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Intra-Individual Comparison of Sinus and Ectopic Beats Probing the Ventricular Gradient's Activation Dependence. J Cardiovasc Dev Dis 2023; 10:jcdd10020089. [PMID: 36826585 PMCID: PMC9964972 DOI: 10.3390/jcdd10020089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Revised: 02/04/2023] [Accepted: 02/15/2023] [Indexed: 02/22/2023] Open
Abstract
Wilson assumed that the ventricular gradient (VG) is independent of the ventricular activation order. This paradigm has often been refuted and was never convincingly corroborated. We sought to validate Wilson's concept by intra-individual comparison of the VG of sinus beats and ectopic beats, thus assessing the effects of both altered ventricular conduction (caused by the ectopic focus) and restitution (caused by ectopic prematurity). We studied standard diagnostic ECGs of 118 patients with accidental extrasystoles: normally conducted supraventricular ectopic beats (SN, N = 6) and aberrantly conducted supraventricular ectopic beats (SA, N = 20) or ventricular ectopic beats (V, N = 92). In each patient, we computed the VG vectors of the predominant beat, VGp→, of the ectopic beat, VGe→, and of the VG difference vector, ΔVGep→, and compared their sizes. VGe→ of the SA and V ectopic beats were significantly larger than VGp→ (53.7 ± 25.0 vs. 47.8 ± 24.6 mV∙ms, respectively; p < 0.001). ΔVGep→ were three times larger than the difference of VGe→ and VGp→ (19.94 ± 9.76 vs. 5.94 mV∙ms, respectively), demonstrating differences in the VGp→ and VGe→ spatial directions. The amount of ectopic prematurity was not correlated with ΔVGep→, although the larger VG difference vectors were observed for the more premature (<80%) extrasystoles. Electrical restitution properties and electrotonic interactions likely explain our findings. We conclude that the concept of a conduction-independent VG should be tested at equal heart rates and without including premature extrasystoles.
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Tereshchenko LG, Sotoodehnia N, Sitlani CM, Ashar FN, Kabir M, Biggs ML, Morley MP, Waks JW, Soliman EZ, Buxton AE, Biering-Sørensen T, Solomon SD, Post WS, Cappola TP, Siscovick DS, Arking DE. Genome-Wide Associations of Global Electrical Heterogeneity ECG Phenotype: The ARIC (Atherosclerosis Risk in Communities) Study and CHS (Cardiovascular Health Study). J Am Heart Assoc 2018; 7:e008160. [PMID: 29622589 PMCID: PMC6015433 DOI: 10.1161/jaha.117.008160] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 03/07/2018] [Indexed: 11/21/2022]
Abstract
BACKGROUND ECG global electrical heterogeneity (GEH) is associated with sudden cardiac death. We hypothesized that a genome-wide association study would identify genetic loci related to GEH. METHODS AND RESULTS We tested genotyped and imputed variants in black (N=3057) and white (N=10 769) participants in the ARIC (Atherosclerosis Risk in Communities) study and CHS (Cardiovascular Health Study). GEH (QRS-T angle, sum absolute QRST integral, spatial ventricular gradient magnitude, elevation, azimuth) was measured on 12-lead ECGs. Linear regression models were constructed with each GEH variable as an outcome, adjusted for age, sex, height, body mass index, study site, and principal components to account for ancestry. GWAS identified 10 loci that showed genome-wide significant association with GEH in whites or joint ancestry. The strongest signal (rs7301677, near TBX3) was associated with QRS-T angle (white standardized β+0.16 [95% CI 0.13-0.19]; P=1.5×10-26), spatial ventricular gradient elevation (+0.11 [0.08-0.14]; P=2.1×10-12), and spatial ventricular gradient magnitude (-0.12 [95% CI -0.15 to -0.09]; P=5.9×10-15). Altogether, GEH-SNPs explained 1.1% to 1.6% of GEH variance. Loci on chromosomes 4 (near HMCN2), 5 (IGF1R), 11 (11p11.2 region cluster), and 7 (near ACTB) are novel ECG phenotype-associated loci. Several loci significantly associated with gene expression in the left ventricle (HMCN2 locus-with HMCN2; IGF1R locus-with IGF1R), and atria (RP11-481J2.2 locus-with expression of a long non-coding RNA and NDRG4). CONCLUSIONS We identified 10 genetic loci associated with ECG GEH. Replication of GEH GWAS findings in independent cohorts is warranted. Further studies of GEH-loci may uncover mechanisms of arrhythmogenic remodeling in response to cardiovascular risk factors.
