Transmediastinal Permanent Ventricular Pacing

A previous report from this institution demonstrated the mechanical superiority of the transthoracic pacemaker over the transvenous, but the former had a much higher morbidity. Since 1968 a transmediastinal extrapleural operation has been used in preference to thoracotomy for permanent epicardial pacing. This report compares 161 patients having 82 transmediastinal (TM) and 100 transvenous (TV) pacemaker electrode implantations. Significant operation-related complications occurred in 17% of the T M group and 19% of the T V group; 1 hospital death occurred in each group. Satisfactory ventricular pacing was established in 100% of the T M patients and 95% of the T V group, including 6% who required electrode repositioning. Pacing was not satisfactory in 5% of the T V group, and conversion to an epicardial system was necessary. Late electrode failure occurred in 24% of the T V group but in only 4% of the T M patients. Erosion or infection of the pacemaker system occurred in 23% of the T V and 7% of the T M patients. The results of this study indicate that the T M method is more reliable than the T V in establishing and maintaining permanent cardiac pacing and that the morbidity in T M as compared with T V implantations is almost the same. previous report from this institution [9] demonstrated that for the establishment and maintenance of permanent ventricular pacing, A an epicardial pacemaker implanted by thoracotomy was more reliable than an endocardia1 transvenous pacemaker. However, the patients undergoing thoracotomy for epicardial electrode placement suffered a significantly higher morbidity than did those having pacing established by the transvenous method [9]. In an attempt to avoid the complications of thoracotomy, a limited extrapleural transmediastinal approach has been used for placement of epicardial electrodes since October, 1968. Similar transmediastinal operations have been employed by Calvin [ll, Frank [21, Jude [6], and Reed [ll] and their co-workers. This report concerns 161 patients undergoing 182 operations for the establishment of permanent ventricular pacing. The transmediastinal (TM) operation was used for the installation of 82 epicardial electrodes, and 100 From the Departments of Surgery and Medicine, Duke University Medical Center, Durham, Presented at the Eighth Annual Meeting of The Society of Thoracic Surgeons, San Francisco, Address reprint requests to Dr. Dixon, Department of Surgery, Duke University Medical N.C. Calif., Jan. 24-26, 1972. Center, Durham, N.C. 27710. 206 THE ANNALS OF THORACIC SURGERY Trunsmediastinal Permanent Ventricular Pacing endocardial electrodes were inserted by the standard transvenous (TV) method. The intent of this retrospective analysis was to assess the efficacy of electrode placement by the T M operation, using the TV method as the basis for comparison. The two operations were compared according to the reliability of permanent cardiac pacing, the complications related to pacemaker implantation, and the postoperative mortality and morbidity. Materials and Methods The records of patients undergoing permanent ventricular pacemaker installation at the Duke University Medical Center from January 1, 1967, through December 31, 1970, were reviewed. For purposes of analysis these were separated into two groups as determined by the method of electrode placement; there were 82 T M and 100 TV patients. The mean age of the two groups of patients was 66 in the T M group (SD 11 years, range 7-87) and 72 in the TV group (SD 10 years, range 39-95). The mean follow-up interval was 12 months in the T M patients and 19 months in the TV patients. The indications for operation were essentially the same for both groups; approximately two-thirds of the patients had complete heart block and one-quarter had congestive heart failure (Table). Hypertension was present in 46% of the T M group and 35% of the TV group; diabetes mellitus and pulmonary, renal, and collagen vascular diseases were equally distributed between both groups. There was electrocardiographic evidence of previous myocardial infarction in 21% of the T M group and 40% of the TV group. OPERATIVE TECHNIQUE: TRANSMEDIASTINAL OPERATION Prior to operation, all patients had adequate cardiac pacing established using a temporary endocardial electrode. The transmediastinal operations were done under general anesthesia with an endotracheal tube in place and with constant monitoring of the direct arterial pressure and the electrocardiogram. The patient was positioned supine on the operating table with the entire left hemithorax and abdomen prepared and draped. An incision from the left lateral sternal border extending transversely over the fifth left costal cartilage was used, and the cartilage was removed extraperichondrially. INDICATIONS FOR PACEMAKER IMPLANTATION IN 161 PATIENTS