US investigators have found that pacing the two lower chambers of the heart, or bi-ventricular pacing, prevented cardiac enlargement as compared to only pacing the right ventricle in pacemaker patients with normal pumping hearts.
Medtronic sponsored the Pacing to Avoid Cardiac Enlargement (PACE) trial which was published in the New England Journal of Medicine.
Bi-ventricular pacing is known to reduce symptoms, extend survival and reduce heart size in symptomatic heart failure patients. However, the technique is not currently approved for use with pacemaker patients with normal pumping hearts.
PACE results showed that after one year of pacing, patients with pacing in both right and left ventricles (bi-ventricular) had no significant changes in left ventricle size while patients paced only in the right ventricle developed enlarged left ventricles.
Patients paced only in the right ventricle were seen to have a significant increase of 6.3mL on average in the size of the left ventricle at the end contraction, and a decrease of 6.8% of blood pumped out of the left ventricle.
“These early results show bi-ventricular pacing may be superior to pacing only in the right ventricle to preserve the heart’s normal left ventricle size and pumping ability for these pacemaker patients,” said PACE lead investigator Professor Cheuk-Man Yu, at Prince of Wales Hospital, The Chinese University of Hong Kong in China.
“As the first randomized study with this patient population, these initial results suggested that ensuring synchrony of the ventricles can help maintain patient health,” he said.