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Affiliation(s)
- Larisa G Tereshchenko
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Nona Sotoodehnia
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA
| | - Colleen M Sitlani
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA
| | - Foram N Ashar
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Muammar Kabir
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR
| | - Mary L Biggs
- Cardiovascular Health Research Unit, Department of Medicine, University of Washington, Seattle, WA
- Department of Biostatistics, University of Washington, Seattle, WA
| | - Michael P Morley
- Penn Cardiovascular Institute and Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | - Jonathan W Waks
- Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center Harvard Medical School, Boston, MA
| | - Elsayed Z Soliman
- Cardiology Section, Division of Public Health Sciences and Department of Medicine, Epidemiological Cardiology Research Center, Wake Forest School of Medicine, Winston Salem, NC
| | - Alfred E Buxton
- Division of Cardiovascular Medicine, Beth Israel Deaconess Medical Center Harvard Medical School, Boston, MA
| | | | - Scott D Solomon
- Brigham and Women's Hospital, Harvard Medical School, Boston, MA
| | - Wendy S Post
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
| | - Thomas P Cappola
- Penn Cardiovascular Institute and Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA
| | | | - Dan E Arking
- McKusick-Nathans Institute of Genetic Medicine, Johns Hopkins University School of Medicine, Baltimore, MD
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Waks JW, Tereshchenko LG. Global electrical heterogeneity: A review of the spatial ventricular gradient. J Electrocardiol 2016; 49:824-830. [PMID: 27539162 DOI: 10.1016/j.jelectrocard.2016.07.025] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Indexed: 11/18/2022]
Abstract
The ventricular gradient, an electrocardiographic concept calculated by integrating the area under the QRS complex and T-wave, represents the degree and direction of myocardial electrical heterogeneity. Although the concept of the ventricular gradient was first introduced in the 1930s, it has not yet found a place in routine electrocardiography. In the modern era, it is relatively simple to calculate the ventricular gradient in three dimensions (the spatial ventricular gradient (SVG)), and there is now renewed interest in using the SVG as a tool for risk stratification of ventricular arrhythmias and sudden cardiac death. This manuscript will review the history of the ventricular gradient, describe its electrophysiological meaning and significance, and discuss its clinical utility.
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Affiliation(s)
- Jonathan W Waks
- Division of Cardiovascular Medicine, Harvard-Thorndike Electrophysiology Institute, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA.
| | - Larisa G Tereshchenko
- Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
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Batchvarov V, Kaski JC, Parchure N, Dilaveris P, Brown S, Ghuran A, Färbom P, Hnatkova K, Camm AJ, Malik M. Comparison between ventricular gradient and a new descriptor of the wavefront direction of ventricular activation and recovery. Clin Cardiol 2006; 25:230-6. [PMID: 12018881 PMCID: PMC6654433 DOI: 10.1002/clc.4950250507] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Total R T cosine (TCRT) is a new descriptor of repolarization heterogeneity that quantifies the deviation between the directions of ventricular depolarization and repolarization. It revives the old concept of ventricular gradient (VG). HYPOTHESIS Our goal was to examine whether TCRT and VG contain nonredundant information by comparing their reaction to autonomic tests, namely, postural changes and Valsalva maneuver. METHODS Digital 12-lead electrocardiograms were recorded in 16 patients with cardiovascular syndrome X (SX, chest pain, exercise-induced ST-depression, normal coronary arteries, 3 men, age 60 +/- 9 years) and 40 healthy volunteers (31 men, age 33 +/- 7 years) during postural changes and Valsalva maneuver. The angle (VGA) [degrees] and magnitude (VGM) [ms.mV] of VG in reconstructed XYZ leads and TCRT (average cosine of the angles between the QRS and T vectors in mathematically reconstructed three-dimensional space) were calculated. RESULTS (mean +/- standard of the mean): In healthy subjects, VGM and TCRT decreased, whereas VGA increased in the sitting and standing compared with supine position (TCRT: 0.61 +/- 0.05,0.47 +/- 0.06,0.29 +/- 0.08, supine, sitting, and standing, p < 0.05) and during phase II Valsalva (TCRT: 0.47 +/- 0.06 vs. 0.61 +/- 0.05, p < 0.01 in supine, 0.24 +/- 0.08 vs. 0.37 +/- 0.07, p < 0.01 in standing). In patients with SX, VGM decreased in the standing position, VGA did not change significantly, while TCRT decreased only in patients without T-wave abnormalities (n = 9) (TCRT in standing and supine: 0.55 +/- 0.09 vs. 0.68 +/- 0.08, p < 0.05). VG(M) increased during Valsalva in patients with SX. Total R T cosine correlated strongly with VGA (r = -0.84, p < 0.00001) and, unlike VGM, did not correlate with heart rate. CONCLUSIONS Ventricular gradient and TCRT contain nonredundant information. In healthy subjects, they react sensitively to autonomic provocation. In patients with SX, their reaction is attenuated, which suggests disturbance of the autonomic control of repolarization.
