Variation of Q value before and after the 1999 Xiuyan, Liaoning Province, M=5.4 earthquake on the basis of analysis on attenuation dispersion of P waves

2005 ◽  
Vol 18 (5) ◽  
pp. 510-520 ◽  
Author(s):  
Xi-qiang Liu ◽  
Qing-wen Sun ◽  
Hong Li ◽  
Yu-yan Shi ◽  
Ai-dong Ji ◽  
...  
Keyword(s):  
Liaoning Province ◽  
Q Value ◽  
P Waves ◽  
Before And After

Abstract 13730: Electrical Axes of P and T but Not QRS Waves on ECG Are New Indicators of Successfulness of the Nuss Operation for Pectus Excavatum Considering Anatomical Severity as Indicated by the Haller Index Acquired by CT

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Nobusada FUNABASHI ◽  
Yoshio Kobayashi
Keyword(s):  
Pectus Excavatum ◽  
Correlation Coefficients ◽  
P Wave ◽  
Invasive Technique ◽  
P Waves ◽  
Haller Index ◽  
Before And After ◽  
Group 2 ◽  
Group 1 ◽  
T Waves

Introduction: Pectus excavatum (PEX) is a depression of the sternum which can physically constrict the heart and cause abnormal ECGs. The Nuss operation is a minimally invasive technique for PEX repair. Hypothesis: As right (RA) and left atria (LA) are compressed in PEX, axes of P, QRS, and T waves are abnormal and the Nuss operation normalizes them. We also took the Haller index (HI) into to account. Methods: 17 PEX patients (14 male, 12±6 years) underwent CT and ECG before and after the Nuss operation. Results: All Nuss operations were successful, and HI was significantly improved from 5.62±2.29 to 3.29±0.65 (P=0.0002). There were no significant differences before and after surgery for electrical axes of P waves (46±20 vs 65±55, P=0.20), and QRS waves (75±33 vs 76±23, P=0.72), but T waves were greater thereafter (22±27 vs 40±19, P=0.001). Correlation coefficients (CC) between the degree of axes of P, QRS and T waves, and HI before operation were -0.23, -0.06, and 0.11, respectively. These values after operation were -0.25, -0.06, and 0.19, respectively. As HI is an indirect indicator of heart compression, we evaluated the degree of RA and LA compression qualitatively as none, mild, and moderate/more. Of 17 patients, 5 had moderate/more compression of RA and/or LA by PEX (group 1); the remaining 12 did not show compression (group 2). Only P wave values were significantly smaller in group 1 than 2 before surgery, but these differences disappeared after surgery. In both groups, degree of axes of T waves was significantly greater after the operation. Conclusion: In patients with PEX, axes of T waves after the Nuss operation became significant greater than before the operation in patients with moderate or more compression of RA and/or LA by PEX. For P waves, this was smaller before the operation in those with compression but this was improved by the Nuss operation. P and T wave axes but not QRS could be therefore non-invasive indicators of Nuss operation success in addition to gross PEX appearance.

Influence of cardiac denervation on subsidiary atrial pacemaker stabilization

1984 ◽  
Vol 247 (4) ◽  
pp. H523-H530
Author(s):  
J. A. Sterba ◽  
L. E. Rinkema ◽  
W. C. Randall ◽  
S. B. Jones ◽  
G. Brynjolfsson
Keyword(s):  
Heart Rate ◽  
Cycle Length ◽  
Atrial Pacing ◽  
Adrenergic Blockade ◽  
P Waves ◽  
Conscious Animal ◽  
Before And After ◽  
Cycle Lengths ◽  
Time Required ◽  
Short Time

Overdrive suppression was determined by measuring cardiac cycle lengths after rapid atrial pacing in nine alert conscious dogs sustaining total intrapericardial denervation. Rapid atrial pacing was performed at 125-400% of spontaneous heart rate for 30 s and at 200% spontaneous rate for 30, 60, 120, and 180 s, with and without cholinergic (atropine 0.2 mg/kg iv) or adrenergic blockade (propranolol 0.5 mg/kg iv). Corrected recovery time (CRT) was defined as the first recovery cycle length minus average control cycle length. To compare responses of the intact sinoatrial node (SAN) and subsidiary atrial pacemakers, CRT was measured in the conscious animal before and after SAN excision. Immediately after SAN excision, a junctional rhythm was frequently observed, but within a short time (min-h), subsidiary atrial pacemaker dominance was established with well-formed P waves and P-R interval averaging 85.3 +/- 3.4 ms. CRT before SAN excision ranged from 100 to 300 ms. Following pacing at 125-400% of spontaneous heart rate soon after SAN excision, CRT was markedly prolonged, ranging up to 6,000 ms. Atropine and propranolol did not influence CRT in the denervated preparation. CRT of subsidiary atrial pacemakers in the normally innervated dog heart returned to control pre-SAN excision values in 1-2 wk. In the denervated heart complete autonomic denervation exaggerated time required for return to control CRT values to 5-8 wk.

