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Introducing the Junctional Rhythms

9. Introducing the Junctional Rhythms. Introducing Junctional Rhythms. Objectives Discuss the origin of junctional rhythms Recall the components of the electrical conduction system Identify premature junctional contractions, including EKG characteristics

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Introducing the Junctional Rhythms

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  1. 9 Introducing the Junctional Rhythms

  2. Introducing Junctional Rhythms • Objectives • Discuss the origin of junctional rhythms • Recall the components of the electrical conduction system • Identify premature junctional contractions, including EKG characteristics • Identify a junctional escape rhythm, including EKG characteristics

  3. Introducing Junctional Rhythms • Objectives (continued) • Identify an accelerated junctional rhythm, including EKG characteristics • Identify a junctional tachycardia rhythm, including EKG characteristics • Discuss the clinical significance of the junctional rhythms

  4. Origin of Junctional Rhythms • The rhythms are classified according to the heart structure in which they begin, or theirsite of origin • Thesinoatrial (SA)node and the atria fail to generate an impulse • If this failure develops, the secondarypacemaker ofthe heart, theAV junction, will assume the role of pacing the heart

  5. Origin of Junctional Rhythms • Rhythms that are initiated in the area of the AV junction are called junctional rhythms • Although junctional rhythms are not considered to be lethal, or life-threatening,you should recall thatpatient assessmentis the most important indicator of clinical significance

  6. Components of Electrical Conduction System of the Heart • Electrical impulseoriginates inSA node • Travels through atriaviainternodal pathways • AV node,brief pause,bundle of His • Rightandleft bundle branches • Purkinje fibersinto the ventricular musculature

  7. Electrical Conduction System of the Heart

  8. Pacemaker Sites

  9. P Waves in Junctional Rhythms • Normally P waves are seen before each QRS • Impulse in junctional rhythm is traveling away from (+) electrodes, P wave will be inverted or negative • The P wave can be hidden in the QRS or follow the QRS complex

  10. The Premature Junctional Contraction (PJC) • Are initiated from a single site in the AV junction and arise earlier than the next anticipated complex of the underlying rhythm • If SA node depolarized by ectopic beat, a noncompensatory pause occurs and underlying rhythm is interrupted

  11. The Premature Junctional Contraction (PJC) • PJC can also cause compensatory pause, a pause that occurs after ectopic beat and underlying rhythm is uninterrupted

  12. Premature Junctional Complexes

  13. Premature Junctional Complexes

  14. Premature Junctional Contraction (Complexes) or PJCs • PJCs are less common than PACs or PVCs • As with all ectopic beats, it is easier to identify PJCs if rhythm is sinus or bradycardia • When interpreting PJCs, you must also determine the underlying rhythm

  15. Junctional Escape Rhythms • The SA node may fail to generate an impulse, or if rate falls below that of the AV node, then AV node will assume the role of pacemaker • This ability is a safety feature • Intrinsic rate of the AV node is 40-60 bpm

  16. Junctional Escape Rhythm • Junctional escape beat • Isolated junctional beat occurs • Junctional escape rhythm • Series of junctional escape beats occur, (sometimes termed junctional bradycardia when rate < 40 bpm • Causes • SA node disease, hypoxia, increased parasympathetic (vagal) tone, cardiac drugs, or complete heart block

  17. Junctional Escape Beats

  18. Junctional Escape Rhythm

  19. Accelerated Junctional Rhythms • Caused by increased automaticity in AV junction, causes junction to discharge impulses at fast rate, then intrinsic rate (40-60 bpm) • Rate is usually around 60 to 100 bpm • Causes include • Hypoxia, digitalis intoxication, inferior wall MI, and rheumatic fever

  20. Accelerated Junctional Rhythm

  21. Accelerated Junctional Rhythm

  22. Junctional Tachycardia Rhythms • Rhythm that arises from AV junctional tissue at a rate of 100 to 180 bpm • If observed to start or end abruptly referred to as paroxysmal rhythm • It may be indistinguishable from supraventricular tachycardic rhythms

  23. Junctional Tachycardia Rhythms Junctional Tachycardia Rhythms • Causes • Underlying ischemic heart disease, frequent ingestion of stimulants, anxiety, hypoxia, Medications such as digitalis, or rheumatic heart disease • Treatment • Aimed at identifying and treating the underlying cause of the dysrhythmia

  24. Junctional Tachycardia

  25. Junctional Tachycardia

  26. Clinical Significance of Junctional Rhythms • Premature Junctional Contractions • Based on frequency of their occurrence and patient’s condition • Isolated PJCs are of minimal significance • Frequent (> than 6/min) more serious dysrhythmias may develop • Management includes only close observation

  27. Clinical Significance of Junctional Rhythms • Junctional Escape Rhythm • Based on patient’s heart rate and clinical condition • Intrinsic rate of AV junction = 40 to 60 bpm • Watch for signs of compromise • If decreased perfusion observed, treat with oxygen, and consider drug therapy • May be tolerated at 50 to 60 bpm

  28. Clinical Significance of Junctional Rhythms • Accelerated Junctional Rhythm • Generally well tolerated by patient • May suggest the possibility of digitalis toxicity • Patient must be carefully monitored for occurrence of other, more serious dysrhythmias

  29. Clinical Significance of Junctional Rhythms • Junctional Tachycardia Rhythm • May be well tolerated in healthy hearts • Not tolerated in patients with cardiac compromise • May report feeling heart “running away or fluttering” • Treatment based on patient’s clinical appearance, signs, and symptoms

  30. Chapter 9 Review Strips

  31. Chapter 9 Review Strips

  32. Chapter 9 Review Strips

  33. Chapter 9 Review Strips

  34. Chapter 9 Review Strips

  35. Chapter 9 Review Strips

  36. Chapter 9 Review Strips

  37. Chapter 9 Review Strips

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