Jouko Karjalainen

Relation between QT intervals and heart rates from 40 to 120 beats/min in rest electrocardiograms of men and a simple method to adjust QT interval values

OBJECTIVES The aim of this study was to establish the relation between QT intervals and a wide range of rest heart rates in men. These data provided the basis of a simple method for adjusting the QT interval for heart rate. BACKGROUND Earlier correction equations give conflicting results, especially at low and high heart rates. METHODS The QT intervals were measured in 324 electrocardiograms of healthy young men. The sample was weighted for low and high heart rates. A curve relating QT intervals and heart rates from 40 to 120 beats/min was constructed. The QT interval at 60 beats/min was used as the reference value, and an adjusting nomogram for different heart rates was created. The reliabilities of the nomogram and three earlier QT correction equations were tested in the study group and in 396 middle-aged men. RESULTS The nomogram method presented (QTNc = QT + correcting number) adjusted the QT interval most accurately over the whole range of heart rates on the basis of smallest mean-squared residual values between measured and predicted QT intervals. The Fridericia formula (QTFc = QT/RR1/3) gave the best correction at low, but failed at high, heart rates. The linear regression equation (QTLc = QT + 0.154[1 - RR], Framingham Study) was reliable at normal, but failed at low and high, heart rates. The Bazett formula (QTc = QT/RR1/2) performed poorest at all heart rates. The relation between QT and RR intervals was determined by three linear regressions expressing the slopes 0.116 for heart rates < 60 beats/min, 0.156 for heart rates from 60 to 100 beats/min and 0.384 for heart rates > 100 beats/min. CONCLUSIONS The QT-RR relation over a wide range of heart rates does not permit the use of one simple adjustment equation. A nomogram providing, for every heart rate, the number of milliseconds that the QT interval must be corrected gives excellent adjustment.

Angiotensinogen gene M235T polymorphism predicts left ventricular hypertrophy in endurance athletes

OBJECTIVES We studied whether left ventricular mass in athletes associates with polymorphisms in genes encoding components of the renin-angiotensin system. BACKGROUND Adaptive left ventricular hypertrophy is a feature of the athletes heart. However, similarly training athletes develop left ventricular mass to a different extent, suggesting that genetic factors may modulate heart size. METHODS We measured left ventricular mass by echocardiography in 50 male and 30 female elite endurance athletes aged 25 +/- 4 (mean +/- SD) years. Deoxyribonucleic acid samples were prepared for genotyping of angiotensinogen (AGT) gene M235T polymorphism, angiotensin-converting enzyme (ACE) gene insertion/deletion (I/D) polymorphism and angiotensin II type 1 receptor (AT1) gene A1166C polymorphism. RESULTS The AGT gene M235T genotypes were significantly associated with left ventricular mass independently of blood pressure in both genders (p = 0.0036 for pooled data). TT homozygotes had greater mass compared with MM homozygotes in both men (147 +/- 12 g/m vs. 132 +/- 15 g/m, p = 0.032) and women (121 +/- 12 g/m vs. 101 +/- 13 g/m, p = 0.019). There was a gender difference in the relation between myocardial mass and AGT genotype, MT heterozygotes resembling MM homozygotes among women and TT homozygotes among men. The other studied gene polymorphisms were not associated with left ventricular mass. CONCLUSIONS Angiotensinogen gene M235T polymorphism is associated with the variability in left ventricular hypertrophy induced by endurance training, with athletes homozygous for the T allele having the largest hearts. We found no association between ACE gene I/D or AT1 gene A1166C polymorphisms and left ventricular mass.

