Discussion:
Due to the different fixation way, cardiac perforation remains one of
the severe complications of leadless pacemaker. It is recommended to
implant it at the septum of the right ventricle to minimize the
incidence of cardiac perforation 2,4 though it is not
easy to achieve in all patients, especially in small hearts or cor
pendulum (drop hearts) cases. According to the
literatures2,3 [2,3], the risk factors for cardiac
perforation in leadless pacemaker included female, low body mass index,
history of myocardial infarction and lung diseases. Therefore, each
patient should be carefully estimated before implantation, especially in
cases with these risk factors. Our patient was an old female with low
body mass index on dual anti-platelet therapy, which increased the
peri-procedure bleeding risk, although the study by Kiani
S5 et al showed continuation of therapeutic
anticoagulation during MICRA implantation was feasible and safe. It is
challenging to implant the leadless pacemaker in small-size heart cases
since the shape of the delivery catheter is fixed. In our patient, it is
not easy to perform Micra TPS across the tricuspid valve and accidently
place it into coronary sinus after multiple attempts. Left anterior
oblique view and angiography were useful to distinguish Micra TPS
locating at coronary sinus or right ventricle. Other than cardiac injury
by the fixation apparatus after deployment of Micra, cardiac perforation
resulting from the delivery catheter against the ventricular wall has
also been illustrated. Togashi I 6et al reported a
case of subclinical cardiac perforation caused by the edge of the device
cup penetrating into the ventricular wall prior to the deployment of the
leadless pacemaker. Another 91-year-old female case reported by Hai JJ4 et al developed cardiac perforation due to contrast
injection against the RV anterior wall before verification of sheath
location. The cause of pericardial effusion in the present case was
probably the coronary vein injury by the edge of the device cup, since
pericardial effusion was detected by angiography when the catheter was
placed into coronary sinus (Figure 1 ). The pericardial effusion
aggravated and pericardial tamponade occurred probably due to dual
anti-platelet therapy together with anti-coagulation of heparin. In
terms of short half-life period, bivalirudin might be more suitable than
heparin for peri-implantation anti-coagulation in patients on dual
anti-platelet therapy to reduce the bleeding risk.