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Affiliation(s)
- Velislav Batchvarov
- Department of Cardiological Sciences, St George's Hospital Medical School, London, UK.
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Batchvarov VN, Hnatkova K, Poloniecki J, Camm AJ, Malik M. Prognostic value of heterogeneity of ventricular repolarization in survivors of acute myocardial infarction. Clin Cardiol 2005; 27:653-9. [PMID: 15562938 PMCID: PMC6654101 DOI: 10.1002/clc.4960271115] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
BACKGROUND The expansion of indications for implantation of cardioverter-defibrillators (ICD) has enhanced the need for risk stratification of patients post myocardial infarction (MI), while the improved treatment of acute MI has decreased mortality and diminished the prognostic power of traditional risk variables. HYPOTHESIS Increased heterogeneity of ventricular repolarization quantified by TCRT (total cosine R-to-T, angular difference between spatial QRS and T loops, decreased with increase in repolarization heterogeneity) is an independent predictor of mortality in patients post MI. METHODS Left ventricular ejection fraction (EF), QRS duration on signal-averaged ECG, number of ventricular ectopic beats (VE)/h, heart rate variability (HRV) triangular index, heart rate turbulence slope on 24-h Holter recording, and TCRT were analyzed in 334 survivors of acute MI followed up for 41 +/- 20 months. RESULTS In multivariate analysis, EF < 35% (relative risk [RR] 2.3, 95% confidence interval [CI] 1.1-4.7, p = 0.023), VE > 10/h (RR 2.2, CI 1.0-4.6, p = 0.044), HRV < 20 U (RR 2.2, CI 1.1-4.5, p = 0.032), and TCRT < -0.896 (RR 4.3, CI 2.2-8.5, p = 0.00001) were independent predictors of cardiac mortality (11%). Independent predictors of arrhythmic mortality (5%) were VE, HRV, and TCRT (RR 5.8, CI 2.1-15.6, p = 0.0004). Cardiac and arrhythmic mortality of patients with both EF <35% and TCRT < -0.896 were >60 and >30%, respectively, compared with 17 and 7% in those with only EF <35% or TCRT < -0.896. CONCLUSION Decreased TCRT, which reflects increased repolarization heterogeneity, is a strong and independent predictor of cardiac and arrhythmic death in patients post MI.
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Affiliation(s)
- Velislav N Batchvarov
- Department of Cardiac and Vascular Sciences, St. George's Hospital Medical School, London, England.
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Batchvarov V, Hnatkova K, Ghuran A, Poloniecki J, Camm AJ, Malik M. Ventricular gradient as a risk factor in survivors of acute myocardial infarction. Pacing Clin Electrophysiol 2003; 26:373-6. [PMID: 12687848 DOI: 10.1046/j.1460-9592.2003.00052.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The total cosine between R and T (TCRT) (angular difference between the spatial QRS and T wave loops) is a technical elaboration of the concept of ventricular gradient (VG), whose power as a risk stratifier in post-MI patients has already been demonstrated. Recently, it was reported that TCRT differed significantly between healthy men and women, which suggested that its predictive power might be gender dependent. The aim of the study was to investigate TCRT and its association with cardiac mortality in male and female survivors of acute MI. TCRT was measured from digital Frank orthogonal XYZ-lead ECGs recorded before hospital discharge in 681 survivors of acute MI (82% men, age: men 57.0 +/- 8.4 years, women 59.6 +/- 8.1 years, P = 0.002). During a follow-up censored at 5 years, cardiac mortality rates were 9.7% and 12.1% in men and women, respectively (P = 0.42). There were no significant difference in TCRT between men and women (-0.150 +/- 0.704 vs -0.070 +/- 0.731, P = 0.26). In univariate Cox regression analysis, TCRT < -0.88 was related to a 5-year cardiac mortality in men (relative risk [RR] 3.67, 95% confidence interval [CI] 2.13-6.34, P = 1.9 x 10(-6)), and women (RR 5.16, 95% CI 1.83-14.56, P = 0.0015). Depressed TCRT was strongly associated with increased long-term cardiac mortality in survivors of acute MI. Its predictive power did not differ significantly between the sexes. The role of TCRT as a risk-stratifier in post-MI patients deserves further prospective assessment in multivariate models with established risk factors.
