DDD Pacemaker: Fractured Ventricular Lead

Report:

Dual AV pacing 99/min 1

No ventricular capture, atrial 100% pacing 7

Right bundle branch block 2

Comment:

The patient arrived to Casualty in sinus rhythm with sinus pauses and both escape and premature SVEBs (Fig 114a). He still had the SSS. The pacemaker was, at the time, a VVI unit due to a permanent mode switch from DDD to VVI for atrial rates over 170/min performed by the patient’s Cardiologist three months previously. It completely fails to capture the ventricle and fails to sense the native complexes for most of the trace.

The unit was reprogrammed to its original DDD mode and a magnet was applied to the impulse generator, demonstrating 100% atrial capture (with AV interval 0.32”) and no ventricular capture. This lack of capture may be fortunate in view of the R-on-T situation. The atrial capture cannot be seen directly in terms of atrial deflections but can be inferred from the rate and the obviously supraventricular RBBB complexes.

Later, at fluoroscopy, the ventricular lead was seen to be fractured and was replaced.

Unfortunately, the DDD mode resulted in more sensed and paced tachycardia later on (Fig 114b) and the unit was reprogrammed again to a VVI mode. Fig 114a. Sinus rhythm and arrests, with junctional escapes and failed ventricular pacemaker. The RBBB is the same as above in Fig 114.

Fig 115. 61 year old man with “racing heart” feeling like his previous episodes of AF. Sotalol, 40 mg IV, restored sequential AV pacing at 60/min.