Recurrent pericarditis in children and adolescents: Report of 15 cases

OBJECTIVES The aim of this study was to analyze the clinical findings, course, and treatment of recurrent pericarditis (RP) in patients with onset in childhood and adolescence. BACKGROUND Recurrent pericarditis is a chronic condition that has presented problems in management. Knowledge about this disease is based on observations in adults, and no series of children has previously been published. METHODS Fifteen children (nine males, six females) in whom pericarditis had recurred at least twice were encountered in the period 1985 to 1998. Their age at onset was 6.5 to 16.8 years (mean 11.6 years), and the follow-up was 4.0 to 16.2 years (mean 8.0 years). RESULTS Recurrent pericarditis was preceded by open-heart surgery by 1 month to 5 years earlier in 7 of 15 patients. The six children with an atrial septal defect (ASD) had an operation at an older age (mean 9.9 years) than usual (mean 4.8 years). The risk of RP in children operated on for ASD at the age of six years or later was 5%. An initial attack of pericarditis was associated with pleuritis and/or pneumonia in 10 of 15 patients and with colitis in 2 of 15 patients During follow-up, the patients had 2 to 30 recurrences (mean 9.9). Later attacks tended to be milder. At the end of follow-up, 7 patients had been without attacks for >or=4 years, whereas after 4 to 16 years, the remaining patients still had active disease. No instance of constriction was found. Altogether, 11 of 15 patients were treated with corticosteroids. However, corticosteroids, whether alone or with methotrexate (n = 5), azathioprine (n = 1), cyclosporine (n = 1), or colchicine (n = 4) did not prevent recurrences. CONCLUSIONS The most frequent background for RP in children was the closure of ASD after the age of six years. Its course was unpredictable and often chronic, irrespective of the underlying cause or the therapy given. Colchicine did not prevent relapses.

Altered MicroRNA Expression of Nasal Mucosa in Long-Term Asthma and Allergic Rhinitis

Background: Asthma and allergic rhinitis (AR) commonly coexist and can be taken as manifestations of one syndrome. Evidence exists that microRNAs (miRNAs) are important in controlling inflammatory processes and they are considered promising biomarkers. However, little is known about the differences in miRNA expression in patients with chronic allergic airway disease. This study evaluated the inflammatory and miRNA profiles of the nasal mucosa of patients with long-term asthma with and without AR. Methods: We analyzed inflammatory cells, cytokines, and miRNAs in nasal biopsies and measured exhaled and nasal nitric oxide levels during the nonpollen season in 117 middle-aged men who had suffered mainly from allergic asthma for approximately 20 years and also in 33 healthy controls. Results: The differences in the number of nasal eosinophils and cytokine expression levels were modest in nasal biopsies taken from asthmatics. Downregulation of miR-18a, miR-126, let-7e, miR-155, and miR-224 and upregulation of miR-498, miR-187, miR-874, miR-143, and miR-886-3p were observed in asthmatic patients in comparison to controls. The differences in miRNA expression were mainly similar in asthmatics with and without AR. With regard to asthma severity, a trend of increased miRNA expression in persistent asthma was seen, whereas the downregulation of certain miRNAs was most distinct in nonpersistent-asthma patients. Conclusions: Differences in miRNA expression in the nasal mucosa of subjects with long-term asthma and AR can be seen also when no markers of Th2-type inflammation are detected. Asthma severity had only a minor impact on miRNA expression.

Muscle fiber-type distribution predicts weight gain and unfavorable left ventricular geometry: a 19 year follow-up study

BackgroundSkeletal muscle consists of type-I (slow-twitch) and type-II (fast-twitch) fibers, with proportions highly variable between individuals and mostly determined by genetic factors. Cross-sectional studies have associated low percentage of type-I fibers (type-I%) with many cardiovascular risk factors.MethodsWe investigated whether baseline type-I% predicts left ventricular (LV) structure and function at 19-year follow-up, and if so, which are the strongest mediating factors. At baseline in 1984 muscle fiber-type distribution (by actomyosin ATPase staining) was studied in 63 healthy men (aged 32–58 years). The follow-up in 2003 included echocardiography, measurement of obesity related variables, physical activity and blood pressure.ResultsIn the 40 men not using cardiovascular drugs at follow-up, low type-I% predicted higher heart rate, blood pressure, and LV fractional shortening suggesting increased sympathetic tone. Low type-I% predicted smaller LV chamber diameters (P ≤ 0.009) and greater relative wall thickness (P = 0.034) without increase in LV mass (concentric remodeling). This was explained by the association of type-I% with obesity related variables. Type-I% was an independent predictor of follow-up body fat percentage, waist/hip ratio, weight gain in adulthood, and physical activity (in all P ≤ 0.001). After including these risk factors in the regression models, weight gain was the strongest predictor of LV geometry explaining 64% of the variation in LV end-diastolic diameter, 72% in end-systolic diameter, and 53% in relative wall thickness.ConclusionLow type-I% predicts obesity and weight gain especially in the mid-abdomen, and consequently unfavourable LV geometry indicating increased cardiovascular risk.

