Demand Dynamic Bio-girdling in Heart Failure: Improved Efficacy of Dynamic Cardiomyoplasty by LD Contraction during Aortic Out-flow

Abstract

Purpose The value of dynamic cardiomyoplasty has been brought into question by the disappointing results produced by slow contraction-relaxation cycle and possibly degeneration of the latissimus dorsi muscle (LD) secondary to temporary tenotomy and chronic daily electrical stimulation. Objective of our study is to determine whether daily periods of rest introduced by demand stimulation in the continuous contraction protocol produce systolic assistance and improve clinical results. Methods Twelve dynamic cardiomyoplasty patients (mean age 58.2±5.8 years, M/F=11/1, sinus rhythm/atrial fibrillation=11/1) with dilated myocardiopathy were enrolled in an unrandomized trial of Demand Dynamic Heart Bio-Girdling in a public regional teaching hospital. Periods of LD inactivity, each lasting several hours, were introduced daily on a heart rate-based demand regime. To avoid full transformation of LD, fewer impulses per day were delivered, daily providing the LD with long periods of rest (Demand light stimulation). The contractile properties were measured by transcutaneous non-invasive LD tensiomyogram interrogation (LD tensiomyogram). Bio-Girdle activation was synchronized to heart beat by combining tensiomyogram and echocardiography. Clinical, echocardiographic and hemodynamic records, as well as aortic flow measurements by Doppler aortic flow wire were taken during the follow-up. Main findings Mean duration of the demand stimulation follow-up was 40.2+13.8 months. At five years, “Demand stimulation” shows: 1) no operative death; 2) 83% actuarial survival; 3) highly significant 47.4% decrease of the NYHA class (from 3.17±0.38 to 1.67±0.77, p=0.0001); 4) 41.6% improvement of LVEF (from 22.6±4.38 to 32.0±7.0, p=0.001); 5) 7.5±3.0% increase in aortic flow velocity peak in assisted vs. unassisted beats, and 6) preservation of LD from slowness (TFF value 33±7.86 at follow-up versus 15.8±11.1 Hz just before switching from continuous to demand stimulation, p=0.0001) and muscle degenerative atrophy. Conclusions In dynamic cardiomyoplasty the demand light stimulation maintains LD contraction properties over time, produces effective systolic assistance, and improves clinical results. Demand dynamic bio-girdling is a safe and effective treatment for end-stage heart failure in selected patients.