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Ekg Cases 7 8 09 Level 1 Part2
 

Ekg Cases 7 8 09 Level 1 Part2

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    Ekg Cases 7 8 09 Level 1 Part2 Ekg Cases 7 8 09 Level 1 Part2 Presentation Transcript

    • Case-oriented EKG’s (level 1- easiest part two) MDFPR July 8, 2009 M. LaCombe
    • The normal EKG waveform
    • A normal EKG
    • The frontal plane (QRS) axis:
    • Case #13 A 61-year-old man with a history of hypertension and congestive heart failure presents to the emergency department with shortness of breath after eating breakfast. All of the following statements about his ECG are correct EXCEPT: a) The QRS axis is normal b) The rhythm is sinus tachycardia c) The PR interval is within normal limits d) There is a complete left bundle branch block e) The voltage in the chest leads meets criteria for left ventricular hypertrophy
    • The QRS axis is normal The rhythm is sinus tachycardia The PR interval is within normal limits There is a complete left bundle branch block The voltage in the chest leads meets criteria for left ventricular hypertrop
    • d) There is no left bundle branch block (LBBB). The QRS axis is normal at approximately 0. The rate is approximately 100 beats per minute, and there are upright P waves in lead II, fulfilling the criteria for sinus tachycardia. This patient is likely tachycardic because of neurohormonal changes related to congestive heart failure (CHF) exacerbation, namely increased sympathetic tone and decreased vagal tone. The PR interval is normal at 0.16 second (normal PR < 0.20 second). There is ECG evidence of left ventricular hypertrophy (see below). The criteria for complete LBBB include: 1. QRS duration > 0.12 second 2. A wide deep QS complex in V1 3. A wide tall R wave in V6
    • Additional comments: LVH can lead to a number of ECG abnormalities, including prominent voltage in the chest leads and selected limb leads, a widened QRS, T wave inversions in leads with tall R waves, left axis deviation, and left atrial abnormality (LAA). Voltage criteria for left ventricular hypertrophy (LVH) should be used with caution, as various criteria have limited sensitivity or specificity. Commonly used voltage criteria include one or more of the following: 1. SV1 + RV5 or V6 > 35 mm (3.5 mV) 2. RaVL > 11 mm (1.1 mV) 3. For men: SV3 + RaVL > 28 mm (2.8 mV) 4. For women: SV3 + RaVL > 20 mm (2.0 mV) This ECG shows clear evidence of LVH with LAA, T wave inversions in the lateral leads, and very prominent voltage in the chest leads (SV1 + RV5 = 45 mm).The lateral T wave inversions could be related to LVH or they could indicate lateral wall ischemia. However, this patient’s serial cardiac enzymes were all negative. His shortness of breath was due to worsening of his CHF, resulting in pulmonary edema. He improved with standard therapy.
    • Case #14 A 76-year-old woman who has had severe asthma since age 18 comes to the emergency department complaining of increased shortness of breath. Which one of the following statements is true concerning her admission ECG? a) The PR interval is prolonged b) The QRS axis is normal c) There is normal R wave progression d) There is a complete right bundle branch block e) There is evidence of right ventricular hypertrophy
    • a) The PR interval is prolonged b) The QRS axis is normal c) There is normal R wave progression d) There is a complete right bundle branch block e) There is evidence of right ventricular hypertrophy
    • E) There is evidence of right ventricular hypertrophy Sinus rhythm is present with a relatively fast resting rate (93/min). The PR interval is normal at approximately 0.16 second (normal PR < 0.20 second). The QRS axis is approximately 180(biphasic in lead aVF and positive in lead aVR) and thus dramatically deviated to the right. The R wave progression is reversed, with tall right precordial R waves and an rS complex in the left chest leads!Recall that in the normal ECG, there is an rS complex in lead V1. The R wave becomes relatively larger and the S wave smaller in lead V2. The ratio of the R wave to the S wave becomes 1 at the so-called transition zone, usually in lead V3 or V4. By lead V6, the QRS complex has usually evolved to become a qR complex. This process is referred to as normal R wave progression. In this ECG, however, there is a qR complex in lead V1 and an rS complex in lead V6.There is an incomplete, not complete right bundle branch block (RBBB) (QRS duration between 0.10 and 0.12 second).The tall right precordial R waves (with a qR complex in lead V1) and the right axis deviation (RAD) are essentially diagnostic of right ventricular hypertrophy (RVH.)The ST-T changes in V1-V3 are also consistent with RV overload (sometimes called an RV strain pattern). The P waves in lead II are slightly peaked but do not meet strict criteria for right atrial overload (2.5mm or more in height).
