Positive Concordant Precordial Pattern

Report:

Pacemaker rhythm 63/min 2

1:1 retrograde conduction 3

Positive concordant precordial pattern 5

Comment:

This is a temporary, bipolar unit, inserted in CCU. The patient had a very large right ventricle or the lead is inadvertently placed in the posterior interventricular vein: virtually the entire ventricular myocardium is paced from behind.

A far-fetched alternative explanation would be that the electrode is in the left atrium (through an ASD or patent foramen ovale) and impinging on the bundle of Kent there, pacing the LV in the WPA ‘A’ manner! It’s a thought, but the retrograde P waves make this unlikely hypothesis extremely unlikely.

Below (Fig 126a) is the patient’s permanent DDD pacemaker, responding to sinus P waves as well as trigeminal atrial ectopics. This is the same DDD unit that produced paced bigeminy in Case 117. It was positioned under image intensification and is not as posteriorly (dis)placed as the temporary wire.

Fig 126a. DDD unit, a day later. There are frequent, but late, SVEBs also triggering the pacemaker. The ventricular electrode is in standard position.

Fig 127. 50 year old man in CCU with myocardial infarction.