33 results on '"Gussak, Ihor"'
Search Results
2. Clinical Significance of J Waves in Patients Undergoing Therapeutic Hypothermia for Out-of-Hospital Cardiac Arrest.
- Author
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Harhash A, Gussak I, Cassuto J, and Winters SL
- Subjects
- Female, Heart Arrest diagnosis, Humans, Hypothermia, Induced methods, Male, Middle Aged, Retrospective Studies, Treatment Outcome, Arrhythmias, Cardiac diagnosis, Arrhythmias, Cardiac etiology, Electrocardiography methods, Emergency Medical Services methods, Heart Arrest prevention & control, Hypothermia, Induced adverse effects
- Abstract
Background: Hypothermia is associated with the development of J waves. However, little is known about the impact of these electrocardiogram (ECG) findings on the development of ventricular arrhythmias and patient outcomes during therapeutic hypothermia (TH) postresuscitation from out-of-hospital cardiac arrest (OHCA). We investigated the prevalence of J waves in OHCA patients prior to and during TH. Additionally, we explored the incidence of atrial and ventricular arrhythmias and in-hospital mortality for patients with and without J waves either at baseline, during TH, or both., Methods: We conducted a retrospective analysis of patients who suffered OHCA and underwent TH (goal temperature of 32-34°C). Fifty-nine patients were stratified dependent upon the presence of or the development of J waves on surface ECGs. Descriptive analysis and logistic regression modeling were used to assess the population differences and mortality, respectively, between patients who developed J waves during TH and those who did not., Results: There was no difference in the development of in-hospital atrial or ventricular arrhythmias between patients with J waves present during TH (16%) and those without (17.6%, P = 0.834). Compared to patients without J waves at baseline and during TH, those with J waves present both at baseline and during TH had significantly worse survival (hazard ratio = 12.42, P = 0.046)., Conclusions: While J waves are common ECG findings during TH in patients resuscitated from OHCA, our study demonstrated an increase in mortality for patients with J waves present both at baseline and during TH., (© 2016 Wiley Periodicals, Inc.)
- Published
- 2017
- Full Text
- View/download PDF
3. J-Wave syndromes expert consensus conference report: Emerging concepts and gaps in knowledge.
- Author
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Antzelevitch C, Yan GX, Ackerman MJ, Borggrefe M, Corrado D, Guo J, Gussak I, Hasdemir C, Horie M, Huikuri H, Ma C, Morita H, Nam GB, Sacher F, Shimizu W, Viskin S, and Wilde AA
- Subjects
- Brugada Syndrome mortality, Brugada Syndrome physiopathology, Death, Sudden, Cardiac epidemiology, Global Health, Humans, Incidence, Survival Rate trends, Brugada Syndrome diagnosis, Consensus Development Conferences as Topic, Death, Sudden, Cardiac etiology, Electrocardiography
- Published
- 2016
- Full Text
- View/download PDF
4. Early repolarization syndrome: a decade of progress.
- Author
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Gussak I and Antzelevitch C
- Subjects
- Humans, Syndrome, Arrhythmias, Cardiac diagnosis, Arrhythmias, Cardiac physiopathology, Electrocardiography methods, Heart Conduction System physiopathology, Terminology as Topic
- Published
- 2013
- Full Text
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5. Author's response to letter to the editor from Perez and Froelicher.
- Author
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Antzelevitch C and Gussak I
- Subjects
- Humans, Arrhythmias, Cardiac diagnosis, Arrhythmias, Cardiac physiopathology, Electrocardiography methods, Heart Conduction System physiopathology, Terminology as Topic
- Published
- 2013
- Full Text
- View/download PDF
6. Computerized extraction of electrocardiograms from continuous 12-lead holter recordings reduces measurement variability in a thorough QT study.
- Author
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George S, Rodriguez I, Ipe D, Sager PT, Gussak I, and Vajdic B
- Subjects
- Adult, Anti-Infective Agents, Aza Compounds, Cross-Over Studies, Diagnosis, Computer-Assisted, Female, Fluoroquinolones, Humans, Long QT Syndrome chemically induced, Male, Middle Aged, Moxifloxacin, Quinolines, Research Design, Young Adult, Algorithms, Electrocardiography methods, Long QT Syndrome physiopathology
- Abstract
Continuous Holter recordings are often used in thorough QT studies (TQTS), with multiple 10-second electrocardiograms (ECGs) visually selected around predesignated time points. The authors hypothesized that computer-automated ECG selection would reduce within-subject variability, improve study data precision, and increase study power. Using the moxifloxacin and placebo arms of a Holter-based crossover TQTS, the authors compared interval duration measurements (IDMs) from manually selected to computer-selected ECGs. All IDMs were made with a fully automated computer algorithm. Moxifloxacin-induced changes in baseline- and placebo-subtracted QT intervals were similar for manual and computer ECG selection. Mean 90% confidence intervals were narrower, and within-subject variability by mixed-model covariance was lower for computer-selected than for manual-selected ECGs. Computer ECG selection reduced the number of subjects needed to achieve 80% power by 40% to 50% over manual. Computer ECG selection returns accurate ddQTcF values with less measurement variability than manual ECG selection by a variety of metrics. This results in increased study power and reduces the number of subjects needed to achieve desired power, which represents a significant potential source cost savings in clinical drug trials.
- Published
- 2012
- Full Text
- View/download PDF
7. Wireless remote monitoring of reconstructed 12-lead ECGs after ablation for atrial fibrillation using a hand-held device.
