (contraction & relaxation) of the myocardium. It is a representation of the electrical events of the cardiac cycle. These impulses are transmitted to the surface of the body where they are detected & picked up by the electrodes & measured by electrocardiograph.
- 5. Clinical use of ECG To assess the cardiac functions, e.g. rate, rhythm, & conduction. TO diagnose cardiac rhythm disorders, e.g. heart attack TO diagnose cardiac diseases, e.g. MI To evaluate effects of the treatments, e.g. administration of cardiac drugs.
- 6. Rate Rhythm Cardiac disease Effect of treatments Normal = 60 100 beats / min Irregular Cardiomyopathy Inotropic effect Tachycardia Fast Myocardial infarction Chonotropic effect Bradycardia Slow Heart attack Rhythmic effect
- 7. ECG lead placement 12. Leads ECG Placement 3. Standard limbs leads 3. Augmated limbs leads 6. Precordial leads
- 8. Standard limb leads LEADS I, II, III These are the bipolar leads that register the voltage between two electrodes
- 9. Augmated limb leads Leads aVR, aVL, aVF These are the unipolar leads that register the activity in the heart which is directed or located below electrode
- 10. Precordial lead placement V1: 4th intercostal space, right sternal border V2: 4th intercostal space, left sternal border V3: midway between V2 and V4 V4: 5th intercostal space, left midclavicular line V5: level with V4 anterior axillary line V6: level with V4 mid axillary line
- 13. Leads V1 & aVR- Represent right side of the heart Leads V2, V3, V4- Represent transition between the right & left side of the heart Leads V5, V6. I, aVL- Represent left side of the heart Leads II, III, aVF- Represent the inferior part of the heart
- 14. Einthoven’s triangle It is an imaginary formation of the three leads in a triangle used in ECG The heart being a centre of a euilateral triangle, whose apices are at a right arm, left leg & left arm. The triangle, thus formed is called Einthoven’s triangle
- 16. Normal ECG
- 17. Components of ECG ECG consist of waves, complexes, segments & intervals Waves Complexes Segments Intervals P, Q, R, S, T, U QRS P-Q, S-T, T-P P-R, Q-T, R-R
- 19. P wave Significance – Depolarization of atria Time period - <0.12 sec Abnormalities – Abnormal or absence of SA node abnormality P-R Interval Significance – Time for the impulses to reach the ventricales Time period - <0.20 sec Abnormalities – prolonged P-R intervals indicates conduction of block
- 20. S-T Segment Significance – Completion of depolarization of ventricales Time period - <0.20 sec Abnormalities – Elevation/Depression represent infarction/ischemia of myocardium QRS Complex Significance – Depolarization of ventricales Time period - <0.12 sec Abnormalities – prolonged QRS complex –Abnormal conduction – BBB T wave Significance – Complete electrical recovery of the ventricles Time period - <0.20 sec Abnormalities – Flat-ischemia/Inverted-infarction
- 21. Abnormalities of the waves Absent of the p wave in atrial fibrillation, atrial flutter, ventricular tachycardia, hyperkalemia Abnormal Q wave - MI Abnormal R wave – right ventricular hypertrophy left ventricular hypertrophy Abnormal QRS complex – bundle branch block, intraventricular conduction defect, ventricular arrhythmias Abnormal U wave – left ventricular systolic & diastolic overload (inverted) hypokalemia, cardiovascular drugs (prominent U wave)
- 22. Abnormalities of the waves Abnormal PR segment – sinus tachycardia, acute pericarditis, atrial infarction (depression) Abnormalities of ST segment – CVA, pulmonary embolism(depression) Abnormalities of P-R interval – coronary artery disease, acute rheumatic fever (Prolonged P-R interval) Abnormalities of Q-T interval – hyperkalemia, hypercalcemia (shortened Q-T interval)/ mitral valve prolapse, electrolyte deficiency (prolonged Q-T prolonged)
- 23. The ECG paper Horizontally One small box – 0.04 sec One large box – 0.20 sec Vertically One large box – 5mm (0.5 mv)
- 25. Calculating the Heart Rate Count the number large square between two consecutive ‘R’ waves then divide the result by 300 Count number of ‘R’ waves in a 6 sec strip then multiply the result by 10(this method especially good for irregular heart rates) With a rate ruler
- 26. How to read ECG Heart Rate (calculating heart rate with following method) Heart Rhythm(regular irregular/irregularly irregular Cardiac Axis (describe overall direction of electrical spread within heart, to determine cardiac axis need to look at leads I,II,III) Look P wave present or absent(check duration, direction& shape, if P wave are absent indicate irregular rhythm suggest atrial fibrillation PR interval (a prolonged or short indicate certain disease)
- 28. QRS complex (width, height, morphology) ST segment (elevated or depressed indicate MI) T wave U wave (>0.5 mm deflection)
- 29. Causes of poor ECG signal oily, dirty & scaly skin Dirty electrodes Improper application Loose electrodes Broken cable wire
- 34. Thank You