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5th part ECG basics: supraventricular arrhythmias Dr Salah Mabrouk Khallaf

Heart rate regular regular iiregularity iiregular iregularity tachycadia bradycardia sinus atrial junctionla ectopics rythm arrest supraventricular arrythmia

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5th part ECG basics: supraventricular arrhythmias Dr Salah Mabrouk Khallaf

  1. 1. ECG BASICSECG BASICS 55thth LectureLecture Supraventricular arrhythmias By Salah Mabruok Khalaf South Egypt Cancer Institute 2017 Course of Medical Oncology Medical Oncology department
  2. 2. Introduction to ECG Rhythm Analysis • The analysis should begin with identifying three categories 1. Impulse origin 2. Rate 3. Regularity
  3. 3. Introduction to ECG Rhythm Analysis 1- impulse origin (i.e., where is the abnormal rhythm coming from?)  Sinus Node (e.g., sinus tachycardia)  Atria (e.g., PAC)  AV junction (e.g., junctional escape rhythm)  Ventricles (e.g., PVC)
  4. 4. Introduction to ECG Rhythm Analysis 2-Rate (i.e., relative to the "expected rate" for that pacemaker location) o Accelerated - faster than expected (e.g., accelerated junctional rhythm @ 75bpm) o Slower than expected (e.g., marked sinus bradycardia @ 40bpm) o Normal (e.g., junctional escape rhythm) o N.B. expected rate SA Node 60 - 100 beats/minute. AV Node 40 - 60 beats/minute. Ventricular cells 20 - 45 bpm.
  5. 5. Calculate Rate • Option 1( for regular and irregular rhythm) – Count the # of R waves in a 6 second rhythm strip, then multiply by 10. Interpretation? 7 x 10 = 70 bpm
  6. 6. Calculate Rate • Option 1( for regular and irregular rhythm) – Count the # of R waves in a 6 second rhythm strip, then multiply by 10. Interpretation? 5 x 10 = 50 bpm
  7. 7. Option 2 (for regular rhythm) – Find a R wave that lands on a bold line. – Count the # of large boxes to the next R wave. Then calculate the rate from this equation • OR HR=---------------------------------------- R wave No of Large squares in RR interval 300
  8. 8. • Option 2 (cont) – Memorize the sequence: 300 - 150 - 100 - 75 - 60 - 50 Interpretation? 3 0 0 1 5 0 1 0 0 7 5 6 0 5 0 Approx. 1 box less than 100 = 95 bpm
  9. 9. Option 2 (for regular rhythm) more accurate – Find a R wave that lands on a bold line. – Count the # of large boxes to the next R wave. Then calculate the rate from this equation • OR HR=---------------------------------------- No of small squares in RR interval 1500 In this ECG HR = 1500/16 = 93
  10. 10. 3-Regularity of ventricular or atrial response • Look at the R-R distances (using a caliper or markings on a pen or paper). • Regular (are they equidistant apart)? Occasionally irregular? Regularly irregular? Irregularly irregular? Regular (e.g., PSVT) Regular irregularity (e.g., ventricular bigeminy) Irregular irregularity (e.g., atrial fibrillation or MAT) R R
  11. 11. Supraventricular arrhythmias 1.Sinus Bradycardia 2.Sinus Tachycardia 3.Sinus arrhythmia 4.Sinus node dysfunction(SND) 5.Premature atrial complexes and atrial bigeminy 6.Premature junctional complexes 7.Atrial fibrillation 8.Atrial flutter 9.Ectopic atrial tachycardia and rhythm 10.Multifocal atrial tachycardia 11.Wandering Pacemaker 12.Paroxysmal supraventricular tachycardia 13.Junctional Escape Beat 14.Junctional Escape rhythm 15.Accelerated Junctional Rhythm 16.Junctional Bradycardia 17.Junctional tachycardia
  12. 12. Supraventricular Arrhythmias 1. Sinus Bradycardia <60 bpm =30• Rate? • Regularity? regular normal 0.10 s • P waves? • PR interval? 0.12 s • QRS duration? Interpretation? Sinus Bradycardia
  13. 13. • Causes of Bradycardia • A- Intrinsic Causes • Idiopathic degeneration (aging) • Infarction or ischemia • Infiltrative diseases – Sarcoidosis – Amyloidosis – Hemochromatosis • Infectious diseases – Chagas' disease – Endocarditus • Immune diseases – Systemic lupus erythematosis. – Rheumatoid arthritis – Scleraderma. • Iatrogenic trauma – Valve replacement – Correction of congenital heart disease – Heart transplantation .
