Long-term effects of non-excitatory cardiac contractility modulation electric signals on the progression of heart failure in dogs.
OBJECTIVE
We previously showed that acute delivery of non-excitatory cardiac contractility modulation (CCM) electric signal during the absolute refractory period improved LV function in dogs with chronic heart failure (HF). In the present study we examined the long-term effects of CCM signal delivery on the progression of LV dysfunction and remodeling in dogs with chronic HF.


METHODS
Chronic HF was produced in 12 dogs by multiple sequential intracoronary microembolizations. The CCM signal was delivered using a lead implanted in the distal anterior coronary vein. A right ventricular and a right atrial lead were implanted and used for timing of CCM signal delivery. In six dogs, CCM signals were delivered continuously for 6 h daily with an average amplitude of 3.3 V for 3 months. Six HF dogs did not have leads implanted and served as controls.


RESULTS
In control dogs, LV end-diastolic volume (EDV) and LV end-systolic volume (ESV) increased (64+/-5 ml vs. 75+/-6 ml, P=0.003; 46+/-4 ml vs. 57+/-4 ml, P=0.003; respectively), and ejection fraction (EF) decreased (28+/-1% vs. 23+/-1%, P=0.001) over the course of 3 months of follow-up. In contrast, CCM-treated dogs showed a smaller increase in EDV (66+/-4 vs. 73+/-5 ml, P=0.01), no change in ESV, and an increase in EF from 31+/-1 to 34+/-2% (P=0.04) after 3 months of therapy.


CONCLUSIONS
In dogs with HF, long-term CCM therapy prevents progressive LV dysfunction and attenuates global LV remodeling. These findings provide compelling rationale for exploring the use of CCM for the treatment of patients with chronic HF.
Morita
Hideaki
H
Department of Medicine, Henry Ford Heart and Vascular Institute, Henry Ford Hospital, 2799 West Grand Boulevard, Detroit, MI 48202, USA.
Suzuki
George
G
Haddad
Walid
W
Mika
Yuval
Y
Tanhehco
Elaine J
EJ
Goldstein
Sidney
S
Ben-Haim
Shlomo
S
Sabbah
Hani N
HN
D000818:Animals; D006328:Cardiac Catheterization; D017023:Coronary Angiography; D004285:Dogs; D004452:Echocardiography; D004599:Electric Stimulation Therapy / Q000379:methods; D006333:Heart Failure / Q000503:physiopathology / Q000628:therapy*; D006439:Hemodynamics; D008365:Manometry; D023421:Models, Animal; D009200:Myocardial Contraction / Q000502:physiology*; D016277:Ventricular Function, Left / Q000502:physiology*