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18-lead electrocardiogram and vectocardiogram from subsets of 12-Lead electrocardiogram with only 2 chest leads
S132
Poster Session III / Journal of Electrocardiology 39 (2006) S128 – S133
Derivation of 12-lead/18-lead electrocardiogram and vectocardiogram from subsets of 12-Lead electrocardiogram with only 2 chest leads John Y. Wang,a JW Warren,b BM Hora´c˘ek,b( aPhilips Medical Systems, Andover, MA, USA; bDalhousie University, Halifax, Nova Scotia, Canada) The objective of this study was to develop and evaluate transformation coefficients for synthesis of standard 12-lead electrocardiogram (ECG), 18-lead ECG (with additional leads V7, V8, V9, V3R, V4R, and V5R), and Frank vectocardiogram (VCG) from reduced lead sets using 3 limb electrodes at Mason-Likar sites combined with 2 chest electrodes chosen from V1 to V6 sites. There are 15 such lead-set combinations, and each can be recorded with 6-wire cable. We used a study population from a Dalhousie University (Halifax, Nova Scotia, Canada) database, consisting of 892 individuals: 290 healthy subjects, 497 patients who previously suffered a myocardial infarction, and 105 patients with a history of spontaneous ventricular tachycardia but no evidence of a previous myocardial infarction. For each subject, 120-lead ECG recordings of 15-second duration were aligned and averaged, all samples of the QRST complex for leads of interest were extracted, and these data were used to derive—by regression analysis— coefficients for lead transformations. The coefficients were then used to reconstitute complete 12-lead/18-lead ECG and VCG from 15 predictor sets, and the success of this synthesis was assessed by 2 measures for goodness of fit: similarity coefficient (SC in percentage) and relative error (RE in percentage). Our results show that chest leads V2 and V4 are the best pair for reconstituting the 12-lead ECG (SC = 96.91, RE = 25.53), followed closely by V3 and V5, V2 and V5, V3 and V4, and V1 and V4. The best pair for reconstituting the entire 18-lead set is V1 and V4 (SC = 93.82, RE = 31.93), followed by V1 and V3, V1 and V5, and V1 and V6. The best pair for synthesis of the Frank X, Y, Z leads is V3 and V6 (SC = 96.31, RE = 26.07), followed by V1 and V3, V1 and V4, and V3 and V5. In conclusion, our study demonstrates that good approximation of 12-lead/18-lead ECG and VCG can be achieved by using a lead system using 6-wire cable, provided that electrodes are judiciously placed.
doi:10.1016/j.jelectrocard.2006.08.083
Computer simulation of electrophysiology study with whole-heart model Daming Wei,a,b( aUniversity of Aizu; Ikki-machi, Aizu-Wakamatsu City, Fukushima 965-8580, Japan; bOsamu Okazaki, International Medical Center of Japan, #222, 1-21-1 Toyama, Shinjyuku-ku, Tokyo 162-8655, Japan) Interests in whole-heart modeling have been focused on body surface or epicardial potentials. The focus of the present study is on intracardiac potentials and applications to the electrophysiology study (EPS) and catheter ablation. In this article, computer simulations of EPS based on a whole-heart model are presented. The Wei-Harumi model was extended to incorporate endocardial boundary and intracavitary domain based on a volume conductor model with multiple interfaces and piecewise homogeneity. Numeric solutions were developed and compared with analytic solutions of a 3-shell model of volume
conductor model similar to Rudy et al. Consistency higher than 95% was achieved between numeric and analytic solutions. Basic protocols in EPS were simulated with the whole-heart model. Examples include basic functional test protocols, atrial extrastimulus test protocols, and ventricular extrastimulus test protocols. A simulation of localizing the position of accessory pathway in heart model of the WPW syndrome was also presented. In all these simulations, the simulated electrograms showed similar characteristics to those obtained in the electrophysiologic laboratory. One example of simulated electrogram is shown in Fig. 1. This study suggested a new direction in the study of whole-heart modeling.
