| 1. |
- Barquero-Perez, Oscar, et al.
(författare)
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On the influence of heart rate and coupling interval prematurity on heart rate turbulence
- 2017
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Ingår i: IEEE Transactions on Biomedical Engineering. - 1558-2531. ; 64:2, s. 302-309
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Heart rate turbulence (HRT) has been successfully explored for cardiac risk stratification. While HRT is known to be influenced by the heart rate (HR) and the coupling interval (CI), nonconcordant results have been reported on how the CI influences HRT. The purpose of this study is to investigate HRT changes in terms of CI and HR by means of an especially designed protocol. Methods: A dataset was acquired from 11 patients with structurally normal hearts for which CI was altered by different pacing trains and HR by isoproterenol during electrophysiological study (EPS). The protocol was designed so that, first, the effect of HR changes on HRT and, second, the combined effect of HR and CI could be explored. As a complement to the EPS dataset, a database of 24-h Holters from 61 acute myocardial infarction (AMI) patients was studied for the purpose of assessing risk. Data analysis was performed by using different nonlinear ridge regression models, and the relevance of model variables was assessed using resampling methods. The EPS subjects, with and without isoproterenol, were analyzed separately. Results: The proposed nonlinear regression models were found to account for the influence of HR and CI on HRT, both in patients undergoing EPS without isoproterenol and in low-risk AMI patients, whereas this influence was absent in high-risk AMI patients. Moreover, model coefficients related to CI were not statistically significant, p > 0.05, on EPS subjects with isoproterenol. Conclusion: The observed relationship between CI and HRT, being in agreement with the baroreflex hypothesis, was statistically significant (p < 0.05), when decoupling the effect of HR and normalizing the CI by the HR. Significance: The results of this study can help to provide new risk indicators that take into account physiological influence on HRT, as well as to model how this influence changes in different cardiac conditions.
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| 2. |
- Gil, Eduardo, et al.
(författare)
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Heart Rate Turbulence Analysis Based on Photoplethysmography
- 2013
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Ingår i: IEEE Transactions on Biomedical Engineering. - 1558-2531. ; 60:11, s. 3149-3155
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Tidskriftsartikel (refereegranskat)abstract
- The goal of this paper is to determine whether the photoplethysmography (PPG) can replace the ECG-based detection of heart rate turbulence. Using the PPG, classification of ventricular premature beats (VPBs) is accomplished with a linear classifier. The two conventional parameters turbulence onset and slope are studied together with a recently introduced parameter characterizing turbulence shape. Performance is studied on a dataset with 4131 VPBs, recorded from a total of 27 patients in different clinical contexts (hemodialysis treatment, intensive care monitoring, and electrophysiological study). The sensitivity/specificity of VPB classification was found to be 90.5/99.9%, with an accuracy of 99.3%, suggesting that classification of VPBs can be reliable made from the PPG. The main difference between the two types of turbulence analysis stems from the fact that the pulse transit time varies largely immediately after the VPB. Out of the 22 patients which had a sufficient number of VPBs, the outcome of the ECG-and PPG-based analysis was identical in 21. It is concluded that the PPG may serve as a surrogate technique for the ECG in turbulence analysis.
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| 3. |
- Henriksson, Mikael, et al.
(författare)
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Changes in f-wave characteristics during cryoballoon catheter ablation
- 2018
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Ingår i: Physiological Measurement. - : IOP Publishing. - 0967-3334 .- 1361-6579. ; 39:10
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Changes in ECG-derived parameters are studied in atrial fibrillation (AF) patients undergoing cryoballoon catheter ablation.APPROACH: Parameters characterizing f-wave frequency, morphology by phase dispersion, and amplitude are estimated using a model-based statistical approach. These parameters are studied before, during, and after ablation, as well as for AF type (paroxysmal/persistent). Seventy-seven (49/28 paroxysmal/persistent) AF patients undergoing de novo catheter ablation are included in the study, out of which 31 (16/15 paroxysmal/persistent) were in AF during the whole procedure. A signal quality index (SQI) is used to identify analyzable segments.MAIN RESULTS: f-wave frequency decreased significantly during ablation (p = 0.001), in particular after ablation of the inferior right pulmonary vein (p < 0.05). Frequency and phase dispersion differed significantly between paroxysmal and persistent AF (p = 0.001 and p < 0.05, respectively).SIGNIFICANCE: This study demonstrates that a decrease in f-wave frequency can be distinguished during catheter ablation. The use of an SQI ensures reliable analysis and produces results significantly different from those obtained without an SQI.
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| 4. |
- Henriksson, Mikael, et al.
(författare)
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Short-term reproducibility of parameters characterizing atrial fibrillatory waves
- 2020
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Ingår i: Computers in Biology and Medicine. - : Elsevier BV. - 0010-4825. ; 117
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To study reproducibility of f-wave parameters in terms of inter- and intrapatient variation. Approach: Five parameters are investigated: dominant atrial frequency (DAF), f-wave amplitude, phase dispersion, spectral organization, and spatiotemporal variability. For each parameter, the variance ratio R, defined as the ratio between inter- and intrapatient variance, is computed; a larger R corresponds to better stability and reproducibility. The study population consists of 20 high-quality ECGs recorded from patients with atrial fibrillation (11/9 paroxysmal/persistent). Main results: The well-established parameters DAF and f-wave amplitude were associated with considerably larger R-values (13.1 and 21.0, respectively) than phase dispersion (2.4), spectral organization (2.4), andspatiotemporal variability (2.7). The use of an adaptive harmonic frequency tracker to estimate the DAF resulted in a larger R (13.1) than did block-based maximum likelihood estimation (6.3). Significance: This study demonstrates a noticeable difference in reproducibility among f-wave parameters, a resultwhich should be taken into account when performing f-wave analysis.
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