Case presentation
We present the case of a 44-year old male who presented with a syncope
and documented symptomatic sinus arrests on an insertable cardiac
monitor (Reveal LINQTM, Medtronic Inc, Minneapolis,
MN). Given his young age of the patient and the presence of a first
degree atrioventricular block on his twelve lead electrocardiogram, the
patient was planned for HBP. HBP was performed by delivering the
SelectSecure 3830 pacing lead (Medtronic) through a long preshaped
delivery sheat (C315HIS, Medtronic) towards the His region. After
localizing a clear His signal with the tip of the pacing lead, the lead
was screwed in by 4 to 5 clockwise rotations. At this first HBP implant
site (Figure 1, upper panel), HBP resulted in selective HBP (S-HBP) at
both high and low output with pacing threshold of 0.5V at 1.0ms pulse
width. This first HBP implant site was accepted as final position. The
day after implant, pacing thresholds were stable and the chest X-ray
showed correct positioning of the HBP lead after which the patient was
dismissed.
At three weeks after implant, the patient presented with exit block on
the HBP lead. Interrogation of the pacemaker confirmed the absence of HB
capture in unipolar pacing configuration and increased pacing thresholds
up to 6V at 1.0ms in bipolar configuration. During lead revision, no
macro-dislocation of the HBP lead was observed on fluoroscopy (Figure 1,
middle panel) A new HBP lead was guided towards the His bundle region,
keeping the first HBP lead in position to serve as anatomical reference
(dual lead technique). The first screw attempt of this second HBP lead
resulted in non-selective HBP (NS-HBP) at high pacing thresholds and
transition towards S-HBP at 1.5V at 1.0ms (loss of capture at 0.75V at
1.0ms). Before slitting the guide sheat of this second HBP-lead, the
first HBP lead was removed by 5 counter-clockwise rotations after which
the lead came loose and could be completely removed without any
resistance. No additional extraction tools were needed. No significant
tissue was seen at the tip of the explanted lead. Pacing thresholds for
the new HBP lead were stable the day after, but a systolic cardiac
murmur was heard upon auscultation. Transthoracic echocardiography
revealed the presence of a small perimembranous ventricular septal
defect (VSD), located basal to the insertion of the new HBP lead (Figure
1, lower panel). The VSD presented with a restrictive left to right
shunt on color Doppler with maximum flow velocitiy of 4,5 m/s; no aortic
regurgitation, right ventricular dilatation or pulmonary hypertension
were present. The peri-membranous VSD persisted with stable flow
velocities over the left to right shunt during 6 months follow up. As
the patient remained asymptomatic without developing hemodynamic sings
of pulmonary arterial hypertension, VSD closure was not considered and
regular follow-up was proposed. 7