scholarly journals Characterization of Changes in P-Wave VCG Loops Following Pulmonary-Vein Isolation

Sensors ◽  
2021 ◽  
Vol 21 (5) ◽  
pp. 1923
Author(s):  
Nuria Ortigosa ◽  
Óscar Cano ◽  
Frida Sandberg
Keyword(s):  
Atrial Fibrillation ◽  
Catheter Ablation ◽  
Pulmonary Vein ◽  
Pulmonary Vein Isolation ◽  
P Wave ◽  
Atrial Fibrillation Recurrence ◽  
Time Segment ◽  
P Waves ◽  
Before And After ◽  
Propagation Pattern

Atrial fibrillation is the most common type of cardiac arrhythmia in clinical practice. Currently, catheter ablation for pulmonary-vein isolation is a well-established treatment for maintaining sinus rhythm when antiarrhythmic drugs do not succeed. Unfortunately, arrhythmia recurrence after catheter ablation remains common, with estimated rates of up to 45%. A better understanding of factors leading to atrial-fibrillation recurrence is needed. Hence, the aim of this study is to characterize changes in the atrial propagation pattern following pulmonary-vein isolation, and investigate the relation between such characteristics and atrial-fibrillation recurrence. Fifty patients with paroxysmal atrial fibrillation who had undergone catheter ablation were included in this study. Time-segment and vectorcardiogram-loop-morphology analyses were applied to characterize P waves extracted from 1 min long 12-lead electrocardiogram segments before and after the procedure, respectively. Results showed that P-wave vectorcardiogram loops were significantly less round and more planar, P waves and PR intervals were significantly shorter, and heart rate was significantly higher after the procedure. Differences were larger for patients who did not have arrhythmia recurrences at 2 years of follow-up; for these patients, the pre- and postprocedure P waves could be identified with 84% accuracy.

Influence of Nuss surgical operation for pectus excavatum on electrocardiogram abnormality considering anatomical severity as indicated by Haller index acquired by computed tomography and age

2020 ◽  
Vol 41 (Supplement_2) ◽  
Author(s):  
N Funabashi ◽  
Y Kobayashi
Keyword(s):  
Pectus Excavatum ◽  
Minimal Invasive ◽  
P Wave ◽  
Invasive Technique ◽  
Nuss Procedure ◽  
P Waves ◽  
Sinus Arrhythmia ◽  
Haller Index ◽  
Unenhanced Ct ◽  
Before And After

Abstract Background Pectus excavatum (PEX) is a depression of the sternum relative to costal cartilages and sometimes depress heart anatomically which cause abnormal ECG change. Nuss operation is minimal invasive technique for PEX repair. Purpose We speculated this Nuss operation would improve these ECG abnormalities. We also considered the Haller index (HI) and age to these influences. HI is an anatomical severity indicator of PEX calculated from CT. Methods A total of 17 patients (14 male, 12±6 years), who underwent Nuss operation for PEX, underwent unenhanced CT and ECG before and after the Nuss operation. Results All Nuss operation was successfully performed. On CT, HI was significantly improved from 5.62±2.29 to 3.29±0.65 (P=0.0002). A P wave with a negative portion >1 mm deep and >40 ms duration in V1 lead, incomplete right bundle branch block (RBBB), sinus arrhythmia, and right-axis deviation of a QRS wave were diagnosed in 15, 6, 12, and 5 patients, respectively. Comparing before with after Nuss operation, there were no significant differences of the degree of electrical axis of QRS waves, the degree of electrical axis of P waves, or the PQ interval, respectively (All P=NS). Absolute values of voltage of a negative portion of the P wave in V1 lead was significantly improved after the operation (1.55±1.25 vs 0.76±0.91mm, P<0.001). Among 12 patients with sinus arrhythmia, only one patient improved to that without. Among 6 patients with incomplete RBBB, only one patient improved to that without. The correlation coefficient (CC) between “values of the improvement of negative portion of the P wave in V1 lead after the operation” and “HI before operation” was 0.305 (P<0.05). The CC between “absolute values of the improvement of negative portion of the P wave in V1 lead after the operation” and “age at the operation” was −0.216 (P<0.05). Conclusion In patients with PEX, successful Nuss operation could achieve improvement of negative portion of the P wave in V1 lead positively correlated with “HI before operation” and negatively correlated with “age”. Nuss procedure would be more effective to abnormal ECG change, when anatomical severity is severer or age is younger. Improvement of negative P wave Funding Acknowledgement Type of funding source: None

