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Biomedical subjects

H V Huikuri

Publications and source records attributed to H V Huikuri.

At least 19 recordsLinked to original sources
PubMed2005

Natriuretic peptides and mortality after stroke.

BACKGROUND AND PURPOSE: 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. METHODS: 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. RESULTS: 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). CONCLUSIONS: Plasma levels of natriuretic peptides are elevated in the acute phase of stroke and predict poststroke mortality.

Aged↗
PubMed2005

The -1C to T polymorphism in the annexin A5 gene is not associated with the risk of acute myocardial infarction or sudden cardiac death in middle-aged Finnish males.

OBJECTIVE: A common polymorphism (-1C to T) in the translation initiation sequence of annexin A5 (ANV) gene has recently been associated with a decreased risk of acute myocardial infarction (AMI). The aim of the present study was to analyze the association between the ANV genepolymorphism and the risk of AMI and ischemic sudden cardiac death (SCD) in middle-aged Finnish males. MATERIAL AND METHODS: A case-control study involving three distinct groups of subjects was carried out: (1) victims of SCD (n=98), (2) survivors of AMI (n=212), and (3) randomly selected control subjects without any history of coronary heart disease (n=243). The ANV polymorphism was genotyped in each study group. RESULTS: Among the control group of healthy Finnish males the prevalence rates of the CC, CT, and TT genotypes were 83.1%, 15.2%, and 1.6%, respectively. Among the survivors of AMI, the prevalence rates of CC, CT, and TT were 79.7%, 20.3%, and 0%, respectively, and among the victims of SCD 83.7%, 16.3%, and 0%, respectively. No significant differences in the genotype or allele distributions were observed between the study groups. CONCLUSION: The -1C to T polymorphism in the ANV gene is not associated with the risk of AMI or SCD in middle-aged Finnish males.

5' Untranslated Regions↗
PubMed2005

Suppressed circadian heart rate dynamics in temporal lobe epilepsy.

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.

Adult↗
PubMed2004

Heart rate dynamics predict poststroke mortality.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSION: Abnormal long-term HR dynamics predict poststroke mortality. This measure may have value in the risk stratification of stroke patients.

Aged↗
PubMed2004

Prevalence and prognosis of subjects with Brugada-type ECG pattern in a young and middle-aged Finnish population.

AIMS: The purpose of this study was (1) to determine the prevalence of Brugada syndrome ECG abnormalities ("Brugada sign") in two Finnish populations and (2) to evaluate the natural course of subjects with the "Brugada sign". METHODS AND RESULTS: The study population consisted of 2479 healthy male Air Force applicants (age 18-30 years), and 542 healthy middle-aged subjects (age 40-60 years). All subjects underwent a thorough physical examination and 12-lead ECG in 1980-1990 (first population) and in 1991-1992 (second population). The ECG criteria suggested by the European Society of Cardiology were used to identify subjects with the "Brugada sign". Fifteen (0.61%) subjects in the first population and three subjects in the second population (0.55%) fulfilled the ECG criteria for type 2 or 3 Brugada syndrome, i.e., they had J-point elevation and a saddleback-type ST-segment configuration in the right precordial leads. Type 1 Brugada ECG abnormality (coved ST-segment elevation) was not seen in any subject. No mortality or life-threatening ventricular arrhythmias occurred in either study population during follow-up (19+/-2 years and 11+/-1 years, respectively). CONCLUSION: The benign natural course of the patients with the "Brugada sign" suggests that in asymptomatic subjects without a family history of sudden cardiac death, type 2 or 3 Brugada ECG pattern is a normal variant rather than a specific predictor of life-threatening ventricular arrhythmias.

Adult↗
PubMed2003

Depressive symptoms and the risk of sudden cardiac death among the elderly.