- Author
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Gussak I, Vukajlovic D, Vukcevic V, George S, Bojovic B, Hadzievski L, Simic G, Stojanovic B, Angelkov L, and Panescu D
- Subjects
- Chi-Square Distribution, Electrocardiography, Ambulatory, Female, Humans, Male, Middle Aged, Sensitivity and Specificity, Statistics, Nonparametric, Atrial Fibrillation physiopathology, Atrial Fibrillation surgery, Catheter Ablation, Electrocardiography instrumentation
- Abstract
Objective: Atrial fibrillation (AF) surveillance using a wireless handheld monitor capable of 12-lead electrocardiogram reconstruction was performed, and arrhythmia detection rate was compared with serial Holter monitoring., Methods: Twenty-five patients were monitored after an AF ablation procedure using the hand-held monitor for 2 months immediately after and then for 1 month approximately 6 months postablation. All patients underwent 12-lead 24-hour Holter monitoring at 1, 2, and 6 months postablation., Results: During months 1-2, 425 of 2942 hand-held monitor transmissions from 21 of 25 patients showed AF/atrial flutter (Afl). The frequency of detected arrhythmias decreased by month 6 to 85/1128 (P < .01) in 15 of 23 patients. Holter monitoring diagnosed AF/Afl in 8 of 25 and 7 of 23 patients at months 1-2 and month 6, respectively (P < .01 compared with wireless hand-held monitor). Af/Afl diagnosis by wireless monitoring preceded Holter detection by an average of 24 days., Conclusions: Wireless monitoring with 12-lead electrocardiogram reconstruction demonstrated reliable AF/Afl detection that was more sensitive than serial 12-lead 24-hour Holter monitoring., (Copyright © 2012 Elsevier Inc. All rights reserved.)
- Published
- 2012
- Full Text
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8. Detection of QT prolongation using a novel electrocardiographic analysis algorithm applying intelligent automation: prospective blinded evaluation using the Cardiac Safety Research Consortium electrocardiographic database.
- Author
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Green CL, Kligfield P, George S, Gussak I, Vajdic B, Sager P, and Krucoff MW
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- Anti-Infective Agents therapeutic use, Double-Blind Method, Electrocardiography drug effects, Fluoroquinolones, Follow-Up Studies, Humans, Long QT Syndrome drug therapy, Long QT Syndrome physiopathology, Moxifloxacin, Prospective Studies, Reproducibility of Results, Algorithms, Automation instrumentation, Aza Compounds therapeutic use, Electrocardiography methods, Long QT Syndrome diagnosis, Quinolines therapeutic use
- Abstract
Background: The Cardiac Safety Research Consortium (CSRC) provides both "learning" and blinded "testing" digital electrocardiographic (ECG) data sets from thorough QT (TQT) studies annotated for submission to the US Food and Drug Administration (FDA) to developers of ECG analysis technologies. This article reports the first results from a blinded testing data set that examines developer reanalysis of original sponsor-reported core laboratory data., Methods: A total of 11,925 anonymized ECGs including both moxifloxacin and placebo arms of a parallel-group TQT in 181 subjects were blindly analyzed using a novel ECG analysis algorithm applying intelligent automation. Developer-measured ECG intervals were submitted to CSRC for unblinding, temporal reconstruction of the TQT exposures, and statistical comparison to core laboratory findings previously submitted to FDA by the pharmaceutical sponsor. Primary comparisons included baseline-adjusted interval measurements, baseline- and placebo-adjusted moxifloxacin QTcF changes (ddQTcF), and associated variability measures., Results: Developer and sponsor-reported baseline-adjusted data were similar with average differences <1 ms for all intervals. Both developer- and sponsor-reported data demonstrated assay sensitivity with similar ddQTcF changes. Average within-subject SD for triplicate QTcF measurements was significantly lower for developer- than sponsor-reported data (5.4 and 7.2 ms, respectively; P < .001)., Conclusion: The virtually automated ECG algorithm used for this analysis produced similar yet less variable TQT results compared with the sponsor-reported study, without the use of a manual core laboratory. These findings indicate that CSRC ECG data sets can be useful for evaluating novel methods and algorithms for determining drug-induced QT/QTc prolongation. Although the results should not constitute endorsement of specific algorithms by either CSRC or FDA, the value of a public domain digital ECG warehouse to provide prospective, blinded comparisons of ECG technologies applied for QT/QTc measurement is illustrated., (Copyright © 2012 Mosby, Inc. All rights reserved.)
- Published
- 2012
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9. Detection of acute myocardial infarction from serial ECG using multilayer support vector machine.
- Author
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Dhawan A, Wenzel B, George S, Gussak I, Bojovic B, and Panescu D
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- Aged, Female, Humans, Male, Middle Aged, Electrocardiography methods, Myocardial Infarction diagnosis, Support Vector Machine
- Abstract
Acute Myocardial Infarction (AMI) remains a leading cause of mortality in the United States. Finding accurate and cost effective solutions for AMI diagnosis in Emergency Departments (ED) is vital. Consecutive, or serial, ECGs, taken minutes apart, have the potential to improve detection of AMI in patients presented to ED with symptoms of chest pain. By transforming the ECG into 3 dimensions (3D), computing 3D ECG markers, and processing marker variations, as extracted from serial ECG, more information can be gleaned about cardiac electrical activity. We aimed at improving AMI diagnostic accuracy relative to that of expert cardiologists. We utilized support vector machines in a multilayer network, optimized via a genetic algorithm search. We report a mean sensitivity of 86.82%±4.23% and specificity of 91.05%±2.10% on randomized subsets from a master set of 201 patients. Serial ECG processing using the proposed algorithm shows promise in improving AMI diagnosis in Emergency Department settings.
