Calcium in Electromechanical Dissociation

Report:

Supraventricular tachycardia, probably sinus, 180/min

Third degree AV block

Junctional escape rhythm 26/min

Short QT interval consistent with hypercalcæmia

Comment:

Electromechanical dissociation (EMD) is not an ECG diagnosis. Sometimes the closed chest massage artefact provides a clue, but this is not seen here: CPR had been stopped earlier.

The recordings often look like this one in young people with healthy hearts given large doses of adrenaline and calcium during EMD.

The strips below are from another patient, whose EMD was caused by myocardial free wall rupture. He received 20 cc of 10% CaCl2 during and after the top strip (in 1977). Note again the marked shortening of the QT interval in the lower strip.

It is convenient to remember that only two factors shorten the QT interval: hypercalcæmia and digoxin (which releases intracellular calcium). This is one of the shortest differential diagnoses in internal medicine; distinction students have to add hyperthermia, vagal stimulation175 and a normal kangaroo heart176!

If you have any suggestions for or feedback on this report, please let us know.