Hypertension in master endurance athletes

Objective To determine whether long-term very vigorous endurance training prevents hypertension. Design Cohort study of master orienteering runners and controls. Setting Finland. Subjects and methods In 1995, a health questionnaire was completed by 264 male orienteering runners (response rate 90.4%) who had been top-ranked in competitions among men aged 35–59 years in 1984, and by 388 similarly aged male controls (response rate 87.1%) who were healthy at the age of 20 years and free of overt ischemic heart disease in 1985. Main outcome measure Self-report of medication for hypertension. Results In the endurance athlete group, the crude prevalence (8.7%) of subjects who had used medication for hypertension was less than a third of that in the control group (27.8%). Even after adjusting for age and body mass index, the difference between the groups was still significant (odds ratio for athletes 0.43, 95% confidence interval 0.25–0.76). Conclusions Long-term vigorous endurance training is associated with a low prevalence of hypertension. Some of the effect can be explained by a lower body mass, but exercise seems to induce a lower rate of hypertension by other mechanisms than by decreasing body weight.

Muscle Fiber-Type Distribution as a Predictor of Blood Pressure A 19-Year Follow-Up Study

The known association between physical activity and low blood pressure may be influenced by inherited characteristics. Skeletal muscle consists of type I (slow-twitch) and type II (fast-twitch) muscle fibers, with proportions highly variable between individuals and mostly determined by genetic factors. A high percentage of type I fibers (type I%) has been associated with low blood pressure in cross-sectional studies. We investigated whether type I percentage predicts future blood pressure levels and explains part of the association between physical activity and blood pressure. At baseline, in 1984, muscle fiber-type distribution, physical activity, and body mass index (BMI) were determined in 64 healthy men (age, 32 to 58 years). At follow-up, in 2003, blood pressure, physical activity, and BMI were determined in these men. In subjects without antihypertensive medication (n=43), type I percentage accounted for 5%/18% of the variation in systolic/diastolic blood pressure. A high type I percentage predicted, independent of both baseline (in 1984) and follow-up (in 2003), physical activity, BMI, and low systolic and diastolic blood pressure. Adjusted for all baseline covariates, a 20-unit higher type I percentage predicted a 11.6-mm Hg lower systolic blood pressure (P=0.018) and a 5.0-mm Hg lower diastolic blood pressure (P=0.018). High levels of physical activity in 1984 predicted low diastolic blood pressure, but this association was lost when type I percentage was included into the model. A high proportion of type I fibers in skeletal muscle is an independent predictor of low blood pressure and explains part of the known association between high levels of physical activity and low blood pressure.

Genetic influences on resting electrocardiographic variables in older women: a twin study.

Background: Previous studies in young and middle‐aged men and women have shown that resting electrocardiographic (ECG) variables are influenced by genetic factors. However, the extent to which resting ECG variables are influenced by genetic factors in older women is unknown. Thus, the aim of this study was to estimate the relative contribution of genetic and environmental influences to individual differences in resting ECG variables among older female twins without overt cardiac diseases.

Reduced work ability in middle-aged men with asthma from youth- a 20-year follow-up

We studied, whether asthma diagnosed in childhood or early adulthood affects work ability 20 years later. We used Finnish Defence Force registers, 1986-1990, to select: (1) conscripts with asthma to represent a mild/moderate asthma group (n=485), (2) asthmatics who were exempted from military service to represent a relatively severe asthma group (n=393) and (3) a control group (n 1500) without asthma. A questionnaire consisting of validated questions on asthma and work ability was sent out in 2009. A total of 54% of the men in the first study group, 44% of those in the second study group and 44% of the controls answered. The mean age of the participants was 41 (range 37-51). Self-assessed current work ability compared with lifetime best had decreased in 28.9% of the first asthma group, in 31.1% of the second asthma group, and in 19.7% of the controls (p = 0.0007). Current smoking (OR 2.5), only basic education (OR 2.6), being a manual worker (OR 2.7) and current severe asthma (OR 3.8) associated most strongly with decreased work ability among the asthmatics. Both mild and more severe asthma at the age of around 20 seems to be associated with reduced work ability in 40-year-old males.

Atopic sensitization to common allergens without symptoms or signs of airway disorders does not increase exhaled nitric oxide

Background:  Elevated fractional exhaled nitric oxide (FENO) associates positively with symptomatic atopy among asthmatics and in the general population. It is, however, unclear whether sensitization to common allergens per se– as verified with positive skin prick tests – affects FENO in healthy individuals.