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- 2012
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10. Algorithm for quantitative 3 dimensional analysis of ECG signals improves myocardial diagnosis over cardiologists in diabetic patients.
- Author
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Wenzel BJ, George S, Lakkireddy D, Vanga S, Bommana S, Gussak I, Simic G, Bojovic B, Hadzievski L, and Panescu D
- Subjects
- Female, Humans, Male, Middle Aged, Observer Variation, Reproducibility of Results, Sensitivity and Specificity, Algorithms, Body Surface Potential Mapping methods, Diabetes Mellitus, Type 2 complications, Diabetes Mellitus, Type 2 diagnosis, Diagnosis, Computer-Assisted methods, Electrocardiography methods, Myocardial Infarction complications, Myocardial Infarction diagnosis
- Abstract
Unlabelled: Acute myocardial infarction (AMI) diagnosis in type II diabetes (DM2) patients is difficult and ECG findings are often non-diagnostic or inconclusive. We developed computer algorithms to process standard 12-lead ECG input data for quantitative 3-dimensional (3D) analysis (my3KGTM), and hypothesized that use of the my3KGTM's array of over 100 3D-based AMI diagnostic markers may improve diagnostic accuracy for AMI in DM2 patients., Methods: We identified 155 consecutive DM2 patients age >25 yrs with chest discomfort or shortness of breath who were evaluated at an urban emergency department (130 patients (pts)) or the cardiac catheterization laboratory (25 pts) for possible AMI. The first digital 12-lead ECG for each patient, obtained within 30 min of presentation, was evaluated by (1) 2 blinded expert cardiologists, and (2) my3KGTM. In each case, the ECG was classified as either likely AMI or likely non-AMI. "Gold standard" was the final clinical diagnosis. Statistical analysis was McNemar's test with continuity correction., Results: The 155 DM2 patients were 50% male, mean age 56.8 ± 12.0 yrs; 44 pts had a final clinical diagnosis of AMI (17 ST Elevation Myocardial Infarctions (STEMI), 27 Non-ST Elevation Myocardial Infarctions (NSTEMI)) and 111 had no AMI., Conclusions: Relative to standard 12L ECG read by cardiologists, quantitative 3D ECG analysis showed significant and substantial gains in sensitivity for AMI diagnosis in DM2 patients, without loss in specificity. Sensitivity gains were particularly high in patients exhibiting NSTEMI, the most common form of AMI in DM2.
- Published
- 2011
- Full Text
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11. Wireless monitoring of reconstructed 12-lead ECG in atrial fibrillation patients enables differential diagnosis of recurrent arrhythmias.
- Author
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Vukajlovic D, Gussak I, George S, Simic G, Bojovic B, Hadzievski L, Stojanovic B, Angelkov L, and Panescu D
- Subjects
- Adult, Aged, Arrhythmias, Cardiac complications, Atrial Fibrillation complications, Diagnosis, Differential, Humans, Middle Aged, Arrhythmias, Cardiac diagnosis, Atrial Fibrillation physiopathology, Electrocardiography instrumentation, Radio Waves
- Abstract
Unlabelled: Differential diagnosis of symptomatic events in post-ablation atrial fibrillation (AF) patients (pts) is important; in particular, accurate, reliable detection of AF or atrial flutter (AFL) is essential. However, existing remote monitoring devices usually require attached leads and are not suitable for prolonged monitoring; moreover, most do not provide sufficient information to assess atrial activity, since they generally monitor only 1-3 ECG leads and rely on RR interval variability for AF diagnosis. A new hand-held, wireless, symptom-activated event monitor (CardioBip; CB) does not require attached leads and hence can be conveniently used for extended periods. Moreover, CB provides data that enables remote reconstruction of full 12-lead ECG data including atrial signal information. We hypothesized that these CB features would enable accurate remote differential diagnosis of symptomatic arrhythmias in post-ablation AF pts., Methods: 21 pts who underwent catheter ablation for AF were instructed to make a CB transmission (TX) whenever palpitations, lightheadedness, or similar symptoms occurred, and at multiple times daily when asymptomatic, during a 60 day post-ablation time period. CB transmissions (TXs) were analyzed blindly by 2 expert readers, with differences adjudicated by consensus., Results: 7 pts had no symptomatic episodes during the monitoring period. 14 of 21 pts had symptomatic events and made a total of 1699 TX, 164 of which were during symptoms. TX quality was acceptable for rhythm diagnosis and atrial activity in 96%. 118 TX from 10 symptomatic pts showed AF (96 TX from 10 pts) or AFL (22 TX from 3 pts), and 46 TX from 9 pts showed frequent PACs or PVCs. No other arrhythmias were detected. Five pts made symptomatic TX during AF/AFL and also during PACs/PVCs., Conclusions: Use of CB during symptomatic episodes enabled detection and differential diagnosis of symptomatic arrhythmias. The ability of CB to provide accurate reconstruction of 12 L ECGs including atrial activity, combined with its ease of use, makes it suitable for long-term surveillance for recurrent AF in post-ablation patients.
