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International Journal of Environmental... Jun 2020The aim of this study was to systematically review the current literature on the electromyographic (EMG) activity of six core muscles (the rectus abdominis, the internal...
The aim of this study was to systematically review the current literature on the electromyographic (EMG) activity of six core muscles (the rectus abdominis, the internal and external oblique, the transversus abdominis, the lumbar multifidus, and the erector spinae) during core physical fitness exercises in healthy adults. A systematic review of the literature was conducted on the Cochrane, EBSCO, PubMed, Scopus, and Web of Science electronic databases for studies from January 2012 to March 2020. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines were used. The inclusion criteria were as follows: a) the full text available in English; b) a cross-sectional or longitudinal (experimental or cohorts) study design; c) the reporting of electromyographic activity as a percentage of maximum voluntary contraction (% MVIC), millivolts or microvolts; d) an analysis of the rectus abdominis (RA), transversus abdominis (TA), lumbar multifidus (MUL), erector spinae (ES), and the internal (IO) or external oblique (EO); e) an analysis of physical fitness exercises for core training; and f) healthy adult participants. The main findings indicate that the greatest activity of the RA, EO, and ES muscles was found in free-weight exercises. The greatest IO activity was observed in core stability exercises, while traditional exercises showed the greatest MUL activation. However, a lack of research regarding TA activation during core physical fitness exercises was revealed, in addition to a lack of consistency between the studies when applying methods to measure EMG activity.
Topics: Cross-Sectional Studies; Electromyography; Exercise; Exercise Therapy; Humans; Muscle, Skeletal; Physical Fitness
PubMed: 32560185
DOI: 10.3390/ijerph17124306 -
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 -
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