  14. 14. • Extrinsic Causes • Autonomically mediated syndromes (i.e. vomiting, sleeping, etc.) – Carotid-sinus hypersensitivity: from vagus innervation hypertonicity – Neurocardiac syncope – Situational disturbances: coughing, micturition, defecation, vomiting • Drugs – Antiarrhythmic agents: pronestyl, quinidine, etc. – B-Adrenergic blockers. – Calcium-channel blockers: – Digoxin • Hypothyroidism • Hypothermia • Hypokalemia • Hyperkalemia:
  15. 15. 2. Sinus Tachycardia >100 bpm =130• Rate? • Regularity? regular normal 0.08 s • P waves? • PR interval? 0.16 s • QRS duration? Interpretation? Sinus Tachycardia
  16. 16. Causes of Sinus Tachycardia • Thyrotoxicosis • Anemia • Anxiety • Coronary ischemia and myocardial infarction , failure • Chronic pulmonary disease • Caffeine, nicotine, cocaine, or amphetamines • Hyperthermia • Hyperdynamic circulation • Hypovolemia with hypotension and shock • Hypoxia • Pheochromocytoma • Pulmonary embolism
  17. 17. • 3- Sinus Arrhythmia • Respiratory sinus arrhythmia • The rate usually increases with inspiration and decreases with expiration. • This rhythm is most commonly seen with breathing due to fluctuations in parasympathetic vagal tone.
  18. 18. • Non respiratory sinus arrhythmia • Ventriculophasic sinus arrhythmia is a non-respiratory sinus arrhythmia seen in complete AV block. • The PP interval enclosing a QRS complex is shorter than a PP interval not enclosing a QRS.
  19. 19. 4-Sinus node dysfunction(SND) Sinus pause Sinus arrest Sinus block • First degree SA block can not be diagnosed by surface ECG. • Second degree SA block is usually diagnosed when the sinus pause is in the multiples of resting sinus cycles. • Third degree SA block is same as sinus arrest and subsidiary pacemaker will function in these patients. • If the pauses are not in exact multiples, sinus arrest is diagnosed.
  20. 20. Sinus pause • When sinus cycle length exceeds 15 % of the previous sinus cycle it is referred to as sinus pause.
  21. 21. Sinus pause
  22. 22. 2nd degree SAN block Electrocardiogram: Sinoatrial Exit Block
  23. 23. 2nd degree SAN block
  24. 24. Sinus arrest = 3rd degree SAN block Pauses in excess of three seconds. • The following example shows a delay between beats of over four seconds. The RR interval is highlighted. Electrocardiogram: Sinus Arrest
  25. 25. 5. Premature atrial complexes • Occur as single or repetitive events and have unifocal or multifocal origins. • The ectopic P wave (called P') is often hidden in the ST-T wave of the preceding beat "Search for the P on the T wave“ • The P'R interval is normal or prolonged because the AV junction is often partially refractory when the premature impulse enters it. • ECG. The compensatory pause after a PAC is usually incomplete
  26. 26. Atrial Bigeminy • Each normal beat is followed by an atrial premature beat
  27. 27. Sinus Rhythm with Atrial Bigeminy.
  28. 28. Atrial Trigeminy • For each 2 normal beat is followed by an atrial premature beat • If every third beat in an ECG rhythm strip is a PAC
  29. 29. Atrial quadrigeminy • For each 3 normal beat is followed by an atrial premature beat
  30. 30. Atrial Parasystole PACs, shown by arrows, occur at a common inter- ectopic interval or at multiples of this interval.
  31. 31. Atrial Parasystole
  32. 32. • Non-Conducted or Blocked Premature Atrial Contractions (PAC's)
  33. 33. 6-Atrial Escape Beats • Must have the following qualities: 1. They must occur at the end of a pause. 2. They must have a 'P' wave that is a different shape than the sinus 'P' waves. 3. They must have a 'PR' interval that is at least .12 s (3 small squares) or more in length. 4. The 'QRS' complex of the escape beat must be the same shape and size as the other sinus 'QRS' complexes. Note difference between atrial escape rhythm and atrial premature complexes is the site of compensatory pause (before abnormal impulse in AEB and after abnormal beat in PACs
  34. 34. 6.Premature junctional complexes • Similar to PAC's in clinical implications, but occur less frequently. • The PJC focus, located in the AV junction, captures the atria (retrograde) and the ventricles (antegrade). • The retrograde P wave may appear before, during, or after the QRS complex; if before, the PR interval is usually short (i.e., <0.12 s).