- Published
- 2011
- Full Text
- View/download PDF
12. Vectorcardiographic and electrocardiographic criteria to distinguish new and old left bundle branch block.
- Author
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Shvilkin A, Bojovic B, Vajdic B, Gussak I, Ho KK, Zimetbaum P, and Josephson ME
- Subjects
- Aged, Female, Humans, Male, Middle Aged, Time Factors, Vectorcardiography, Bundle-Branch Block diagnosis, Electrocardiography
- Abstract
Background: There are no established criteria to differentiate new from old left bundle branch block (LBBB). This complicates management of patients with LBBB and suspected acute coronary syndrome., Objectives: The purpose of this study was to develop electrocardiographic (ECG) criteria to differentiate new and old LBBB., Methods: All LBBB tracings (n = 3,706) in a hospital ECG database were retrieved. New (<24 hours, n = 39) and old (>24 hours, n = 1,760) LBBB tracings were identified. QRS and T-wave amplitudes, directions, and durations were measured digitally. Vectorcardiograms were reconstructed from 12-lead ECGs using inverse Dower transform and analyzed with Cardio3KG software. Receiver operator characteristic (ROC) curves were used to develop decision rules to distinguish new and old LBBB., Results: The new LBBB group had larger T-vector magnitude (1.20 +/- 0.07 vs. 0.71 +/- 0.01 mV), smaller QRS vector magnitude (2.13 +/- 0.12 vs. 2.47 +/- 0.02 mV), and a lower QRS/T vector magnitude ratio (QRS/T; 1.79 +/- 0.03 vs. 3.92 +/- 0.04) compared with the old LBBB group (mean +/- standard error of the mean, P <.001). The ratio of deepest S to largest T wave in precordial leads (Max S/T) was significantly smaller in the new compared with in the old LBBB group (1.66 +/- 0.05 vs. 3.54 +/- 0.08; P <.001). A decision rule using QRS/T <2.25 and Max S/T <2.5 had 100% sensitivity and 96%-68% specificity in diagnosing new LBBB, including subsets of patients with tachycardia and ischemia., Conclusions: QRS/T and Max S/T allow accurate discrimination between new and old LBBB suitable for both computerized and manual analysis. If confirmed in prospective studies, this finding can improve management of patients with chest pain and LBBB., (Copyright 2010 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)
- Published
- 2010
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13. Comparison of QTinno, a fully automated electrocardiographic analysis program, to semiautomated electrocardiographic analysis methods in a drug safety study in healthy subjects.
- Author
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Sarapa N, Gussak I, Vajdic B, George S, Hadzievski L, Francom SF, and Kowey P
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- Drug-Related Side Effects and Adverse Reactions, Humans, Reference Values, Reproducibility of Results, Sensitivity and Specificity, Algorithms, Diagnosis, Computer-Assisted methods, Drug Evaluation methods, Electrocardiography methods, Software
- Abstract
Background: Improved automated methods for electrocardiographic (ECG) analysis are needed, particularly for drug development purposes., Objectives: This study compared a novel fully automated method for ECG analysis (QTinno; NewCardio, Santa Clara, CA) to 2 semiautomated digital methods: global measurement from the earliest QRS onset to the latest T-wave offset on representative superimposed beats (global) and tangent measurement on 3 consecutive beats in one lead (tangent)., Methods: All 3 methods were used to determine uncorrected and rate-corrected QT interval duration (QT and QTcF) and related metrics in 1422 digital 12-lead ECGs from a phase 1 drug study. Global and tangent annotations were manually adjusted by the same 3 cardiologists wherever necessary. No adjustments were made in QTinno determinations., Results: QTinno returned QTcF change from time-matched baseline (DeltaQTcF) that differed minimally from both global and tangent methods (mean pairwise difference: 0.1 millisecond between QTinno and global, 1.1 milliseconds between QTinno and tangent). The average absolute QT and QTcF intervals by QTinno were approximately 5 milliseconds longer than global and 25 milliseconds longer than by tangent. QTinno had lower intrinsic variability for DeltaQTcF than either global or tangent (between-subject SD: QTinno 4.0 milliseconds, global 5.6 milliseconds, tangent 6.4 milliseconds; within-subject SD: QTinno 4.8 milliseconds, global 7.4 milliseconds, tangent 10.6 milliseconds). All methods were robust in detecting the largest placebo-adjusted mean time-matched DeltaQTcF (15-25 milliseconds) induced by study drug., Conclusions: The methods show good agreement for drug-induced QTc prolongation. Lower intrinsic variability of DeltaQTcF by QTinno could facilitate smaller sample sizes or increase study power in thorough QTc studies.
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- 2009
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14. Visual 3Dx: algorithms for quantitative 3-dimensional analysis of ECG signals.
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Bojovic B, Hadzievski L, Vukcevic VD, Panescu D, Gussak I, George S, Shvilkin A, and Vajdic B
- Subjects
- Balloon Occlusion adverse effects, Coronary Occlusion complications, Coronary Occlusion physiopathology, Electrophysiological Phenomena, Humans, Myocardial Ischemia diagnosis, Myocardial Ischemia etiology, Myocardial Ischemia physiopathology, Sensitivity and Specificity, Algorithms, Electrocardiography instrumentation
- Abstract
Introduction: The 12-lead ECG is useful for cardiac diagnosis but has limited sensitivity and specificity. To address this, we developed the Visual3Dx, a comprehensive method for describing cardiac electrical activity in time and space. The Visual3Dx transforms the ECG input into a time-variable heart vector, and normalizes each lead input to assure equal representation from all cardiac regions., Methods: We compared the Visual3Dx to the standard 12-lead ECG for detection of acute myocardial ischemia (AMI) in 2 clinical models. Model 1 was AMI after 90 s of balloon coronary occlusion in 117 cases. Model 2 was 122 consecutive patients who: (1) presented to an urban emergency department with chest pain; (2) were admitted to coronary care and developed elevated cardiac troponin levels; and (3) had coronary arteriography within 6 hrs., Results: In Model 1, the 12 lead ECG developed ST segment deviation diagnostic of AMI in 78/117 occlusions (67%), whereas using the same input ECG data, the Visual3Dx was diagnostic of AMI in 105/117 occlusions (90%; p<0.001). In Model 2, the first 12 lead ECG was diagnostic of AMI in 80/122 (66%), whereas the Visual3Dx was diagnostic in 103/122 (84%). In both Models, the largest sensitivity gains were seen in left circumflex and right coronary artery occlusions., Conclusions: The Visual3Dx is a promising tool for 3D quantitative analysis of cardiac electrical activity that may improve diagnosis of AMI, especially in electrically remote regions of the heart. Additional studies will define diagnostic specificity and further improve 3D biomarkers of AMI.
