BACKGROUNDSudden cardiac death (SCD) is a significant mode of death causing 15-20% of all deaths in high-income countries. Coronary artery disease (CAD) is the most common cause of SCD in both sexes, ...and SCD is often the first manifestation of underlying CAD in women. This case-control study aimed to determine the factors associated with SCD due to CAD in women.METHODSThe study group consisted of women with CAD-related SCD (N = 888) derived from the Fingesture study conducted in Northern Finland from 1998 to 2017. All SCDs underwent medicolegal autopsy. The control group consisted of women with angiographically verified CAD without SCD occurring during the 5-year-follow-up (N = 610). To compare these groups, we used medical records, autopsy findings, echocardiograms, and electrocardiograms (ECGs).RESULTSSubjects with SCD were older (73.2 ± 11.3 vs. 68.8 ± 8.0, p < 0.001) and were more likely to be smokers or ex-smokers (37.1% vs. 27.6%, p = 0.045) compared to control patients. The proportion of subjects with prior myocardial infarction (MI) was higher in controls (46.9% vs. 41.4% in SCD subjects, p = 0.037), but in contrast, SCD subjects were more likely to have underlying silent MI (25.6% vs. 2.4% in CAD controls, p < 0.001). Left ventricular hypertrophy (LVH) was more common finding in SCD subjects (70.9% vs. 55.1% in controls, p < 0.001). Various electrocardiographic abnormalities were more common in subjects with SCD, including higher heart rate, atrial fibrillation, prolonged QTc interval, wide or fragmented QRS complex and early repolarization. The prevalence of Q waves and T inversions did not differ between the groups.CONCLUSIONSUnderlying LVH and previous MI with myocardial scarring are common and often undiagnosed in women with CAD-related SCD. These results suggest that untreated CAD with concomitant myocardial disease is an important factor in SCD in women.
Short-QT syndrome is an inherited disorder characterized by a short QT interval and an increased risk of sudden cardiac death. The clinical significance of a short QT interval observed in a randomly ...recorded ECG is not known. Therefore, we assessed the prevalence and prognostic significance of a short QT interval in a general population.
QT intervals were measured from the 12-lead ECGs of 10 822 randomly selected middle-aged subjects (5658 males, mean age 44+/-8.4 years) enrolled in a population study and followed up for 29+/-10 years. The end points were all-cause and cardiovascular mortality. In addition to Bazett's method (corrected QT interval, or QTc), the Fridericia (QTfc) and nomogram (QTnc) methods were used to correct the QT interval for heart rate. The cutoff values for short QT intervals were defined as 320 ms (very short) and 340 ms (short). The prevalence of QT interval <320 ms based on QTc, QTfc, and QTnc was 0.10%, 0.08%, and 0.06%, and the prevalence of QT interval <340 ms was 0.4%, 0.3%, and 0.3%, respectively. The majority of subjects with short QT intervals were males. All-cause or cardiovascular mortality did not differ between subjects with a very short or short QT interval and those with normal QT intervals (360 to 450 ms). There were no sudden cardiac deaths, aborted sudden cardiac deaths, or documented ventricular tachyarrhythmias among subjects with a QTfc <340 ms.
A short QT interval does not appear to indicate an increased risk for all-cause or cardiovascular mortality in middle-aged nonreferral, community-based individuals.
•After the age of 60, most sudden cardiac deaths (SCD) in women are ischemic origin.•The clinical profile of ischemic SCD in women is age-dependent.•Overweight is more common among younger women with ...SCD.•Myocardial scars and fibrosis are more common in older ischemic SCD subjects.