AIMS: Mental depression is associated with an increased risk of cardiovascular mortality, but the reasons for this association are not well known. We tested the hypothesis that depressive symptoms (DS) may specifically increase the risk of sudden cardiac death (SCD) among the elderly subjects. METHODS: All persons aged 70 years or over of a defined area in Northern Finland (n=1113) were the target population, and 915 (82%); 336 men and 579 women, participated in the questionnaire on depressive symptoms according to the Short Zung Depression Rating Scale. Potential risk factors of SCD were examined in the same connection, and the mode of death was examined via the official death certificates during the following eight years. SCD and non-SCD as well as overall mortality, cardiac mortality and non-fatal myocardial infarction (MI) were the end-points. RESULTS: Four hundred and seventy-six subjects out of 915 (52%) died during the follow-up of 8 years. Thirty-eight of deaths were SCDs (8%) and non-SCD occurred in 106 subjects (22%). In univariate analysis, a high score of DS was a significant predictor of subsequent SCD; hazard ratio 2.67 (95% confidence interval 1.34-5.32), non-SCD; 1.67 (1.06-2.63), cardiac mortality; 1.90 (1.30-2.78) and total mortality; 1.88 (1.52-2.32), but not that of non-fatal MI; 1.74 (0.89-3.38). SCD was also predicted by gender (P<0.01), MI (P<0.01) and tablet- or insulin-treated diabetes mellitus (P<0.01). In multivariate Cox regression analysis by adjusting for the clinical variables, high score of DS remained as a significant predictor of SCD; hazard ratio 2.74 (1.37-5.50) and total mortality; 1.70 (1.37-2.10), but not of cardiac mortality 1.50 (0.998-2.27), non-SCD; 1.38 (0.85-2.24) and non-fatal MI; 1.37 (0.69-2.71). CONCLUSIONS: Depressive symptoms increase the risk of SCD, but not that of non-SCD and non-fatal MI among the elderly subjects.

Aged↗
PubMed2003

Effect of cardiac vagal outflow on complexity and fractal correlation properties of heart rate dynamics.

1. Cardiac vagal outflow is the major factor determining the magnitude of heart rate (HR) variability analysed by traditional time and frequency domain methods. New analysis techniques, such as fractal and complexity methods, have been developed to probe non-linear features in HR behaviour that may not be detectable by traditional methods. 2. We investigated the effects of vagal blockade (glycopyrrolate i.v. 5 microg kg-1 h-1 for 2 h, n = 8 vs. unmedicated control group, n = 8) and various breathing patterns (n = 12) on two non-linear measures of HR variability--detrended fluctuation analysis (DFA) and approximate entropy (ApEn)--in healthy male volunteers. 3. Glycopyrrolate decreased the mean (+/-SD) ApEn from 1.46 +/- 0.18 to 0.85 +/- 0.24 (P = 0.001 in comparison with the control group), and increased the short-term (alpha 1) and intermediate-term (alpha 2) fractal scaling exponents of DFA, alpha 1 from 0.96 +/- 0.19 to 1.43 +/- 0.29 (P = 0.003) and alpha 2 from 1.13 +/- 0.10 to 1.34 +/- 0.14 (P < 0.001). 4. Decrease in fixed respiration rate from 15 to 6 breaths min-1 increased alpha 1 from 0.83 +/- 0.25 to 1.18 +/- 0.27 (P < 0.001), but decreased alpha 2 from 0.88 +/- 0.09 to 0.45 +/- 0.17 (P < 0.001) and ApEn from 1.26 +/- 0.12 to 1.10 +/- 0.14 (P = 0.028). Rapid breathing (24 min-1) had no influence on these non-linear measures of HR variability. Hyperventilation (15 min-1, tidal volume increased voluntarily by 0.5 l) decreased alpha 1 from 0.83 +/- 0.25 to 0.66 +/- 0.28 (P = 0.002) but did not affect alpha 2 or ApEn. 5. To conclude, vagal blockade alters the fractal scaling properties of R-R intervals (alpha 1, alpha 2) and reduces the complexity (ApEn) of HR behaviour. Both the fractal and complexity measures of HR variability can also be influenced by changes in the breathing pattern.

Adolescent↗
PubMed2003

Relationship between the frequency of paroxysmal episodes of atrial fibrillation and pulmonary venous flow pattern.