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- 2009
- Full Text
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15. Is a narrow and tall QRS complex an ECG marker for sudden death?
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Wolpert C, Veltmann C, Schimpf R, Antzelevitch C, Gussak I, and Borggrefe M
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- Adolescent, Adult, Atrial Fibrillation prevention & control, Humans, Male, Risk Factors, Syncope prevention & control, Young Adult, Atrial Fibrillation physiopathology, Death, Sudden, Cardiac prevention & control, Electrocardiography, Heart Conduction System physiopathology, Syncope physiopathology
- Published
- 2008
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16. Short QT syndrome--5 years of progress.
- Author
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Gussak I and Bjerregaard P
- Subjects
- Diagnosis, Differential, Humans, Male, Syndrome, Atrial Fibrillation diagnosis, Dyspnea diagnosis, Electrocardiography methods, Electrocardiography trends, Ventricular Fibrillation diagnosis
- Published
- 2005
- Full Text
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17. Short QT syndrome.
- Author
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Bjerregaard P and Gussak I
- Subjects
- Arrhythmias, Cardiac mortality, Clinical Trials as Topic, Female, Humans, Male, Practice Guidelines as Topic, Practice Patterns, Physicians', Syndrome, Anti-Arrhythmia Agents therapeutic use, Arrhythmias, Cardiac diagnosis, Arrhythmias, Cardiac therapy, Electrocardiography methods
- Abstract
Short QT syndrome (SQTS) is an inheritable primary electrical disease of the heart, discovered in 1999. It is characterized by an abnormally short QT interval (<300 ms) and a propensity to atrial fibrillation and sudden cardiac death (SCD). Like in the case of long QT syndrome there is more than one genetic mutation that can lead to a short QT interval in the ECG and so far two have been identified. Shortening of the effective refractory period combined with increased dispersion of repolarization is the likely substrate for reentry and life threatening tachyarrhythmias. Only 22 people have been classified as having SQTS: 15 from the actual measurement of a short QT interval in their ECG and 7 by history, all having died from SCD. It is very likely that several cases, especially among children, have been overlooked, since the shortness of the QT interval only becomes apparent at heart rates <80 beats/min. The best form of treatment is still not known, but prevention of atrial fibrillation has been accomplished by propafenone, and an implantable cardioverter defibrillator is recommended for prevention of SCD.
- Published
- 2005
- Full Text
- View/download PDF
18. Brugada syndrome: report of the second consensus conference.
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Antzelevitch C, Brugada P, Borggrefe M, Brugada J, Brugada R, Corrado D, Gussak I, LeMarec H, Nademanee K, Perez Riera AR, Shimizu W, Schulze-Bahr E, Tan H, and Wilde A
- Subjects
- Arrhythmogenic Right Ventricular Dysplasia diagnosis, Bundle-Branch Block physiopathology, Defibrillators, Implantable, Diagnosis, Differential, Heart Conduction System drug effects, Heart Conduction System physiopathology, Humans, Risk Assessment, Tachycardia, Ventricular complications, Ventricular Fibrillation complications, Bundle-Branch Block diagnosis, Bundle-Branch Block therapy, Death, Sudden, Cardiac etiology, Electrocardiography drug effects
- Abstract
Since its introduction as a clinical entity in 1992, the Brugada syndrome has progressed from being a rare disease to one that is second only to automobile accidents as a cause of death among young adults in some countries. Electrocardiographically characterized by a distinct ST-segment elevation in the right precordial leads, the syndrome is associated with a high risk for sudden cardiac death in young and otherwise healthy adults, and less frequently in infants and children. Patients with a spontaneously appearing Brugada ECG have a high risk for sudden arrhythmic death secondary to ventricular tachycardia/fibrillation. The ECG manifestations of Brugada syndrome are often dynamic or concealed and may be unmasked or modulated by sodium channel blockers, a febrile state, vagotonic agents, alpha-adrenergic agonists, beta-adrenergic blockers, tricyclic or tetracyclic antidepressants, a combination of glucose and insulin, hypo- and hyperkalemia, hypercalcemia, and alcohol and cocaine toxicity. In recent years, an exponential rise in the number of reported cases and a striking proliferation of articles defining the clinical, genetic, cellular, ionic, and molecular aspects of the disease have occurred. The report of the first consensus conference, published in 2002, focused on diagnostic criteria. The present report, which emanated from the second consensus conference held in September 2003, elaborates further on the diagnostic criteria and examines risk stratification schemes and device and pharmacological approaches to therapy on the basis of the available clinical and basic science data.
