Validation and clinical use of a novel diagnostic device for screening of atrial fibrillation.

AIMS: Patients with asymptomatic and undiagnosed atrial fibrillation (AF) are at increased risk of heart failure and ischaemic stroke. In this study, we validated a new diagnostic device, the MyDiagnostick, for detection of AF by general practitioners and patients. It records and stores a Lead I electrocardiogram (ECG) which is automatically analysed for the presence of AF. METHODS AND RESULTS: In total, 192 patients (age 69.4 ± 12.6 years) were asked to hold the MyDiagnostick for 1 min, immediately before a routine 12-lead ECG was recorded. Atrial fibrillation detection and ECGs stored by the MyDiagnostick were compared with the cardiac rhythm on the 12-lead ECG. In a second part of the study, the MyDiagnostick was used to screen for AF during influenza vaccination in the general practitioner's office. Atrial fibrillation was present in 53 out of the 192 patients (27.6%). All AF patients were correctly detected by the MyDiagnostick (sensitivity 100%; 95% confidence interval 93-100%). MyDiagnostick AF classification in 6 out of 139 patients in sinus rhythm was considered false positive (specificity 95.9%; 95% confidence interval 91.3-98.1%). During 4 h of influenza vaccination in 676 patients (age 74 ± 7.1 years), the MyDiagnostick correctly diagnosed AF in all 55 patients (prevalence 8.1%). In 11 patients (1.6%), AF was not diagnosed before, all with a CHA2DS2VASc score of >1. CONCLUSION: The high AF detection performance of the MyDiagnostick, combined with the ease of use of the device, enables large screening programmes for detection of undiagnosed AF.

Intensive lipid lowering may reduce progression of carotid atherosclerosis within 12 months of treatment: the METEOR study.

BACKGROUND: In several statin trials, vascular event rates for treatment groups begin to separate 1 year after commencement of treatment. For atherosclerosis progression, the temporal sequence of the effect has not been defined. We used data from the Measuring Effects on intima media Thickness: an Evaluation Of Rosuvastatin (METEOR) trial to determine the earliest time point at which significant differences in atherosclerosis progression rates could be detected after initiation of statin therapy. METHODS: The METEOR trial was a double-blind, randomized placebo-controlled trial that studied the effect of LDL-C lowering with 40 mg rosuvastatin on the rate of change of carotid intima media thickness (CIMT) measured by B-mode ultrasound amongst 984 low risk subjects. Ultrasound assessments were made at baseline and every 6 months up to 2 years. RESULTS: Rosuvastatin treatment was associated with a 49% reduction in LDL-C-C, a 34% reduction in total cholesterol, an 8.0% increase in HDL-C and a 16% reduction in triglycerides (all P < 0.0001 compared with placebo). The difference in rate of mean maximum CIMT progression between the rosuvastatin and placebo groups (based on near and far wall measurements from both left and right common carotid and internal carotid segments and carotid bifurcation) was not statistically significant after 6 months (0.0023 mm year(-1) and 0.0106 mm year(-1), respectively P = 0.34). After 12 months, CIMT progression rates were significantly different between the groups: 0.0032 mm year(-1) and 0.0133 mm year(-1) in the rosuvastatin-treated and placebo-treated groups, respectively (P = 0.049). This divergence grew with further follow-up: -0.0009 mm year(-1) and 0.0131 mm year(-1) after 18 months (P < 0.001) and -0.0014 mm year(-1) and 0.0131 mm year(-1) after 24 months of treatment (P < 0.001). Results were stronger for the mean common CIMT progression (based on near and far wall measurements from both left and right common carotid segments). CONCLUSION: Aggressive LDL-C lowering seems to exert its beneficial effect on atherosclerosis progression during the first 12 months of treatment. This parallels the timing of event reduction seen in clinical trials and suggests that the efficacy of lipid lowering treatment on CIMT progression can be evaluated in trials with a duration of 1 year, given sufficient sample size, high precision of measurements and a treatment effect comparable to that seen in METEOR.

Endothelial function in young subjects with vaso-vagal syncope.

BACKGROUND: The aim of this study was to determine whether endothelial function and inappropriate peripheral vasomotion have a significant role in the pathogenesis of neurally mediated syncope. METHODS: In 16 patients (mean age 28.2+/-5.8 years) with previous vaso-vagal syncope and in matched healthy subjects, endothelium-dependent flow-mediated dilation (FMD) and endothelium-independent response to glyceryl trinitrate (GTN), 25 mug, were measured in the brachial artery from high-resolution ultrasonography. Heart rate variability (HRV) analysis at rest and during tilt test was compared between two groups. RESULTS: In the subjects with positive tilt test, all HRV parameters were significant higher respect to subjects with negative tilt test (P<0.001). The patients with positive tilt test, showed persistent, marked variability of heart rate (HR), due to increased vagal activity with withdrawal sympathetic tone and consequently reduction of blood pressure (BP) (-30.4+/-4.2 mmHg, P<0.001) accompanied by a decrease in HR (-24.3+/-4.5 beats/min, P<0.001) compared to negative tilt test subjects. These findings prove the real presence of vagal hypertone in patients with syncope. In our study, HR reached values lower than 40 beats/min. FMD in patients with neurally mediated syncope were significantly greater than those in controls (respectively, 9.2+/-2.8% vs. 4.6+/-1.4%, P<0.01) whereas no differences were shown in the response to GTN (18.4+/-4.4% vs. 16.1+/-4.2%, n.s.). CONCLUSIONS: The augmented endothelial function and the abnormal vasodilation of peripheral arteries in association with bradycardia play an important role in the development of vaso-vagal syncope in young subjects.

