Partial Cardiac Assistance Begun Immediately after Latissimus Dorsi Muscle Mobilization and Cardiomyoplasty

Cardiomyoplasty, in which the latissimus dorsi muscle (LDM) assists the heart, is a relatively new surgical treatment for heart failure. Currently, the LDM is unstimulated for the first two weeks postoperatively, then stimulated for the next four weeks with one or two impulses every other heart beat. We wanted to determine if the LDM could provide assistance earlier than six weeks postoperatively. In four control sheep electrical stimulation (ES) was not applied to the LDM; in four sheep, ES was begun two hours after LDM mobilization; in another four sheep, ES mimicking cardiac assist (work-rest regimen) was added to the protocol twice daily for 30 minutes. In animals with the protocol mimicking cardiac assist, contractile force (CF) changed minimally on days 6, 11, and 16 following two successive 30 minute fatigue tests (98 ± 3%; 102 ± 3%, and 104 + 2 % respectively). The typical ischemic state of the mobilized LDM was not aggravated with this protocol. The percent area occupied by capillaries increased to 5.04 ± 0.33% (compared with 3.02 ± 0.6% in control muscle). In the control series, CF decreased to 85 ± 4%, 78 ± 3%, and 77 ± 3% on days 6, 11, and 16, respectively. We concluded that a cautious stimulation regimen using a work-rest protocol and a slow rate of contraction does allow for earlier partial cardiac assist.