Answer MI 17

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Where is this myocardial infarction located?

ECG MI 17. Click on image for enlargement.

Answer

• Following the 7+2 steps:
  • Rhythm
    • In leads V1 to V3 there is apparantly no relationship between the P waves and the QRS complexes. Furthermore the QRS complexes are broad and have a RBBB pattern (V1:RSR), thus the rhythm is probably a ventricular escape rhythm. Leads V4-V6 however show a narrow complex preced by a P wave, probably the result of a rhythm change to sinus rhythm.
  • Hartfrequency
    • Use the 'count the squares' method (a bit less than 3 large squares ~> 300-150-100), thus about 58 bpm.
  • Conduction (PQ,QRS,QT)
    • During sinus beats: PQ-interval=250msec, QRS duration=0.11sec, QT interval=400ms (equals QTc at this rate). The wide complexes have a QRS duration of +- 160 ms.
  • Heartaxis
    • Negative in AVF and II, thus a left axis deviation.
  • P wave morphology
    • The p wave is rather difficult to discern. It seems normal in V4-V6 and positive in AVF and negative in AVR.
  • QRS morphology
    • RBBB pattern in V1 with ST changes (depression precordial leads). Leads V3 and V4 have probably been poled to the right chest. No pathologic Q waves.
  • ST morphology
    • ST elevation in II,III, and AVF and also in V3 (V3right). Hyperacute T waves with ST depression in V1-V2 an I, AVR and AVL.
  • Compare with the old ECG (not available, so skip this step)
  • Conclusion?

Inferior-posterior myocardial infarction with complete AV block and ventricular excape rhythm with RBBB pattern and left axis, followed by sinus-rhythm. Probably RCA occlusion (ST depression in I)