    • Additional comments: RV hypertrophy occurs over time in response to pressure or volume overload in conditions such as primary pulmonary hypertension, chronic obstructive pulmonary disease (COPD), pulmonic stenosis, and atrial septal defect (ASD). This patient was diagnosed with an asthma exacerbation superimposed on severe COPD and improved with oral steroids and albuterol nebulizer therapy.
    • Case #15: A 55-year-old man was admitted to the hospital for a bleeding peptic ulcer. His admission ECG is notable for the all of the following EXCEPT: a) The rhythm is sinus tachycardia b) The QRS axis is normal c) The precordial transition zone is in lead V3 d) There is probable left ventricular hypertrophy e) The PR interval is within normal limits
    • a) The rhythm is sinus tachycardia b) The QRS axis is normal c) The precordial transition zone is in lead V3 d) There is probable left ventricular hypertrophy e) The PR interval is within normal limits
    • d) There is probable left ventricular hypertrophy The rate is approximately 100 beats per minute, and there are upright P waves in lead II, fulfilling the criteria for sinus tachycardia. This patient is likely tachycardic because of volume depletion and anemia secondary to blood loss. The QRS axis is normal at +15. The transition zone is in lead V3, where the ratio of R wave to S wave equals approximately 1. The PR interval is normal at 0.17 second (normal PR < 0.20 second). There is no ECG evidence of left ventricular hypertrophy (LVH), such as prominent voltage in the chest leads, left ventricular conduction delay, T wave inversions in leads with tall R waves, left axis deviation, or left atrial abnormality.
    • Let’s take a moment to review the steps you should follow every time you read an ECG. Try to get into the habit of following the steps in the same order each time: 1. Check the standardization and quality of the ECG (The usual calibration is 25 mm/sec and 10mm/mV) 2. Calculate the heart rate 3. Analyze the rhythm (Is it sinus; sinus plus ectopic beats; or some entirely non-sinus mechanism such as atrial fibrillation, ventricular tachycardia or a junctional escape rhythm?) 4. Check the PR interval 5. Check the P wave size 6. Check the QRS width 7. Check the QT interval 8. Check the mean QRS electrical axis 9. Check the QRS voltage 10. Check the R wave progression in the chest leads 11. Look for abnormal Q waves 12. Look for ST segment abnormalities 13. Look for T wave abnormalities 14. Look for prominent U waves
    • Case #16: This ECG from an 18 year old male shows all of the following EXCEPT? a) Normal variant early repolarization pattern b) Physiologic sinus arrhythmia c) Normal AV conduction d) Left axis deviation e) Transition zone in lead V3
    • a) Normal variant early repolarization pattern b) Physiologic sinus arrhythmia c) Normal AV conduction d) Left axis deviation e) Transition zone in lead V3
    • d) Left axis deviation This ECG shows a normal variant that is commonly referred to as early repolarization pattern." There are ST elevations in leads V2- V6 and in some of the limb leads. Slight notching of the terminal QRS (V4) is often seen in conjunction with this pattern. The ST segment retains its normal upward concavity. The QRS axis here is normal (about +30 degrees). The QRS transition zone (R=S) is in lead V3, a normal finding. AV conduction is normal, indicated by the normal PR interval (about 0.14 sec.) The slight variation in heart rate is due to physiologic (respiratory) sinus arrhythmia.
