Inhibition of Left Ventricular Pacing during Cardiac Resynchronization

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

“…The available literature provides numerous circumstances when LVTP or LVPP affects some of the timing cycles related to antibradycardia pacing and under special circumstances inhibits LV pacing. These include T‐wave oversensing by the LV channel and far‐field atrial sensing by the LV channel before RV activity during sinus rhythm and atrial tachyarrhythmia (D'Ivernois & Barold, ). Moreover, when LVURI interval is longer than RV upper tracking interval resynchronisation stops due to repeated LVURI restarting (Barold & Kucher, ; Barold, Mello Porto, & Kucher, ).…”

Anomalous pacing in a biventricular device due to spontaneous premature beats: What is the mechanism?

“…The LVPP is designed to prevent LV pacing during the LV vulnerable period after a LV sensed event; this is particularly relevant when the LV sensed event is not sensed on the RV channel (as in this case). Inhibition of LV pace output by the LVPP algorithm is indicated by the “Inh‐LVP” marker …”

Left ventricular sensing by cardiac resynchronization devices

“…The occurrence of puzzling frequent and irregular “LVinh” events may occur when there is stable RV pacing in association with LV sensing of rapidly occurring signals as in far‐field atrial LV sensing of atrial fibrillation or in the presence of ventricular fibrillation sensed only by the LV as in dissimilar rhythms …”

“…Far‐field atrial sensing by the LV lead is almost invariably caused by displacement or malposition of the LV lead toward the coronary sinus from where left atrial activity may be sensed (Figure ) . Far‐field sensing of atrial activity by the LV channel does not affect RV timing cycles but it must be corrected because it reduces or eliminates therapeutic biventricular pacing for heart failure.…”

“…Far‐field atrial sensing by the left ventricular (LV) channel of Boston Scientific (BSc) cardiac resynchronization therapy (CRT) devices (Boston Scientific, Marlborough, MA, USA) has been reported to cause LV inhibition. In such cases, the devices responded by delivering “LV inh” markers . In this issue of PACE, Larsen et al documented LV inhibition of a normally functioning BSc CRT device by a mechanism unrelated to atrial oversensing.…”