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Anatolian Journal of Cardiology Nov 2016
Topics: Arrhythmias, Cardiac; Electrocardiography; Humans; Risk Assessment
PubMed: 27872443
DOI: 10.14744/AnatolJCardiol.2016.21130 -
Arquivos Brasileiros de Cardiologia May 2018Sudden cardiac death is the most frequent death mechanism in Chagas disease, responsible for 55% to 65% of the deaths of patients with chronic Chagas cardiomyopathy... (Observational Study)
Observational Study
BACKGROUND
Sudden cardiac death is the most frequent death mechanism in Chagas disease, responsible for 55% to 65% of the deaths of patients with chronic Chagas cardiomyopathy (CCC). The most often involved electrophysiological mechanisms are ventricular tachycardia and ventricular fibrillation. The implantable cardioverter defibrillator (ICD) has a beneficial role in preventing sudden death due to malignant ventricular arrhythmias, and, thus the correct identification of patients at risk is required. The association of microvolt T-wave alternans (MTWA) with the appearance of ventricular arrhythmias has been assessed in different heart diseases. The role of MTWA is mostly unknown in patients with CCC.
OBJECTIVES
To evaluate the association between MTWA and the occurrence of malignant ventricular arrhythmias in patients with CCC.
METHOD
This is a case-control study including patients with CCC and ICD, with history of malignant ventricular arrhythmias (case group), and patients with CCC and no history of those arrhythmias (control group). The MTWA test results were classified as negative and non-negative (positive and indeterminate). The significance level adopted was a = 0.05.
RESULTS
We recruited 96 patients, 45 cases (46.8%) and 51 controls (53.1%). The MTWA test was non-negative in 36/45 cases (80%) and 15/51 controls (29.4%) [OR = 9.60 (95%CI: 3.41 - 27.93)]. After adjustment for known confounding factors in a logistic regression model, the non-negative result continued to be associated with malignant ventricular arrhythmias [OR = 5.17 (95%CI: 1.05 - 25.51)].
CONCLUSION
Patients with CCC and history of malignant ventricular arrhythmias more often have a non-negative MTWA test as compared to patients with no history of arrhythmia.
Topics: Arrhythmias, Cardiac; Case-Control Studies; Chagas Disease; Death, Sudden, Cardiac; Defibrillators, Implantable; Electrocardiography; Female; Humans; Male; Middle Aged; Risk Factors; Survival Analysis; Tachycardia, Ventricular
PubMed: 29641645
DOI: 10.5935/abc.20180056 -
Congestive Heart Failure (Greenwich,... 2007With the rise in the use of device therapy implants, we are better identifying appropriate chronic heart failure patients for primary implantable defibrillator therapy... (Review)
Review
With the rise in the use of device therapy implants, we are better identifying appropriate chronic heart failure patients for primary implantable defibrillator therapy who are at risk of ventricular arrhythmia. As our knowledge expands, however, controversial issues emerge. Guidelines have been endorsed by the major international societies, such as the American College of Cardiology (ACC), the American Heart Association (AHA), and the European Society of Cardiology. In view of certain variances in recommendations and new data, a recent joint guideline statement has been issued from these 3 societies regarding management of ventricular arrhythmia and preventing sudden cardiac death in patients with left ventricular dysfunction and heart failure. In this review, the recent joint statement is compared with those from the Heart Failure Society of America (Heart Failure Practice Guidelines 2006) and ACC/AHA (Heart Failure Guidelines 2005), with a special emphasis on new expanded criteria for primary prevention in both ischemic and nonischemic heart disease. In addition, the authors review current guidelines for electrophysiology testing in chronic left ventricular dysfunction and the emerging role of microvolt T-wave alternans as a means of risk stratification.
Topics: Adrenergic beta-Antagonists; Death, Sudden, Cardiac; Defibrillators, Implantable; Electrophysiologic Techniques, Cardiac; Heart Failure; Humans; Potassium Channel Blockers; Practice Guidelines as Topic; Primary Prevention; Risk Assessment; Tachycardia, Ventricular; Ventricular Dysfunction, Left; Ventricular Fibrillation
PubMed: 17673876
DOI: 10.1111/j.1527-5299.2007.07329.x -
Cardiovascular Digital Health Journal Aug 2022Qualitative differences in 12-lead electrocardiograms (ECG) at onset have been reported in patients with takotsubo syndrome (TTS) and acute anterior myocardial...
BACKGROUND
Qualitative differences in 12-lead electrocardiograms (ECG) at onset have been reported in patients with takotsubo syndrome (TTS) and acute anterior myocardial infarction (Ant-AMI). We aimed to distinguish these diseases by machine learning (ML) approach of microvolt-level quantitative measurements.
