Abstract Heart rate (HR) variability has been extensively studied in cardiac patients, especially in patients surviving an acute myocardial infarction (AMI) and also in patients with congestive heart ...failure (CHF) or left ventricular (LV) dysfunction. The majority of studies have shown that patients with reduced or abnormal HR variability have an increased risk of mortality within a few years after an AMI or after a diagnosis of CHF/LV dysfunction. Various measures of HR dynamics, such as time-domain, spectral, and non-linear measures of HR variability have been used in risk stratification. The prognostic power of various measures, except of those reflecting rapid R–R interval oscillations, has been almost identical, albeit some non-linear HR variability measures, such as short-term fractal scaling exponent have provided somewhat better prognostic information than the others. Abnormal HR variability predicts both sudden and non-sudden cardiac death. Because of remodeling of the arrhythmia substrate after AMI, early measurement of HR variability to identify those at high risk should likely be repeated later in order to assess the risk of fatal arrhythmia events. Future randomized trials using HR variability/turbulence as one of the pre-defined inclusion criteria will show whether routine measurement of HR variability/turbulence will become a routine clinical tool for risk stratification of cardiac patients.
Following the publication of the Task Force document on heart rate variability (HRV) in 1996, a number of articles have been published to describe new HRV methodologies and their application in ...different physiological and clinical studies. This document presents a critical review of the new methods. A particular attention has been paid to methodologies that have not been reported in the 1996 standardization document but have been more recently tested in sufficiently sized populations. The following methods were considered: Long-range correlation and fractal analysis; Short-term complexity; Entropy and regularity; and Nonlinear dynamical systems and chaotic behaviour. For each of these methods, technical aspects, clinical achievements, and suggestions for clinical application were reviewed. While the novel approaches have contributed in the technical understanding of the signal character of HRV, their success in developing new clinical tools, such as those for the identification of high-risk patients, has been rather limited. Available results obtained in selected populations of patients by specialized laboratories are nevertheless of interest but new prospective studies are needed. The investigation of new parameters, descriptive of the complex regulation mechanisms of heart rate, has to be encouraged because not all information in the HRV signal is captured by traditional methods. The new technologies thus could provide after proper validation, additional physiological, and clinical meaning. Multidisciplinary dialogue and specialized courses in the combination of clinical cardiology and complex signal processing methods seem warranted for further advances in studies of cardiac oscillations and in the understanding normal and abnormal cardiac control processes.
The Early Repolarization Pattern: A Consensus Paper Macfarlane, Peter W; Antzelevitch, Charles; Haissaguerre, Michel ...
Journal of the American College of Cardiology,
07/2015, Letnik:
66, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The term early repolarization has been in use for more than 50 years. This electrocardiographic pattern was considered benign until 2008, when it was linked to sudden cardiac arrest due to idiopathic ...ventricular fibrillation. Much confusion over the definition of early repolarization followed. Thus, the objective of this paper was to prepare an agreed definition to facilitate future research in this area. The different definitions of the early repolarization pattern were reviewed to delineate the electrocardiographic measures to be used when defining this pattern. An agreed definition has been established, which requires the peak of an end-QRS notch and/or the onset of an end-QRS slur as a measure, denoted Jp, to be determined when an interpretation of early repolarization is being considered. One condition for early repolarization to be present is Jp ≥0.1 mV, while ST-segment elevation is not a required criterion.
Fragmented QRS complex with visible notching on standard 12-lead electrocardiogram (ECG) is understood to represent depolarization abnormalities and to signify risk of cardiac events. Depolarization ...abnormalities with similar prognostic implications likely exist beyond visual recognition but no technology is presently suitable for quantification of such invisible ECG abnormalities. We present such a technology.
A signal processing method projects all ECG leads of the QRS complex into optimized three perpendicular dimensions, reconstructs the ECG back from this three-dimensional projection, and quantifies the difference (QRS 'micro'-fragmentation, QRS-μf) between the original and reconstructed signals. QRS 'micro'-fragmentation was assessed in three different populations: cardiac patients with automatic implantable cardioverter-defibrillators, cardiac patients with severe abnormalities, and general public. The predictive value of QRS-μf for mortality was investigated both univariably and in multivariable comparisons with other risk factors including visible QRS 'macro'-fragmentation, QRS-Mf. The analysis was made in a total of 7779 subjects of whom 504 have not survived the first 5 years of follow-up. In all three populations, QRS-μf was strongly predictive of survival (P < 0.001 univariably, and P < 0.001 to P = 0.024 in multivariable regression analyses). A similar strong association with outcome was found when dichotomizing QRS-μf prospectively at 3.5%. When QRS-μf was used in multivariable analyses, QRS-Mf and QRS duration lost their predictive value.
