2 nd section

1. 2nd section

2. IV. Hypertrophy Hypertrophy criteria are fairly straightforward; we will be looking for enlargement of any of the four chambers. 1. LVH: (Left ventricular hypertrophy). Add the larger S wave of V1 or V2 (not both), measure in mm, to the larger R wave of V5 or V6. If the sum is > 35mm, it meets "voltage criteria" for LVH. Also consider if R wave is > 12mm in aVL. LVH is more likely with a "strain pattern" which is asymmetric T wave inversion in those leads showing LVH 2. RVH: (Right ventricular hypertrophy). R wave > S wave in V1 and R wave decreases from V1 to V6. 3. Atrial hypertrophy: (leads II and V1). Right atrial hypertrophy - Peaked P wave in lead II > 2.5mm amplitude. V1 has increase in the initial positive deflection. Left atrial hypertrophy - Notched wide (> 3mm) P wave in lead II. V1 has increase in the terminal negative deflection.

3. IV. Hypertrophy

4. IV. Hypertrophy Figure 32: Right ventricular hypertrophy and right atrial enlargement

5. IV. Hypertrophy Figure 33: Left ventricular hypertrophy (S wave V2 plus R wave of V5 greater than 35mm) and left atrial enlargement (II and V1).

6. IV. Hypertrophy Quiz Concentrate on the hypertrophy for the following unknown tracings. #1 Hypertrophy

7. IV. Hypertrophy Quiz Left ventricular and left atrial hypertrophy. S wave in V2 plus R wave in V5 > 35. The left atrial hypertrophy is noticaeable by a P wave that is long in lead II, with an increase in the negative terminal deflection in lead V1.

8. IV. Hypertrophy Quiz Concentrate on the hypertrophy for the following unknown tracings. #2 Hypertrophy

9. IV. Hypertrophy Quiz Left ventricular and left atrial hypertrophy. The R wave in aVL is greater than 12mm. The left atrial hypertrophy is barely noticeable by a P wave that is notched and wide in lead II and with an increase in the negative terminal deflection in lead V1.

10. IV. Hypertrophy Quiz Concentrate on the hypertrophy for the following unknown tracings. #3 Hypertrophy

11. IV. Hypertrophy Quiz Right ventricular and right atrial hypertrophy. The R wave is greater than the S wave in V1 and the R wave gets progressively smaller from V1 to V6. Normally, the R wave should increase from V1 to V6. The right atrial hypertrophy is marked by peaked P waves in lead II and a large intitial positive deflection of the P wave in lead V1.

12. V. Infarct Accurate ECG interpretation in a patient with chest pain is critical. Basically, there can be three types of problems - ischemia is a relative lack of blood supply (not yet an infarct), injury is acute damage occurring right now, and finally, infarct is an area of dead myocardium. It is important to realize that certain leads represent certain areas of the left ventricle; by noting which leads are involved, you can localize the process. The prognosis often varies depending on which area of the left ventricle is involved (i.e. anterior wall myocardial infarct generally has a worse prognosis than an inferior wall infarct). V1-V2 anteroseptal wall V3-V4 anterior wall V5-V6 anterolateral wall II, III, aVF inferior wall I, aVL lateral wall V1-V2 posterior wall (reciprocal)

14. IV. V. Infarct Represented by symmetrical T wave inversion (upside down). The definitive leads for ischemia are: I, II, V2 - V6. Acute damage - look for elevated ST segments. (Pericarditis and cardiac aneurysm can also cause ST elevation; remember to correlate it with the patient. Look for significant "patholgic" Q waves. To be significant, a Q wave must be at least one small box wide or one-third the entire QRS height. Remember, to be a Q wave, the initial deflection must be down; even a tiny initial upward deflection makes the apparent Q wave an R wave. Infarct 1. Ischemia 2. Injury 3. Infarct

15. IV. Infarct V. Infarct Figure 34: Ischemia: Note symmetric T wave inversions in leads I, V2-V5.

16. IV. Infarct V. Infarct Figure 35: Injury: Note ST segment elevation in leads V2-V3 (anteroseptal/anterior wall).

17. IV. Infarct V. Infarct Figure 36: Infarct: Note Q waves in leads II, III, and aVF (inferior wall).

18. IV. Infarct V. Infarct For the posterior wall, remember that vectors representing depolarization of the anterior and posterior portion of the left ventricle are in opposite directions. So, a posterior process shows up as opposite of an anterior process in V1. Instead of a Q wave and ST elevation, you get an R wave and ST depression in V1.

