Millner, Russell William James;
(1992)
Studies in experimental dynamic cardiomyoplasty.
Doctoral thesis (M.D.), Institute of Psychiatry.
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Abstract
Dynamic cardiomyoplasty, using the patients own skeletal muscle to treat heart failure, is an evolving technique. It has reached clinical practise before its effectiveness has been established in experimental models of chronic left ventricular failure. A major reason for this has been the lack of appropriate and reliable heart failure models. A pilot model of dynamic cardiomyoplasty of the right ventricle with acute heart failure induced with intravenous propranolol is presented. Left ventricular failure is then shown to occur in a recently reported model of anterior/apical left ventricular aneurysm. This model of moderate left ventricular failure is used to investigate the haemodynamic benefits of dynamic cardiomyoplasty. Haemodynamic studies are performed at the initial operation, both before and after infarction, and then after a three month muscle conditioning protocol. The development of an aneurysm is confirmed by post-mortem examination at this point. The results show that when dynamic cardiomyoplasty is compared with a control group of animals with just an aneurysm, or with a control group of animals in which the aneurysm has just been wrapped with muscle but without stimulation (adynamic cardiomyoplasty), that at rest the benefits are negligible. When the animals are stressed by volume loading, then comparison of the function curves created shows that there are significant improvements in haemodynamic parameters with dynamic cardiomyoplasty. These improvements are seen both in the comparison between the cardiomyostimulator off and on curves for the dynamic cardiomyoplasty group, as well as the comparison between the two control groups and the cardiomyostimulator on curves from the dynamic cardiomyoplasty group. Investigation of myocardial revascularisation in these models failed to find significant collateralisation between the mobilised latissimus dorsi flap and the myocardium. Investigations of myocyte diameter showed that there was no difference in myocyte size between control muscle and muscle that had been mobilised as a pedicle flap, either with or without neuro-muscular stimulation. The relationship between these results and the reported clinical findings of improved functional classification without haemodynamic improvement at rest are discussed.
| Type: | Thesis (Doctoral) |
|---|---|
| Qualification: | M.D. |
| Title: | Studies in experimental dynamic cardiomyoplasty. |
| Open access status: | An open access version is available from UCL Discovery |
| Language: | English |
| Additional information: | Thesis digitised by Proquest |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10107995 |
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