Activity-rest stimulation protocol improves cardiac assistance in dynamic cardiomyoplasty

Objective: No data have ever been published regarding cardiac assistance in demand dynamic cardiomyoplasty (DDCMP). We tested the efficacy of the Doppler flow wire in measuring beat-to-beat aortic flow velocity and evaluating cardiac assistance in demand cardiomyoplasty patients. Methods: The technique was tested in seven patients (M/F = 6/1; age = 57.1 ± 6.2 years; atrial fibrillation/sinus rhythm = 1/6; NYHA = 1.4 ± 0.5). Measurements were done using a 0.018inch peripheral Doppler flow wire advanced through a 5F arterial femoral sheath. Three 1-min periods with the stimulator off and three 1-min periods with clinical stimulation were recorded. We measured peak aortic flow velocity in all beats. Latissimus dorsi (LD) mechanogram was simultaneously recorded. Results: Comparison between pre-operative and follow-up data showed significantly higher values of tetanic fusion frequency (TFF) and ejection fraction at follow-up, whereas mean NYHA class was significantly lower. Statistical analysis showed an increase in aortic flow velocity not only in assisted versus rest period, but also in assisted versus unassisted beats (8.42 ± 6.98% and 7.55 ± 3.07%). A linear correlation was found between the increase in flow velocity and LD wrap TFF (r² = 0.53). Conclusions: In DDCMP, systolic assistance is significant and correlated to LD speed of contraction; demand stimulation protocol maintains muscle properties and increases muscle performance.