19. V. Infarct Figure 37: Posterior wall infarct. Notice tall R wave in V1. Posterior wall infarcts are often associated with inferior wall infarcts (Q waves in II, III and aVF).

20. IV. Infarct V. Infarct Two other caveats: One is that normally the R wave gets larger as you go to V1 to V6. If there is no R wave "progression" from V1 to V6 this can also mean infarct. The second caveat is that, with a left bundle branch block, you cannot evaluate "infarct" on that ECG. In a patient with chest pain and left bundle branch block, you must rely on cardiac enzymes (blood tests) and the history.

21. V. Infarct Quiz For the following ECG tracings identify the type of problem (ischemia, injury, infarct) and the area of the left ventricle involved. # 1

22. V. Infarct Quiz Acute injury in the anterior, anterolateral, and lateral wall (ST elevation in V2-V6, I and aVL). # 1

23. V. Infarct Quiz For the following ECG tracings identify the type of problem (ischemia, injury, infarct) and the area of the left ventricle involved. # 2

24. V. Infarct Quiz Infarct in the antereoseptal and anterior wall (Q waves in V2-V4 there is also a probable inferior infarct (Q waves in II, III, and aVF). # 2

25. V. Infarct Quiz For the following ECG tracings identify the type of problem (ischemia, injury, infarct) and the area of the left ventricle involved. # 3

26. V. Infarct Quiz Ischemia across the entire anterior and lateral wall (T wave inversions in V2-V6, I and aVL). Also note, the injury pattern in V2 of ST elevation, the prominent Q waves in V2 and V3 show that some of the myocardium has also reached the infarct stage. # 3

27. VI. Fasicular Blocks Anterior fasicular block - the most common. You will see left axis deviation (-30 to -90) and a small Q wave in lead I and an S in lead III (Q1S3). The QRS will be slightly prolonged (0.1 - 0.12 sec). Figure 39: Anterior fasicular block.

28. VII. Summary • One Last Differential Diagnosis • Four cases of an R wave taller than an S wave in V1 (normally R wave always < S wave in V1. • 1. Right bundle branch block. • 2. Right ventricular hypertrophy. • 3. Posterior wall myocardial infarction. • 4. Wolff-Parkinson-White. • Suggestions/Summary • Look at each ECG for rate, rhythm, axis, hypertrophy, and infarct. The systemic interpretation guidelines on the next slide will serve as a quick reference, it is a summary of the entire course and what you need to know. • If possible, compare the recent ECG to a previous ECG on the same patient to see what is new or old. This may be clinically important.

29. VII. Summary Guidelines SYSTEMATIC INTERPRETATION GUIDELINES for Electrocardiograms RATERate calculationCommon method: 300-150-100-75-60-50Mathematical method: 300/# large boxes between R wavesSix-second method: # R-R intervals x10 RHYTHMRhythm Guidelines:1. Check the bottom rhythm strip for regularity, i.e. - regular, regularly irregular, and irregularly irregular. 2. Check for a P wave before each QRS, QRS after each P. 3. Check PR interval (for AV blocks) and QRS (for bundle branch blocks). Check for prolonged QT. 4. Recognize "patterns" such as atrial fibrillation, PVC's, PAC's, escape beats, ventricular tachycardia, paroxysmal atrial tachycardia, AV blocks and bundle branch blocks.

30. VII. Summary Guidelines AXIS Lead ILead aVF 1. Normal axis (0 to +90 degrees) Positive Positive 2. Left axis deviation (-30 to -90) Also check lead II. To be true left axis deviation, it should also be down in lead II. Positive Negative 3. Right axis deviation (+90 to +180) Negative Positive 4. Indeterminate axis (-90 to -180) Negative Negative Left axis deviation differential: LVH, left anterior fasicular block, inferior wall MI.Right axis deviation differential: RVH, left posterior fascicular block, lateral wall MI.

31. VII. Summary Guidelines HYPERTROPHY1. LVH -- left ventricular hypertrophy = S wave in V1 or V2 + R wave in V5 or V6 > 35mm or aVL R wave > 12mm. 2. RVH -- right ventricular hypertrophy = R wave > S wave in V1 and gets progressively smaller to left V1-V6 (normally, R wave increases from V1-V6). 3. Atrial hypertrophy (leads II and V1) Right atrial hypertrophy -- Peaked P wave in lead II > 2.5 mm in amplitude. V1 has increase in the initial positive direction.Left atrial hypertrophy -- Notched wide (> 3mm) P wave in II. V1 has increase in the terminal negative direction.

