The athlete's heart

Exercise training has an effect on myocardial metabolism and the coronary vasculature. Alterations in the autonomic nervous system tone appear to account for the bradycardia often seen in athletes. Cardiomyopathy is the main threat to health and life in the young competitive athlete. For the older jogger or marathoner, coronary disease is the most common cause of a sudden cardiac catastrophe. A thorough medical history and physical examination is the least expensive and the most effective means of screening athletes for underlying cardiovascular disease. This can be supplemented with additional studies such as the chest X-ray, resting and exercise ECG, ambulatory monitoring, radionuclear stress scanning, echocardiography, and electrophysiologic evaluations. The main therapeutic dilemmas occur in the symptomatic athlete who has variations from normal on physical examination and laboratory study. Prudence is advised when the examining physician cannot exclude a situation that could potentially result in an exercise-related death.     

Limits of ventricular function: from athlete's heart to a failing heart

The interest in the study of ventricular function has grown considerably in the last decades. In this review, we analyse the extreme values of ventricular function as obtained with Doppler echocardiography. We mainly focus on the parameters that have been used throughout the history of Doppler echocardiography to assess left ventricular (LV) systolic and diastolic function. The ‘athlete's heart’ would be the highest expression of ventricular function whereas its lowest expression is represented by the failing heart, independently from the original aetiology leading to this condition. There are, however, morphological similarities (dilation and hypertrophy) between the athlete's and the failing heart, which emerge as physiological and pathophysiological adaptations, respectively. The introduction of new assessment techniques, specifically speckle tracking, may provide new insight into the properties that determine ventricular filling, specifically left ventricular twisting. The concept of ventricular function must be always considered, although it may not be always possible to distinguish the normal heart of sedentary individuals from that of highly trained hearts based solely on echocardiographic or basic studies.     

The athlete's electrocardiogram

The electrocardiogram performed in the competitive athlete may manifest abnormal electrocardiographic findings; these findings may indicate either normal variant syndromes as well as true cardiac pathology. The normal variant syndromes include ST-segment and T-wave abnormalities, rhythm disturbances, and intraventricular conduction delay--it must be stressed that these electrocardiographic findings are, in fact, normal variants, not indicative of underlying pathology. Other presentations in these same competitive athletes describe significant cardiac pathology, including syndromes predisposing the patient to sudden cardiac death and other potentially dangerous dysrhythmias and diagnostic of acute coronary syndrome. This article reviews the various findings in this group of patients.     

Assessment of QT interval duration and dispersion in athlete's heart

An athlete's heart is characterized by morphological and functional changes occurring as a consequence of regular physical exercise. We sought to determine if these physiological changes lead to ventricular repolarization abnormalities in trained athletes. Forty-four trained athletes and 35 sex- and age-matched healthy sedentary controls were included in the study. A 12-lead surface electrocardiogram (ECG) was obtained from all participants. Maximum QT (QTmax) and minimum QT (QTmin) interval durations, QT dispersion (QTd) and corrected QT dispersion (QTcd) were calculated for each ECG record. Heart rate, systolic and diastolic blood pressure values were found to be identical in both groups. QTmax and QTmin interval durations were not statistically different between the athletic and control groups. Similarly, QTd and QTcd did not differ significantly between the two groups. No association was observed between an athlete's heart and ventricular heterogeneity compared with healthy sedentary controls, despite physiological and structural changes.     

The role of quantitative myocardial contrast echocardiography in the study of coronary microcirculation in athlete's heart.

Quantitative myocardial contrast echocardiography was performed with harmonic power Doppler analysis using the background subtraction and Levovist (Schering AG, Berlin, Germany) as contrast agent in a triggered modality. Quantitative analysis of echocontrast was performed offline with PC software, obtaining the transit curves of microbubbles through the coronary capillary system. Coronary microcirculation in athletes showed a behavior substantially comparable with control participants, although at a higher level. Training determines a physiologic left ventricular hypertrophy that counterbalances the dilatation in the left ventricular chambers because of the higher blood volume in athletes compared with control participants. Angiogenesis and several functional adaptations (relaxation of small coronary arteries, increased production of nitric oxide by the coronary endothelium, or both), represent the potential mechanisms that allow an optimal distribution of oxygen and of substrates to the hypertrophied myocardium of the athletes.     

Different alterations in the insulin-stimulated glucose uptake in the athlete's heart and skeletal muscle.