In three populations with different clinical characteristics, QRS-μf was a powerful mortality risk factor independent of several previously established risk indices. Electrophysiologic abnormalities that contribute to increased QRS-μf values are likely responsible for the predictive power of visible QRS-Mf.
To study social and clinical characteristics of victims of sudden cardiac death (SCD) due to alcoholic cardiomyopathy (ACM).
The study population comprised a subset of Fingesture cohort. All subjects ...were verified SCD victims determined to have ACM as cause of death in medico-legal autopsy between 1998 and 2017 in Northern Finland. The Finnish Population Register Centre provided SCD victims' last place of residence. Population data of residential area were obtained from Statistics Finland.
From a total of 5869 SCD victims in Fingesture cohort, in 290 victims the cause of SCD was ACM (4.9%; median age 56 (50-62) years; 83% males). In 64 (22.1%) victims, the diagnosis of cardiac disease was made prior to death and in 226 (77.9%) at autopsy. There were no significant differences in autopsy findings between victims with or without known cardiac diagnosis, but steatohepatitis (94.5%) and liver cirrhosis (64,5%) were common in both groups. Alcoholism was more often recorded in the known cardiac disease group (64.1% vs 47.3%, p=0.023). Majority were included in the working age population (ie, under 65 years) (54.8% and 53.1%, p=0.810). In high-income communities, 28.8% of ACM SCD victims had previously diagnosed cardiac disease, the proportion in the middle-income and low-income communities was 18.6% (p=0.05).
Majority of SCD victims due to ACM did not have previously diagnosed cardiac disease, but documented risk consumption of alcohol was common. This emphasises the importance of routine screening of alcohol consumption and signs of cardiomyopathy in heavy alcohol users in primary healthcare.
Coronary artery disease (CAD) mortality has declined substantially over the past decades thanks to advancing medical and interventional/surgical treatments; therefore, the prognostic value of the ...heart rate variability in CAD in the current treatment era is not well established. We evaluated the prognostic significance of baseline heart rate variability in 1,757 ARTEMIS study patients with angiographically verified CAD. During an average follow-up time of 8.7 ± 2.2 years, a total of 285 (16.2%) patients died. Of the patients, 63 (3.6%) suffered sudden cardiac death or were resuscitated from sudden cardiac arrest (SCD/SCA), 60 (3.4%) experienced non-sudden cardiac death (NSCD), and death attributable to non-cardiac causes (NCD) occurred in 162 (9.2%) patients. For every 10 ms decrease in standard deviation of normal to normal intervals the risk for SCD/SCA, NSCD and NCD increased significantly: HR 1.153 (95% CI 1.075–1.236, p<0.001), HR 1.187 (95% CI 1.102–1.278, p<0.001) and HR 1.080 (95% CI 1.037–1.125, p<0.001), respectively. The natural logarithm of the low-frequency component of the power spectrum and the short-term scaling exponent of the detrended fluctuation analysis also had significant association with all modes of death (p<0.001). After relevant adjustment, standard deviation of normal-to-normal intervals retained its association with NSCD and NCD (p<0.01), the natural logarithm of the low-frequency component of the power spectrum with all modes of death (p from <0.05 to <0.01), and the short-term scaling exponent of the detrended fluctuation analysis with SCD/SCA (p<0.05) and NCD (p<0.001). In conclusion, impairment of many measures of heart rate variability predicts mortality but is not associated with any specific mode of death in patients with stable CAD during the current treatment era, limiting the clinical applicability of heart rate variability to targeting therapy.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Early-repolarization patterns on electrocardiography are generally considered to be benign. However, this study with 30 years of follow-up in a Finnish population indicates that early-repolarization ...patterns in the inferior and lateral leads are associated with an increased risk of death from cardiac causes and from arrhythmia.
This study with 30 years of follow-up indicates that early-repolarization patterns in the inferior and lateral leads are associated with an increased risk of death from cardiac causes and from arrhythmia.
For decades, early repolarization, which is characterized by an elevation of the junction between the end of the QRS complex and the beginning of the ST segment (J point) from baseline on standard 12-lead electrocardiography, has been considered to be an innocuous finding,
1
but the presence of this pattern in leads other than V
1
through V
3
(especially in the inferior or lateral leads) has recently been associated with vulnerability to ventricular fibrillation in independent case–control studies.
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–
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Little is known about the prognostic significance of this electrocardiographic pattern in the general population.
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We conducted a community-based study to . . .
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