Right latissimus dorsi cardiomyoplasty improves left ventricular function by increasing peak systolic elastance (Emax)

Lishan Aklog, Michael Murphy, Frederick Y. Chen, Wendel J. Smith, Rita G. Laurence, Robert F. Appleyard, Lawrence H. Cohn

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

Background: Dynamic cardiomyoplasty remains a promising but poorly understood surgical modality for selected patients with dilated cardiomyopathy. Despite encouraging clinical results, objective evidence of enhanced ventricular function using traditional indexes (cardiac output, ejection fraction, and dP/dt) has been difficult to document after cardiomyoplasty. Several investigators have suggested that cardiomyoplasty acts partly by unloading the left ventricle. These indexes all depend somewhat on loading conditions, however, and might not detect such an interaction. The time-varying elastance model provides an index of contractility, Emax, that is relatively insensitive to changes in loading conditions. We applied this model to study the effect of right latissimus dorsi cardiomyoplasty on left ventricular function in an acute canine model. Methods and Results: Five dogs underwent acute cardiomyoplasty using untrained right latissimus dorsi muscle. Instrumentation included Millar pressure transducers in the left ventricle and aortic root, an electromagnetic flow probe around the ascending aorta, and a volume conductance catheter in the left ventricle. A cuffed nerve electrode around the thoracodorsal nerve and a right ventricular sensing lead were connected to a Medtronic Cardiomyostimulator (5 V, 30 Hz, 1:1 synchronization). Transient caval occlusions were performed with the stimulator both off and on to calculate Emax and the slope of the end-systolic pressure-volume relationship (Ees). Turning the stimulator on significantly increased peak systolic elastance (Emax) and end-systolic elastance (Ees) in all five dogs by an average of 56% and 78%, respectively (Pmax despite inconsistent changes in other indexes underlies the importance of using load-insensitive indexes of ventricular function when studying cardiomyoplasty.

Original languageEnglish (US)
JournalCirculation
Volume90
Issue number5 II
StatePublished - Nov 1994
Externally publishedYes

Fingerprint

Cardiomyoplasty
Superficial Back Muscles
Left Ventricular Function
Heart Ventricles
Ventricular Function
Dogs
Pressure Transducers
Venae Cavae
Electromagnetic Phenomena
Dilated Cardiomyopathy
Cardiac Output
Aorta
Canidae
Electrodes
Catheters
Research Personnel
Blood Pressure
Muscles

Keywords

  • Cardiomyoplasty
  • Elastance
  • Left ventricular function

ASJC Scopus subject areas

  • Physiology
  • Cardiology and Cardiovascular Medicine

Cite this

Aklog, L., Murphy, M., Chen, F. Y., Smith, W. J., Laurence, R. G., Appleyard, R. F., & Cohn, L. H. (1994). Right latissimus dorsi cardiomyoplasty improves left ventricular function by increasing peak systolic elastance (Emax). Circulation, 90(5 II).

Right latissimus dorsi cardiomyoplasty improves left ventricular function by increasing peak systolic elastance (Emax). / Aklog, Lishan; Murphy, Michael; Chen, Frederick Y.; Smith, Wendel J.; Laurence, Rita G.; Appleyard, Robert F.; Cohn, Lawrence H.

In: Circulation, Vol. 90, No. 5 II, 11.1994.

Research output: Contribution to journalArticle

Aklog, L, Murphy, M, Chen, FY, Smith, WJ, Laurence, RG, Appleyard, RF & Cohn, LH 1994, 'Right latissimus dorsi cardiomyoplasty improves left ventricular function by increasing peak systolic elastance (Emax)', Circulation, vol. 90, no. 5 II.
Aklog, Lishan ; Murphy, Michael ; Chen, Frederick Y. ; Smith, Wendel J. ; Laurence, Rita G. ; Appleyard, Robert F. ; Cohn, Lawrence H. / Right latissimus dorsi cardiomyoplasty improves left ventricular function by increasing peak systolic elastance (Emax). In: Circulation. 1994 ; Vol. 90, No. 5 II.
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