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Affiliation(s)
- Velislav Batchvarov
- Department of Cardiological Sciences, St. George's Hospital Medical School, Cranmer Terrace, London SW17 0RE, England.
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Sugino M, Inden Y, Sawada T, Tsuboi N, Hirayama H, Ito T, Shimizu A, Iino S, Yoshida Y, Akahoshi M, Kondo T, Hirai M, Saito H. Comparison of vectorcardiographic and 12-lead electrocardiographic detections of abnormalities in repolarization properties due to preexcitation in patients with Wolff-Parkinson-White syndrome: proposal of a novel concept of a "remodeling gradient". JAPANESE HEART JOURNAL 2000; 41:295-312. [PMID: 10987349 DOI: 10.1536/jhj.41.295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Repolarization abnormalities after radiofrequency ablation in patients with manifest Wolff-Parkinson-White syndrome (WPW) have been attributed to cardiac memory of pre-existing changes in repolarization properties. We compared spatial ventricular gradient (VG) from vectorcardiograms with QRST values of 12-lead ECG in 41 patients with WPW (group A, manifest WPW due to left-sided accessory pathway (n = 20); group B, manifest WPW due to right-sided accessory pathway (n = 12); group C, concealed WPW (n = 9)) before and after ablation. Group N (n = 607) served as control. In groups A and B, the abnormalities of spatial VG and QRST values of 12-lead ECG that existed before and 1 day after ablation significantly decreased 1 week after ablation. In group C, spatial VG and QRST values of 12-lead ECG showed no significant changes. The diagnostic ability of spatial VG is almost equivalent to that of the QRST value of ECG in detecting repolarization abnormalities in patients with WPW before and after ablation. We propose a new concept of a "remodeling gradient" directing from the preexcited area to the opposite side of the ventricle as a result of preexcitation-induced electrical remodeling.
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Affiliation(s)
- M Sugino
- First Department of Internal Medicine, University of Nagoya School of Medicine, Japan
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8
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Kawakami Y, Shimada S, Sakai Y, Suwa M, Nagao H, Hirota Y, Kawamura K, Adachi I, Narabayashi I. Do repolarization abnormalities in hypertrophic cardiomyopathy represent impaired fatty acid utilization? An observation with QRST isointegral maps. J Electrocardiol 1997; 30:21-9. [PMID: 9005883 DOI: 10.1016/s0022-0736(97)80031-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
To identify the clinical significance of the isointegral body surface map of the QRST interval (QRST map) and the occurrence of repolarization abnormalities in patients with hypertrophic cardiomyopathy (HCM), the QRST map and signal-averaged electrocardiogram were evaluated in 50 patients with HCM, in 33 of whom the results were compared with nuclear images both for radioiodine-labeled fatty acid metabolism and for radiothallium perfusion. The QRST departure map was used to determine two parameters of difference between patient and control recordings: the subnormal area (the number of lead points at which the departure index values were negative and lay more than 2 SDs from the mean of the normal control group) and the subnormal minimum (the absolute value of the minimum in the departure map). Late potentials were detected in 6 (12%) of the 50 patients; they were observed in 3 of the 5 patients with dilated-phase HCM but in only 3 (7%) of the other 45 patients. The subnormal area and minimum values were lower in nonobstructive HCM than in dilated-phase HCM. Of the 33 patients examined by myocardial imaging, 28 (33%) had a filling defect or decreased uptake, as shown on fatty acid metabolic images, and 10 of the 28 also showed abnormal myocardial perfusion images, while the 18 others showed normal perfusion images. These 28 patients showed significantly larger values of the subnormal area and minimum than patients with normal results in both image tests, regardless of whether or not myocardial perfusion imaging abnormalities were present. The localization of filling defects or of decreased uptake presented in fatty acid metabolic images corresponded to the position of the minimum on the QRST departure map. These results suggest that the QRST map is useful for detection of repolarization abnormalities in HCM and that these abnormalities are highly related to impaired fatty acid utilization of the myocardium.
