Genetic testing increases the likelihood of a diagnosis of familial hypercholesterolaemia among people referred to lipid clinics: Danish national study.

BACKGROUND AND AIMS: It is unclear to what extent genetic testing improves the ability to diagnose familial hypercholesterolaemia (FH). We investigated the percentage with FH among individuals referred to Danish lipid clinics, and evaluated the impact of genetic testing for a diagnosis of FH. METHODS: From September 2020 through November 2021, all patients referred for possible FH to one of the 15 Danish lipid clinics were invited for study participation and >97% (n = 1488) accepted. The Dutch Lipid Clinical Network criteria were used to diagnose clinical FH. The decision of genetic testing for FH was based on local practice. RESULTS: A total of 1243 individuals were referred, of whom 25.9% were diagnosed with genetic and/or clinical FH. In individuals genetically tested (n = 705), 21.7% had probable or definite clinical FH before testing, a percentage that increased to 36.9% after genetic testing. In individuals with unlikely and possible FH before genetic testing, 24.4% and 19.0%, respectively, had a causative pathogenic variant. CONCLUSIONS: In a Danish nationwide study, genetic testing increased a diagnosis of FH from 22% to 37% in patients referred with hypercholesterolaemia suspected of having FH. Importantly, approximately 20% with unlikely or possible FH, who without genetic testing would not have been considered having FH (and family screening would not have been undertaken), had a pathogenic FH variant. We therefore recommend a more widespread use of genetic testing for evaluation of a possible FH diagnosis and potential cascade screening.

High-sensitivity C-reactive protein and exercise-induced changes in subjects suspected of coronary artery disease.

BACKGROUND: Inflammation plays a major role in the development of atherosclerosis. We wanted to investigate the effects of exercise on high-sensitivity (hs) C-reactive protein (CRP) in subjects who were suspected of having coronary artery disease (CAD). METHODS: Blood samples were obtained before, 5 minutes after, and 20 hours after an exercise test in 155 subjects who were suspected of CAD. Coronary anatomy was evaluated by computed tomography coronary angiography and/or coronary angiography. RESULTS: Median baseline hs-CRP was higher in subjects with ≥50% coronary artery lumen diameter stenosis (n=41), compared with non-CAD-subjects (n=114), 2.93 mg/L (interquartile range 1.03-5.06 mg/L) and 1.30 mg/L (interquartile range 0.76-2.74 mg/L), respectively, P=0.007. In multivariate analyses testing conventional risk factors, hs-CRP proved borderline significant, odds ratio =2.32, P=0.065. Adding baseline hs-CRP to the results of the exercise test did not improve the diagnostic evaluation. Baseline natural logarithm (Ln) hs-CRP was positively associated with body mass index and baseline Ln-transformed hs troponin T levels, and negatively associated with the daily life activity level. An increase in hs-CRP of 0.13 mg/L (interquartile range 0.05-0.24 mg/L) from baseline to 5 minutes after peak exercise was found (P<0.0001), but the increase was not associated with presence of CAD. From baseline to 20 hours after exercise, no increase in hs-CRP was found. CONCLUSION: In conclusion, hs-CRP was not independently associated with CAD. Hs-CRP increased immediately as a response to the exercise, and the increase was modest and not associated with CAD. The results indicate that exercise has potential to cause unwanted variations in hs-CRP and that exercise prior to hs-CRP measurements in subjects included in epidemiological studies, therefore, should be avoided.

Diagnostic value of exercise-induced changes in circulating high sensitive troponin T in stable chest pain patients.

OBJECTIVE: We investigated the diagnostic value of exercise-induced increase in cardiac Troponin T (cTnT) in stable chest pain subjects. METHODS: CTnT was measured before and 20 h after an exercise test in 157 subjects suspected of coronary artery disease (CAD). RESULTS: CAD subjects (n = 41) had higher baseline cTnT levels compared to non-CAD subjects (n = 116), 6.39 ng/l and 3.00 ng/l, respectively, p < 0.0001, and were more likely to increase in cTnT (70.7% versus 27.6%, p < 0.0001). Net Reclassification Index for the combined variable was 19%, p = 0.02. CONCLUSIONS: Exercise-induced increase in cTnT was found to be associated with CAD and cTnT measurements improved the diagnostic evaluation.

Modest weight loss in moderately overweight postmenopausal women improves heart rate variability.

PURPOSE: To evaluate the effects of weight loss on heart rate (HR) and heart rate variability (HRV) parameters in overweight postmenopausal women. DESIGN AND METHODS: Forty-nine overweight postmenopausal women with an average body mass index of 28.8 ± 1.9 kg/m(2) underwent a 12-week dietary weight-loss programme. Accepted variables for characterization of HRV were analysed before and after the weight loss by 24-h ambulatory ECG monitoring; mean and standard deviation for the time between normal-to-normal complexes (MeanNN and SDNN, respectively), and the mean of standard deviations of normal-to-normal intervals for each 5-min period (SDNNindex). Baseline body fat mass (FM%) and changes in body composition was determined by dual X-ray absorptiometry. Before and after the weight-loss period, total abdominal fat, intra-abdominal fat (IAAT), and subcutaneous abdominal fat (SCAT) were measured by single-slice MRI at L3. RESULTS: The weight loss of 3.9 ± 2.0 kg was accompanied by an improvement of HRV. SDNN increased by 9.2% (p = 0.003) and SDNNindex increased by 11.4% (p = 0.0003). MeanNN increased by 2.4%, reflecting a decrease in mean heart rate from 74.1 to 72.3 beats/min (p = 0.033). Systolic blood pressure (SBP) decreased by 2.7%, total cholesterol by 5.1% and high-sensitivity C-reactive protein (hsCRP) by 15.8% (p = 0.002). Improvements in SDNN and cholesterol were correlated with weight loss (r = -0.329, p = 0.024 and r = 0.327, p = 0.020, respectively) but changes in HR, SBP, and hsCRP were not. IAAT and the IAAT/SCAT-ratio were found to be negatively associated with HRV parameters but changes in body composition were not associated with changes in HRV. CONCLUSIONS: The observed improvement of HRV seems to be facilitated by weight loss. IAAT and the IAAT/SCAT ratio were found to be associated with low HRV.