scholarly journals Comparison of Autorefraction, Cyclorefraction, and Subjective Manifest Refraction in Keratoconic Eyes

2021 ◽  
Author(s):  
Athar Zareei ◽  
Marziyeh Alamolhoda ◽  
Milad Abdolahian ◽  
Kiana Khatami ◽  
Shahram Bamdad
Keyword(s):  
Corneal Astigmatism ◽  
Q Value ◽  
Factors Associated ◽  
Starting Point ◽  
Manifest Refraction ◽  
Before And After ◽  
Multivariable Regression ◽  
The Difference ◽  
Cylindrical Axis ◽  
Significant Factors

Abstract Purpose: This study aimed to estimate the agreement of astigmatism between an autorefractor (Topcon), cycloplegic refraction, subjective manifest refraction, front and back corneal astigmatism. Moreover, this study aimed to investigate which factors influence the difference between cycloplegic refraction and subjective manifest refraction in these keratonic eyes.Methods: subjective manifest refraction, Autorefractmeter were measured in 64 keratonic eyes of 43 patients (21-45 years old) before and after using cycloplegic drop. We measured Corneal values by using Scheimpflug tomography. Astigmatic power was converted to vectors. The agreement of astigmatism between an autorefractor (Topcon), cycloplegic refraction, subjective manifest refraction, front and back corneal astigmatism was measured overall and in each vector. The difference between Cycloplegic refraction and subjective manifest refraction was calculated in each vector axis. Factors were anticipated associated with discrepancy by using Multivariable Regression Analysis.Results: The maximum estimations of agreement were found berween autorefratometer and subjective manifest refraction in cylindrical power(Icc:0.703,P<0.026), cylindrical axis(Icc:0.943,P<0.0001) and astigmatic vestors of J0 (Icc:0.972,P<0.0001) and J45( Icc:827,P=0.006). The significant factors Associated With discrepancy between cyclorefraction and subjective manifest refraction in both vectors(J0 and J45) were Q-value(B Coefficient= -4.91, P<0.0001) (B Coefficient=1.01, P<0.0001), corneal astigmatism(B Coefficient= 0.66, P=0.001) (B Coefficient=0.11, P=0.001), Kmax(B Coefficient= -0.52, P<0.0001) (B Coefficient=0.07, P=0.02), IHA(B Coefficient=0.04, P=0.005) (B Coefficient= -0.03, P<0.0001). The significant associated factors for axis changes between cycloplegic refraction and subjective manifest refraction were cone location (B Coefficient= -33.34, P=0.001) and corneal astigmatism(B Coefficient= -0.1, P=0.04).Conclusion: Maximum agreement of subjective manifest refraction astigmatism is with auto refractometer in keratoconus patients, so it could be said that the result of the auto refractometer is the most appropriate starting point during subjective refraction in these patients. It can be predicted that the closer the keratoconus cone location relative to the center of the cornea and the lower the keratoconus patient's corneal astigmatism, the more the probability of axis changes by cycloplegic drop.

scholarly journals Is there a change in P wave parameters following pulmonary vein isolation (PVI) using radiofrequency ablation (RF) vs. cryoballoon ablation (CRYO) for paroxysmal atrial fibrillation (PAF)?

