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Comparison of RR-intervals in rabbit heart in in-vivo, ex-vivo and under ischemia
Abstract / Journal of Electrocardiology 46 (2012) e1–e37 Methods: We propose a computer method based on Fourier and linear transformation of ECG records, called NURSE-ECG, which increases resolution of the QRS complex. The high-resolution ECG proposed in this work combines the records from particular electrodes, each of computer enhanced resolution. NURSE-ECG provides an opportunity to detect even relatively small changes in electrical activity of particular segments of the cardiac muscle. In order to perform quantitative analysis, the heart muscle was divided into particular segments. Results: The correct NURSE-ECG and standard activities of cardiac muscle segments were calculated. The quantitative analyses of NURSE-ECG records of people with ischemia were undertaken. The results obtained for people subjected to SPECT examination show a good correlation between the results of SPECT examination and the decrease in electrical activity of the cardiac muscle fragments observed by the HRVEC method (SE = 96%, SP = 92%). Conclusion: Preliminary analysis of the sensitivity and specificity of the high signal resolution NURSE-ECG in IHD diagnostics has proved the method to be very promising in the diagnosis of ischemic heart disease. http://dx.doi.org/10.1016/j.jelectrocard.2013.05.061
New algorithms and new technologies in computerized ECG analysis: a challenge in long-term follow-up studies S. Perz a, C. Meisinger a, S. Kääb b, M.F. Sinner b, R. Küfner a, K.H. Englmeier a a Helmholtz Zentrum München b University Hospital Munich, Großhadern Introduction: Epidemiologic studies require consistently operating methods of data collection and analysis. In principle, this is provided by computerized ECG analysis largely avoiding intra- and inter-observer variability, but only if the same system has always been used. To determine electrocardiographic changes over a 25 year follow-up, the results of the population-based Monica Augsburg Survey 1984/85 (N = 4022) have to be compared with the results of the KORA Age study. In the baseline examination, the Sicard 803 system was used, whereas in the follow-up study, the HES Amedtec ECG pro system (HES) was used. Both systems analysed the 12 lead resting ECG, but using different hardware and software. Methods: To adjust for systematic differences in the performance of the two systems, we analysed the ECGs of a subsample of 50 study participants using both systems simultaneously and compared the measurements of the quantitative analysis applying matched pairs T tests. Results: Of the global measurements, PQ duration and QRS duration did not show significant differences when comparing the HES with the Sicard 803 results (Table 1). However, QT intervals were considerably (18.1 ms) longer when using the HES system. For lead specific parameters (lead II), measurements were partly smaller, partly almost identical and partly larger according to HES. As a consequence, all parameters of interest have to be evaluated. Table 1 Comparison of HES and Sicard 803 measurement distributions (n = 50). Measurement
HES
PQ dur (ms) QRS dur (ms) QT interval (ms) R wave dur II (ms) R wave amp II (μV) S wave dur II (ms) S wave amp II (μV)
166.5 94.4 410.9 56.7 922.0 37.1 211.7
Sicard 803 ± ± ± ± ± ± ±
24.7 15.6 29.6 19.9 329.3 20.9 149.5
165.4 93.6 392.8 67.5 922.0 31.7 179.2
± ± ± ± ± ± ±
Difference
25.8 1.1 ± 6.8 17.0 0.8 ± 7.3 26.3 18.1 ± 9.6 19.1 − 10.8 ± 13.6 373.7 0.0 ± 60.8 19.7 5.4 ± 16.2 145.8 32.5 ± 61.0
P 0.323 0.455 0.000 0.000 1.000 0.118 0.016
Conclusion: Appropriate interpretation of ECG measurement changes – determined in follow-up studies – requires systematic control of possible bias according to technology change of the ECG analysis systems used. http://dx.doi.org/10.1016/j.jelectrocard.2013.05.062
e17
Comparison of RR-intervals in rabbit heart in in-vivo, ex-vivo and under ischemia O. Janoušek a, M. Ronzhina a, J. Koláøová a, M. Nováková b, P. Scheer c, I. Provazník a a Brno University of Technology, Brno, Czech Republic b Masaryk University, Brno, Czech Republic c University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic Introduction: Use of heart rate variability for diagnostic purposes is highly topical. Although many studies of heart rate variability in-vivo have been published, only a few studies pay attention to isolated hearts, mainly because it can be studied only in patients with cardiac denervation. Ischemia is believed to influence nonautonomic mechanism of the heart. Detailed analysis of the both denervation and ischemia influence may have significant diagnostic contribution. Methods: Seven isolated New Zealand rabbit hearts in Langendorff setup and five in-vivo New Zealand rabbit hearts were studied. Control period (15 min) was recorded for both