- Published
- 2005
- Full Text
- View/download PDF
19. Brugada syndrome: report of the second consensus conference: endorsed by the Heart Rhythm Society and the European Heart Rhythm Association.
- Author
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Antzelevitch C, Brugada P, Borggrefe M, Brugada J, Brugada R, Corrado D, Gussak I, LeMarec H, Nademanee K, Perez Riera AR, Shimizu W, Schulze-Bahr E, Tan H, and Wilde A
- Subjects
- Arrhythmogenic Right Ventricular Dysplasia diagnosis, Bundle-Branch Block physiopathology, Defibrillators, Implantable, Diagnosis, Differential, Heart Conduction System drug effects, Heart Conduction System physiopathology, Humans, Risk Assessment, Tachycardia, Ventricular complications, Ventricular Fibrillation complications, Bundle-Branch Block diagnosis, Bundle-Branch Block therapy, Death, Sudden, Cardiac etiology, Electrocardiography drug effects
- Abstract
Since its introduction as a clinical entity in 1992, the Brugada syndrome has progressed from being a rare disease to one that is second only to automobile accidents as a cause of death among young adults in some countries. Electrocardiographically characterized by a distinct ST-segment elevation in the right precordial leads, the syndrome is associated with a high risk for sudden cardiac death in young and otherwise healthy adults, and less frequently in infants and children. Patients with a spontaneously appearing Brugada ECG have a high risk for sudden arrhythmic death secondary to ventricular tachycardia/fibrillation. The ECG manifestations of Brugada syndrome are often dynamic or concealed and may be unmasked or modulated by sodium channel blockers, a febrile state, vagotonic agents, alpha-adrenergic agonists, beta-adrenergic blockers, tricyclic or tetracyclic antidepressants, a combination of glucose and insulin, hypo- and hyperkalemia, hypercalcemia, and alcohol and cocaine toxicity. In recent years, an exponential rise in the number of reported cases and a striking proliferation of articles defining the clinical, genetic, cellular, ionic, and molecular aspects of the disease have occurred. The report of the first consensus conference, published in 2002, focused on diagnostic criteria. The present report, which emanated from the second consensus conference held in September 2003, elaborates further on the diagnostic criteria and examines risk stratification schemes and device and pharmacological approaches to therapy on the basis of the available clinical and basic science data.
- Published
- 2005
- Full Text
- View/download PDF
20. Short QT syndrome: mechanisms, diagnosis and treatment.
- Author
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Bjerregaard P and Gussak I
- Subjects
- ERG1 Potassium Channel, Ether-A-Go-Go Potassium Channels, Genetic Predisposition to Disease, Humans, Mutation, Missense, Myocardium metabolism, Potassium Channels, Voltage-Gated genetics, Potassium Channels, Voltage-Gated metabolism, Prognosis, Propafenone therapeutic use, Anti-Arrhythmia Agents therapeutic use, Atrial Fibrillation diagnosis, Atrial Fibrillation genetics, Atrial Fibrillation therapy, Death, Sudden, Cardiac etiology, Death, Sudden, Cardiac prevention & control, Electric Countershock, Electrocardiography
- Abstract
Short QT syndrome is an inheritable primary electrical disease of the heart that was discovered in 1999. The disorder is characterized by an abnormally short QT interval (<300 ms) and a propensity to atrial fibrillation, sudden cardiac death or both. As in the case of long QT syndrome, more than one relevant genetic mutation has been identified that can lead to a short QT interval on electrocardiography; so far two have been identified. Shortening of the effective refractory period combined with increased dispersion of repolarization is the likely substrate for re-entry and life-threatening tachyarrhythmias. Thus far, 22 people have been classified as having short QT syndrome: 15 from the actual measurement of a short QT interval on electrocardiograms and 7 by history after they died from sudden cardiac death. Several cases, especially among children, have probably been overlooked, since the shortness of the QT interval becomes apparent only at heart rates less than 80 beats/min. The best form of treatment is still unknown, but prevention of atrial fibrillation has been accomplished by propafenone. Implantation of an implantable cardioverter defibrillator is recommended for prevention of sudden cardiac death.
- Published
- 2005
- Full Text
- View/download PDF
21. Electrocardiographic "lambda" wave and primary idiopathic cardiac asystole: a new clinical syndrome?
- Author
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Gussak I, Bjerregaard P, and Kostis J
- Subjects
- Death, Sudden, Cardiac, Humans, Syndrome, Electrocardiography, Heart Arrest physiopathology
- Published
- 2004
- Full Text
- View/download PDF
22. Drug-induced cardiac toxicity: emphasizing the role of electrocardiography in clinical research and drug development.
- Author
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Gussak I, Litwin J, Kleiman R, Grisanti S, and Morganroth J
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- Clinical Trials as Topic, Drug Evaluation legislation & jurisprudence, Drug Evaluation trends, Heart physiopathology, Heart Diseases chemically induced, Heart Diseases diagnosis, Heart Diseases prevention & control, Humans, Research legislation & jurisprudence, Research standards, Research trends, Drug Evaluation standards, Drugs, Investigational adverse effects, Electrocardiography, Heart drug effects
- Abstract
This review describes the role of electrocardiography in clinical research and drug development, and addresses its utility in defining cardiac toxicity from noncardiac investigational drugs. Principles for designing electrocardiographic monitoring for cardiac safety in clinical trials are also reviewed.
