Acute cardiac resynchronization therapy for chronic thromboembolic pulmonary hypertension

The clinical severity of right ventricular disease is largely determined by
right-to-left ventricular dyssynchrony, i.e., delay of electrical activity
between the right and left ventricles. Moreover, in patients with chronic
thromboembolic pulmonary hypertension (CTEPH), we found that acute correction
of this dyssynchrony by temporary pacing during routine preoperative (i.e.,
prior to pulmonary endarterectomy, the best therapy for CTEPH) cardiac
catheterization results in significant improvement in cardiac output.

In this study, we aim to establish whether temporary pacing is also effective
in CTEPH patients who are not eligible for pulmonary endarterectomy, or those
in whom pulmonary endarterectomy has failed. These severely symptomatic
patients, for whom no effective therapy exists, potentially benefit greatly
from this novel therapy: if temporary pacing should prove effective, future
studies may test the efficacy of chronic pacing (with implanted pacemakers).

Acute intervention study.

Acute cardiac resynchronization therapy (CRT), i.e., temporary right atrial and
right ventricular pacing.

Acute CRT will be conducted in the catheterization room with the use of 2
pacing catheters (in the right atrium and the right ventricle apex), inserted
into the femoral vein under local anaesthesia. This is a standard configuration
for electrophysiologic studies, that we conduct routinely. We therefore do not
expect adverse events from this study. The whole procedure will take 60-90 min.
These studies can only be conducted in this patient group (CTEPH patients),
because we have established the pathophysiological basis and efficacy of CRT in
this patient group. Chronic CRT may be considered in those patients in whom
acute CRT in the present study improves cardiac output.