Clinical outcomes of upgrades
The clinical outcomes before and after upgrades were shown in Figure 1. After upgrades, the LVEF significantly increased from baseline 33.76±7.54% to 40.41±9.06% (P<0.001) (Figure 1A). The paced QRSd markedly decreased from 184.2±23.76ms at baseline to 120.5±16.67ms after HPSP (P<0.001)(Figure 1B). The LVEDD reversed from 59.29±7.74 mm to 53.91±5.92 mm (P<0.001)(Figure 1C). The NYHA functional class improved to 2.00±0.76 from 2.55±0.91 at baseline during follow-up (P<0.001).