- Published
- 2004
- Full Text
- View/download PDF
23. ECG phenomenon of idiopathic and paradoxical short QT intervals.
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Gussak I, Brugada P, Brugada J, Antzelevitch C, Osbakken M, and Bjerregaard P
- Subjects
- Humans, Risk Factors, Arrhythmias, Cardiac etiology, Death, Sudden, Cardiac etiology, Electrocardiography, Heart physiopathology
- Published
- 2002
- Full Text
- View/download PDF
24. J Wave Syndromes Consensus Conference: Emerging Concepts & Gaps in Knowledge
- Author
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Antzelevitch, Charles, Yan, Gan-Xin, Ackerman, Michael J., Borggrefe, Martin, Corrado, Domenico, Guo, Jihong, Gussak, Ihor, Hasdemir, Can, Horie, Minoru, Huikuri, Heikki, Ma, Changsheng, Morita, Hiroshi, Nam, Gi-Byoung, Sacher, Frederic, Shimizu, Wataru, Viskin, Sami, and Wilde, Arthur A. M.
- Subjects
Survival Rate ,Electrocardiography ,Death, Sudden, Cardiac ,Consensus Development Conferences as Topic ,Incidence ,Humans ,Global Health ,Article ,Brugada Syndrome - Published
- 2016
25. Detection of QT prolongation using a novel ECG analysis algorithm applying intelligent automation: Prospective blinded evaluation using the Cardiac Safety Research Consortium ECG database
- Author
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Green, Cynthia L., Kligfield, Paul, George, Samuel, Gussak, Ihor, Vajdic, Branislav, Sager, Philip, and Krucoff, Mitchell W.
- Subjects
Aza Compounds ,Moxifloxacin ,Reproducibility of Results ,Article ,Automation ,Electrocardiography ,Long QT Syndrome ,Anti-Infective Agents ,Double-Blind Method ,Quinolines ,Humans ,Prospective Studies ,Algorithms ,Fluoroquinolones ,Follow-Up Studies - Abstract
The Cardiac Safety Research Consortium (CSRC) provides both "learning" and blinded "testing" digital electrocardiographic (ECG) data sets from thorough QT (TQT) studies annotated for submission to the US Food and Drug Administration (FDA) to developers of ECG analysis technologies. This article reports the first results from a blinded testing data set that examines developer reanalysis of original sponsor-reported core laboratory data.A total of 11,925 anonymized ECGs including both moxifloxacin and placebo arms of a parallel-group TQT in 181 subjects were blindly analyzed using a novel ECG analysis algorithm applying intelligent automation. Developer-measured ECG intervals were submitted to CSRC for unblinding, temporal reconstruction of the TQT exposures, and statistical comparison to core laboratory findings previously submitted to FDA by the pharmaceutical sponsor. Primary comparisons included baseline-adjusted interval measurements, baseline- and placebo-adjusted moxifloxacin QTcF changes (ddQTcF), and associated variability measures.Developer and sponsor-reported baseline-adjusted data were similar with average differences1 ms for all intervals. Both developer- and sponsor-reported data demonstrated assay sensitivity with similar ddQTcF changes. Average within-subject SD for triplicate QTcF measurements was significantly lower for developer- than sponsor-reported data (5.4 and 7.2 ms, respectively; P.001).The virtually automated ECG algorithm used for this analysis produced similar yet less variable TQT results compared with the sponsor-reported study, without the use of a manual core laboratory. These findings indicate that CSRC ECG data sets can be useful for evaluating novel methods and algorithms for determining drug-induced QT/QTc prolongation. Although the results should not constitute endorsement of specific algorithms by either CSRC or FDA, the value of a public domain digital ECG warehouse to provide prospective, blinded comparisons of ECG technologies applied for QT/QTc measurement is illustrated.
- Published
- 2012
26. Vectorcardiographic determinants of cardiac memory during normal ventricular activation and continuous ventricular pacing.
- Author
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Shvilkin, Alexei, Bojovic, Bosko, Vajdic, Branislav, Gussak, Ihor, Zimetbaum, Peter, and Josephson, Mark E.
- Abstract
Background: Cardiac memory (CM) refers to persistent T-wave changes on resumption of normal conduction after a period of abnormal ventricular activation. Traditionally, to observe CM, normal ventricular activation had to be restored, limiting the exploration of this phenomenon in clinical practice. Objective: This study sought to prove that CM can be detected during continuous aberrant activation and to establish factors affecting its magnitude using a vectorcardiographic technique. Methods: Sixteen nonpacemaker-dependent patients (11 male, age 72 ± 8 years, mean ± SD) undergoing pacemaker/internal cardioverter-defibrillator implantation were paced in DDD mode with a short atrioventricular (AV) delay for 7 days to induce CM. Electrocardiograms were acquired during AAI and DDD pacing at a constant rate before and after CM induction. Dower transform–derived vectorcardiograms were reconstructed and analyzed. Results: T vector during AAI pacing changed in both magnitude (baseline, 0.26 ± 0.10 mV; Day 7, 0.39 ± 0.13 mV, P < .01) and direction aligning with the paced QRS vector (baseline DDD QRS − AAI T angle 125° ± 36°; Day 7, 39° ± 21°, P < .01). During DDD pacing, there was no change in T-vector direction, but T amplitude decreased (baseline, 1.06 ± 0.32 mV; Day 7, 0.71 ± 0.26 mV, P < .01). CM measured as T-vector peak displacement (TPD) was identical in AAI and DDD mode (TPD 0.46 ± .0.17 mV and 0.46 ± 0.17 mV, respectively). Individual CM magnitude correlated with QRS/T-vector amplitude ratio during DDD pacing at baseline (r = 0.90). Conclusion: CM can be reliably shown during continuous ventricular pacing, expanding its application to situations in which abnormal ventricular activation persists. Its magnitude is determined by the QRS/T-amplitude ratio of the ventricular paced beat. [Copyright &y& Elsevier]
- Published
- 2009
- Full Text
- View/download PDF
27. False-Negative and False-Positive ECG Diagnoses of Q Wave Myocardial Infarction in the Presence of Right Bundle-Branch Block.
