Patient Characteristics
A total of 108 consecutive patients were enrolled with 27 in the non-radiography group and 81 in the radiography group. All enrolled patients underwent successful implantation of MicraTMpacemaker. Patient baseline characteristics and pacemaker indications were summarized in Table 1. Of 108 patients, 48 (44.4%) had sinus node dysfunction, 52 (48.1%) had II-III degrees of atrioventricular conduction block, and 8 (7.4%) had both sinus node dysfunction and atrioventricular conduction block. Overall, baseline LVEF and LVEDD were normal in both groups. The baseline ECG QRS duration was 91.0±24.3 msin the non-radiography group and 98.0±24.3 ms in the radiography group (P = 0.206).