Inhibition of left ventricular stimulation due to left ventricular lead failure and the left ventricular T‐wave protection algorithm in patient with cardiac resynchronization therapy and pacemaker dependency

Abstract

The electrocardiogram (ECG) interpretation in patients with cardiac resynchronization therapy (CRT) is often a perplexing problem. The difficulty in the device evaluation increases in the presence of unfamiliar timing cycles and a lead dysfunction. Authors describe a special function of a Biotronik CRT devices called the left ventricle T-wave protection (LVTP), and demonstrate its behavior in a patient with left ventricular (LV) lead failure. This report shows that sometimes it might be difficult to understand the loss of resynchronization in 12-lead ECG when LVTP feature is on, and a malfunction of left ventricular lead sensing occurs.

Left ventricular inhibition during cardiac resynchronization caused by sensed left‐sided ventricular premature complexes

“…The observations in our two cases of left‐sided VPCs and the example using an LV signal from a defective LV lead confirm that the CRT response report of Larsen et al involving a Boston Scientific device can also occur with BIOTRONIK devices similarly designed with LV sensing. The observations show that a missing scheduled LVp event strongly suggests that its timing coincides with an LVURI initiated by a preceding LVs event.…”

“…The absence of any RVEGM activity mandates investigation for a defective LV lead. False signals from a defective LV lead or T‐wave sensing of the LV should always be excluded . The analysis of a single LVp inhibition helps understanding of the LV sensing function of CRT devices …”

“…The device therefore inhibits the LVp event scheduled to be released 20 ms before the expected RVp. The RVp event coupled with the inhibited LVp event appears ineffective because it falls in the myocardial refractory period generated by the small and unsensed Follow-up revealed evidence of a defective LV lead 3 (Figure 4).…”

“…Based on the interventricular conduction delay (RVp‐LVs) and the relatively fast basic rate, the LVs event generated by the above RVp initiates an LVURI which again extends beyond the next scheduled LVp event thereby starting a desynchronization arrhythmia. Follow‐up revealed evidence of a defective LV lead (Figure ).…”

Left ventricular sensing by cardiac resynchronization devices

“…The recording of LV EGMs permits the diagnosis of device-induced arrhythmias, lead displacement with possible atrial far-field oversensing, electrical lead malfunction, and other abnormalities [12][13][14][15][16] ( Figure 1). Dissimilar rhythms can be recorded or documented by simultaneous recording of the EGM from both ventricles.…”