AIMS: Chronic atrial fibrillation causes mechanical remodelling of the atria, but it is uncertain whether self-terminating episodes of paroxysmal atrial fibrillation (PAF) alter atrial mechanical function during normal sinus rhythm. This study was designed to assess the relationship between the frequency of symptomatic arrhythmic episodes and pulmonary venous flow (PVF) pattern among patients with PAF. METHODS AND RESULTS: The effect of symptomatic arrhythmic episodes on PVF was studied in 85 patients with lone PAF (age 48+/-8 years, 66 men). PVF was measured with transthoracic echocardiography during sinus rhythm. Adequate recordings of PVF were achieved in 81 (95%) patients. Peak systolic PVF had an inverse correlation (r=-0.35, P=0.002) with the frequency of PAF episodes. The peak systolic PVF was 76+/-14 cm/s vs 62+/-12 cm/s (P=0.008) among the quartiles with the most and the least frequent episodes of PAF, respectively. There were no significant differences in the other echocardiographic measurements or demographic variables. CONCLUSIONS: Frequent arrhythmic episodes significantly diminished systolic PVF among patients with PAF, suggesting that PAF results in gradual mechanical remodelling of the atrium, which may favour recurrence and perpetuation of AF and/or formation of atrial thrombus.

Atrial Fibrillation↗
PubMed2002

Polymorphisms of genes affecting thrombosis and risk of myocardial infarction.

BACKGROUND: As thrombosis is an essential factor in the pathogenesis of acute myocardial infarction (AMI), the genes of proteins affecting haemostasis are good candidate genes for AMI. DESIGN: Associations of the known polymorphisms of the coagulation factor VII (FVII) gene (R353Q), the coagulation factor XIII (FXIII) gene (V34L) and the glycoprotein Ia (Gp1a) gene (C807T) with the occurrence of AMI were studied in 142 AMI survivors and 142 age- and sex-matched control subjects. RESULTS: Among those who smoked, the L34 allele of the amino acid FXIII polymorphism was less common in the AMI patients (16%) than in the controls (27%) (P = 0.06), suggesting a possible interaction of AMI risk between the FXIII genotype and smoking status. No differences in the allele or genotype frequencies of the studied polymorphisms were seen between the whole study groups. Logistic regression analysis showed the carriers of the L34 allele of the FXIII amino acid polymorphism to have a significantly (P = 0.03) lower AMI risk compared with those homozygous for the V34 allele (odds ratio = 0.54, 95% confidence interval 0.31-0.93). CONCLUSION: The L34 allele of the amino acid polymorphism of the FXIII gene is associated with a decreased risk of AMI, and this protecting association seems to be more pronounced in smokers.

Blood Coagulation Factors↗
PubMed2002

Heart rate dynamics in refractory and well controlled temporal lobe epilepsy.

OBJECTIVES: Disorders of cardiovascular and other autonomic nervous system functions are often found in patients with temporal lobe epilepsy (TLE). Cardiovascular dysregulation in TLE has previously been quantified assessing traditional time and frequency domain measures of heart rate (HR) variability from short term ECG recordings. However, new complexity and fractal measures of HR variability based on non-linear dynamics and fractals ("chaos theory") may disclose certain patterns of HR dynamics that cannot be detected using only conventional measures. METHODS: In addition to the traditional spectral and non-spectral components of HR variability, fractal correlation properties, approximate entropy (ApEn) of RR interval dynamics, and the slope of the power law relation were measured from 24 hour ambulatory ECG recordings to evaluate interictal autonomic cardiovascular regulatory function in 19 patients with refractory TLE, 25 patients with well controlled TLE, and in 34 healthy age and sex matched control subjects. RESULTS: The traditional time and frequency domain measures were lower in patients with TLE than in controls (p<0.05). In addition, the power law slope (p<0.005) and ApEn (p<0.05) were also reduced in TLE patients. Furthermore, ApEn was smaller in patients with refractory TLE than in patients with well-controlled TLE ( p<0.01), whereas the long term fractal correlation value alpha2 was lower in patients with well controlled TLE (p<0.05). An altered HR variation was not associated with any particular AED regimen. CONCLUSIONS: In addition to reduced overall HR variability, the long term fractal organisation and complexity of HR dynamics seem to be altered in TLE. These abnormalities in HR behaviour may partly contribute to the occurrence of adverse cardiovascular events, such as life threatening arrhythmias in patients with TLE.

