Abstract 19041: Institution of Localized High Frequency Electrical Stimulation Targeting Early Myocardial Infarction: Effects on Left Ventricular Function and Geometry
Background: Therapeutic strategies that are focused upon transforming an existing myocardial infarction (MI) and thereby altering the course of post-MI remodeling process have not been forthcoming. This study tested the hypothesis that localized high frequency stimulation (LHFS) instituted within a formed MI region using low amplitude electrical pulses would favorably change the trajectory of changes in LV geometry and function.
Methods: At 7 days following MI induction (coronary ligation), pigs were randomized for LHFS (n=5, 240bpm, 0.8V, 0.05ms pulses) or unstimulated (UNSTIM, n=6). LV geometry and function was measured at baseline (pre-MI) and at 7, 14, 21, and 28 days post-MI using echocardiography. MI size at 28 days post-MI was determined by planimetry.
Results: At 7 days post-MI and before randomization to LHFS, LV ejection fraction (LVEF) and end-diastolic volume (LVEDV) was equivalent (Table). However, LVEDV increased in a time dependent manner in the MI UNSTIM group, but the time dependent increase in LVEDV was reduced with LHFS. For example, by 28 days post-MI, LVEDV increased by 32% in the MI UNSTIM group but only by 12% in the MI LHFS group (p<0.05). While LVEF appeared unchanged between MI groups, estimates of pulmonary capillary wedge pressure (PCWP), a hemodynamic index for progression to LV failure, increased by 62% in the MI UNSTIM and actually decreased by 17% in the MI LHFS group at 28 days (p<0.05). MI size was equivalent, indicative of no difference in the extent of absolute myocardial injury.
Conclusions: The unique findings from this study are two-fold. First, targeting the MI region following the resolution of the acute event using a localized stimulation approach is feasible. Second, localized stimulation modified a key parameter of adverse post-MI remodeling (dilation) and progression to heart failure. These findings demonstrate that the MI region itself is a modifiable tissue and responsive to localized electrical stimulation.
Author Disclosures: M.C. Genau: None. P.E. Perreault: None. E. Romito: None. H. Doviak: None. C.B. Logdon: None. S. Ruble: None. S. Barlow: None. F.G. Spinale: Research Grant; Significant; NIH. Consultant/Advisory Board; Modest; Boston Scientific, Novartis, Amgen, Acorda.
- © 2016 by American Heart Association, Inc.