ECG: Atrial Rhythm


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ECG: Atrial Rhythm

  1. 1. ECG of the week<br />Prof. P. Vijayaraghavan Unit<br />A.KarthickRamalingam<br />FIRST YEAR PGM 5<br />
  2. 2. Background<br />60 year old Mrs. Ponnamma, known hypertensive presented with history suggestive of anginal type of chest pain, ECG was taken.<br />
  3. 3. ECG-1<br />
  4. 4. Findings<br />Rate 88/min<br />NSR<br />P wave axis 60<br />QRS axis Normal<br />ST straightening LII ,LIII, aVF<br />T inversion L III<br />
  5. 5. ECG-2<br />
  6. 6. Findings<br />Rate: 84/min<br />Atrial rhythm<br />P wave axis - 90<br />P ‘ – L II , L III,<br />aVF ,V2 to V6 <br />P --L I, aVR , a VL, V1<br />QRS axis normal<br />T inversion L II , L III, aVF<br /> ST depression L III, aVF<br />Findings of ectopic atrial rhythm<br />
  7. 7. Repeat ECG taken for the patient reverted back to sinus rhythm and was similar to ECG 1 <br />
  8. 8. <ul><li>To differentiate rightatrial from left atrial rhythm
  9. 9. P wave morphology is useful in differentiating left from right atrial foci.
  10. 10. This is a function of the anatomical relationship of the atria, with the left atrium being a more posterior and leftward structure than the right atrium.
  11. 11. As such, leads V1 and aVL are useful discriminators. </li></li></ul><li>Left atrial<br />Right atrial<br /><ul><li>A positive or biphasic P wave in aVL has a positive predictive accuracy of 83% and negative predictive value of 85% for a right atrial focus.
  12. 12. In contrast, a positive P wave in V1 is a feature of left atrial foci. It has a sensitivity and specificity of 93% and 88% respectively.</li></li></ul><li>Right Atrial Rhythm<br />In right atrial rhythm the depolarization begins in the right atrium and spreads posteriorly and superiorly towards the left atrium (towards aVL). This inscribes a positive deflection (p wave) in aVL. <br />
  13. 13. <ul><li>LEFT ATRIAL RHYTHM
  14. 14. In left atrial rhythm the depolarization of atria begins in the left atria and spreads anteriorly towards right atrium(in the direction of V1). This inscribes a positive deflection (p wave) in lead V1.</li></li></ul><li>The exceptions to the above criteria are ectopic foci with origin at the high crista terminalis (right atrial - near SA node) and impulse originating near the atrial septum.<br />
  15. 15. In our patient a positive p wave in V1 with a negative p in V6 is suggestive of a left atrial rhythm.<br />
  16. 16. THANKYOU <br />