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Affiliation(s)
- Y Kawakami
- Third Division, Department of Internal Medicine, Osaka Medical College, Japan
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9
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Geller JC, Rosen MR. Persistent T-wave changes after alteration of the ventricular activation sequence. New insights into cellular mechanisms of 'cardiac memory'. Circulation 1993; 88:1811-9. [PMID: 8403326 DOI: 10.1161/01.cir.88.4.1811] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
BACKGROUND "Cardiac memory" refers to persistent T-wave changes on ECG that follow resumption of sinus rhythm after a period of altered activation sequence. Previous studies demonstrated that cardiac memory in intact dogs was abolished by 4-aminopyridine (4-AP), which blocks both the transient outward potassium current, Ito, and IK. METHODS AND RESULTS We used standard microelectrode techniques to study the mechanism for cardiac memory in canine ventricular subepicardial and subendocardial slabs measuring 15 x 30 x 1 to 2 mm. Bipolar electrodes were used to stimulate slabs parallel to fiber axis, simulating normal activation, and perpendicular to fiber axis, simulating ventricular pacing. Four 30-minute periods of normal activation at a basic cycle length of 650 milliseconds were interrupted by three 20-minute periods of ventricular pacing at a basic cycle length of 450 milliseconds. We first recorded action potentials differentially from epicardial and endocardial slabs. The stimulation protocol induced changes in the "T" wave of the difference signals that mimicked cardiac memory and that could be explained on the basis of the transmural gradient in repolarization between epicardium and endocardium. This result was not obtainable with slow and rapid pacing from one site only. In subsequent experiments, action potential characteristics of epicardial and endocardial slabs were studied by the same pacing protocol with alternation between simulated normal activation and ventricular pacing. During ventricular pacing, the epicardial phase 1 notch and plateau amplitude decreased compared with normal activation. 4-AP (3 mmol/L) decreased notch size and plateau amplitude during normal activation in epicardium but not endocardium. In contrast, the local anesthetic lidocaine did not change notch size or plateau amplitude in epicardium or endocardium. CONCLUSIONS These results suggest that the contribution to repolarization of specific potassium channels influences the memory phenomenon and that by blocking Ito and reducing the transmural voltage gradient for repolarization, 4-AP abolishes cardiac memory.
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Affiliation(s)
- J C Geller
- Department of Pharmacology, Columbia University, New York, NY
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10
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Suzuki A, Hirai M, Hayashi H, Ichihara Y, Adachi M, Oguchi S, Nishiyama A, Shimizu S, Watarai M, Shiga Y. Effects of right ventricular pacing on QRST isointegral maps in patients with and without myocardial infarction: body surface distribution of significant changes in QRST area compared to supraventricular complex. Pacing Clin Electrophysiol 1993; 16:751-9. [PMID: 7683802 DOI: 10.1111/j.1540-8159.1993.tb01655.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
To assess the effects of right ventricular (RV) pacing on body surface QRST distributions, we recorded QRST isointegral maps (I-maps) during sinus rhythm and RV pacing in 25 patients with anterior myocardial infarction (MI), 19 with inferior MI, and 14 without MI. The QRST values at each lead point recorded during sinus rhythm and RV pacing with an 87-lead system were analyzed with a paired t-test in each patient. An abnormal decrease in the QRST value of the I-map was assessed by the difference map, which indicated a "-2SD area," where the QRST integral value was less than the normal range (mean - 2SD) calculated from 608 normal individuals. The I-maps were similar during the two activation sequences in patients with and without MI. However, during RV pacing, QRST values significantly decreased over the upper right anterior chest and increased over the lower left anterior chest and back. The sigma DMs (sum of QRST integral values below the normal range) for both activation sequences were strongly correlated in patients with anterior MI and with inferior MI (r = 0.91 and r = 0.92, respectively; P < 0.001). Although small but significant changes in QRST values were detected, the distribution of the "-2SD area" and the sigma DM were similar during both activation sequences in patients with prior MI. Thus, these findings demonstrate that an altered activation sequence produces small but significant changes in QRST values but that I-maps still provide information that is useful for the diagnosis of MI during RV pacing.