Adult↗
PubMed2001

Heart rate variability in ischemic heart disease.

Major untoward events, such as life-threatening arrhythmias and acute coronary events, have been suggested to be triggered by the activation of the autonomic nervous system in patients with coronary artery disease. Analysis of heart rate variability by conventional time and frequency domain methods, as well as by newer methods derived from nonlinear system theory, has offered a novel approach for studying the abnormalities in cardiovascular neural regulation in ischemic heart disease. Heart rate variability has been shown to be altered among patients with ischemic heart disease as compared to their age-matched controls without the evidence of ischemic heart disease. There are also obvious differences in various measures of heart rate variability between patients with uncomplicated coronary artery disease and those with coronary artery disease with complicated myocardial infarction. Impaired high-frequency oscillations of heart rate is the most prominent feature in patients with uncomplicated coronary artery disease, suggesting mainly an impairment in vagal autonomic regulation. Patients with prior myocardial infarction have a reduced overall heart rate variability, and a specific spectral pattern with a reduced low-frequency spectral component has been observed in patients with prior myocardial infarction and impaired left ventricular function. Recent studies have shown that the new nonlinear measures, particularly fractal analysis methods of heart rate dynamics, can detect subtle changes in heart rate behavior that are not easily detected by traditional analysis methods from ambulatory recordings. Patients with prior myocardial infarction have steeper power-law slope analyzed from the ultra and very low-frequency spectral bands, and they also have more random short-term heart rate dynamics analyzed by the detrended fluctuation method. A large body of data indicate that reduced overall heart rate variability is associated with an increased risk of mortality and nonfatal cardiac events in patient with ischemic heart disease. Of particular note, recent studies indicate that fractal analysis methods perform even better than the traditional analysis methods of heart rate variability as predictors of death and the onset of life-threatening arrhythmic events in post-infarction populations. These findings support the notion that heart rate variability analysis methods, such as fractal and complexity measures as well as conventional techniques, give valuable clinical information among patients with ischemic heart disease.

Autonomic Nervous System↗
PubMed2001

Fractal analysis and time- and frequency-domain measures of heart rate variability as predictors of mortality in patients with heart failure.

Time-domain measures of heart rate (HR) variability provide prognostic information among patients with congestive heart failure (CHF). The prognostic power of spectral and fractal analytic methods of HR variability has not been studied in the patients with chronic CHF. The aim of this study was to assess whether traditional and fractal analytic methods of HR variability predict mortality among a population of patients with CHF. The standard deviation of RR intervals, HR variability index, frequency-domain indexes, and the short-term fractal scaling exponent of RR intervals were studied from 24-hour Holter recordings in 499 patients with CHF and left ventricular ejection fraction < or =35%. During a mean follow-up of 665 +/- 374 days, 210 deaths (42%) occurred in this population. Conventional and fractal HR variability indexes predicted mortality by univariate analysis. For example, a short-term fractal scaling exponent <0.90 had a risk ratio (RR) of 1.9 (95% confidence interval [CI] 1.4 to 2.5) and the SD of all RR intervals <80 ms had an RR of 1.7 (95% CI 1.2 to 2.1). After adjusting for age, functional class, medication, and left ventricular ejection fraction in the multivariate proportional-hazards analysis, the reduced short-term fractal exponent remained the independent predictor of mortality, RR 1.4 (95% CI 1.0 to 1.9; p <0.05). All HR variability indexes were more significant univariate predictors of mortality in functional class II than in class III or IV. Among patients with moderate heart failure, HR variability measurements provide prognostic information, but all HR variability indexes fail to provide independent prognostic information in patients with the most severe functional impairment.

Aged↗