- Author
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Gussak, Ihor, Wright, R. Scott, Bjerregaard, Preben, Chaitman, Bernard R., Zhou, Sophia H., Hammill, Stephen C., and Kopecky, Stephen L.
- Subjects
- *
HEART block , *BUNDLE-branch block , *MYOCARDIAL infarction , *ELECTRODIAGNOSIS , *VECTORCARDIOGRAPHY , *ELECTROCARDIOGRAPHY , *HEART disease diagnosis - Abstract
Right bundle-branch block (RBBB) has not traditionally been seen as an obstacle to ECG diagnosis of Q wave myocardial infarction (MI) – in clinical electrocardiography and vectorcardiography – because this conduction disturbance is not believed to cause significant alterations in the spatial orientation of initial excitation wavefronts. In the era of large-scale clinical trials, however, where serial ECG analysis is among the major diagnostic tools in MI classification, both false-positive and false-negative diagnoses of MI in the presence of RBBB have become increasingly evident. Because of the limited detectability of Q wave MI by ECG in the presence of RBBB, the electrocardiographic finding of Q wave MI should not be regarded as an independent diagnostic tool. It is best to utilize independent corroboration to establish the diagnosis of transmural infarction when RBBB is present. Further investigations are warranted to better delineate sensitivity, specificity, and predictive value of Q wave MI in the presence of RBBB. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
28. Idiopathic Short QT Interval:A New Clinical Syndrome?
- Author
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Gussak, Ihor, Brugada, Pedro, Brugada, Josep, Wright, R. Scott, Kopecky, Stephen L., Chaitman, Bernard R., and Bjerregaard, Preben
- Subjects
- *
FAMILIAL diseases , *HEART disease diagnosis , *ELECTROCARDIOGRAPHY , *ATRIAL fibrillation , *SUDDEN death , *CARDIAC arrest , *CLINICAL medicine - Abstract
In this first clinical report of an idiopathic familial persistently short QT interval (QTI), we describe three members of one family (a 17-year-old female, her 21-year-old brother, and their 51-year-old mother) demonstrating this ECG phenomenon, associated in the 17-year-old with several episodes of paroxysmal atrial fibrillation requiring electrical cardioversion. Similar ECG changes seen in an unrelated 37-year-old patient were associated with sudden cardiac death. Our report also describes other manifestations of abnormal shortening of the QTI and considers the possible arrhythmogenic potential of the short QTI. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
29. Exercise-Induced ST Segment Elevation in Q Wave Leads in Postinfarction Patients: Defining Its Meaning and Utility in Today’s Practice.
- Author
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Gussak, Ihor, Wright, R. Scott, Kopecky, Stephen L., and Hammill, Stephen C.
- Subjects
- *
QUALITATIVE research , *MYOCARDIAL revascularization , *ELECTROCARDIOGRAPHY , *ELECTROPHYSIOLOGY , *PROGNOSIS , *CORONARY disease , *PATIENTS ,MYOCARDIAL infarction diagnosis - Abstract
Most attempts to identify qualitative and quantitative techniques for assessing myocardial viability and the likelihood of improved function after revascularization in patients with healed myocardial infarcts have focused on treatment strategies and prognosis. This review examines the true value of the electrocardiographic phenomenon of exercise-induced ST segment elevation (EISTE) in Q wave leads as a diagnostic tool for the assessment of myocardial viability. The prognostic potential and clinical utility of the EISTE phenomenon are inhibited both by the heart’s electrophysiologic response to exercise-induced metabolic and hemodynamic changes, and by the ECG’s limited facility in assessing myocardial preservation. The use of EISTE as an independent indicator for surgical intervention is proscribed by these limitations. The EISTE phenomenon could serve as a useful tool in the first line of discrimination in patients with healed Q wave myocardial infarction, and may justify further diagnostic work-up in patients under consideration for a revascularization procedure. In the era of sophisticated nuclear and echo techniques, accurate imaging studies should not be replaced by ECG analysis alone in the search for viable tissue, except when financial costs are of major importance. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
30. Short QT Syndrome: A Predictable Story.
- Author
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Brugada, Josep, Gussak, Ihor, and Brugada, Pedro
- Subjects
- *
SHORT QT syndrome , *MORTALITY , *ELECTROCARDIOGRAPHY , *SYNCOPE , *DISEASES in women - Abstract
No abstract available [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
31. Diagnostic Electrocardiography
- Author
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Bjerregaard, Preben, Gussak, Ihor, editor, and Antzelevitch, Charles, editor
- Published
- 2013
- Full Text
- View/download PDF
32. Brugada Syndrome: Cellular Mechanisms and Approaches to Therapy
- Author
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Antzelevitch, Charles, Viskin, Sami, Gussak, Ihor, editor, and Antzelevitch, Charles, editor
- Published
- 2013
- Full Text
- View/download PDF
33. Cardiac Memory: From Electrical Curiosity to Clinical Diagnostic and Research Tool
- Author
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Shvilkin, Alexei, Gussak, Ihor, editor, and Antzelevitch, Charles, editor
- Published
- 2013
- Full Text
- View/download PDF
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