Figure 5.

Atrioventricular (AV) delay optimization protocol. The relative change in systolic blood pressure (SBP) between 8 beats of AAI pacing and 8 beats of dual chamber atrial synchronous–His pacing at a given atrioventricular delay (AVD) is determined [AV delay = 80 ms in this example (top left)]. This is a single alternation (plotted bottom left). A minimum of six alternations are made for each AVD (middle sections top and bottom). This process is repeated for each AV delay between 40 and 320 ms (less if intrinsic AV conduction occurs before 320 ms). The optimal AV delay is then derived from the plotted parabola (bottom right). In this example, the optimal AV delay was 160 ms. BP, blood pressure; ECG, electrocardiogram.