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Affiliation(s)
- A Suzuki
- First Department of Internal Medicine, University of Nagoya School of Medicine, Japan
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11
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Hirai M, Suzuki A, Hayashi H, Tomita Y, Adachi M, Ichihara Y, Terazawa T, Takatsu F, Saito H. Effects of simulated left bundle branch block on QRST time-integral values of 12-lead electrocardiograms in patients with and without prior anterior wall myocardial infarction. Am J Cardiol 1992; 70:984-9. [PMID: 1414917 DOI: 10.1016/0002-9149(92)90348-3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The effects of right ventricular pacing, which simulated left bundle branch block (BBB), on QRST time-integral values of 12-lead electrocardiograms (ECGs) were examined, and the clinical usefulness of QRST values for estimating the severity of left ventricular wall motion abnormalities due to a prior anterior wall myocardial infarction (MI) in the setting of left BBB were evaluated. Digitized ECGs were recorded during normal sinus rhythm and simulated left BBB in 38 patients (24 with and 14 without prior anterior wall MI). QRST values were calculated in each lead point of 12-lead ECGs. Data from 608 normal subjects were used as control values; the mean +/- 2 SD of these values was regarded as the normal range. The parameter sigma DE was defined as the sum of the differences between the normal mean QRST value and the QRST values of a given patient in leads where the QRST value was less than the normal range. The correlation coefficient of sigma DE for the 2 activation sequences was highly significant. Although small but significant changes were seen in QRST values in leads I, II, III, aVR, aVF and V1 during simulated left BBB, left precordial leads showed no significant changes in QRST values. A criterion of sigma DE > 40 mV.ms for detecting an anterior wall MI showed a sensitivity of 88%, a specificity of 93%, and a diagnostic accuracy of 89%. The sigma DE was significantly (p < 0.001) correlated with the asynergy index calculated from left ventriculograms.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- M Hirai
- First Department of Internal Medicine, University of Nagoya School of Medicine, Japan
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12
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Ichihara Y, Hayashi H, Tomita Y, Adachi M, Kondo K, Suzuki A, Nagasaka M, Hirai M, Saito H. Small differences among body surface and epicardial QRST integral maps recorded during normal activation and experimentally simulated left bundle branch block or preexcitation in canine hearts. J Electrocardiol 1992; 25:315-22. [PMID: 1402517 DOI: 10.1016/0022-0736(92)90037-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
QRST integral maps were constructed from 87-lead body surface electrocardiograms (ECGs) and from 45-lead epicardial electrograms during artificial pacing, which simulated left bundle branch block (LBBB) and Wolff-Parkinson-White syndrome in 12 dogs. Although the ECGs and electrograms differed in configuration for each conduction model, the body surface and the epicardial QRST integral maps showed only small differences. Correlation coefficients (r) and root mean square differences (rms) were calculated to assess quantitatively the similarities in the QRST integral maps among the different conduction models. Mean r values between the normal conduction and the left bundle branch block models were 0.95 in the body surface maps and 0.89 in the epicardial maps. Mean r values between the normal conduction and the Wolff-Parkinson-White ECG models were 0.97 in the body surface maps and 0.91 in the epicardial maps, and rms values were small enough. The small differences were also verified by the difference maps and by paired t tests. QRST integral maps on the epicardium and on the body surface were largely independent of altered activation sequences in both the left bundle branch block and the Wolff-Parkinson-White ECG models.
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Affiliation(s)
- Y Ichihara
- First Department of Internal Medicine, Nagoya University School of Medicine, Japan
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Hanashima K, Kubota I, Ozawa T, Shibata T, Yamaki M, Ikeda K, Yasui S. Effect of altered activation sequence on epicardial QRST area and refractory period in dogs. Circulation 1991; 84:1346-53. [PMID: 1884457 DOI: 10.1161/01.cir.84.3.1346] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
BACKGROUND We investigated the effects of activation sequence on cardiac surface QRST areas and refractory periods in experiments on dogs. METHODS AND RESULTS Right and left ventricular pacings were performed, and the pacing site was altered every 6 minutes. After 4 minutes of a given pacing, 54 unipolar electrograms distributed over the entire cardiac surface were recorded. Next, refractory periods at electrode sites near pacing electrodes were measured. Paired right ventricular/left ventricular (RV/LV) pacing data were obtained six or seven times in each sample. Although the QRST isoarea maps during the two activation orders were qualitatively similar, it was recognized consistently from the right ventricle-left ventricle difference map that leads around the RV free wall had positive values and that leads around the LV free wall and apex had negative values. Compared with the same leads at RV and LV pacing, QRST areas were larger when pacing sites were near the leads. The local QRST areas of individual leads at which we measured local refractory period were consistently larger during drive from proximal pacing sites than during drive from distant pacing sites. Refractory periods were consistently longer during proximal pacing than during distal pacing, and there was a positive correlation between change in local QRST area and change in refractory period (r = 0.64) during altered activation sequence, whereas there was an inverse correlation between change in QRST area and change in refractory period (r = -0.91) during localized myocardial warming. CONCLUSIONS Both local QRST areas and local refractory periods were dependent on the activation sequence, and there was a positive correlation between QRST areas and refractory periods during various activation sequences compared with localized myocardial warming.
