Fig. 2

“In-office” ECG dromotropic CRT optimisation. A case of nonischemic heart failure patient with a baseline LV ejection fraction of 22%, and a baseline ECG with LBBB with “Strauss criteria”, who underwent CRT-P implantation followed by routine post-implant ECG optimisation as shown. At 2-month follow-up, the LV ejection fraction raised up to 50%. From left, the first couples of standard 12 leads ECG tracings show the baseline pre-implant ECG with a typical (“Strauss”) LBBB pattern with intrinsic RV bundle conduction slightly longer but preserved, being a baseline PR interval = 190 ms. The second and third couples of ECG tracing AV delay settings show the sequential AV delay programming (summarised the shortest at 100 ms and the longest at 200 ms) to reach a RV sensing at a fixed simultaneous LV-RV offset (= 0 ms), in order to check for the RV sense timing and promote fusion also for baseline longer intrinsic AV delays. In the fourth couple of ECG tracings, at the latest AV delay which induce detection of RV sense EGM by device telemetry, the LV offset is then programmed advancing the LV by the formula: sensed/paced A-RV interval minus the P-R interval derived by the baseline EC. LBBB left bundle branch block; LV left ventricle (pacing); RV right ventricle (pacing); offset VV delay programming with LV-RV which means LV pacing advances the RV pacing