METHODS
We enrolled 56 consecutive patients with sinus rhythm TTS (median age, 77 years; 16 men), and 1-to-1 random matching was performed based on age and sex of the patients. The ECG in the emergency room was evaluated using an automated system (ECAPs12c; Nihon-Koden). Statistical and ML predictive models for TTS were constructed using clinical features and ECG parameters.
RESULTS
Statistically significant differences were observed in 25 parameters; the V ST level at the J point (V STJ) showed the lowest value ( < .001). V STJ ≤+18 μV showed the highest accuracy for TTS (0.773). The highest area under the receiver operating characteristic curve (AUROC) was shown in the aVR ST level at 1/16th of the preceding R-R interval after the J point (aVR STmid: 0.727). Conversely, the light gradient boosting machine (model_LGBM) and extra tree classifier (model_ET) indicated higher accuracy (model_LGBM: 0.842, model_ET: 0.831) and AUROC (model_LGBM: 0.868, model_ET 0.896) than other statistical models. V STJ had high feature importance and Shapley additive explanation values in the 2 ML models.
CONCLUSION
ML applied to automated microvolt-level ECG measurements showed the possibility of distinguishing between TTS and Ant-AMI, which may be a clinically useful ECG-based discriminator.
PubMed: 36046427
DOI: 10.1016/j.cvdhj.2022.07.001 -
International Archives of... Jul 2021Mismatch negativity (MMN) is a promising instrument for the investigation of different auditory disorders, as it does not need behavioral responses. To analyze...
Mismatch negativity (MMN) is a promising instrument for the investigation of different auditory disorders, as it does not need behavioral responses. To analyze the influence of the ear, gender and age variables in the MMN in children with typical development; and to compare the different measures of this potential, using verbal and nonverbal stimuli in the sample studied, providing reference values. Observational, descriptive, cross-sectional, quantitative study, with 23 children, aged from 5 to 11 years and 11 months old, divided by age group. Mismatch negativity was performed using verbal and nonverbal stimuli, and the data was analyzed by means of the statistical Student -test. No significant differences were noted for the ear, gender and age variables in the MMN with both stimuli. There were significant differences for the latency, duration and area variables when the stimuli were compared. The reference values established for nonverbal stimuli were: latency 249.8 milliseconds, amplitude 2.28 µv, duration 82.97 milliseconds, and area 137.3 microvolt x microseconds (μVx μs); as for the verbal stimuli, they were: latency 265.3 milliseconds, amplitude - 2.82 µv, duration 110.5 milliseconds, and area 225.5 microvolt x microseconds (μVx μs). The variables studied did not influence the recordings of the MMN. Latency, duration and area of the MMN with verbal stimuli were higher. It was possible to furnish reference values for children with typical development in the age group studied.
PubMed: 34377175
DOI: 10.1055/s-0040-1713590 -
BMC Cardiovascular Disorders Jan 2009Studies have demonstrated that the use of implantable cardioverter defibrillators (ICDs) is effective for the primary prevention of arrhythmic events but due to imposing... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Studies have demonstrated that the use of implantable cardioverter defibrillators (ICDs) is effective for the primary prevention of arrhythmic events but due to imposing costs, there remains a need to identify which patients will derive the greatest benefit. Microvolt T-wave alternans (MTWA) has been proposed to assist in this stratification.
METHODS
We systematically searched the literature using MEDLINE, EMBASE, Current Contents, the Cochrane Library, INAHTA, and the Web of Science to identify all primary prevention randomized controlled trials and prospective cohort studies with at least 12 months of follow-up examining MTWA as a predictor of mortality and severe arrhythmic events in patients with severe left-ventricular dysfunction. The search was limited to full-text English publications between January 1990 and May 2007. The primary outcome was a composite of mortality and severe arrhythmias. Data were synthesized using Bayesian hierarchical models.
RESULTS
We identified no trials and 8 published cohort studies involving a total of 1,946 patients, including 332 positive, 656 negative, 84 indeterminate, and 874 non-negative (which includes both positive and indeterminate tests) MTWA test results. The risk of mortality or severe arrhythmic events was higher in patients with a positive MTWA compared to a negative test (RR = 2.7, 95% credible interval (CrI) = 1.4, 6.1). Similar results were obtained when comparing non-negative MTWA to a negative test.
CONCLUSION
A positive MTWA test predicts mortality or severe arrhythmic events in a population of individuals with severe left ventricular dysfunction. However, the wide credible interval suggests the clinical utility of this test remains incompletely defined, ranging from very modest to substantial. Additional high quality studies are required to better refine the role of MTWA in the decision making process for ICD implantation.
