Agonal Rhythm & Atrial ‘Infarction’

Report:

Atria ?sinus rhythm

Runs of accelerated idioventricular rhythm(s)

AV dissociation (from third strip down)

Progressive QRS prolongation in the AIVR or AJR

Progressive PT segment elevation c/c atrial infarction

Atrial ?sinus bradycardia (bottom strip)

Comment:

Agonal rhythm is easy to recognize in its usual setting but difficult to define. The rate is inappropriately slow (as here) and tends to become slower and slower and there is progressive hypotension or EMD ab initio. Sinus rhythm may or may not persist to the asystolic end, or become blocked, or dissociated (as here). Subsidiary pacemakers tend to take over the ventricles.

The interesting feature in these strips is the striking PT segment elevation. Although not as diagnostic as elevation concordant with a completely positive P wave, in this case it can be seen to progress – not an electrical filter vagary of the monitoring system. It is a sign of atrial ischæmia, given that true infarction may or may not follow; even if it did, it is in no way analogous, electrocardiographically, to its left ventricular counterpart. It resembles infarction (or ischæmia) of the right ventricle, another very thin-walled structure: fleeting elevation and then, usually, nothing; certainly no Q waves206. In some, a corrobatory conduction defect (LAA for atria, RBBB for RV) may supervene.

But not in this case. The patient had terminal COAD and was “allowed” to die. Nobody took his 12-lead ECG and, in this world, there was no follow-up. The next two pages show the rhythms’ evolution. There is some striking ST segment elevation for the biphasic QRS complexes from time to time, and in the end. This is common207.

His admission ECG, taken 3 weeks before death, is shown in Fig 275c: RVH from cor pulmonale.