doi:10.1016/j.jelectrocard.2006.08.084
Analysis of QTc interval and T-wave morphology during early transmural ischemia in humans Joel Xue,a Marcin Kowalski,b David Kenigsberg,b Sanjaya Khanal,b Ian Rowlandson,a Subramaniam C. Krishnan, MD,d ( aGE Healthcare, Milwaukee, WI, USA; bHenry Ford Hospital, Detroit, MI, USA; cMedical College of Virginia; dUniversity of California at Irvine Medical Center) Background: Currently, the decisions regarding emergent reperfusion strategies in patients with acute myocardial infarction rely largely on the presence of ST-segment elevation on the electrocardiogram (ECG). However, the presence of ST elevations may not be only ECG changes during early transmural ischemia. We analyzed ECG intervals and T-wave morphology using the principal component analysis (PCA) in patients undergoing elective balloon angioplasty to better understand ECG changes during early transmural ischemia Methods: We used 12-lead Holter Recorder (SeerMCk; GE Healthcare) to continuously record 12-lead ECG at 500 samples per second in 8 patient undergoing elective balloon angioplasty. The automated ECG interval analysis was conducted using the Interval Editork (GE Healthcare), which provided trending for regular ST segments, T-wave parameter, and a group of naval parameters based on PCA. We identified ECG parameters that are most closely linked to repolarization phase of action potential duration and morphology. We specifically studied changes of QT/QTc interval, ST deviation, ratio of PCA components (second to first), and PCA-based QRST angle during early transmural ischemia. Both QTc Bazett and QTc Fridericia intervals were calculated. Results: Transmural ischemia induced by the first balloon occlusion prolonged both the QTc Bazett interval (449 F 10 vs 471 F 9 milliseconds, P b .01) and QTc Fridericia interval (442 F 8 vs 461F 11 milliseconds, P b .01) in 9 (100%) of 9 of patients. The PCA-based QRST angle average difference before and after the first balloon occlusion is 248 ( P b .01), which also showed significant changes during early transmural ischemia when compared with baseline. Regular frontal plane QRST angle did not show significant difference. Conclusion: QT/QTc interval and PCA-based T-wave morphology descriptors can be important indicators of early transmural ischemia. doi:10.1016/j.jelectrocard.2006.08.085
Posterior leads to improve electrocardiogram detection of acute and recent posterior myocardial infarction associated with left circumflex occlusion Sophia H. Zhou, RH Startt Selvester, L Xia, E Tragardh, O Pahlm, BM Horaceck, RE Gregg, ED Helfenbein, JM Lindauer (Advanced Algorithm Research Center, Philips Medical Systems, Thousand Oaks, CA, USA)
Fig. 1. Electrograms of high right atrium (HRA), hiss bundle electrogram (HBE), and right ventricle (RV) simulated with Whole-heart model.
Underrecognition and undertreatment of left circumflex (LCx) occlusion remains a serious problem in patients with acute coronary syndrome. As the most rapid, economical, and pervasive admission test, diagnostic electrocardiogram (ECG) has the potential to improve early diagnosis. This study is designed to use the posterior leads to improve diagnostic ECG accuracy in patients with known high-grade LCx occlusion.
Poster Session III / Journal of Electrocardiology 39 (2006) S128 – S133
Derivation of 12-lead/18-lead electrocardiogram and vectocardiogram from subsets of 12-Lead electrocardiogram with only 2 chest leads John Y. Wang,a JW Warren,b BM Hora´c˘ek,b( aPhilips Medical Systems, Andover, MA, USA; bDalhousie University, Halifax, Nova Scotia, Canada) The objective of this study was to develop and evaluate transformation coefficients for synthesis of standard 12-lead electrocardiogram (ECG), 18-lead ECG (with additional leads V7, V8, V9, V3R, V4R, and V5R), and Frank vectocardiogram (VCG) from reduced lead sets using 3 limb electrodes at Mason-Likar sites combined with 2 chest electrodes chosen from V1 to V6 sites. There are 15 such lead-set combinations, and each can be recorded with 6-wire cable. We used a study population from a Dalhousie University (Halifax, Nova Scotia, Canada) database, consisting of 892 individuals: 290 healthy subjects, 497 patients who previously suffered a myocardial infarction, and 105 patients with a history of spontaneous ventricular tachycardia but no evidence of a previous myocardial infarction. For each subject, 120-lead ECG recordings of 15-second duration were aligned and averaged, all samples of the QRST complex for leads of interest were extracted, and these data were used to derive—by regression analysis— coefficients for lead transformations. The coefficients were then used to reconstitute complete 12-lead/18-lead ECG and VCG from 15 predictor sets, and the success of this synthesis was assessed by 2 measures for goodness of fit: similarity coefficient (SC in percentage) and relative error (RE in percentage). Our results show that chest leads V2 and V4 are the best pair for reconstituting the 12-lead ECG (SC = 96.91, RE = 25.53), followed closely by V3 and V5, V2 and V5, V3 and V4, and V1 and V4. The best pair for reconstituting the entire 18-lead set is V1 and V4 (SC = 93.82, RE = 31.93), followed by V1 and V3, V1 and V5, and V1 and V6. The best pair for synthesis of the Frank X, Y, Z leads is V3 and V6 (SC = 96.31, RE = 26.07), followed by V1 and V3, V1 and V4, and V3 and V5. In conclusion, our study demonstrates that good approximation of 12-lead/18-lead ECG and VCG can be achieved by using a lead system using 6-wire cable, provided that electrodes are judiciously placed.
