Control of ventricular unloading using an electrocardiogram-synchronized Thoratec paracorporeal ventricular assist device
Publisher DOI
PubMed ID
23317942
Abstract
OBJECTIVE: Current pulsatile ventricular assist devices operate asynchronous with the left ventricle in fixed-rate or fill-to-empty modes because electrocardiogram-triggered modes have been abandoned. We hypothesize that varying the ejection delay in the synchronized mode yields more precise control of hemodynamics and left ventricular loading. This allows for a refined management that may be clinically beneficial. METHODS: Eight sheep received a Thoratec paracorporeal ventricular assist device (Thoratec Corp, Pleasanton, Calif) via ventriculo-aortic cannulation. Left ventricular pressure and volume, aortic pressure, pulmonary flow, pump chamber pressure, and pump inflow and outflow were recorded. The pump was driven by a clinical pneumatic drive unit (Medos Medizintechnik AG, Stolberg, Germany) synchronously with the native R-wave. The start of pump ejection was delayed between 0% and 100% of the cardiac period in 10% increments. For each of these delays, hemodynamic variables were compared with baseline data using paired t tests. RESULTS: The location of the minimum of stroke work was observed at a delay of 10% (soon after aortic valve opening), resulting in a median of 43% reduction in stroke work compared with baseline. Maximum stroke work occurred at a median delay of 70% with a median stroke work increase of 11% above baseline. Left ventricular volume unloading expressed by end-diastolic volume was most pronounced for copulsation (delay 0%). CONCLUSIONS: The timing of pump ejection in synchronized mode yields control over left ventricular energetics and can be a method to achieve gradual reloading of a recoverable left ventricle. The traditionally suggested counterpulsation is not optimal in ventriculo-aortic cannulation when maximum unloading is desired.
Date Issued
2013
Publication Type
Article
Subject(s)
Subjects
Animals
•
Aorta
•
Arterial Pressure
•
Disease Models
•
Animal
•
Electrocardiography
•
Heart Rate
•
Heart-Assist Devices
•
Prosthesis Design
•
Pulmonary Circulation
•
Pulsatile Flow
•
Regional Blood Flow
•
Sheep
•
Stroke Volume
•
Time Factors
•
Ventricular Dysfunction
•
Left
•
Ventricular Function
•
Left
•
Ventricular Pressure
Language(s)
en
Author(s)
Amacher, Raffael | |
Ferreira, Antonio | |
Guzzella, Lino | |
Antaki, James |
Journal
Journal of thoracic and cardiovascular surgery
Publisher
Mosby
ISSN
0022-5223
Access(Rights)
metadata.only