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Affiliation(s)
- K Hanashima
- First Department of Internal Medicine, Yamagata University School of Medicine, Japan
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14
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Nagasaka M, Hayashi H, Hirai M, Ichihara Y, Takahama S, Kondo K, Saito H. Detection of myocardial infarction in the presence of Wolff-Parkinson-White syndrome by QRST isoarea map in dogs. Am Heart J 1991; 121:763-9. [PMID: 2000742 DOI: 10.1016/0002-8703(91)90186-l] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The possibility of detecting myocardial infarction (MI) in the presence of Wolff-Parkinson-White (WPW) syndrome by means of body surface QRST isoarea maps was studied in eight dogs. Eighty-seven body surface ECGs were recorded simultaneously. Recordings were taken during right atrial (RA) and right atrial and right ventricular (RA + RV) sequential pacing, which simulated WPW syndrome, during control periods and at 1-hour intervals for up to 5 hours after occlusion of the left anterior descending coronary artery. In ECGs during the RA drive, diagnostic findings of MI such as abnormal Q waves were observed but became obscure during the RA + RV drive. On the contrary, the QRST values over the anterior chest during both drives were positive soon after coronary occlusion, decreased gradually as time passed, and became abnormally negative after 5 hours. The QRST isoarea maps during RA and RA + RV pacing showed quite similar patterns and were highly correlated with each other throughout this study (r greater than 0.95). These findings demonstrate that localized abnormalities resulting from MI are evident in QRST isoarea maps even in the presence of preexcitation and fusion.
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Affiliation(s)
- M Nagasaka
- First Department of Internal Medicine, Nagoya University School of Medicine, Japan
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15
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Callaghan F, Vollmann W, Livingston A, Boveja B, Abels D. The ventricular depolarization gradient: effects of exercise, pacing rate, epinephrine, and intrinsic heart rate control on the right ventricular evoked response. Pacing Clin Electrophysiol 1989; 12:1115-30. [PMID: 2476749 DOI: 10.1111/j.1540-8159.1989.tb01934.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A new pacing technique is described that permits high fidelity recording of the paced ventricular evoked response, including cardiac depolarization. Integration of the paced R wave yields the ventricular depolarization gradient (GD), which is dependent on activation sequence and the spatial dispersion of activation times. GD was studied in 27 dogs to determine the effects of treadmill exercise at fixed rate pacing (n = 10), elevation of heart rate in the absence of stress (n = 20), epinephrine at fixed rate (n = 6), and exercise in the presence of normal chronotrophic response (n = 7). Low level exercise (1 mph, 2 min, 15 degrees) at a fixed heart rate produced significant (P less than 0.0005) decreases in GD that averaged -10.8 +/- 4.0% (mean +/- SD). The rate of change in GD was faster at the onset of exercise than at its cessation (P less than 0.0005). Artificial elevation of heart rate at rest produced significant (P less than 0.0005) increases in GD; mean sensitivity of GD to rate was 0.27 +/- 0.12%/beats/min. Intravenous injection of epinephrine produced significant (P less than 0.001) decreases in GD at two dosage levels (2.5 and 5.0 micrograms/kg) when evaluated at two baseline pacing rates (150 and 190 beats/min); mean changes in GD were -20.64 +/- 0.53% (2.5 micrograms/kg at 150 beats/min), -25.19 +/- 4.20% (5.0 micrograms/kg at 150 beats/min), -14.18 +/- 5.19% (2.5 micrograms/kg at 190 beats/min), and -24.22 +/- 4.94% (5.0 micrograms/kg at 190 beats/min). Sensitivity of GD to epinephrine was dose-dependent (P less than 0.01) at each baseline rate, but was independent (P greater than 0.05) of the rate itself. In the presence of a normal chronotropic response, GD remained unchanged (P greater than 0.5) during exercise in spite of significant elevation in heart rate (105.0 to 167.1 beats/min, P less than 0.001). These data suggest the presence of an intrinsic negative-feedback control mechanism that maintains GD constant in the healthy heart during homeostatic disturbance. Applications in closed-loop rate adaptive pacing are described.
