Are heart rate monitors valuable tools for diagnosing arrhythmias in endurance athletes?

Millions of physically active individuals worldwide use heart rate monitors (HRMs) to control their exercise intensity. In many cases, the HRM indicates an unusually high heart rate (HR) or even arrhythmias during training. Unfortunately, studies assessing the reliability of these devices to help control HR disturbances during exercise do not exist. We examined 142 regularly training endurance runners and cyclists, aged 18-51 years, with unexplained HR abnormalities indicated by various HRMs to assess the utility of HRMs in diagnosing exertion-induced arrhythmias. Each athlete simultaneously wore a Holter electrocardiogram (ECG) recorder and an HRM during typical endurance training in which they had previously detected "arrhythmias" to verify the diagnosis. Average HRs during exercise were precisely recorded by all types of HRMs. No signs of arrhythmia were detected during exercise in approximately 39% of athletes, and concordant HRs were recorded by the HRMs and Holter ECG. HRMs indicated surprisingly high short-term HRs in 45% of athletes that were not detected by the Holter ECG and were artifacts. In 15% of athletes, single ventricular/supraventricular beats were detected by the Holter ECG but not by the HRM. We detected a serious tachyarrhythmia in the HRM and Holter ECG data with concomitant clinical symptoms in only one athlete, who was forced to cease exercising. We conclude that the HRM is not a suitable tool for monitoring heart arrhythmias in athletes and propose an algorithm to exclude the suspicion of exercise-induced arrhythmia detected by HRMs in asymptomatic, physically active individuals.

Cardiothoracic ratio may be misleading in the assessment of right- and left-ventricular size in patients with repaired tetralogy of Fallot.

AIM: To assess the relationship between cardiothoracic ratio (CTR) and ventricular and atrial volumes in patients with repaired tetralogy of Fallot (TOF). MATERIALS AND METHODS: Patients with repaired TOF undergoing cardiac magnetic resonance (CMR) and chest radiography within 1 day were included (n = 82; median age: 24.7 years, interquartile range: 21.5-35.9). The CTR was obtained from upright posteroanterior chest roentgenograms. Analyses of CMR images and radiographs were performed in a blinded fashion. RESULTS: There were 35.1% (13/37) of patients with normal CTR (<0.5) who had severe right ventricular (RV) dilatation. There were six patients (13.3%, 6/45) with high CTR with both normal RV and left-ventricular (LV) volumes. CTR did not correlate with either RV or LV volumes but showed a weak correlation with right- and left-atrial volumes (r = 0.43, p = 0.0001; r = 0.27, p = 0.01, respectively). CTR ≥0.5 showed poor ability in the identification of severe RV dilatation (sensitivity: 61.8%, specificity: 50%). The combination of CTR and signs of RV enlargement on lateral radiographs did not improve the diagnostic accuracy of any of those parameters alone. CONCLUSION: CTR in patients with repaired TOF reflected atrial rather than ventricular dilatation. The use of CTR or lateral radiographs in patients with repaired TOF may lead to false conclusions concerning ventricular size.

Stable right ventricular size and function during short-term follow-up in patients with pulmonary regurgitation after tetralogy of Fallot repair.

AIM: To assess changes in ventricular size and function over time in conservatively treated adult patients with repaired tetralogy of Fallot (TOF) and significant pulmonary regurgitation (PR). MATERIALS AND METHODS: Patients with repaired TOF who had undergone more than one cardiac magnetic resonance study were identified. To confine the cause of ventricular size and function deviation to PR, patients with residual ventricular septal defect, more than mild regurgitation at a valve other than the pulmonary valve, and known coronary artery disease were excluded. RESULTS: The final analysis included 27 adults with PR fraction >20%. During a follow-up of mean 2.1 ± 0.8 years, there was no change in right ventricular (RV) end-diastolic volume (EDV; 162.1 ± 27.6 versus 164 ± 29.6 ml/m(2), p = 0.5). Left ventricular (LV) EDV showed a small decrease (85.1 ± 16.2 versus 81.5 ± 14.1 ml/m(2), p = 0.02). The mean PR fraction, PR volume, and peak RV outflow tract gradient did not change. Additionally, both RV ejection fraction (EF) and LVEF remained stable over the follow-up period (48.1 ± 6.5 versus 48.4 ± 6.7%, p = 0.83, and 57.3 ± 5.4 versus 57.2 ± 5.1 %, p = 0.91, respectively). Only two asymptomatic patients (7.4% of the study group) developed symptoms and the remaining did not deteriorate. CONCLUSION: The RVEDV, RVEF, and LVEF remained stable over a mean follow-up of approximately 2 years in the majority of adult patients after TOF repair with significant PR and a wide range of RVEDV.

Speciation of heavy metals in marine sediments vs their bioaccumulation by mussels.

Total contents and speciation of selected heavy metals, including Al, Fe, Co, Ni, Pb, Zn, Cu, Cr, were measured in sediment samples and mussels Mya arenaria and Astarte borealis collected in the Horsund Fjord off Spitsbergen (Norwegian Sea) and the Bay of Gdansk (Baltic Sea). The investigation aimed at revealing differences in the accumulation pattern of heavy metals in mussels inhabiting sediments characterized by varying metal bioavailability. The contents of metals adsorbed to sediments and associated with iron and manganese hydroxides, which were obtained by sequential extraction, were utilized as a measure of metal bioavailability. The contents of Cd, Pb, Zn, Cu and Cr in mussels collected off Spitsbergen were generally lower than those in mussels from the Baltic Sea. In sediments collected off Spitsbergen the bioavailable fraction represented a small proportion (0-3.7% adsorbed metals and 0-11% associated with metals hydroxides) of total heavy metal contents. In sediments from the Baltic Sea the percentages of metals adsorbed and bound to hydroxides were 1-46% and 1-13%, respectively. The differences in bioavailable metal contents measured in sediments were utilized to explain the different contents of metals in mussels collected in the corresponding sites.

[Visual manual localization in the horizontal plane in persons with vertical deviations of the eyes]. / Wzrokowa lokalizacja reczna w plaszczyznie poziomej u osób z pionowymi odchyleniami oczu.

PURPOSE: To check the behavior of the visual manual localization (v.m.l.) in the horizontal plane which can represent the state of the cortical connections between visual occipital centers and motor centers for the hand movement. MATERIAL AND METHODS: The examinations were performed using the manual localizer. The authors examined 14 patients with vertical deviations of the eyes caused by hyperfunction of the oblique inferior muscles and rectus inferior muscle in the left eye. V.m.l. examined both without the test and with the provoking test were in the range of the physiological norm which excludes the organic changes in the central nervous system. RESULTS: The authors suggest that the reason of the vertical deviations of the eyes is not localized in the higher parts of the nervous system but probably depends on unequal development of the connections in the nuclei of the oculomotor nerves.