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Chapter 2 - ECG Supraventricular Rythms Early beats arising from above the ventricles. PAC, PJC

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Text of Chapter 2 - ECG Supraventricular Rythms Early beats arising from above the ventricles. PAC, PJC

  • Chapter 2 - ECGSupraventricular RythmsEarly beats arising from above the ventricles.PAC, PJC

  • Normal Sinus Rhythm

    Sinus ArrythmiaIrregular rhythm (R-R). Can be caused by respiration. HR increases with inspiration (vagal nerve depressed) and decreases with expiration (vagal nerve stimulated). Phasic SA due to respirations vs. Non-phasic SA not due to respirations

  • Normal Sinus RythmA. Figure 2.4, page 21. Sinus Tachycardia and SA Nodal Re-Entrant Tachycardia

    If obtained under resting conditions this would be considered:SA Nodal Re-Entrant Tachycardia (pg. 23). Occurs suddenly with abrupt termination, but slower than SVT with only a rate of 120-150. Depolarizing spins around the SA node, circling repeatedly causing a high heart rate at rest.

  • Sinus Bradycardia cause: fitness, meds, diseaseIn this example, the heart rate is 34 beats min1.

  • Sinus Pauses Difficult to know why a delay occuring before the appearance of a P wave Failure of SA Node to depolarizeNote: after pause rhythm resumes with a P wave that is normal with a normal QRS.

    SA Block depolarization does not escape from the SA NodeNote: Rhythm resumes with a normal QRS.

  • Sinus Pause

  • PAC premature, ectopic beat arising somewhere other than the SA Node. Arises in atria or AV node. P wave morphology is different. PR interval will differ (shorter) due to change in time for conduction to move to ventricles. QRS is normal. Blocked or non-conducted PAC. AV node is still in the refractory period. *= ectopic focus

  • Junctional Premature Complex or PJCPremature beats w/- or absent P waves due to origin at or near the AV NodeSometime difficult to decide origin so both terms will work.

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