The Journal of Thoracic and Cardiovascular Surgery, Vol 103, 1200-1206, Copyright © 1992 by The American Association for Thoracic Surgery and The Western Thoracic Surgical Association
Dynamic cardiomyoplasty for hemodynamic support during acute pulmonary hypertension. An experimental study
A Hill, C Li, C Tchervenkov, C Desrosiers and RC Chiu
Department of Surgery, Montreal General Hospital/McGill University, Quebec, Canada.
The efficacy of dynamic cardiomyoplasty for hemodynamic support during
acute pulmonary hypertension was studied. Five dogs underwent a right
latissimus dorsi cardiomyoplasty. Each dog was later studied in a short-
term experiment. A graded acute pulmonary hypertension was induced by
infusion of glass microspheres into the pulmonary artery. This resulted in
decrease in pulmonary artery flow, systemic pressure, and systemic flow.
The cardiomyoplasty was then stimulated with a new R wave synchronous
rate-responsive pulse-train stimulator (Prometheus system). This pacemaker
delivers a pulse train with the duration of stimulation determined as a
proportion of the RR interval. At an optimal level of hemodynamic
impairment, the dynamic cardiomyoplasty was able to immediately improve
pulmonary artery flow 26.4% +/- 5.84% (standard error of the mean) (p less
than 0.005, paired t test), mean systemic arterial pressure 11.6% +/- 3.7%
(p less than 0.05), and thoracic aortic flow 15.7% +/- 6.3% (p less than
0.05). The degree of improvement in hemodynamic variables could be
correlated with the magnitude of hemodynamic impairment present (e.g., r =
0.78; p less than 0.005 for pulmonary blood flow). We conclude that a
significant beneficial effect of dynamic cardiomyoplasty on hemodynamics in
short- term canine pulmonary hypertension is demonstrated in this study.
Thus cardiomyoplasty may be useful in patients with right heart failure
associated with increased pulmonary vascular resistance.
