Introduction: The leadless pacemakers are implanted routinely under fluoroscopic image, yet the pacing sites and corresponding paced electrocardiography (ECG) remain unclear. This study was to determine the computed tomography (CT)-verified location of the leadless Micra™ pacemakers (Micra™) and ECG characteristics. Methods: 20 consecutive patients who met the pacemaker indications for bradycardia and underwent fluoroscopy assisted Micra TM implantation were enrolled. All subjects underwent a postoperative CT scan to determine the precise location of the Micra TM pacing tip. Paced 12-lead ECG characteristics were analysed and correlated with the Micra TM tip location. Results: In the nine partitions of fluoroscopic RAO images, 14 (70%) of 20 patients had the Micra TM tip in zone 5, 5 (25%) in zone 6 and 1 in zone 2. Reconstructed CT 3-D cardiac images found Micra TM tips mostly clustered near the anterior insertion between the RV septum and free wall with 12 cases at the insertion-septal side and 8 at the free-wall side. ECG morphological analysis found that the peak deviation index in ECG lead V1 was 0.402±0.061 for Micra TM tips at the insertion-septal side and 0.542±0.053 in the free-wall side (P <0.001 between two sides) and paced clumsy R wave was often observed for tips at the free-wall side though there was no difference in QRS duration between two sides. Conclusion. In routine Micra TM implantation, the pacing sites were often located in the anterior insertion region, either at the insertion-septal or free-wall side. The ventricular activation propagation likely depended on the pacing sites.

Postcardiac injury syndrome (PCIS) is commonly seen complication caused by radiofrequency catheter ablation (RFCA) of persistent atrial fibrillation (persAF). We describe a rare case of PCIS with severe pulmonary hypertension (PAH) accompanied by severe tricuspid regurgitation (TR) following RFCA for persAF.

The esophageal injury after cryoballoon ablation is much rarer than that after radio-frequency ablation.Although it‘s rare, once progressed into atrioesophageal fistula, it could cause a catastrophic iatrogenic tragedy.We report on the occurrence of esophageal injury of A 71-year-old female with symptomatic paroxysmal AF who underwent cryoballoon pulmonary vein isolation. The patient complaint about chest pain exacerbated by swallowing on the postoperative day. Endoscopy detected the esophageal thermal lesions. After 7 days of interventions, the symptoms relieved and retest of endoscopy showed normal esophageal mucosa.We suggest that esophageal protection in cryoballoon ablation is just as important as in RF ablation.

Brief Introduction: This article summarizes a case of successful radiofrequency ablation of atrial tachycardia in a patient with dextrocardia in combination with intracardiac echocardiography, and summarizes the relevant experience.

Background: Implanting leadless pacemakers in the right ventricular (RV) apex is prone to causing pericardial tamponade and myocardial perforation. Objective: To investigate the feasibility and safety of right ventriculography-guided implantation of Micra TM leadless pacemaker (Micra) in the RV mid-septum. Methods: 108 consecutive patients who underwent Micra implantation intended in the mid-septum were enrolled and randomized (3:1) into the radiography group (n=81) with assistance of right ventriculography to illustrate the RV septum and the non-radiography group (n=27). All subjects underwent a postoperative computed tomography (CT) scan to determine the Micra location. The Micra location assessed by CT image was compared between the two groups to confirm the accuracy of the intended pacing site. The duration of the procedure, X-ray exposure dose and time were also compared between the two groups. Results: Reconstructed CT 3-D cardiac imaging found the Micra location in the intended mid-septum in 13 patients (48.1%, 13/27) in the non-radiography group and 76 patients (93.8%, 76/81) in the radiography group ( P< 0.0001 between two groups). There was no significant difference in procedure interval between the two groups while the X-ray exposure (564.86±112.44 vs. 825.85±156.12mGy, P < 0.0001), X-ray exposure time (7.79±1.43vs. 12.03±2.86 min, P < 0.0001) and the number of fluoroscopy re-positioning (2.79±1.03, vs. 6.41±1.82, P<0.0001) were significantly less in the radiography group than in the non-radiography group. No implantation-related complications were observed in both groups. Conclusion Right ventriculography increases the accuracy of Micra TM pacemaker implantation in the mid-septum and reduces X-ray exposure.