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Affiliation(s)
- F Callaghan
- Telectronics Pacing Systems, Miami, Florida 33102-5202
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16
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Nadeau R, Ackaoui A, Giorgi C, Savard P, Shenasa M, Pagé P. PQRST isoarea maps from patients with the Wolff-Parkinson-White syndrome: an index for global alterations of ventricular repolarization. Circulation 1988; 77:499-503. [PMID: 3342481 DOI: 10.1161/01.cir.77.3.499] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Isoarea maps during the PQRST sequence were computed in 22 healthy subjects and 48 patients with Wolff-Parkinson-White (WPW) syndrome. Thirty-eight patients with WPW were on no medication and 10 were treated with class I, II, or III antiarrhythmic drugs. Seventeen isoarea maps were recorded before and 17 were recorded after accessory pathway ablation. One patient had intermittent preexcitation. Body surface maps from all healthy subjects were similar, although the magnitudes of the maxima and minima showed significant variability. In all patients with WPW who were on no medication and in those on class I and II agents, PQRST maps were normal. Two patients taking amiodarone had abnormal PQRST maps, as did patients early after surgery. In the patient with intermittent preexcitation, PQRST maps were very similar during normal and preexcited beats. In conclusion, our results support the theory that the PQRST time integral reflects intrinsic recovery properties of the heart and is independent of the activation sequence.
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Affiliation(s)
- R Nadeau
- Research Center, Hôpital du Sacré-Coeur de Montréal, Quebec, Canada
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17
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Rosenbaum MB, Blanco HH, Elizari MV, Lázzari JO, Vetulli HM. Electrotonic Modulation of Ventricular Repolarization and Cardiac Memory. DEVELOPMENTS IN CARDIOVASCULAR MEDICINE 1983. [DOI: 10.1007/978-94-009-6781-6_4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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18
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Rosenbaum MB, Blanco HH, Elizari MV, Lázzari JO, Davidenko JM. Electrotonic modulation of the T wave and cardiac memory. Am J Cardiol 1982; 50:213-22. [PMID: 7102553 DOI: 10.1016/0002-9149(82)90169-2] [Citation(s) in RCA: 280] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Alterations in the sequence of ventricular activation (left bundle branch block occurring spontaneously or induced by atrial pacing; right ventricular pacing) were studied and shown to induce two opposite changes in the order of ventricular repolarization. One, which causes classic secondary T wave changes, occurs and disappears instantaneously, and is proportional in magnitude to the QRS complex but of opposite direction. The other, which requires a long time to reach its maximal effect and to be dissipated, shows the same direction as the abnormal QRS forces but becomes apparent only when normal activation is restored. The former is a well known consequence of prolongation of the activation time, but the latter appears to be modulated by electrotonic interactions occurring during cardiac activation, in such a way that repolarization is delayed in sites where depolarization begins, and accelerated in sites where depolarization terminates. Our study suggests that electrotonically modulated T wave changes show accumulation and memory, and may persist for days or weeks after the provoking stimulus (the change in the activation sequence) is discontinued. The fact that any shift of the activation sequence may produce "pseudoprimary" T wave changes that may persist long after cessation of the triggering factor has wide clinical implications. Electrotonic modulation of ventricular repolarization is a basic electrophysiologic mechanism that may account for several features of normal and abnormal T waves, and for the possible existence of a heart memory.
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Abstract
These studies were designed to explore the effects of ectopic left ventricular stimulation on the area distributions recorded during the QRS, ST-T and QRST intervals. Twenty rabbit hearts were suspended in a spherical volume conductor, perfused with an electrolyte solution and stimulated from an anterior and/or a posterior subepicardial left ventricular site. ECG signals were sensed from 32 surface electrodes and were processed to compute areas under the three intervals, to construct area maps and to fit the computed areas to a single moving dipole equivalent cardiac generator model. Results demonstrated that control distributions were overtly nondipolar in 62.5% of cases. Second, ectopic pacing increased the dipolarity of the QRS and ST-T intervals significantly by both dipole ranging and isoarea methods. All area distributions became dipolar. Last, the QRST distribution response to ectopic stimulation varied widely, with major as well as minor changes in patterns occurring with alteration in excitation sequence. Thus, (1) ectopic stimulation changed electrical field properties of mean cardiac forces, and (2) QRST area distributions were dependent upon activation sequence. Each of these observations has direct bearing upon the ventricular gradient concept.
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20
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Abildskov JA, Burgess MJ, Urie PM, Lux RL, Wyatt RF. The unidentified information content of the electrocardiogram. Circ Res 1977; 40:3-7. [PMID: 830436 DOI: 10.1161/01.res.40.1.3] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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21
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Abstract
We measured refractory periods at ventricular sites in the dog heart during drive from ventricular test sites and during combined drive from the test sites and other ventricular sites or the atrium. We found that ventricular activation sequence caused significant alterations on refractory period. Combined drive from two sites which resulted in fusion complexes was associated with shorter refractory periods at the test sites than those observed during drive at the test sites only. Our findings are explicable because earlier excitation and consequent earlier recovery of surrounding areas during fusion beats exerts an electrotonic influence on test sites.
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