Evaluation of stimulation parameters on aortomyoplasty, using Latissimus Dorsi muscle in a goat model: an acute study

Hakami, Ardeshir; Santamore, William P.; Stremel, Richard W.; Tobin, Gordon R.; Hjortdal, Vibeke E.

doi:10.1016/s1010-7940(99)00211-0

Cited by 4 publications

(3 citation statements)

References 10 publications

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“…The stimulation signal consists of a rectangular, biphasic impulse at a constant voltage, with a width of 1 ms, at a frequency of 200 Hz. Two different amplitude levels were applied at a threshold level associated with minimal muscle contractions, corresponding approximately to 10 V, and a second threshold level accompanied by muscle contractions corresponding to 25-30 V (4)(5)(6)(7)(8). It is known that the form of the impulse signal, with a short width of 1 ms, has practically no influence on the muscular contraction.…”

Section: Methodsmentioning

confidence: 99%

“…Recently, a new method has been proposed for improving cardiac function by ECG-triggered muscular counterpulsation (MCP, CardioLa Ltd., Winterthur, Switzerland) (4)(5)(6)(7)(8). This method is based on the hypothesis that ECG-triggered contraction of the skeletal musculature leads to a compression of peripheral veins and arteries associated with a change in pulse wave propagation and a decrease in peripheral vascular resistance (4)(5)(6)(7)(8).…”

Section: Introductionmentioning

confidence: 99%

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ECG-Triggered Muscular Counterpulsation for Treatment of Low Cardiac Output

et al. 2007

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Background. Skeletal muscular counterpulsation (MCP) has been used as a new non-invasive technique for treatment of low cardiac output. The MCP method is based on ECG-triggered skeletal muscle stimulation. The purpose of the present study was to evaluate acute hemodynamic changes induced by MCP in the experimental animal. Methods. Eight anaesthetized pigs (43±4 kg) were studied at rest and after IV β-blockade (10 mg propranolol) before and after MCP Muscular counterpulsation was performed on both thighs using trains (75 ms duration) of multiple biphasic electrical impulses with a width of 1 ms and a frequency of 200 Hz at low (10 V) and high (30 V) amplitude. ECG-triggering was used to synchronize stimulation to a given time point. LV pressure-volume relations were determined using the conductance catheter. After baseline measurements, MCP was carried out for 10 minutes at low and high stimulation amplitude. The optimal time point for MCP was determined from LV pressure-volume loops using different stimulation time points during systole and diastole. Best results were observed during end-systole and, therefore, this time point was used for stimulation. Results. Under control conditions, MCP was associated with a significant decrease in pulmonary vascular resistance (-18%), a decrease in systemic vascular resistance (-11%) and stroke work index (-4%), whereas cardiac index (+2%) and ejection fraction (+6%) increased slightly. Pressure-volume loops showed a leftward shift with a decrease in end-systolic volume. After β-blockade, cardiac function decreased (HR, MAP, EF, dP/dt max), but it improved with skeletal muscle stimulation (HR +10% and CI +17%, EF +5%). There was a significant decrease in pulmonary (-19%) and systemic vascular resistance (-29%). Conclusions. In the animal model, ECG-triggered skeletal muscular counterpulsation is associated with a significant improvement in cardiac function at baseline and after IV β-blockade. Thus, MCP represents a new, non-invasive technique which improves cardiac function by diastolic compression of the peripheral arteries and veins, with a decrease in systemic vascular resistance and increase in cardiac output.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

ECG-Triggered Muscular Counterpulsation for Treatment of Low Cardiac Output

et al. 2007

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“…In one technique, the latissimus dorsi muscle (LDM) is wrapped en bloc around the aorta and secured to itself [3-5, 10, 13, 23, 25, 30]. In the second technique, a 4-5 cm wide strip of the lateral portion of LDM is isolated and wrapped as a helical coil around the descending thoracic aorta [2,14,20,21]. These two wrap techniques have not been compared using a consistent experimental protocol.…”

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confidence: 99%

Optimizing muscle wrap orientation for aortomyoplasty

Rovner

Cmolik

Thompson

et al.

Proceedings of the 1996 Fifteenth Southern Biomedical Engineering Conference

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Background: Aortomyoplasty is a treatment for heart failure in which the latissimus dorsi muscle is wrapped around the aorta and stimulated to contract during diastole to provide chronic diastolic counterpulsation. We hypothesized that the manner in which the latissimus dorsi muscle is wrapped around the aorta determines the effectiveness of counterpulsation. Methods: Nine mongrel dogs were studied. The left latissimus dorsi muscle (LDM) was isolated and wrapped around the descending thoracic aorta using three different muscle wrap techniques-a helical coil (HC) wrap, a circumferential (CM) wrap, and a "wringer" (WR) wrap. The three wraps were done in each dog. Left-ventricular and aortic pressures and coronary and aortic blood flows proximal and distal to the muscle-wrapped region were measured. Mean diastolic aortic pressure, endocardial-viability ratio, coronary blood flow, and blood volume ejected from the wrapped segment (wrap stroke volume) were calculated. Results: Wrap stroke volume was greater for the WR (5.24±1.00 mL, p<0.05 compared with HC), compared with the CM (3.70±0.64 mL) or the HC (1.96±0.83 mL). The i ncreases in mean diastolic aortic pressure were similar for the WR (10.6±4.7%) and CM (9.7±4.4%) wraps and these were greater than the HC wrap (4.9±4.7%). Endocardialviability ratio was increased similarly by the WR (19.3±10.8%) and CM (19.8±14.6%) wraps and these increases were greater than observed during the HC wrap (10.5±6.3%). The WR wrap provided the greatest increase in coronary blood flow (24.3±23.0%) compared with the CM (17.8±12.9%) and HC (5.7±4.6%). Conclusion: These data suggest that: 1) all muscle wrap techniques effect diastolic counterpulsation; 2) muscle wrap orientation influences ameliorative potential; and 3) wringer and adjacent are better than helical coil. Chronic studies should be done to test whether the differences are maintained.

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