groups. In addition, each isolated heart underwent episodes (15 min) of coronary artery occlusion, followed by three reperfusion periods (15 min). Electrograms from isolated hearts were recorded by three orthogonal leads positioned orthogonally around the heart. Signals were amplified and digitized with sampling rate 2 kHz and 16-bit analogue-to-digital converter. Electrocardiograms from in-vivo hearts were recorded by a SEIVA recording system with body surface wire electrodes attached to the skin with miniature clips in the position duplicating orthogonal leads in the ex-vivo setup. Five-minute long segments of electrograms have been manually evaluated from each phase of the experiment and inaccurate R-peaks were excluded from analysis. Results: The histogram and boxplot have been used for comparison of RR-intervals of in-vivo and ex-vivo hearts and RR-intervals of the isolated hearts under normal and ischemic condition. The typical value of RR-interval prolonged from 250 ms in the in-vivo heart to 350 ms in the ex-vivo heart. During ischemia, the RR-interval dramatically prolonged to 600 ms. Subsequent reperfusion had no significant effect on the RR-interval, and no effect was observed during repeated ischemia and reperfusion periods. Variability of RR-intervals slightly decreased after heart excision from 226–273 ms in-vivo to 329–368 ms ex-vivo and significantly rose to 532–680 ms in the first episode of ischemia. RR-interval variability remained almost the same in subsequent ischemia and reperfusion repetitions. Conclusions: The results show that denervation of the heart causes only prolongation of heart rate; however its regularity remains comparable with that of in-vivo hearts. It supports the hypothesis that heart rate variability persists in excited hearts. Ischemia causes irreversible changes of intracardiac mechanisms regulating heart activity. RR-intervals in ischemia significantly differ from those in-vivo and ex-vivo. http://dx.doi.org/10.1016/j.jelectrocard.2013.05.063
Multi-scale integrative model of the human atria and torso: a platform for the investigation of atrial arrhythmias E.A. Perez Alday a, M.A. Colman a, P. Langley b, A.V. Holden c, H. Zhang a a University of Manchester b Newcastle University c University of Leeds Introduction: Atrial tachycardia (AT), resulting from rapid ectopic atrial activity, may predispose to atrial fibrillation (AF). The regions of the pulmonary veins (PV) are identified as a major source of AF and AT. Such abnormal origin of atrial excitation may be reflected as an alteration in the P-wave morphology (PWM) of the electrocardiogram (ECG). Identifying the presence and the location of the ectopic atrial activity can help to diagnose the early onset of AF. In this study, we develop a biophysically detailed computational model of the human atria and torso, to investigate the relation between PWM and the different origins of atrial ectopic activity. Methods: We apply a recently developed 3D human atrial model to simulate ectopic activity. The 3D model is then placed into a newly developed torso model, taken from the visible human dataset and considers the lungs and
New algorithms and new technologies in computerized ECG analysis: a challenge in long-term follow-up studies S. Perz a, C. Meisinger a, S. Kääb b, M.F. Sinner b, R. Küfner a, K.H. Englmeier a a Helmholtz Zentrum München b University Hospital Munich, Großhadern Introduction: Epidemiologic studies require consistently operating methods of data collection and analysis. In principle, this is provided by computerized ECG analysis largely avoiding intra- and inter-observer variability, but only if the same system has always been used. To determine electrocardiographic changes over a 25 year follow-up, the results of the population-based Monica Augsburg Survey 1984/85 (N = 4022) have to be compared with the results of the KORA Age study. In the baseline examination, the Sicard 803 system was used, whereas in the follow-up study, the HES Amedtec ECG pro system (HES) was used. Both systems analysed the 12 lead resting ECG, but using different hardware and software. Methods: To adjust for systematic differences in the performance of the two systems, we analysed the ECGs of a subsample of 50 study participants using both systems simultaneously and compared the measurements of the quantitative analysis applying matched pairs T tests. Results: Of the global measurements, PQ duration and QRS duration did not show significant differences when comparing the HES with the Sicard 803 results (Table 1). However, QT intervals were considerably (18.1 ms) longer when using the HES system. For lead specific parameters (lead II), measurements were partly smaller, partly almost identical and partly larger according to HES. As a consequence, all parameters of interest have to be evaluated. Table 1 Comparison of HES and Sicard 803 measurement distributions (n = 50). Measurement
