Feasibility of heart rhythm sensing, pacing and defibrillation with an ICD lead in an alternative position

The use of implantable cardioverter defibrillators (ICDs) is an established
therapy for the prevention of death from ventricular arrhythmia. Recently a
subcutaneous ICD (S-ICD) has been introduced, eliminating the need for
transvenous lead placement in or on the heart which is mandatory for
traditional ICD*s. This less invasive ICD therapy has the potential of reducing
complications associated with traditional ICD systems. The new S-ICD system
already proved to be feasible and safe. With the current S-ICD it is not
possible to administer pacing therapy (no brady pacing or anti-tachy- pacing),
which renders patients with a pacing indication or therapy-refractory
monomorphic ventricular tachycardia*s (VT) ineligible for the S-ICD. Moreover,
given the position of the ICD lead, higher voltage shocks are necessary for
defibrillation. Therefore, the S-ICD is larger than the traditional ICD. New
strategies could potentially resolve these issues.

(1) to determine the feasibility to sense and pace the myocardium with an- ICD
lead placed in an alternative position
(2) to determine the best position for pacing and sensing in the alternative
position
(3) to determine the safety and feasibility to place an ICD lead in the
alternative position.
(4) to determine feasibility to detect and terminate VF (shock therapy) with an
ICD lead placed in an alternative position

This is a feasibility and proof of principle study.

an ICD lead will be temparily be positioned and standard pace/sense
measurements will be performed. If these tests are succesfull, DFT tests will
be performed in the final step

The participant will not benefit from this study. There are no limitations or
additional limitations or visits required for this study. The study increases
radiation burden. Moreover, there are risks associated with the introduction of
the lead in the closed chest. The potential complications usually do not
require treatment. If treatment is required, this may most likely involve
opening of the chest. However, this is already required for the original
procedure, and is therefore no additional burden for the patient.

Risks discussed per step:
Step 2-3: During placement of the lead, a tamponade or cardiac or pulmonary
puncture may occur. Treatment may not be required. However, if treatment is
required, this can be done immediately, as participant is already prepared for
open-chest surgery.
Step 3: the defibrillation treshold test (DFT) is a standard test during
ICD-implants. Although sensing tests are performed in previous steps and prior
to DFT, there is a risk the ICD will not be able to detect or terminate the
VF, due to the different position of the leads. For this, participant is
connected to the external defibrillator which in that case will give a shock to
terminate VF. This is standard practice during ICD-implant.