EP Europace ◽  
2021 ◽  
Vol 23 (Supplement_3) ◽  
Author(s):  
I Antoun ◽  
S Bharat ◽  
A Mavilakandy ◽  
V Pooranachandran ◽  
GA Ng
Keyword(s):  
Atrial Fibrillation ◽  
Pulmonary Vein ◽  
Pulmonary Vein Isolation ◽  
Paroxysmal Atrial Fibrillation ◽  
P Wave ◽  
Cryoballoon Ablation ◽  
Single Shot ◽  
P Waves ◽  
Significant Difference ◽  
Before And After

Abstract Funding Acknowledgements Type of funding sources: None. Pulmonary vein isolation (PVI) is an effective and established therapy for paroxysmal atrial fibrillation (PAF) . PVI can be performed using point by point ablation with radiofrequency (RF) or with single shot techniques such as cryoballoon (CRYO). As P waves represent atrial depolarization, we aimed to study whether P wave metrics may change after PVI and if there are differences between RF and CRYO approaches. Methods We studied 88 matched patients who had PVI for PAF between January 2017 and December 2018 (RF = 44, CRYO = 44). Each patient was in sinus rhythm (SR) prior to ablation. Patients on amiodarone and those who had additional linear ablation were excluded. Patients had continuous ECG monitoring using Labsystem Pro (Boston Scientific Inc). Sampled at 1kHz during the procedure. One-minute recordings before and after PVI were exported and analysed using custom-written software using MatLab (v2018, bandpass 1-50Hz) to annotate P wave onset, peak and end. P wave duration was heart rate corrected (PWDc) by using the Hodges formula and P wave amplitude (PWA). Results P wave metrics were comparable before PVI between both cohorts. Successful PVI was achieved in all patients. There was a trend towards an increase in PWDc in some ECG leads with either RF or CRYO but no significant difference in P wave metrics as a result of PVI ablation or between both ablation modalities. Conclusion In this study, there was no significant change seen in PVI with RF or CRYO and no difference between the 2 ablation modalities. P wave metrics comparison, RF vs CRYO PWDc (ms) PRE, RF (n = 44) POST, RF (n = 44) P PRE, CRYO (n = 44) POST CRYO (n = 44) P P (RF vs CRYO) I 134.7 ± 32 133.5 ± 35 0.813 131.9 ± 36 132.7 ± 39 0.9 0.81 II 140.9 ± 34 144.1 ± 37 0.56 139.4 ± 42 134.4 ± 40 0.51 0.41 III 131.5 ± 31 143.3 ± 37 0.04 132.8 ± 41 130.6 ± 36 0.68 0.074 AVF 137 ± 32 144.7 ± 36 0.15 137.5 ± 42 127.4 ± 37 0.11 0.141 V1 143.9 ± 33 151.8 ± 37 0.17 133.6 ± 37 143.8 ± 38 0.09 0.745 PWA (mV) PRE, RF (n = 44) POST, RF (n = 44) P PRE, CRYO (n = 44) POST CRYO (n = 44) P P (RF vs CRYO) I 0.125 ± 0.08 0.09 ± 0.06 0.002 0.13 ± 0.08 0.14 ± 0.09 0.59 0.076 II 0.238 ± 0.1 0.238 ± 0.1 0.98 0.232 ± 0.1 0.278 ± 0.2 0.1 0.212 III 0.149 ± 0.1 0.153 ± 0.1 0.83 0.189 ± 0.1 0.187 ± 0.1 0.97 0.86 AVF 0.195 ± 0.1 0.196 ± 0.1 0.92 0.197 ± 0.1 0.247 ± 0.1 0.066 0.132 V1 0.122 ± 0.1 0.151± 0.1 0.05 0.138 ± 0.1 0.193 ± 0.2 0.002 0.543 PWDc and PWA comparison following RF vs CRYO.

Deformation Replication

1970 ◽  
Vol 28 ◽  
pp. 280-281
Author(s):  
J. Temple Black
Keyword(s):  
Cutting Speed ◽  
Machining Process ◽  
Depth Of Cut ◽  
Rake Face ◽  
Orthogonal Machining ◽  
Aluminum Chips ◽  
Before And After ◽  
Materials Used ◽  
Glass Knife ◽  
Very High

Tool materials used in ultramicrotomy are glass, developed by Latta and Hartmann (1) and diamond, introduced by Fernandez-Moran (2). While diamonds produce more good sections per knife edge than glass, they are expensive; require careful mounting and handling; and are time consuming to clean before and after usage, purchase from vendors (3-6 months waiting time), and regrind. Glass offers an easily accessible, inexpensive material ($0.04 per knife) with very high compressive strength (3) that can be employed in microtomy of metals (4) as well as biological materials. When the orthogonal machining process is being studied, glass offers additional advantages. Sections of metal or plastic can be dried down on the rake face, coated with Au-Pd, and examined directly in the SEM with no additional handling (5). Figure 1 shows aluminum chips microtomed with a 75° glass knife at a cutting speed of 1 mm/sec with a depth of cut of 1000 Å lying on the rake face of the knife.

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