Long-term dynamic cardiomyoplasty improves chronic and acute myocardial energetics in a model of left ventricular dysfunction.

BACKGROUND

We present the first long-term evaluation of myocardial energetics after dynamic cardiomyoplasty (CMP) in a model of left ventricular (LV) dysfunction.

METHODS AND RESULTS

Seventeen dogs underwent rapid ventricular pacing (RVP) to create heart failure. Eight dogs were randomly selected to undergo cardiomyoplasty. All dogs continued RVP for 6 additional weeks, whereas the CMP dogs underwent a simultaneously delivered synchronized muscle wrap conditioning protocol. After termination of RVP at 10 weeks in all dogs, myoplasty dogs continued to receive muscle wrap stimulation until the terminal study. Pressure-volume analysis to assess LV energetics was conducted at baseline and 4 weeks and 3 months after termination of RVP (6 months after baseline). At 6 months, CMP dogs displayed enhanced contractility, lower volumes, and more optimal energetics compared with control animals. Acute muscle wrap stimulation further increased effective contractility and myocardial efficiency compared with unassisted beats.

CONCLUSIONS

The decrease in NYHA functional class that occurs in patients after dynamic cardiomyoplasty may be secondary to its beneficial effects on long-term myocardial function, volume, and energetics.