HES
PQ dur (ms) QRS dur (ms) QT interval (ms) R wave dur II (ms) R wave amp II (μV) S wave dur II (ms) S wave amp II (μV)
166.5 94.4 410.9 56.7 922.0 37.1 211.7
Sicard 803 ± ± ± ± ± ± ±
24.7 15.6 29.6 19.9 329.3 20.9 149.5
165.4 93.6 392.8 67.5 922.0 31.7 179.2
± ± ± ± ± ± ±
Difference
25.8 1.1 ± 6.8 17.0 0.8 ± 7.3 26.3 18.1 ± 9.6 19.1 − 10.8 ± 13.6 373.7 0.0 ± 60.8 19.7 5.4 ± 16.2 145.8 32.5 ± 61.0
P 0.323 0.455 0.000 0.000 1.000 0.118 0.016
Conclusion: Appropriate interpretation of ECG measurement changes – determined in follow-up studies – requires systematic control of possible bias according to technology change of the ECG analysis systems used. http://dx.doi.org/10.1016/j.jelectrocard.2013.05.062
e17
Comparison of RR-intervals in rabbit heart in in-vivo, ex-vivo and under ischemia O. Janoušek a, M. Ronzhina a, J. Koláøová a, M. Nováková b, P. Scheer c, I. Provazník a a Brno University of Technology, Brno, Czech Republic b Masaryk University, Brno, Czech Republic c University of Veterinary and Pharmaceutical Sciences, Brno, Czech Republic Introduction: Use of heart rate variability for diagnostic purposes is highly topical. Although many studies of heart rate variability in-vivo have been published, only a few studies pay attention to isolated hearts, mainly because it can be studied only in patients with cardiac denervation. Ischemia is believed to influence nonautonomic mechanism of the heart. Detailed analysis of the both denervation and ischemia influence may have significant diagnostic contribution. Methods: Seven isolated New Zealand rabbit hearts in Langendorff setup and five in-vivo New Zealand rabbit hearts were studied. Control period (15 min) was recorded for both groups. In addition, each isolated heart underwent episodes (15 min) of coronary artery occlusion, followed by three reperfusion periods (15 min). Electrograms from isolated hearts were recorded by three orthogonal leads positioned orthogonally around the heart. Signals were amplified and digitized with sampling rate 2 kHz and 16-bit analogue-to-digital converter. Electrocardiograms from in-vivo hearts were recorded by a SEIVA recording system with body surface wire electrodes attached to the skin with miniature clips in the position duplicating orthogonal leads in the ex-vivo setup. Five-minute long segments of electrograms have been manually evaluated from each phase of the experiment and inaccurate R-peaks were excluded from analysis. Results: The histogram and boxplot have been used for comparison of RR-intervals of in-vivo and ex-vivo hearts and RR-intervals of the isolated hearts under normal and ischemic condition. The typical value of RR-interval prolonged from 250 ms in the in-vivo heart to 350 ms in the ex-vivo heart. During ischemia, the RR-interval dramatically prolonged to 600 ms. Subsequent reperfusion had no significant effect on the RR-interval, and no effect was observed during repeated ischemia and reperfusion periods. Variability of RR-intervals slightly decreased after heart excision from 226–273 ms in-vivo to 329–368 ms ex-vivo and significantly rose to 532–680 ms in the first episode of ischemia. RR-interval variability remained almost the same in subsequent ischemia and reperfusion repetitions. Conclusions: The results show that denervation of the heart causes only prolongation of heart rate; however its regularity remains comparable with that of in-vivo hearts. It supports the hypothesis that heart rate variability persists in excited hearts. Ischemia causes irreversible changes of intracardiac mechanisms regulating heart activity. RR-intervals in ischemia significantly differ from those in-vivo and ex-vivo. http://dx.doi.org/10.1016/j.jelectrocard.2013.05.063
Multi-scale integrative model of the human atria and torso: a platform for the investigation of atrial arrhythmias E.A. Perez Alday a, M.A. Colman a, P. Langley b, A.V. Holden c, H. Zhang a a University of Manchester b Newcastle University c University of Leeds Introduction: Atrial tachycardia (AT), resulting from rapid ectopic atrial activity, may predispose to atrial fibrillation (AF). The regions of the pulmonary veins (PV) are identified as a major source of AF and AT. Such abnormal origin of atrial excitation may be reflected as an alteration in the P-wave morphology (PWM) of the electrocardiogram (ECG). Identifying the presence and the location of the ectopic atrial activity can help to diagnose the early onset of AF. In this study, we develop a biophysically detailed computational model of the human atria and torso, to investigate the relation between PWM and the different origins of atrial ectopic activity. Methods: We apply a recently developed 3D human atrial model to simulate ectopic activity. The 3D model is then placed into a newly developed torso model, taken from the visible human dataset and considers the lungs and