BACKGROUND: Preliminary data suggest that the analysis of R-R interval variability by fractal analysis methods may provide clinically useful information on patients with heart failure. The purpose of ...this study was to compare the prognostic power of new fractal and traditional measures of R-R interval variability as predictors of death after acute myocardial infarction. METHODS AND RESULTS: Time and frequency domain heart rate (HR) variability measures, along with short- and long-term correlation (fractal) properties of R-R intervals (exponents alpha(1) and alpha(2)) and power-law scaling of the power spectra (exponent beta), were assessed from 24-hour Holter recordings in 446 survivors of acute myocardial infarction with a depressed left ventricular function (ejection fraction </=35%). During a mean+/-SD follow-up period of 685+/-360 days, 114 patients died (25.6%), with 75 deaths classified as arrhythmic (17.0%) and 28 as nonarrhythmic (6.3%) cardiac deaths. Several traditional and fractal measures of R-R interval variability were significant univariate predictors of all-cause mortality. Reduced short-term scaling exponent alpha(1) was the most powerful R-R interval variability measure as a predictor of all-cause mortality (alpha(1) <0.75, relative risk 3.0, 95% confidence interval 2.5 to 4.2, P<0.001). It remained an independent predictor of death (P<0.001) after adjustment for other postinfarction risk markers, such as age, ejection fraction, NYHA class, and medication. Reduced alpha(1) predicted both arrhythmic death (P<0.001) and nonarrhythmic cardiac death (P<0.001). CONCLUSIONS: Analysis of the fractal characteristics of short-term R-R interval dynamics yields more powerful prognostic information than the traditional measures of HR variability among patients with depressed left ventricular function after an acute myocardial infarction.
Measurement of natriuretic peptides provides prognostic information in various patient populations. The prognostic value of natriuretic peptides among patients with acute stroke is not known, ...although elevated peptide levels have been observed.
A series of 51 patients (mean age, 68+/-11 years) with first-ever ischemic stroke underwent a comprehensive clinical examination and measurements of plasma atrial natriuretic peptides (N-ANP) and brain natriuretic peptides (N-BNP) in the acute phase of stroke. The patients were followed-up for 44+/-21 months. Risk factors for all-cause mortality were assessed. Control populations, matched for gender and age, consisted of 51 patients with acute myocardial infarction (AMI) and 25 healthy subjects.
Plasma concentrations of N-ANP (mean+/-SD, 988+/-993 pmol/L) and N-BNP (751+/-1608 pmol/L) in the stroke patients were at the same level as those in the AMI patients (NS for both), but significantly higher than those of the healthy subjects (358+/-103 pmol/L, P<0.001 and 54+/-26 pmol/L, P<0.01, respectively). Elevated levels of N-ANP and N-BNP predicted mortality after stroke (risk ratio RR 4.3, P<0.01 and RR 3.9, P<0.01, respectively) and after AMI (P<0.05), and remained independent predictors of death after stroke even after adjustment for age, diabetes, coronary artery disease, and medication (RR 3.9, P<0.05 and RR 3.7, P<0.05, respectively).
Plasma levels of natriuretic peptides are elevated in the acute phase of stroke and predict poststroke mortality.
Objectives: To measure interictal circadian rhythm of heart rate (HR) variability in patients with temporal lobe epilepsy (TLE) using a 24 hour ECG recording. Methods: Various conventional and ...dynamic fractal measures of HR variability were analysed in 17 patients with refractory TLE, 20 patients with well controlled TLE, and 37 healthy age and sex matched control subjects. Results: The SD of all RR intervals (p<0.01), the measured power spectral components of HR variability (low frequency power (p<0.01), high frequency power (p<0.05)), and the SD1 (p<0.05) and SD2 (p<0.01) Poincaré two dimensional vector analysis measurements were suppressed in the patients. This suppression was observed during both day and night time; however, it was more pronounced at night, and nocturnal increase in HR variability usually seen in the normal population could not be detected in the patients. The HR variability measures did not correlate with the duration of epilepsy, the age of the patients, or with the anti-epileptic drugs used. Conclusion: TLE was associated with reduced HR variability, which was more pronounced during night than day, and the nocturnal increase in HR variability was abolished in patients with TLE. The alteration in autonomic regulation of HR variability was similar in patients with both refractory and well controlled TLE.
Prolonged PR interval, or first degree AV block, has been traditionally regarded as a benign electrocardiographic finding in healthy individuals, until recent studies have suggested that it may be ...associated with increased mortality and morbidity. The aim of this study was to further elucidate clinical and prognostic importance of prolonged PR interval in a large middle-aged population with a long follow-up.
