Performance evaluation of heart rate turbulence detection using an extended IPFM model

Research output: Chapter in Book/Report/Conference proceedingPaper in conference proceeding

Abstract

The well-known integral pulse frequency modulation (IPFM) model is used to generate the occurrence times of normal sinus rhythm. In a previous study, we extended the model to account for ectopic beats and subsequent variation in sinus rhythm that may accompany an ectopic beat; a phenomenon known as heart rate turbulence (HRT). Inspired by the extended model, a new approach to characterize HRT was presented, being based on Karhunen-Loeve basis functions. An HRT detection procedure was developed which involves a test statistic T(x), resulting from the generalized likelihood ratio test of a linear model.
In this study, detector performance of T(x) is evaluated on both simulated and ECG data, and compared to the performance of turbulence onset (TO) and turbulence slope (TS). Two types of simulations were performed, both adding simulated heart rate variability and HRT to the input of the extended model. The first simulation evaluated HRT detection performance at different signal-to-noise-ratios (SNRs). The second simulation evaluated the influence of QRS detection inaccuracies on HRT detection. The performance was also studied on ventricular ectopic beats (VEBs) selected from 31 patients with myocardial ischemia. The relation between HRT and the degree of blood pressure reduction induced by a VEB (estimated as proportional to the sum of the coupling interval and the compensatory pause), as well as the relation between HRT and heart rate, were analysed.
The simulation results at different SNRs showed that T(x) performs dramatically better than TO and TS. With a 95% sensitivity (Sn), the specificity (Sp) at 5 dB SNR was 94% for T(x), 51% for TO, and 64% for TS. The detection performance of T(x) was equally superior when assuming that QRS jitter was Gaussian with 1 ms std: with Sn=95%, Sp was 99% for T(x), 40% for TO, and 68% for TS. Based on the ECG data, it was found that the degree of blood pressure reduction is essentially proportional to the magnitude of the HRT; this finding was reflected by T(x), TO, as well as TS. Moreover, the three HRT parameters were found to be linearly related to heart rate: low heart rates was associated with large HRT and high heart rates with small HRT. This linear relation is probably due to that a VEB during low heart rates induces a larger blood pressure reduction than during high heart rates.

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Subject classification (UKÄ) – MANDATORY

  • Electrical Engineering, Electronic Engineering, Information Engineering
Original languageEnglish
Title of host publicationComputers in Cardiology
PublisherIEEE - Institute of Electrical and Electronics Engineers Inc.
Pages821-824
Volume34
ISBN (Print)978-1-4244-2533-4
Publication statusPublished - 2007
Publication categoryResearch
Peer-reviewedYes
EventComputers in Cardiology, 2007 - Durham, NC, Durham, NC, United States
Duration: 2007 Sep 302007 Oct 4

Publication series

Name
Volume34
ISSN (Print)0276-6574

Conference

ConferenceComputers in Cardiology, 2007
CountryUnited States
CityDurham, NC
Period2007/09/302007/10/04