  35. 35. P P NO P Conditions of AV nodal impulse 1-AVN give atrium before ventricle Inverted P wave then QRS 2-AVN give ventricle before atrium QRS then Inverted P wave QRS 3-AVN give atrium and ventricle at same time P wave masked in QRS( absent P) av II
  36. 36. Premature Junctional Contraction (PJC) P
  37. 37. 7. Atrial Fibrillation (AF) • Atrial activity is poorly defined; may see course or fine undulations (fibrillation) or no atrial activity at all. If atrial activity is seen, it resembles an old saw (when compared to atrial flutter that often resembles a new saw). • Ventricular response is irregularly irregular and may be fast (HR >100 bpm), moderate (HR = 60-100 bpm), or slow (HR <60 bpm, indicates excessive rate control, AV node disease, or drug toxicity).
  38. 38. • Atrial Fibrillation With Moderate Ventricular Response
  39. 39.  Atrial Fibrillation (AF( • When regular?? • regular ventricular response in complete AV block with an escape or accelerated ectopic pacemaker originating in the AV junction or ventricles (i.e., must consider digoxin toxicity or AV node disease). • The differential diagnosis includes atrial flutter with an irregular ventricular response and multifocal atrial tachycardia (MAT), which is usually irregularly irregular.
  40. 40. Atrial Fibrillation (AF)
  41. 41. • When RAPID AF???? • Atrial fibrillation with rapid ventricular response > 100 /m
  42. 42. 8- Atrial Flutter • Regular atrial activity with a "saw-tooth appearance in leads II, III, aVF • The atrial rate is usually about 300-350/min. • The flutter waves are often difficult to find when there is 2:1 ratio. Therefore, always think "atrial flutter with 2:1 block" whenever there is a regular supraventricular tachycardia @ ~150 bpm! (You won't miss it if you look for it in a 12-lead ECG) • The ventricular response may be 2:1, 3:1 (rare), 4:1, or irregular depending upon the AV conduction properties and AV node slowing drugs on board (e.g., digoxin, beta blockers).
  43. 43. Atrial Flutter
  44. 44. Atrial flutter with variable ventricular response • The saw-tooth flutter waves together with some regularity in its pattern give this ECG rhythm away. Note that the flutter waves occur at a rate close to 300/minute. The R-R intervals suggest rates of close to 100/miute (3:1 ventricular response), then 75/minute (4:1 ventricular response) and later a rate of 60/minute (5:1 response). The atrial flutter is presenting with variable AV blocking resulting in variable ventricular response.
  45. 45. The tracing shows atrial flutter with variable block and atrial rate 300.
  46. 46. • Atrial Flutter With Variable AV Block
  47. 47. 9. Ectopic Atrial Tachycardia and Rhythm • Ectopic, discrete looking, unifocal P' waves with atrial rate <250/min • Ectopic P' waves usually precede QRS complexes with P'R interval < RP' interval (i.e., not to be confused with paroxysmal supraventricular tachycardia with retrograde P waves appearing shortly after the QRS complexes). • Ventricular response may be 1:1 or with varying degrees of AV block (especially in digitalis toxicity) • Ectopic atrial rhythm is similar to ectopic atrial tachycardia, but with HR < 100 bpm.
  48. 48. Ectopic atrial tachycardia.
  49. 49. 10. Multifocal Atrial Tachycardia (MAT) Discrete, multifocal P' waves occurring at rates of 100- 250/min and with varying P'R intervals (should see at least 3 different P wave morphologies in a given lead). • Ventricular response is irregularly irregular (i.e., often confused with A-fib). • May be intermittent, alternating with periods of normal sinus rhythm.