    • Case #17 Which one of the following statements about this ECG from a 24- year-old male is CORRECT? a) The ECG shows right ventricular hypertrophy b) The ECG shows left ventricular hypertrophy c) The ECG is within the normal limits d) The ECG is consistent with severe hypokalemia e) The ECG shows left atrial abnormality
    • a) The ECG shows right ventricular hypertrophy b) The ECG shows left ventricular hypertrophy c) The ECG is within the normal limits d) The ECG is consistent with severe hypokalemia e) The ECG shows left atrial abnormality
    • c) The ECG is within the normal limits The ECG shows sinus rhythm with a physiologic sinus arrhythmia at an average rate of about 60 bpm and is completely within the normal limits. The basic intervals (PR interval 0.15 sec, QRS 0.09 sec, and QT 0.39 sec) are all within normal limits. The P wave duration and morphology are normal. The precordial leads show normal R wave progression with very slight ST segment elevations (V2-V6) consistent with normal variant early repolarization. The QRS axis is normal at about +60 degrees. There is no evidence of left or right ventricular hypertrophy.Severe hypokalemia generally causes repolarization (QT-U) prolongation (usually with flat T waves and sometimes ST sagging), often with prominent U waves.
    • Case #18 ECG diagnosis is sinus rhythm with what conduction abnormality? a) Complete right bundle branch block b) Complete left bundle branch block c) Wolff-Parkinson-White pre-excitation (right sided bypass tract) d) Left anterior fascicular block e) Left posterior fascicular block
    • a) Complete right bundle branch block b) Complete left bundle branch block c) Wolff-Parkinson-White pre-excitation (right sided bypass tract) d) Left anterior fascicular block e) Left posterior fascicular block
    • b) Complete left bundle branch block The ECG shows sinus rhythm with a complete left bundle branch block (LBBB) pattern (QRS duration 0.16 second) with secondary ST-T wave changes. Bundle branch blocks usually have secondary T wave changes such that the ST-T wave vector points opposite in direction of the major vector of the QRS. These secondary ST-T changes are due to the altered sequence of ventricular activation. In a classic right bundle branch block (RBBB), an rSR type complex will be seen in V1. Wolff-White-Parkinson (WPW) pre- excitation produces the classic triad a short PR, wide QRS and delta waves, not present here. Left anterior and left posterior fascicular blocks (hemiblocks) do not cause prominent widening or the QRS duration, and are associated with marked left (-45 degrees or more) or right (+100 degrees or more) axis deviation, respectively. Complete LBBB may be associated with a normal, leftward, or rarely rightward axis.
    • LBBB may mask or mimic the pattern of underlying myocardial infarction. LBBB is also important since it is often a marker of underlying organic heart disease (e.g., due to hypertension, severe coronary disease, cardiomyopathy or valvular disease.)
    • Case #19 What is the cardiac rhythm? a) Sinus with a single premature ventricular complex b) Sinus with SA exit block c) Sinus with A-V Wenckebach d) Sinus with a single premature atrial complex e) Respiratory sinus arrhythmia
    • a) Sinus with a single premature ventricular complex b) Sinus with SA exit block c) Sinus with A-V Wenckebach d) Sinus with a single premature atrial complex e) Respiratory sinus arrhythmia
    • d) Sinus with a single premature atrial complex This ECG shows sinus rhythm, rate about 70 bpm with normal intervals and normal R wave progression. A single isolated premature atrial complex (PAC) (7th beat) is present. The P wave comes very early and there is a slightly different P wave morphology from the sinus beats. The QRS complex is identical to sinus beats. There is also evidence of physiologic early repolarization variant with slight notching of the J point in the antero-lateral leads, e.g. lead V5. Respiratory sinus arrhythmia causes more gradual increases and decreases in heart rate associated with inspiration and expiration, respectively.
