TAILIEUCHUNG - Ebook Making sense of the ECG (3rd edition): Part 2

(BQ) Part 2 book "Making sense of the ECG" presents the following contents: The QRS complex, the ST segment, the ST segment, the QT interval, the QT interval, artefacts on the ECG, pacemakers and implantable cardioverter defibrillators,. | 8 hTQRS 0mpiex Normal QRS complexes have a different appearance in each of the 12 ECG leads Fig. . I aVR Vi V4 II aVL V2 V5 Cc Fig. Normal 12-lead ECG Key point appearance of QRS complex III aVF V3 Ve varies from lead to lead When reviewing an ECG look carefully at the size and shape of the QRS complexes in each lead and ask yourself the following four questions Are any R or S waves too big Are the QRS complexes too small MAKING SENSE OF THE ECG Are any QRS complexes too wide Are any QRS complexes an abnormal shape In this chapter we will help you to answer these questions and to interpret any abnormalities you may find. Are any R or S waves too big The height of the R wave and depth of the S wave vary from lead to lead in the normal ECG as Fig. shows . As a rule in the normal ECG the R wave increases in height from lead V1 to V5 the R wave is smaller than the S wave in leads V1 and V2 the R wave is bigger than the S wave in leads V5 and V6 the tallest R wave does not exceed 25 mm in height the deepest S wave does not exceed 25 mm in depth. Always look carefully at the R and S waves in each lead and check whether they conform to these criteria. If not first of all consider ECG calibration should be 1 mV 10 mm . If the calibration is correct consider whether your patient has one of the following left ventricular hypertrophy right ventricular hypertrophy posterior myocardial infarction Wolff-Parkinson-White syndrome dextrocardia. Each of these conditions is discussed below. If the QRS complex is also abnormally wide think of bundle branch block discussed later in this chapter . Left ventricular hypertrophy Hypertrophy of the left ventricle causes tall R waves in the leads that look at the left ventricle - I aVL V5 and V6 - and the reciprocal mirror image change of deep S waves in leads that look at the right ventricle - V1 and V2. There are many criteria for the ECG diagnosis of left ventricular hypertrophy with varying sensitivity and specificity. .

• Y khoa - Dược
• Making sense of the ECG
• The QRS complex
• The ST segment
• The ST segment
• The QT interval
• The QT interval
• Artefacts on the ECG
• Where the waves come from
• Heart rate
• The P wave
• The PR interval
• The axis
• The Q wave