Complete AV Block in Shock

Report:

Atrial flutter 375/min

Complete (3rd degree) AV block

Junctional rhythm 65/min

Right axis deviation +90o ?LPHB

Right bundle branch block

Acute inferior and anteroseptal infarction

Leads V3-6 probably right-sided: right ventricular infarction

Comment:

The presence of 3rd degree block in atrial flutter is established by observing the F-QRS relationship: they are obviously dissociated in this trace. Sometimes it is more easily seen looking at the impressions F waves are making on the ST segment. The flutter is very fast, reflecting the patient’s hyperadrenergic state in cardiogenic shock.

Lead 1 is equiphasic for the first 0.06”; it often becomes so in anterior infarcts with either hemiblock. Tall R waves in the inferior leads suggest LPHB, but the axis is not sufficiently right for this diagnosis to be made with certainty. The diagnosis of LPHB also requires clinical exclusion of RVH, which is not available. Comparison with a trace taken 30 minutes previously, with 3o AV block and sinus tachycardia 136/min (Fig 97a below) makes the case for LPHB: tall inferior R waves have grown de novo for Fig 97 and the RAD is new.

Involvement of lead V1 , along with the pattern of inferior infarction, denotes right ventricular infarction. Sometimes there is also extensive precordial ST segment elevation with right ventricular infarcts; in this case it’s a bit suspect. The same morphology, diminuendo from V2 through V6. Almost certainly, the V3-6 leads are right-sided, labelled manually in Casualty for the original notes but not so labelled in the computer’s regurgitation for reporting. The case for RV infarction would have been simpler if leads V2-3 showed reciprocal depression rather than elevation: then right-sided leads would be redundant. ST elevation in Lead 3 exceeding that of Lead 2 is another sign (weak, I think) of RV infarction. A good quality echocardiogram would be of value here. As expected, the patient died.

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