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.