Prognostic value of high sensitive C-reactive protein in subjects with silent myocardial ischemia.

OBJECTIVES: The aim of this study was to evaluate the prognostic value of high sensitive C-reactive protein (CRP) in subjects with silent myocardial ischemia (SMI). DESIGN: In total, 678 healthy men and women aged 55 to 75 years with no history of cardiovascular disease or stroke were included. High-sensitive CRP and 48-hour ambulatory ECG monitoring were performed. The primary endpoint was the combined endpoint of death and myocardial infarction. RESULTS: The median follow-up time was 76 months. Seventy-seven subjects (11.4%) had SMI. The combined endpoint occurred in 26% of the subjects with SMI and 14% of the subjects without SMI (P = .005). SMI had a poor prognosis in the group with an elevated CRP ≥ 3.0 µg/mL (hazard ratio, 3.46; 95% confidence interval, 1.67-7.16; P = .001) compared with the group of subjects with SMI and a low CRP <3.0 µg/mL (hazard ratio, 1.37; 95% confidence interval, 0.63-2.98; P = .54). CONCLUSIONS: In apparently healthy subjects, a low level of CRP <3.0 µg/mL selects a low-risk subgroup, despite the presence of SMI.

Decreased nighttime heart rate variability is associated with increased stroke risk.

BACKGROUND AND PURPOSE: Prediction of stroke in healthy individuals is challenging and there is a diurnal variation of stroke onset. We hypothesized that heart rate variability with a focus on nighttime heart rate variability will predict the risk of stroke in apparently healthy middle-age and elderly subjects. METHODS: The population-based cohort of the Copenhagen Holter Study, consisting of 678 healthy subjects between age 55 and 75 years with no history of cardiovascular disease or stroke, was evaluated. All underwent 48-hour ambulatory electrocardiogram monitoring. The SD of normal-to-normal RR intervals (SDNN) was selected as the method of measuring heart rate variability. Nighttime SDNN was measured between 02:00 and 02:15 AM and could be evaluated in 653 subjects. Median follow-up was 76 months. RESULTS: Nighttime SDNN was lower in women than in men (P=0.0008), and in diabetics than nondiabetics (P=0.03). However, smoking, cholesterol, systolic blood pressure, and age were not associated with nighttime SDNN. The risk of stroke was significantly associated with nighttime SDNN in a univariate analysis (HR, 0.66; 95% CI, 0.50-0.88; P=0.004) and after adjustment for conventional risk factors (HR, 0.67; 95% CI, 0.51-0.89; P=0.005) per 10 ms increments of SDNN. Eighty-one percent of all strokes (21/26) occurred in 330 subjects with the lower half of nighttime SDNN (≤38 ms; HR, 4.31; 95% CI, 1.62-11.42; P=0.003). CONCLUSIONS: Nocturnal heart rate variability is a strong marker for the development of stroke in apparently healthy subjects. The mechanism is unknown, but reduced parasympathetic activity may increase the risk of stroke by increasing the risk of arrhythmias.

Mild hyponatremia carries a poor prognosis in community subjects.

OBJECTIVE: Hyponatremia has been shown to predict adverse outcome in congestive heart failure and pneumonia among other common clinical entities, but its significance in the general population is elusive. METHODS: The population-based Copenhagen Holter Study included 671 men and women aged 55 to 75 years with no history of cardiovascular disease, stroke, or cancer. Baseline evaluation included 48-hour ambulatory electrocardiogram monitoring, blood tests, and a questionnaire. Hyponatremia was defined as s-Na < or = 134 mEq/L or s-Na < or = 137 mEq/L according to previously accepted definitions. An adverse outcome was defined as deaths or myocardial infarction. Median follow-up was 6.3 years. RESULTS: Fourteen subjects (2.1%, group A) had s-Na < or = 134 mEq/L, and 62 subjects (9.2%, group B) had s-Na < or = 137 mEq/L. No subject had s-Na < 129 mEq/L. An adverse outcome occurred in 43% of group A, 27% of group B, and 14% of subjects with s-Na >137 mEq/L (controls) (P < .002). Adjusted hazard ratio for adverse outcome was 3.56 (95% confidence interval [CI], 1.53-8.28, P < .005) in group A compared with controls and 2.21 (95% CI, 1.29-3.80, P < .005) in group B after controlling for age, gender, smoking, diabetes, low-density lipoprotein cholesterol, and blood pressure. The hazard ratios were robust for additional adjusting for variables showing univariate association to hyponatremia (ie, beta-blocker and diuretic use, heart rate variability, creatinine, C-reactive protein, and NT-pro brain natriuretic peptide). By excluding diuretic users (18% of subjects), the adjusted hazard ratio for adverse outcome was 8.00 (95% CI, 3.04-21.0, P < .0001) in group A and 3.17 (95% CI, 1.76-5.72, P = .0001) in group B compared with controls. CONCLUSION: Hyponatremia is an independent predictor of deaths and myocardial infarction in middle-aged and elderly community subjects.