Placement accuracy of percutaneous transthoracic pacemakers

Abstract

Experience has shown that the frequency of electrical capture of the heart with percutaneous transthoracic pacemakers is disappointingly low. The authors sought to determine whether the accuracy of vertricular placement could help to explain this observation. Six approaches were used in each of twenty adult patients who were examined at autopsy. Three parasternal approaches used the fifth intercostal space (5ICS). One pacing wire was inserted immediately to the left of the sternum along the parasternal line (5ICS-PS), one wire was inserted 4.0 cm to the left of the midsternal line (5ICS-4), and the third wire was inserted 6.0 cm to the left of the midsternal line (5ICS-6). All parasternal needle insertions were directed medially, dorsally, and cephalad toward the second right costrochondral junction at an angle of 30° to the skin. Three subxiphoid approaches were performed through the left xyphocostal notch at an angle of 30° to the skin. One pacing wire was directed toward the right shoulder (SXRS), one toward the sternal notch (SXSN) and one toward the left shoulder (SXLS). Accuracy of ventricular placement was assessed at autopsy. The success rates for the three parasternal approaches were as follows: 5ICS-PS = 0.85; 5ICS-4 = 0.80; 5ICS-6 = 0.90. For the three subxiphoid approaches success rates were as follows: SXRS = 0.25; SXSN = 0.50; SXLS = 0.65. All three parasternal approaches had higher success rates than the SXRS approach ( P < 0.05). In addition, the 5ICS-PS and 5ICS-6 approaches were more successful than the SXSN approach ( P < 0.05). There was no significant difference in success rates between each of the three parasternal approaches and the SXLS approach ( P > 0.10). Based on these data, the most accurate routes for the percutaneous placement of a transthoracic pacemaker are the 5ICS-PS, 5ICS-6, and SXLS approaches. This may explain in part the low rate of successful electrical capture reported in previous studies in which the SXRS and SXSN approaches were employed. Further studies are needed to address the potential for injuries associated with these approaches.