doi:10.1016/j.jelectrocard.2006.08.083
Computer simulation of electrophysiology study with whole-heart model Daming Wei,a,b( aUniversity of Aizu; Ikki-machi, Aizu-Wakamatsu City, Fukushima 965-8580, Japan; bOsamu Okazaki, International Medical Center of Japan, #222, 1-21-1 Toyama, Shinjyuku-ku, Tokyo 162-8655, Japan) Interests in whole-heart modeling have been focused on body surface or epicardial potentials. The focus of the present study is on intracardiac potentials and applications to the electrophysiology study (EPS) and catheter ablation. In this article, computer simulations of EPS based on a whole-heart model are presented. The Wei-Harumi model was extended to incorporate endocardial boundary and intracavitary domain based on a volume conductor model with multiple interfaces and piecewise homogeneity. Numeric solutions were developed and compared with analytic solutions of a 3-shell model of volume
conductor model similar to Rudy et al. Consistency higher than 95% was achieved between numeric and analytic solutions. Basic protocols in EPS were simulated with the whole-heart model. Examples include basic functional test protocols, atrial extrastimulus test protocols, and ventricular extrastimulus test protocols. A simulation of localizing the position of accessory pathway in heart model of the WPW syndrome was also presented. In all these simulations, the simulated electrograms showed similar characteristics to those obtained in the electrophysiologic laboratory. One example of simulated electrogram is shown in Fig. 1. This study suggested a new direction in the study of whole-heart modeling.
doi:10.1016/j.jelectrocard.2006.08.084
Analysis of QTc interval and T-wave morphology during early transmural ischemia in humans Joel Xue,a Marcin Kowalski,b David Kenigsberg,b Sanjaya Khanal,b Ian Rowlandson,a Subramaniam C. Krishnan, MD,d ( aGE Healthcare, Milwaukee, WI, USA; bHenry Ford Hospital, Detroit, MI, USA; cMedical College of Virginia; dUniversity of California at Irvine Medical Center) Background: Currently, the decisions regarding emergent reperfusion strategies in patients with acute myocardial infarction rely largely on the presence of ST-segment elevation on the electrocardiogram (ECG). However, the presence of ST elevations may not be only ECG changes during early transmural ischemia. We analyzed ECG intervals and T-wave morphology using the principal component analysis (PCA) in patients undergoing elective balloon angioplasty to better understand ECG changes during early transmural ischemia Methods: We used 12-lead Holter Recorder (SeerMCk; GE Healthcare) to continuously record 12-lead ECG at 500 samples per second in 8 patient undergoing elective balloon angioplasty. The automated ECG interval analysis was conducted using the Interval Editork (GE Healthcare), which provided trending for regular ST segments, T-wave parameter, and a group of naval parameters based on PCA. We identified ECG parameters that are most closely linked to repolarization phase of action potential duration and morphology. We specifically studied changes of QT/QTc interval, ST deviation, ratio of PCA components (second to first), and PCA-based QRST angle during early transmural ischemia. Both QTc Bazett and QTc Fridericia intervals were calculated. Results: Transmural ischemia induced by the first balloon occlusion prolonged both the QTc Bazett interval (449 F 10 vs 471 F 9 milliseconds, P b .01) and QTc Fridericia interval (442 F 8 vs 461F 11 milliseconds, P b .01) in 9 (100%) of 9 of patients. The PCA-based QRST angle average difference before and after the first balloon occlusion is 248 ( P b .01), which also showed significant changes during early transmural ischemia when compared with baseline. Regular frontal plane QRST angle did not show significant difference. Conclusion: QT/QTc interval and PCA-based T-wave morphology descriptors can be important indicators of early transmural ischemia. doi:10.1016/j.jelectrocard.2006.08.085
Posterior leads to improve electrocardiogram detection of acute and recent posterior myocardial infarction associated with left circumflex occlusion Sophia H. Zhou, RH Startt Selvester, L Xia, E Tragardh, O Pahlm, BM Horaceck, RE Gregg, ED Helfenbein, JM Lindauer (Advanced Algorithm Research Center, Philips Medical Systems, Thousand Oaks, CA, USA)
Fig. 1. Electrograms of high right atrium (HRA), hiss bundle electrogram (HBE), and right ventricle (RV) simulated with Whole-heart model.
Underrecognition and undertreatment of left circumflex (LCx) occlusion remains a serious problem in patients with acute coronary syndrome. As the most rapid, economical, and pervasive admission test, diagnostic electrocardiogram (ECG) has the potential to improve early diagnosis. This study is designed to use the posterior leads to improve diagnostic ECG accuracy in patients with known high-grade LCx occlusion.