We evaluated 12-lead electrocardiograms of 10 785 individuals aged 30-59 years (mean age 44 years, 52% males) recorded between 1966 and 1972, and followed the subjects for 30 ± 11 years. Prolonged PR interval was defined as PR >200 ms, with further analysis performed using PR ≥220 ms. Main endpoints were all-cause mortality, cardiovascular mortality, and sudden cardiac death, and other endpoints included hospitalizations due to cardiovascular causes. During the baseline examination, prolonged PR interval >200 ms was present in 2.1% of the subjects, but PR interval normalized to ≤200 ms in 30% of these individuals during the follow-up. No increase in mortality or in hospitalizations due to coronary artery disease, heart failure, atrial fibrillation, or stroke was associated with prolonged PR interval (P = non-significant for all endpoints). These results were not changed after multivariate adjustment or in several subanalyses.
In the middle-aged general population, prolonged PR interval normalizes in a substantial proportion of subjects during the time course, and it is not associated with an increased risk of all-cause or cardiovascular mortality.
Impaired cardiovascular autonomic regulation assessed by heart rate (HR) variability provides prognostic information in patients with heart disease as well as among elderly. Reduced HR variability ...has been described in stroke patients, but the prognostic significance of HR variability measures after stroke has not been studied.
A series of 84 patients (mean age 59 +/- 12 years) with an acute first-ever ischemic stroke underwent a comprehensive clinical investigation, laboratory tests, and 24-hour EKG recordings and were followed up for 7 years (mean 83 +/- 54 months). Various conventional and newer qualitative measures of HR variability were analyzed from the baseline 24-hour EKG. Risk factors for all-cause mortality were assessed.
During the follow-up, 33 (39%) patients died and 51 survived. Among all the variables analyzed, abnormal long-term HR variability measure power-law slope beta (beta < -1.5), reflecting an altered distribution of spectral characteristics over ultra and very low frequency bands, was the best univariate predictor of death (hazard ratio 4.5, 95% CI 2.2 to 9.5, p < 0.001). High age, poor Scandinavian Stroke Scale score, and abnormal short-term HR variability scaling measure (alpha) also predicted mortality in univariate analysis. In multivariate analysis, after adjustment for age, the only independent predictor of the risk of death was abnormal long-term power-law slope beta (hazard ratio 3.8, CI 1.8 to 8.2, p < 0.001). Conventional HR variability measures showed no prognostic power.
Abnormal long-term HR dynamics predict poststroke mortality. This measure may have value in the risk stratification of stroke patients.
BACKGROUND: New methods of R-R interval variability based on fractal scaling and nonlinear dynamics ("chaos theory") may give new insights into heart rate dynamics. The aims of this study were to (1) ...systematically characterize and quantify the effects of aging from early childhood to advanced age on 24-hour heart rate dynamics in healthy subjects; (2) compare age-related changes in conventional time- and frequency-domain measures with changes in newly derived measures based on fractal scaling and complexity (chaos) theory; and (3) further test the hypothesis that there is loss of complexity and altered fractal scaling of heart rate dynamics with advanced age. METHODS AND RESULTS: The relationship between age and cardiac interbeat (R-R) interval dynamics from childhood to senescence was studied in 114 healthy subjects (age range, 1 to 82 years) by measurement of the slope, beta, of the power-law regression line (log power-log frequency) of R-R interval variability (10(-4) to 10(-2) Hz), approximate entropy (ApEn), short-term (alpha(1)) and intermediate-term (alpha(2)) fractal scaling exponents obtained by detrended fluctuation analysis, and traditional time- and frequency-domain measures from 24-hour ECG recordings. Compared with young adults (<40 years old, n=29), children (<15 years old, n=27) showed similar complexity (ApEn) and fractal correlation properties (alpha(1), alpha(2), beta) of R-R interval dynamics despite lower spectral and time-domain measures. Progressive loss of complexity (decreased ApEn, r=-0.69, P<0.001) and alterations of long-term fractal-like heart rate behavior (increased alpha(2), r=0.63, decreased beta, r=-0.60, P<0.001 for both) were observed thereafter from middle age (40 to 60 years, n=29) to old age (>60 years, n=29). CONCLUSIONS: Cardiac interbeat interval dynamics change markedly from childhood to old age in healthy subjects. Children show complexity and fractal correlation properties of R-R interval time series comparable to those of young adults, despite lower overall heart rate variability. Healthy aging is associated with R-R interval dynamics showing higher regularity and altered fractal scaling consistent with a loss of complex variability.
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