Topics: Arrhythmias, Cardiac; Controlled Clinical Trials as Topic; Cost-Benefit Analysis; Defibrillators, Implantable; Exercise Test; Humans; MEDLINE; Predictive Value of Tests; Quality Assurance, Health Care; Sensitivity and Specificity; Ventricular Dysfunction, Left
PubMed: 19175926
DOI: 10.1186/1471-2261-9-5 -
Clinical Neurophysiology : Official... Oct 2022Periods of low-amplitude electroencephalographic (EEG) signal (quiescence) are present during both anesthetic-induced burst suppression (BS) and postictal generalized...
OBJECTIVE
Periods of low-amplitude electroencephalographic (EEG) signal (quiescence) are present during both anesthetic-induced burst suppression (BS) and postictal generalized electroencephalographic suppression (PGES). PGES following generalized seizures induced by electroconvulsive therapy (ECT) has been previously linked to antidepressant response. The commonality of quiescence during both BS and PGES motivated trials to recapitulate the antidepressant effects of ECT using high doses of anesthetics. However, there have been no direct electrographic comparisons of these quiescent periods to address whether these are distinct entities.
METHODS
We compared periods of EEG quiescence recorded from two human studies: BS induced in 29 healthy adult volunteers by isoflurane general anesthesia and PGES in 11 patients undergoing right unilateral ECT for treatment-resistant depression. An automated algorithm allowed detection of EEG quiescence based on a 10-microvolt amplitude threshold. Spatial, spectral, and temporal analyses compared quiescent epochs during BS and PGES.
RESULTS
The median (interquartile range) voltage for quiescent periods during PGES was greater than during BS (1.81 (0.22) microvolts vs 1.22 (0.33) microvolts, p < 0.001). Relative power was greater for quiescence during PGES than BS for the 1-4 Hz delta band (p < 0.001), at the expense of power in the theta (4-8 Hz, p < 0.001), beta (13-30 Hz, p = 0.04) and gamma (30-70 Hz, p = 0.006) frequency bands. Topographic analyses revealed that amplitude across the scalp was consistently higher for quiescent periods during PGES than BS, whose voltage was within the noise floor.
CONCLUSIONS
Quiescent epochs during PGES and BS have distinct patterns of EEG signals across voltage, frequency, and spatial domains.
SIGNIFICANCE
Quiescent epochs during PGES and BS, important neurophysiological markers for clinical outcomes, are shown to have distinct voltage and frequency characteristics.
Topics: Adult; Algorithms; Electroconvulsive Therapy; Electroencephalography; Humans; Isoflurane; Seizures
PubMed: 36030576
DOI: 10.1016/j.clinph.2022.07.493 -
Cardiology Journal 2022Major adverse cardiovascular events (MACE) constitutes the main cause of morbidity and mortality in ischemic heart failure (HF) patients. The prognostic value of the...
BACKGROUND
Major adverse cardiovascular events (MACE) constitutes the main cause of morbidity and mortality in ischemic heart failure (HF) patients. The prognostic value of the autonomic nervous system parameters and microvolt T-wave alternans (MTWA) in this issue has not been identified to date. The aim herein, was to assess the usefulness of the abovementioned parameters in the prediction of MACE in HF patients with left ventricular systolic dysfunction of ischemic origin.
METHODS
Baroreflex sensitivity (BRS), heart rate variability (HRV), MTWA and other well-known clinical parameters were analyzed in 188 ischemic HF outpatients with left ventricular ejection fraction (LVEF) ≤ 50%. During 34 (14-71) months of follow-up, 56 (30%) endpoints were noted.
RESULTS
Univariate Cox analyses revealed BRS (but not HRV), MTWA, age, New York Heart Association functional class III, LVEF, implantable cardioverter-defibrillator presence, use of diuretics and antiarrhythmic drugs, diabetes, and kidney insufficiency were defined as significant predictors of MACE. Pre-specified cut-off values for MACE occurrence for the aforementioned continuous parameters (age, LVEF, and BRS) were: ≥ 72 years, ≤ 33%, and ≤ 3 ms/mmHg, respectively. In a multivariate Cox analysis only BRS (HR 2.97, 95% CI 1.35-6.36, p < 0.006), and LVEF (HR 1.98, 95% CI 0.61-4.52, p < 0.038) maintained statistical significance in the prediction of MACE.
CONCLUSIONS
Baroreflex sensitivity and LVEF are independent of other well-known clinical parameters in the prediction of MACE in patients with HF of ischemic origin and LVEF up to 50%. BRS ≤ 3 ms/mmHg and LVEF ≤ 33% identified individuals with the highest probability of MACE during the follow-up period.