Ambulatory blood pressure monitoring and endothelium-dependent vasodilation in the elderly athletes.

AIM: Regular exercise is a key component of cardiovascular risk prevention strategies, because it is associated with a variety of beneficial metabolic and vascular effects that reduce mortality and the incidence of cardiovascular adverse events. Endothelium plays an important role in the local regulation of vascular tone and structure, mainly by nitric oxide (NO) synthesis and action. Aim of the present study was to evaluate in elderly athletes the effect of regular aerobic exercise on arterial blood pressure (BP) and on endothelium-dependent flow-mediated dilation (FMD) of the brachial artery. METHODS: The study population included 30 male subjects (mean age 65.6+/-5.6 years), who had practiced endurance running at a competitive level for at least 40 years, and 28 age- and sex-matched subjects (mean age 64.5+/-4.5 years) with sedentary lifestyle and free of cardiovascular disease. Athletes and control subjects underwent standard 12-lead ECG, clinic BP, 24-h ambulatory BP monitoring and endothelium-dependent FMD and endothelium-independent response to glyceryl trinitrate (GTN), 400 microg, in the brachial artery by high-resolution ultrasonography. RESULTS: Systolic clinic and ambulatory 24-h BP were significantly lower in the athletes, than in the controls (P<0.001, respectively). Systolic and diastolic 24-h BP variability, when assessed either by the standard deviation (S.D.), or by the coefficient of variation (CV), were also significantly lower in the athletes (P<0.01). The athletes also had a lower 24-h, day-time and night-time heart rate (HR) (P<0.01), as well as a lower HR variability (P<0.01). As regards circadian BP change, the %Delta was statistically significant greater in athletes (P<0.05). Elderly athletes showed higher FMD than elderly sedentary subjects (P<0.001), whereas no differences were shown in the response to GTN. CONCLUSIONS: Our results, suggest that long-term physical activity can counteract the age-related endothelial dysfunction that characterizes sedentary aging, preserving the capacity of the endothelium-dependent vasodilation and reduces BP values improving arterial pressure control.

Ultrasound protocols to measure carotid intima-media thickness: a post-hoc analysis of the OPAL study.

OBJECTIVE: Ultrasound protocols to measure carotid intima-media thickness (CIMT) differ in the number of carotid walls, segments and angles measured. No published evidence is available to help decide which approach is best, i.e. the most reproducible and providing the largest CIMT progression rate measured with highest precision. We compared different ultrasound protocols in a post-hoc analysis in the 'Osteoporosis Prevention and Arterial effects of tiboLone' (OPAL) study, a 3-year randomized controlled trial among healthy postmenopausal women. RESEARCH DESIGN AND METHODS: Based on combinations of 60 CIMT measurements per participant (two sides, two walls, three segments, five angles), 66 theoretical protocols were constructed. Each protocol was assessed and ranked on: (1) reproducibility (intra-class correlation (ICC), mean difference of duplicate scans) and (2) CIMT progression rate and its precision (standard error) in the placebo group. RESULTS: Duplicate scans at baseline and end of study were available for 675 women (89% of 759 subjects). ICC ranged from 0.69 to 0.88. Mean difference in CIMT of duplicate scans and its standard deviation, ranged from 0.0010 to 0.0137 mm and from 0.0561 to 0.1770, respectively. CIMT rate of progression ranged from -0.0001 to 0.0113 mm/year. The protocols with highest reproducibility and highest CIMT progression-precision were mean common CIMT protocols measuring both near and far wall at > or = 2 angles. The mean maximum protocol measuring three segments at > or = 2 angles performed best, yet with lower estimates as for common CIMT protocols. CONCLUSIONS: In healthy middle-aged subjects mean common CIMT protocols that include measurements at both near and far walls at multiple (> or = 2) angles provide highest reproducibility combined with largest estimates of CIMT progression measured with high precision and are to be recommended in this population.

C-reactive protein and hypertension: is there a causal relationship?

There is a large body of evidence indicating that inflammation plays a crucial role in all steps characterizing the atherosclerotic process. C-Reactive Protein is a circulating marker of inflammation which recently emerged as a powerful independent determinant of cardiovascular events. Hypertension is closely linked to inflammation. Experimental data and results from cross-sectional studies in humans indicate a relationship between CRP levels and blood pressure. In particular, CRP seems to be related with markers of arterial stiffness, thus suggesting a specific interaction between CRP and systolic blood pressure. However, such observational studies cannot provide any direct evidence for a cause-effect relation. Prospective studies are likely candidates to better define the putative causal relationship on this association. Available results from longitudinal studies are scanty, and do not allow to draw definitive conclusions. Moreover, prospective, placebo-controlled intervention trials documenting that reduction of CRP levels by pharmacological treatment might lead to a reduced risk to develop hypertension are not yet available. Without such crucial information, at the present time the causal connection between inflammation and blood pressure, although regarded as an intriguing possibility, remains undiscovered.

Hand function in low-risk preterm infants: its relation to muscle power regulation.

Some preterm infants show a discrepancy in muscle power often recognisable as hyperextension of trunk and shoulders. Even if there is no evident pathology involved, the hyperextension influences later hand function. In this study we assessed a group of healthy infants (N=51) at the age of 39 weeks: 32 were born preterm (and corrected for gestational age) and 19 were born at term. Both quantitative and qualitative measures of hand function were obtained. It was found that the preterm infants scored significantly lower scores in both assessments for hand function. Moreover, a significant correlation was found between the quality of hand function at the age of 39 weeks and hyperextension of the trunk at 18 weeks. Hyperextension of the trunk at 18 weeks had a high predictive value for poor hand function at 39 weeks and thus should hold implications for clinical and therapeutic management.