6. Millivolts Milliseconds 0 200 400 600 -0.5 0 0.5 1.0 QRS The width of the QRS complex should not exceed 110 ms, less than 3 little squares P R T Q S
7. The QRS complex should be dominantly upright in leads I and II I II III aVR aVL aVF
8. QRS and T waves tend to have the same general direction in the limb leads I II III aVR aVL aVF
9. V 1 V 2 V 3 V 4 V 5 V 6 The R wave in the precordial leads must grow from V1 to at least V4
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39. 65 year old man(H/O DM,HTN) presented with a 1 hour history of severe central crushing chest pain. He is sweaty, clammy and has vomited twice .
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41. A 26 year old woman presented 1 week post delivery of her first baby. She has sharp L sided chest pain and she is short of breath.
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43. 50 years old female with chronic renal failure,chest pain & dizziness she is hypertensive on lisinopril
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45. 26 Old army officer had flu last week,felt chest pain while driving his car,pain increased by deep breath,he has no history of DM or HTN,nonsmoker,lipid profile LDL 2.0 MMMOL/ L
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47. 26 Old army officer had flu last week, felt chest pain while driving his car, pain increased by deep breath, ECG after 5 days .
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Editor's Notes
QRS waveform nomenclature The ECG consists of a small deflection called the P wave, arising from the atria, a more complicated deflection called the QRS complex due to ventricular depolarisation and a final T wave resulting from repolarisation of the ventricles. The QRS complex of waves is the largest deflection of the ECG and is always spiky in shape. All sharp deflections resulting from electrical activation of the ventricles are called QRS complexes. However, these waves can vary immensely in size, and arrangement. The QRS complex is very important when diagnosing myocardial infarction. In order to be able to describe these complexes, a nomenclature for the waves is needed. This can be done using combinations of the letters q, r, s, Q, R, S, lower case letters denoting small waves and upper case larger waves. The first positive wave is labelled with r or R Any second positive wave is labelled r´ or R´ A negative wave which follows an R wave or r wave is labelled S or s A negative wave that precedes an R or r wave, is labelled a q or Q wave Any wave that is entirely negative is labelled qs or QS. Using these rules and nomenclature all QRS complexes can be described, enabling more accurate diagnosis.
Rule 2 The QRS complex is due to depolarisation of the ventricles. The width of the QRS complex should not exceed 110 ms (less than 3 little squares). A wider QRS is sometimes seen in healthy people, but may represent an abnormality of intraventricular conduction.
Rule 3 The QRS complex should be dominantly upright in leads I and II. Slight disparities are likely to be acceptable.
Rule 4 The QRS and T waves tend to have the same direction in the standard leads.
Rule 6 The normality of QRS complexes recorded from the precordial leads is dependent on both morphological and dimensional criteria.