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Intraperitoneal migration of epicardial leads and abdominally placed generators is a potentially serious complication. We report the case of an 83-year-old man who experienced intraperitoneal migration of an epicardial pacing system and consequent small-bowel obstruction. Laparotomy was required in order to free constrictive lead adhesions. The patient's postoperative recovery was satisfactory after the placement of a new pacemaker generator in the abdominal wall. Predisposing factors are analyzed and the literature is reviewed in order to clarify the mechanisms of sequelae associated with the migration of epicardial pacemakers from the abdominal wall. To the best of our knowledge, this is the 1st report of pacemaker migration having caused bowel obstruction that required urgent laparotomy in an adult.
Epicardial pacing is useful for treating bradycardia, especially in children and adults in whom the transvenous route is inaccessible or inappropriate. Surgical approaches to epicardial lead implantation include median sternotomy in association with another major cardiac procedure; extrapleural approaches, including subxiphoid, left parasternal, and left subcostal; and, less often, a left mini-thoracotomy.1–3 In these approaches, the generator can be placed in a pocket that is created either posterior to muscle in the left rectus sheath or in the subcutaneous tissue at the level of the upper quadrant of the abdominal wall. Several surgical complications—primarily pain, inflammation, and hematoma—have been described when the abdominal wall is used in such a manner.4,5 Intraperitoneal migration of the pulse-generator system, a very uncommon finding, has been associated with diarrhea, intestinal obstruction, and stimulation of the surrounding structures.6–10 To the best of our knowledge, this is the 1st report of pacemaker migration having caused bowel obstruction that required urgent laparotomy in an adult.
In 1998, a thin, 77-year-old man underwent transvenous pacemaker implantation because of sick sinus syndrome. His medical history included a duodenopancreatectomy in 1994 due to an ampulloma.
The patient was referred to our cardiac surgical unit in March 2001 because of suspected pacemaker lead endocarditis. Blood cultures obtained on admission tested positive for coagulase-negative staphylococci.
Preoperative echocardiography confirmed the presence of large vegetations along the lead and the septal tricuspid cusp. Moderate mitral incompetence with preserved ventricular function and paradoxical septal motion were observed. Therefore, complete removal of the pacemaker system was indicated. Lead extraction was performed through a median sternotomy with complete cardiopulmonary bypass. The vegetations over the septal tricuspid cusp were removed, and the valve structure was preserved.
After cardiopulmonary bypass was discontinued, 2 sutureless epicardial electrodes (ELC 54-UP, Biotronik GmbH & Co. KG; Berlin, Germany) were implanted, one in the left paraseptal area and one on the right ventricular diaphragmatic surface. Both electrodes were attached to a Y adapter (A1-CS-SB, Biotronik) and connected to the pulse generator (Axios SR, Biotronik) in a bipolar mode. Before sternal closure, the generator was placed beneath the left anterior rectus sheath in a pocket that was created by means of blunt dissection. The patient's postoperative course was uneventful; normal cardiac pacing and positioning of the pacemaker were confirmed on radiography and electrocardiography (ECG). After the patient was discharged from the hospital, he was monitored at our outpatient clinic every 6 months; he had no significant complaints and evidenced normal cardiac pacing.
In November 2005, the patient, now 83 years of age, was admitted to our emergency department because of diffuse abdominal pain and vomiting. Clinical examination and laboratory data showed no significant abnormalities. Abdominal radiographs revealed subocclusion of the small proximal bowel, with air-fluid levels and little gas from the colon to the rectum. The pacemaker was located inside the peritoneum, in the left lower quad-rant. It was observed that the generator moved down and rotated counterclockwise when the patient stood up after lying down (Fig. 1).
A computed tomographic scan of the abdomen revealed gastric and jejunal dilation, and a normal colon and ileum. An ECG showed normal pacing at 70 beats/min. Conservative treatment with nasogastric aspiration and parenteral fluid administration improved the patient's clinical condition. However, 72 hours later, severe abdominal pain and vomiting recurred, leading to a diagnosis of complete bowel obstruction. An urgent laparotomy was performed, and the generator was found to be lodged in an omental pouch that adhered to the transverse colon. The electrodes and the adapter were encircling the proximal jejunal loops, which we dissected from the adhesions. No necrosis of the bowel was observed. A new generator and the intra-abdominal segments of the leads were repositioned in the subcutaneous tissue at the lower left quadrant, outside the peritoneal cavity. An ECG confirmed normal pacing. The patient's postoperative course was uneventful. At his May 2007 outpatient follow-up, he was asymptomatic and doing well.
Electrical and surgical complications related to epicardial pacemaker implantation have progressively diminished, due to improved technology and surgical approaches. The usual site for generator placement after epicardial implantation is the abdominal wall. Placement of the unit in the subcutaneous tissue can result in skin erosion and infection, particularly in small children and thin adults. As an alternative, the generator can be placed within the rectus sheath behind the muscle.4,5 In this method, the unit is concealed and protected in a fasciomuscular pocket that is constructed by means of blunt dissection. Generator migration into the peritoneal cavity, although uncommon, has been reported as a potentially life-threatening complication when a submuscular pocket is used. Our thorough review of the English-language medical literature revealed only 5 cases of intraperitoneal migration of epicardial pacemakers6–10 either in children6,7,9 or in adults.8,10 In these cases and in ours, a median sternotomy or subxiphoid approach had been used, and the generator had been placed behind the rectus muscle. We speculate that the blunt dissection at the weakest point of the anterior abdominal wall could have been involved in the mechanism of intraperitoneal migration. In addition, atrophic fasciae and muscles may contribute to this complication in elderly patients.
Intraperitoneal migration can be a mildly symptomatic clinical situation. Diarrhea, abdominal discomfort, and nerve stimulation are functional disturbances that have been described.6,9,10 In unipolar systems,8 cessation of pacemaker activity can be a serious sequela in pacing-dependent patients. The possibility of a life-threatening event due to intestinal obstruction must also be taken into account.7 Therefore, as soon as migration is detected, even in an asymptomatic patient, repositioning of the unit should be viewed as mandatory.
In conclusion, intraperitoneal pulse-generator migration is a serious although unusual complication, and it is always associated with epicardial lead implantation. Therefore, when a submuscular abdominal pocket is used as an implantation site, especially in elderly and thin patients, we recommend affixing the electrode to the surrounding tissues near the generator, in order to prevent intra-abdominal migration.
Address for reprints: Angel L. Fernández, MD, Department of Cardiac Surgery, Hospital Clínico Universitario, Ave. Choupana, s/n, 15706 Santiago de Compostela, Spain. E-mail: se.aigoloidraces@gfla