32. VII. Summary Guidelines INFARCT Ischemia Injury Infarct Represented by symmetrical T wave inversion (upside down). Look in leads I, II, V2-V6. Acute damage -- look for elevated ST segments. "Pathologic" Q waves. To be significant, a Q wave must be at least one small square wide or one-third the entire QRS height. Certain leads represent certain areas of the left ventricle: V1-V2 anteroseptal wall V3-V4 anterior wall V5-V6 anterolateral wall II, III, aVF inferior wall I, aVL lateral wall V1-V2 posterior wall (reciprocal)

33. VIII. Clinical Cases The following clinical case examples could be taken from the charts of any busy primary care practice. They are designed to show you some clinical applications of the basic ecg skills taught in this program. You will receive a brief clinical description first, and then you will be asked to interpret the patients twelve lead electrocardiogram. Interpret the electrocardiogram using the “Systematic interpretation guidelines”. The emphasis is on complete interpretation to include: 1. Rate, 2. Rhythm & Intervals, 3. Axis, 4. Hypertrophy and 5. Infarct. Always try to clinically correlate the ecg with the patient presentation.

34. VIII. Clinical Cases Case 1 A 60-year-old "walk-in" patient without a primary care physician arrives at your clinic near the end of a busy afternoon clinic session. The patient is not on any medications and has not seen a physician in years. The patient complains of several hours of severe chest pressure and as he lives nearby he thought he would come to your clinic and try to see a physician. Although the vital signs were remarkable only for some bradycardia, the medical assistant is concerned that the patient appears ill. A stat ecg was done and you are asked to see this patient immediately. The following ecg is handed to you as you are on your way to see this patient

35. VIII. Clinical Cases Case 1 Answer Rate - 50Rhythm - sinus bradycardiaIntervals - PR and QRS intervals are not prolongedAxis - normalHypertrophy - noneInfarct - acute injury pattern of ST elevation noted in V1-V4 Clinical correlation - An acute myocardial infarct can be one of the most dramatic emergencies in a primary care clinic and most seasoned practitioners have seen it on an occasional basis. With the severe chest pain and acute anterior injury pattern, this patient's situation is critical. Immediate medical stabilization is started and stat (911) telemetry transport to the emergency room is arranged.

36. VIII. Clinical Cases Case 2 A 55-year-old patient comes in to get your advice on starting a new exercise program to get back into shape. The program involves heavy aerobic workouts and he needs a form filled out that he is medically cleared to participate in this workout program. In talking to him you learn he has cardiac risk factors for smoking, positive family history, high cholesterol and hypertension. He has a sedentary lifestyle and has not participated in any strenuous physical activity for years. Although his cardiorespiratory review of systems is negative, you are concerned that his activity level is very limited and he has significant risk factors. As part of the workup you obtain the following ecg to interpret:

37. VIII. Clinical Cases Case 2 Answer Rate - about 70Rhythm - sinus rhythm with borderline first degree blockIntervals - PR is prolonged at .2 seconds, QRS is not prolongedAxis - normal quadrantHypertrophy - left ventricular hypertrophy with strain patternInfarct - Q waves noted in V2 and V3 consistent with old myocardial infarct in the anterior septal - anterior wall area Clinical correlation - This patient should NOT be medically cleared at this time. He has significant risk factors, a sedentary lifestyle and signs of previous infarction on ECG. He needs further cardiac evaluation and testing.

38. VIII. Clinical Cases Case 3 A 76-year-old patient, with a history of hypertension, comes to see you. She is currently on a diuretic prescription and is complaining of a few days of "skipped heart beats". She has felt slightly dizzy lately but does not have any other symptoms. Overall she has been feeling well, her only medical issue has been hypertension. Previous electrocardiograms in her chart show normal sinus rhythm and are otherwise unremarkable. Her exam shows an irregular pulse in the 130 rate range but the rest of the exam is unremarkable. You obtain the following electrocardiogram:

39. VIII. Clinical Cases Case 3 Answer Rate - about 130-150 rangeRhythm - atrial fibrillationIntervals - no PR to measure, QRS is not prolongedAxis - normal quadrant (aVF is downward but lead II is upward)Hypertrophy - noneInfarct - none (nonspecific ST changes in lateral leads I and aVL Clinical correlation - Atrial fibrillation is the most common sustained arrhythmia for which patients seek treatment. It is more common in the elderly and is a major cause of thromboembolic events. This patient will need a workup for the etiologies of atrial fibrillation and the usual therapeutic considerations of rate control, anticoagulation and antiarrhythmic therapy.

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