Intramyocardial electrograms for non-invasive rejection monitoring: initial experience with an infection-specific
B Grasser1, F Iberer, G Schreier
1Karl-Franzens-University of Graz, Department of Transplantation, Austria.
Insights
Non-invasive monitoring of heart transplant rejection using intramyocardial electrograms is possible. Analysis of electrogram parameters can help differentiate between rejection and infection, improving graft surveillance.
Area of Science:
- Cardiology
- Biomedical Engineering
- Transplant Medicine
Background:
- Non-invasive graft surveillance is crucial for heart transplant recipients.
- Intramyocardial electrograms offer a potential method for monitoring rejection.
- Distinguishing rejection from infection is clinically significant.
Purpose of the Study:
- To evaluate the utility of intramyocardial electrograms for non-invasive monitoring of heart transplant rejection.
- To develop parameters to differentiate between rejection and infection.
- To assess the feasibility of daily graft surveillance.
Main Methods:
- Analysis of paced intramyocardial electrograms.
- Calculation of a rejection-sensitive parameter from the T wave's maximum descending slope.
- Definition and measurement of an infection-specific parameter.
- Prospective classification of patients based on infection status.
Main Results:
- A rejection-sensitive parameter detected biopsy-proven rejection grade 2 or higher.
- Infection mimicked rejection's effect on the rejection-sensitive parameter.
- An infection-specific parameter was significantly longer in patients with clinical infections.
- Simultaneous decrease in rejection-sensitive and increase in infection-specific parameters indicated infection, while isolated decrease indicated rejection.
Conclusions:
- Intramyocardial electrogram analysis shows promise for non-invasive heart transplant rejection monitoring.
- Discrimination between rejection and infection may be achievable using distinct electrogram parameters.
- This technique could enable frequent or daily graft surveillance.
Abstract:
Non-invasive rejection monitoring based on the analysis of paced intramyocardial electrograms enables repeated or even daily graft surveillance. The rejection-sensitive parameter is calculated from the maximum slope of the descending part of the t wave. Biopsy-proven rejection grade 2 or higher (ISHLT classification) can safely be detected. Nevertheless, infection influences the rejection-sensitive parameter in the same manner as does rejection (99% negative predictive value for rejection grade 2 or higher, 17% positive predictive value). We defined the infection-specific parameter as the time on the O line between the pacemaker stimulus and the crossover with the maximum slope of the descending part of the t wave. Patients were classified prospectively according to infection status: patients without infection and those with clinically apparent infection. Patients with clinically apparent infections had a significantly longer infection-specific parameter. A simultaneous decrease of the rejection-sensitive parameter and an increase in the infection-specific parameter was observed during clinical infection: a decrease in the rejection-sensitive parameter and no changes in the infection-specific parameter were observed during rejection. This preliminary analysis revealed that discrimination of rejection and infection might be possible by the analysis of intramyocardial electrograms.
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