Document Detail

Evaluation of stimulation parameters on aortomyoplasty, using Latissimus Dorsi muscle in a goat model: an acute study.
MedLine Citation:
PMID:  10485426     Owner:  NLM     Status:  MEDLINE    
OBJECTIVE: Dynamic aortomyoplasty using Latissimus Dorsi muscle (LDM) has been shown to improve myocardial function. However, systematic examination of the effects of stimulation parameters on aortic wrap function has not been done. Thus, the present study measures the direct effect of stimulation voltage, pulse train duration, frequency of the pulses, and the duration of the stimulation delay from R wave on the aortic wrap function. METHODS: In eight female goats, the left LDM was wrapped around the descending aorta. The muscle was then subjected to electrical stimulation, altering frequency of stimulation pulses (16.6, 20, 25, 33 and 50 Hz), amplitude (2, 4, 6, 8 and 10 V), and number of pulses (2, 4, 6, 8 and 10 pulses) in a train stimulation. Left ventricular, aortic pressure, and pressure generated by LDM on aorta (wrap pressure) was measured. The changes in hemodynamic parameters mentioned above were calculated and compared for different stimulation parameters during unassisted and assisted cardiac cycles. RESULTS: Aortomyoplasty counterpulsation using LDM provided significant improvement in wrap pressure (78 mmHg +/- 2), aortic diastolic pressure, and changes in aortic diastolic pressure from 2 to 4 V (P < 0.05). Further increase in amplitude did not make any significant improvements of the above mentioned parameters. Significant augmentation of wrap pressure (82 mmHg +/- 2), aortic diastolic pressure (79 mmHg +/- 3) and changes in aortic diastolic pressure (12 mmHg +/- 1) occurred at 6 pulses (P < 0.05). Other changes in number of pulses did not show any significant improvements. Significant improvement of wrap pressure (80 mmHg +/- 2), aortic diastolic pressure (73 mmHg +/- 3) and changes in aortic diastolic pressure (12 mmHg +/- 1) was observed with a frequency of 33 Hz. To examine a wide range of delays from the onset of the QRS complex to LDM stimulation, stimulation was delivered randomly. The exact delay was determined from the ECG signal and superimposed LDM stimulation pulses. CONCLUSIONS: In this study we present a new measurement, wrap pressure. We also present that in aortomyoplasty using LDM, the most significant improvement in wrap pressure, aortic diastolic pressure and changes in aortic diastolic pressure occurs when the stimulation consists of an amplitude of 4 V, a frequency of 33 Hz and a train stimulation of 6 pulses.
A Hakami; W P Santamore; R W Stremel; G Tobin; V E Hjortdal
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery     Volume:  16     ISSN:  1010-7940     ISO Abbreviation:  Eur J Cardiothorac Surg     Publication Date:  1999 Aug 
Date Detail:
Created Date:  1999-10-13     Completed Date:  1999-10-13     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  8804069     Medline TA:  Eur J Cardiothorac Surg     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  228-32     Citation Subset:  IM    
Department of Surgery, University of Louisville, KY, USA.
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MeSH Terms
Aorta, Thoracic / physiology,  surgery*
Blood Pressure
Counterpulsation / methods*
Disease Models, Animal
Electric Stimulation
Heart Failure / physiopathology,  therapy
Muscle Contraction
Muscle, Skeletal / physiology,  transplantation*
Treatment Outcome

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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