Ventricular pacing inhibition by oversensing due to diaphragmatic myopotential during deep inspiration

AbstractAn 80-year-old man, who had dilated cardiomyopathy with right ventricular (RV) dilatation, underwent implantable cardioverter defibrillator (ICD) implantation for advanced atrioventricular block and primary prevention of sudden cardiac death. Tined and screw-in leads were placed on the right atrial appendage and RV apex, respectively. Ventricular pacing inhibition was detected after surgery due to oversensing by diaphragmatic myopotential occurring only during deep inspiration. We performed re-surgery and switched the screw-in lead for a tined lead. The diaphragmatic myopotential decreased, thereby improving oversensing by diaphragmatic myopotential and ventricular pacing inhibition. It might be beneficial to use a tined lead when placing the ventricular lead at the RV apex for implantation of a pacemaker or ICD if oversensing of diaphragmatic myopotential is observed using a screw-in lead.<Learning objective: Oversensing due to diaphragmatic myopotential is rarely observed. However if it occurs, it becomes a critical problem, which causes pacemaker inhibition or inappropriate ICD shock. However, the method of preventing this problem is unknown. In this case, we demonstrated that a tined-lead may be useful for the prevention of oversensing by diaphragmatic myopotential.

Risk Factors for Migration, Fracture, and Dislocation of Pancreatic Stents

Aim. To analyze the risk factors for pancreatic stent migration, dislocation, and fracture in chronic pancreatitis patients with pancreatic strictures. Materials and Methods. Endoscopic stent placements (total 386 times) were performed in 99 chronic pancreatitis patients with pancreatic duct stenosis at our institution between April 2006 and June 2014. We retrospectively examined the frequency of stent migration, dislocation, and fracture and analyzed the patient factors and stent factors. We also investigated the retrieval methods for migrated and fractured stents and their success rates. Results. The frequencies of stent migration, dislocation, and fracture were 1.5% (5/396), 0.8% (3/396), and 1.2% (4/396), respectively. No significant differences in the rates of migration, dislocation, or fracture were noted on the patient factors (etiology, cases undergoing endoscopic pancreatic sphincterotomy, location of pancreatic duct stenosis, existence of pancreatic stone, and approach from the main or minor papilla) and stent factors (duration of stent placement, numbers of stent placements, stent shape, diameter, and length). Stent retrieval was successful in all cases of migration. In cases of fractured stents, retrieval was successful in 2 of 4 cases. Conclusion. Stent migration, fracture, and dislocation are relatively rare, but possible complications. A good understanding of retrieval techniques is necessary

A Case of Endoscopic Mucosal Resection of Carcinoma in Adenoma at the Minor Duodenal Papilla

Here, we describe a case of minor papillary adenocarcinoma in adenoma that was treated with endoscopic mucosal resection (EMR). In a 67-year-old woman, sigmoid colon cancer was incidentally detected on preoperative upper gastrointestinal endoscopy. Endoscopy revealed a slightly elevated lesion at the minor duodenal papilla. The findings of a histopathologic examination were suggestive of adenocarcinoma. Computed tomography and magnetic resonance images identified a minute tumor, whereas endoscopic ultrasonography revealed that the tumor did not spread to the pancreas. We performed EMR of this lesion. There were no complications, and relapse has not occurred in 3 years. Cases of minor papillary adenocarcinoma treated with EMR are quite rare

Early Gastric Cancer Presenting Pyloric or Prepyloric Stenosis

Out of 390 patients with early gastric cancer (EGC) who underwent gastric resection between Jan. 1968 and Jul. 1987, four patients developed pyloric stenosis and one patient developed prepyloric stenosis. Macroscopic types of EGC were II c in three cases and II c + III in two cases. Histologic types were tubular adenocarcinoma in four patients, and poorly differentiated adenocarcinoma in one patient. Cancer existed just right on or immediately adjacent to the pyloric ring in all patients; and extended transversely to the gastric axis in four patients, and longitudinally in one patient. An associated open ulcer and/or ulcer scar in the cancer lesion was seen in four patients, and submucosal fibrosis in three patients to a variety of degree, both of which were thought to be greatly attributed to pyloric or prepyloric stenosis. A duodenal ulcer was not present in any patients

Chest tube insertion is one important factor leading to intercostal nerve impairment in thoracic surgery

Objectives: Chest tube insertion seems to be one important factor leading to intercostal nerve impairment. The purpose of this prospective study was to objectively evaluate intercostal nerve damage using current perception threshold testing in association with chest tube insertion. Methods: Sixteen patients were enrolled in this study. Intercostal nerve function was assessed with a series of 2000-Hz (Aβ fiber), 250-Hz (Aδ fiber), and 5-Hz (C fiber) stimuli using current perception threshold testing (Neurometer CPT/C R). Current perception threshold values at chest tube insertion were measured before surgery, during chest tube insertion and after removal of the chest tube. Intensities of ongoing pain were also assessed using a numeric rating scale (0-10). Results: Current perception thresholds at each frequency after surgery were significantly higher than before surgery. Numeric rating scale scores for pain were significantly reduced from 3.3 to 1.9 after removal of the chest tube (p = 0.004). The correlation between current perception threshold value at 2000 Hz and intensity of ongoing pain was marginally significant (p = 0.058). Conclusions: This is the first study to objectively evaluate intercostal nerve damage at chest tube insertion. The results confirmed that chest tube insertion has clearly deleterious effects on intercostal nerve function