  50. 50. Multifocal Atrial Tachycardia (MAT(
  51. 51. Multifocal Atrial Tachycardia (MAT(
  52. 52. 11-Wandering atrial Pacemaker • A Wandering Atrial Rhythm occurs in an ECG rhythm strip whenever three or more different ectopic sites in the atria take over the function of the SA node and alternate to create the electrical impulse that pace the heart and cause the myocardium to contract. • Wandering Atrial Pacemaker rhythm will have the following qualities: 1. The rhythm will be slightly irregular. The distance between 'QRS' complexes will vary by one or two small squares. 2. There will be three or more different shaped 'P' waves. 3. The 'PR' interval will be at least .12 seconds in length.
  53. 53. 11- Wandering atrial Pacemaker • A slower version of multifocal atrial tachycardia, the narrow QRS complexes, the various P wave configurations and an irregular rate of about 80/minute all support this ECG rhythm to be a wandering pacemaker. • While this rhythm is slightly irregular (this is typical of sinus arrhythmia), the changing P waves is the most important finding.
  54. 54. Wandering atrial Pacemaker
  55. 55. 12. Paroxysmal Supraventricular Tachycardia (PSVT) Basic Considerations: 1. These arrhythmias are circus movement or reciprocating tachycardia because they utilize the mechanism of reentry. 2. The onset: sudden, The offset: sudden, so-called paroxysmal 3. Usually initiated by a premature beat 4. They are usually narrow-QRS tachycardia unless there is preexisting bundle branch block or rate-related aberrant ventricular conduction. 5. There are several types of PSVT depending on the location of the reentry circuit.
  56. 56. Paroxysmal Supraventricular Tachycardia (PSVT(
  57. 57. Paroxysmal Supraventricular Tachycardia (PSVT(
  58. 58. 13- Junctional Escape Beats: • Must have the following qualities: 1. The abnormal beat must come at the end of a pause in the ECG rhythm strip. 2. If the abnormal beat has a 'P' wave preceding the 'QRS' complex, it must have a short 'PR' interval. A short 'PR' interval is below 12 seconds (3 small boxes) in length. 3. The abnormal beat may not have a 'P' preceding it. 4. The 'QRS' complex of the beat must be the same shape and size as all the other sinus beats in rhythm strip.
  59. 59. 14- Junctional Escape Rhythm: This is a sequence of 3 or more junctional escapes occurring at a rate of 40-60 bpm. There may be AV dissociation or the atria may be captured retrogradely by the junctional pacemaker.
  60. 60. • Causes of Junctional escape Rhythm: 1. Healthy athlete at rest 2. Beta Blockers, Ca Channel Blockers, Dig Toxicity 3. Increased parasympathetic tone 4. Acute Inferior MI 5. Rheumatic Heart Disease 6. Post-Cardiac Surgery 7. Valvular Disease 8. SA Node Disease 9. Hypoxia
  61. 61. • This ECG rhythm could be a normal sinus rhythm except that the narrow QRS complexes are not accompanied by any P waves. Therefore, this rhythm that occurs at a rate of about 60/minute originates from the AV junction. Because this rhythm occurs at a rate characteristic of a junctional pacemaker (40-60/minute), this ECG rhythm is a junctional rhythm.
  62. 62. 15-Junctional bradycardia • This rhythm originates from the AV junction. Because this rhythm occurs at a rate slower than the junction typically fires (40-60/minute), this ECG rhythm is called a junctional bradycardia.
  63. 63. 16- Accelerated Junctional Rhythm: This is an active junctional pacemaker rhythm caused by events that perturb pacemaker cells (e.g., ischemia, drugs, and electrolyte abnormalities). The rate is 60-100 bpm
  64. 64. • The ECG rhythm includes a series of narrow QRS complexes, inverted P waves and a rate of about 70/minute. This rhythm originates from the AV junction. Because this rhythm occurs at rates faster than the junction typically fires (40-60/minute) but less than a tachycardia (100/minute), this ECG rhythm is called an accelerated junctional rhythm.
  65. 65. 17- Nonparoxysmal Junctional Tachycardia: This usually begins as an accelerated junctional rhythm but the heart rate gradually increases to >100 bpm. There may be AV dissociation, or retrograde atrial capture may occur. Ischemia (usually from right coronary artery occlusion) and digitalis intoxication are the two most common causes.
  66. 66. • This rapid ECG rhythm includes narrow QRS complexes, an absence of P waves prior to each QRS and a rate faster than 100/minute. This rhythm occurs at a rate of about 180- 190/minute. • Notice the inverted waveform after many of the QRS complexes – possible further evidence for junctional tachycardia (inverted P waves).

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