Discussion
Pacemaker implantation may lead to complications such as infection, hemorrhage, lead dislodgement, and lead perforation. Lead perforation is potentially life-threatening because of damage to adjacent tissues and organs. It is closely related to the procedure and type of leads, and the risk increases with old age (>80 years old), low body mass index (<20 kg/m²), or a history of steroid therapy.
When lead perforation happened, the pacemaker program may find abnormal changes in pacing parameters. However, in our case, the lead tip was still in good contact with the myocardial tissue, so no abnormal parameters were found. X-ray can quickly identify lead displacement and breakage, and it is the most common method for positioning the leads but with poor diagnosis sensitivity of lead perforation. CT is interfered by cardiac motion and metal artifacts, though seen as the gold standard for diagnosing lead perforation, leading to underestimation or overestimation [2]. ECG-gated CT reduces interference from cardiac motion and metal artifacts, but the diagnostic accuracy is still less than 100%. As reported in a study, when the penetrating part of the lead beyond the epicardial fat pad is less than 2 mm, misdiagnosis occurs [2]. In existing case reports, atrial leads often pass through the pericardial cavity and penetrate the lung tissue after perforation, which can be quickly diagnosed by X-ray and CT [3,4]. However, the diagnosis of perforation is not always so simple and easy. A case of lead perforation with repeated pericardial effusion during hospitalization was diagnosed not by pacemaker programming, X-ray or CT, but by angiography [5]. Another case of repeated pericardial effusion within three months with unknown cause, which was finally found lead perforation through open chest exploration, was reported [6]. In our case, it seemed that the atrial lead tip pierced the heart contour in the sagittal plane of CTA, and the part beyond the epicardial fat pad was extremely short. Later, we found the position of the criminal lead was not fixed during the operation, and the tip repeatedly went in and out of atrial wall, which increased the complexity of our diagnosis. Therefore, the penetrating moment captured by CT scan was a prerequisite for the imaging diagnosis of this case. In addition, the artifact factor should be considered.
We firstly describe the intermittent penetrating motion of the atrial lead after perforation, which has important guiding significance for diagnosis of lead perforation. For patients with cardiac pacemaker, once pericardial effusion occurs, even no evidence of perforation in programmed and imaging examinations is found, it is also necessary to consider whether the perforated part of criminal lead is too short.