Topics: Humans; Aged; Baroreflex; Stroke Volume; Death, Sudden, Cardiac; Ventricular Function, Left; Arrhythmias, Cardiac; Heart Failure; Prognosis; Defibrillators, Implantable
PubMed: 33001423
DOI: 10.5603/CJ.a2020.0129 -
Annals of Noninvasive Electrocardiology... Oct 2011Microvolt T-wave alternans (MTWA) has been proposed as a predictor of the risk of ventricular tachyarrhythmias (VT) and sudden cardiac death (SCD). Aim of this study was... (Meta-Analysis)
Meta-Analysis Review
Predictive value of microvolt T-wave alternans for cardiac death or ventricular tachyarrhythmic events in ischemic and nonischemic cardiomyopathy patients: a meta-analysis.
BACKGROUND
Microvolt T-wave alternans (MTWA) has been proposed as a predictor of the risk of ventricular tachyarrhythmias (VT) and sudden cardiac death (SCD). Aim of this study was to perform a systematic review of the literature and a meta-analysis of MTWA in primary prevention patients with ischemic and nonischemic cardiomyopathy.
METHODS
The positive predictive value (PPV), negative predictive value (NPV), and relative risk (RR) of MTWA in predicting death, cardiac death, and SCD during follow-up were reported.
RESULTS
Fifteen studies involving 5681 patients (mean age 62 years, mean ejection fraction 32%) were included. The summary PPV during the average 26-month follow-up was 14% (95% CI: 13-15); NPV was 95% (95% CI: 94-96), and the univariate RR was 2.35 (95% CI: 1.68-3.28). The predictive value of MTWA was similar in patients with ischemic and nonischemic cardiomyopathy. The average RR for SCD or VT events of an abnormal MTWA was 2.40, similar to that for cardiac death. When we grouped the studies together depending upon whether beta-blockers were withheld prior to MTWA screening, the beta-blockers group showed an RR of 5.88. By contrast, the group in which beta-blocker therapy was withheld had an RR of 1.63.
CONCLUSION
A positive MTWA determined an approximately 2.5-fold higher risk of cardiac death and life-threatening arrhythmia and showed a very high NPV both in ischemic and nonischemic patients. An abnormal MTWA test was associated with a 5-fold increased risk for cardiac mortality in the low-indeterminate group and about a 6-fold increased risk in beta-blockers group.
Topics: Adrenergic beta-Antagonists; Cardiomyopathies; Death, Sudden, Cardiac; Defibrillators, Implantable; Electrocardiography; Electrophysiologic Techniques, Cardiac; Female; Humans; Male; Middle Aged; Predictive Value of Tests; Primary Prevention; Prognosis; Risk Assessment; Tachycardia, Ventricular
PubMed: 22008495
DOI: 10.1111/j.1542-474X.2011.00467.x -
Journal of the American Heart... Mar 2022Background Early life trauma has been associated with increased cardiovascular risk, but the arrhythmic implications are unclear. We hypothesized that in patients with... (Clinical Trial)
Clinical Trial
Early Life Trauma Is Associated With Increased Microvolt T-Wave Alternans During Mental Stress Challenge: A Substudy of Mental Stress Ischemia: Prognosis and Genetic Influences.
Background Early life trauma has been associated with increased cardiovascular risk, but the arrhythmic implications are unclear. We hypothesized that in patients with coronary artery disease, early life trauma predicts increased arrhythmic risk during mental stress, measured by elevated microvolt T-wave alternans (TWA), a measure of repolarization heterogeneity and sudden cardiac death risk. Methods and Results In a cohort with stable coronary artery disease (NCT04123197), we examined early life trauma with the Early Trauma Inventory Self Report-Short Form. Participants underwent a laboratory-based mental stress speech task with Holter monitoring, as well as a structured psychiatric interview. We measured TWA during rest, mental stress, and recovery with ambulatory electrocardiographic monitoring. We adjusted for sociodemographic factors, cardiac history, psychiatric comorbidity, and hemodynamic stress reactivity with multivariable linear regression models. We examined 320 participants with noise- and arrhythmia-free ECGs. The mean (SD) age was 63.8 (8.7) years, 27% were women, and 27% reported significant childhood trauma (Early Trauma Inventory Self Report-Short Form ≥10). High childhood trauma was associated with a multivariable-adjusted 17% increase in TWA (=0.04) during stress, and each unit increase in the Early Trauma Inventory Self Report-Short Form total score was associated with a 1.7% higher stress TWA (=0.02). The largest effect sizes were found with the emotional trauma subtype. Conclusions In a cohort with stable coronary artery disease, early life trauma, and in particular emotional trauma, is associated with increased TWA, a marker of increased arrhythmic risk, during mental stress. This association suggests that early trauma exposures may affect long-term sudden cardiac death risk during emotional triggers, although more studies are warranted.
Topics: Arrhythmias, Cardiac; Coronary Artery Disease; Death, Sudden, Cardiac; Electrocardiography; Female; Humans; Ischemia; Middle Aged; Prognosis
PubMed: 35167312
DOI: 10.1161/JAHA.121.021582