    • Note that the terms premature beat, complex and depolarization are used interchangeably. These terms are preferable to premature contractions since not all atrial or ventricular premature depolarizations are actually associated with a mechanical response.Isolated atrial ectopy of this type is very common and may be seen in physiologic and pathologic contexts without any specific clinical implications.
    • Minor Segue: Homework Assignments for Next Week:
    • 1. Who is Diana Prince? 2. Who is Linda Danvers? 3. What is Hestia chiefly known for? 4. What is Ondine’s Curse?
    • 5. Which 3rd year resident once called this home?
    • 6. Name one member of the band Circle of Willis.
    • 7. Who goes by Red, plays the saxaphone, and likes Ursula Le Guin?
    • Case #20 What is the rhythm in this 68 year-old female? a) Multifocal atrial tachycardia b) Wandering atrial pacemaker c) Atrial fibrillation with rapid ventricular response d) Atrial flutter with rapid ventricular response e) Sinus arrhythmia with tremor artifact
    • a) Multifocal atrial tachycardia b) Wandering atrial pacemaker c) Atrial fibrillation with rapid ventricular response d) Atrial flutter with rapid ventricular response e) Sinus arrhythmia with tremor artifact
    • c) Atrial fibrillation with rapid ventricular response This ECG shows atrial fibrillation with a rapid ventricular response rate at about 120 bpm with borderline right axis deviation. Non- specific ST-T changes are present. There is possible left ventricular hypertrophy and possible biventricular hypertrophy.Multifocal atrial tachycardia and wandering atrial pacemaker are excluded as there is no evidence of discrete P waves, either normal or ectopic. Atrial flutter is excluded because of the erratic response whereas in flutter there is a more regularized response.
    • Case #21 What is the rhythm in this asymptomatic 47 year-old man? a) Sinus with pre-excitation variant b) Atrial tachycardia with 2:1 block c) Respiratory sinus arrhythmia d) Ectopic atrial rhythm e) AV junctional escape rhythm
    • a) Sinus with pre-excitation variant b) Atrial tachycardia with 2:1 block c) Respiratory sinus arrhythmia d) Ectopic atrial rhythm e) AV junctional escape rhythm
    • d) Ectopic atrial rhythm This ECG shows an ectopic atrial rhythm with inverted (negative) P waves in lead 11,111, aVF, V5-V6. There is a normal PR interval of 0.15 second. The apparently short PR in V1 and V2 is due to the fact that the beginning of the P wave is nearly isoelectric in these leads (see simultaneously recorded lead II in rhythm strip.) The QRS duration is normal (0.09 second.)Sinus arrhythmia and sinus with pre-excitation are excluded as there are no sinus P waves (upright in lead II invariably). Junctional escape rhythms are usually at slower rates and the P wave is typically hidden within the QRS or appears just before or just after the QRS. The P wave here occurs distinctly before the QRS consistent with an ectopic atrial focus, probably left atrial given the P wave axis.Ectopic atrial rhythms (usually transient) may occur without organic heart disease or with a variety of different cardiac syndromes. The ECG here is otherwise entirely unremarkable.
    • Case #22 All of the following are present in this ECG from a 13 year old boy EXCEPT? a) Sinus bradycardia b) Intraventricular conduction delay c) ST elevations consistent with early repolarization variant d) T wave inversions V1-V2 consistent with (juvenile physiologic variant e) Physiologic precordial transition zone
    • Sinus bradycardia Intraventricular conduction delay ST elevations consistent with early repolarization variant T wave inversions V1-V2 consistent with (juvenile physiologic vari Physiologic precordial transition zone
    • b) Intraventricular conduction delay This ECG shows sinus bradycardia at a rate of 55 bpm. The waveform morphologies are physiologic for a 13 year old male, with slight ST elevations V1 and V2 due to early repolarization variant (and minimal T wave inversions, consistent with the juvenile T wave pattern). QRS duration is normal at about .07 second and AV conduction is normal at .16 second. The precordial transition zone in lead V3 is physiologic.
    • Case #23 This ECG from a 23 year-old female is most consistent with which diagnosis? a) Left atrial abnormality b) Anterior ischemia c) Normal variant T wave inversions V1-V2 d) Hypokalemia e) Left ventricular hypertrophy
    • a) Left atrial abnormality b) Anterior ischemia c) Normal variant T wave inversions V1-V2 d) Hypokalemia e) Left ventricular hypertrophy
    • c) Normal variant T wave inversions V1-V2 This ECG shows sinus rhythm at a rate of about 77 bpm. The basic intervals are normal: PR 0.15 second, QRS 0.08 second and QT 0.35 second. T wave inversions limited to leads V1-V2 are a common physiologic variant in this age group, sometimes referred to as a persistent juvenile T wave pattern. More extensive anterior T wave inversions in young adults may be seen in a variety of settings, including arrhythmogenic right ventricular dysplasia (ARVD); see Circulation 2004; 110: 527.Left atrial abnormality is ruled out as the P wave is normal in amplitude and morphology. There is no evidence of prominent U waves or QT/U prolongation with flat T waves to indicate hypokalemia. There is no evidence of left ventricular hypertrophy.
    • Case #24 24 year-old male seen for complaints of palpitations. What is the rhythm? a) Sinus rhythm with sinus pauses b) Sinus rhythm with atrial premature beats c) Respiratory sinus arrhythmia d) Ectopic atrial rhythm e) Sinus rhythm with AV Wenckebach
    • a) Sinus rhythm with sinus pauses b) Sinus rhythm with atrial premature beats c) Respiratory sinus arrhythmia d) Ectopic atrial rhythm e) Sinus rhythm with AV Wenckebach
    • c) Respiratory sinus arrhythmia This ECG shows a physiologic respiratory sinus arrhythmia (RSA). The progressive fluctuations in sinus rates are apparent in the rhythm strip (lead II), going from fast at the beginning to slow and then return back to fast (rates vary from 84 to 60 and back to 84.) The variability is dependent on cyclic changes in vagal tone associated with the phases of respiration. Ectopic atrial rhythm is excluded as the P waves are consistent in morphology. There are no prolonged sinus pauses and no evidence of premature atrial beats and AV conduction is normal.
    • Case #25 This ECG most consistent with which single drug effect? a) Digoxin b) Quinidine c) Carvedilol d) Flecainide e) Mexiletine
    • a) Digoxin b) Quinidine c) Carvedilol d) Flecainide e) Mexiletine
    • b) Quinidine This ECG shows sinus rhythm at about 67 bpm with an intraventricular conduction delay (QRS 0.12 second) and a mildly prolonged QT-(U) interval of (0.46 second) consistent with quinidine effect. A single isolated atrial premature beat and left atrial abnormality are present. The R wave is at the upper limits of normal in amplitude in lead aVL with borderline voltage for left ventricular hypertrophy. Hypokalemia was ruled out. This patient, a 63 year old man, with a history of systemic hypertension, obstructive sleep apnea and paroxysmal atrial fibrillation, had been treated with quinidine gluconate for many years without adverse effect. Echocardiogram showed normal systolic left ventricular function. The patient was also taking diltiazem. Quinidine toxicity associated with prominent QT (U) prolongation can result in torsade de pointes ventricular tachycardia.
    • Digoxin produces ‘scooped’ ST/T segments. Carvedilol is a beta blocker and would produce a sinus bradycardia. Flecainide, a class 1c antiarrhythmic produces PR and QRS prolongation. Mexiletine is a class 1b agent in the same class as lidocaine. It doesn’t produce any diagnostic EKG changes.