Physical training increases skeletal muscle insulin sensitivity. Since training also causes functional and structural changes in the myocardium, we compared glucose uptake rates in the heart and skeletal muscles of trained and untrained individuals. Seven male endurance athletes (VO2max 72 +/- 2 ml/kg/min) and seven sedentary subjects matched for characteristics other than VO2max (43 +/- 2 ml/kg/min) were studied. Whole body glucose uptake was determined with a 2-h euglycemic hyperinsulinemic clamp, and regional glucose uptake in femoral and arm muscles, and myocardium using 18F-fluoro-2-deoxy-D-glucose and positron emission tomography. Glucose uptake in the athletes was increased by 68% in whole body (P < 0.0001), by 99% in the femoral muscles (P < 0.01), and by 62% in arm muscles (P = 0.06), but it was decreased by 33% in the heart muscle (P < 0.05) as compared with the sedentary subjects. The total glucose uptake rate in the heart was similar in the athletes and control subjects. Left ventricular mass in the athletes was 79% greater (P < 0.001) and the meridional wall stress smaller (P < 0.001) as estimated by echocardiography. VO2max correlated directly with left ventricular mass (r = 0.87, P < 0.001) and inversely with left ventricular wall stress (r = -0.86, P < 0.001). Myocardial glucose uptake correlated directly with the rate-pressure product (r = 0.75, P < 0.02) and inversely with left ventricular mass (r = -0.60, P < 0.05) or with the whole body glucose disposal (r = -0.68, P < 0.01). Thus, in athletes, (a) insulin-stimulated glucose uptake is enhanced in the whole body and skeletal muscles, (b) whereas myocardial glucose uptake per muscle mass is reduced possibly due to decreased wall stress and energy requirements or the use of alternative fuels, or both.     

无创手段对肺心病患者缺氧量化判定的研究

目的 寻找一种无创的辅助判断肺心病患者缺氧程度的评分方法.方法 以急性生理功能和慢性健康状况评分系统Ⅱ(acute physiology and chronic health evaluation Ⅱ,简称APACHE Ⅱ)为框架,自行设计肺心病患者缺氧的量化评分表,对67例肺心病患者缺氧状况进行评分.将评分结果与动脉血气分析进行对比分析,找出其相关性.结果 评分与pH、PaO2、SaO2呈高度负相关性,评分与PaCO2呈高度正相关性.结论 缺氧评分表虽然不能替代血气分析,但作为一种无创手段用以辅助判断肺心病患者缺氧程度,既能有效地减少患者多次穿刺的痛苦,又能达到判断患者缺氧的目的,有一定的临床意义.

Abstract：

Objective To find a grading method for assisting in evaluating hypoxia degree of patients with pulmonary heart disease non-invasively. Methods To design a quantitative method to score degree of hypoxia of 67 patients with pulmonary heart disease by using acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) as a frame and to make comparative analysis between the grading result and artery blood gas to find the correlation. Results There was a negative correlation between evaluation mark and pH、PaO2、SaO2 and a positive correlation between the evaluation mark and PaCO2, according to statistics. Conclusions Although the grading table of hypoxia evaluation can not substitute blood gas analysis, acting as a non-invasive method to assist in evaluating the hypoxia degree of patients with pulmonary heart disease, it can not only relieve patients' repeated punctuation pain, but also achieve the goal of estimating hypoxia.Consequently the non-invasive method to evaluate hypoxia is of clinical value.     

Doppler tissue imaging: regional myocardial function in hypertrophic cardiomyopathy and in athlete's heart.

BACKGROUND: The distinction between hypertrophic cardiomyopathy (HCM) and the athlete's (AT) heart is an important clinical problem, and the analysis of regional myocardial function with Doppler tissue imaging may be useful in the differential diagnosis. OBJECTIVE: Our aim was to compare regional function assessed by Doppler tissue imaging in rowers and in a group of patients with HCM. METHODS: In 24 patients with nonobstructive HCM and in 20 competitive rowers with similar age, blood pressure, and heart rate, we analyzed with pulsed Doppler tissue imaging left ventricular (LV) regional function (velocities, time intervals, heterogeneity and asynchrony indices, and meridional gradient) in the longitudinal (8 segments, apical views) and in the radial (2 segments, short-axis view) axis. RESULTS: Compared with AT, patients with HCM showed: (1). systolic function; (a). longitudinal: lower velocities and meridional gradient; longer precontraction period (PCP); and higher PCP/LV contraction time; (b). radial: lower velocities and gradient; longer PCP; and higher PCP/LV contraction time; (2.diastolic function; (a). logitudinal: lower e (early diastolic), a (late diastolic), and e/a velocities; and longer prerelaxation time and time to peak e. The percentage of segments with e/a < 1 was 25% in the HCM group and 0% in the AT heart group; (b). radial: lower e velocity and gradient; lower e/a gradient; and longer medial prerelaxation and basal time to peak e. Most of these differences also occurred in the nonhypertrophied inferior wall of patients with HCM. CONCLUSIONS: There are significant differences between regional LV function of competitive rowers and patients with HCM. These differences (1). occur in systole and diastole; (2). affect velocities and time intervals; (3). are more striking in the long axis, but are also seen in the short axis, and (4). also occur in nonhypertrophied segments, suggesting the usefulness of the technique in the differential diagnosis between the 2 situations, namely in individuals that fall in Maron's "grey zone."     

Sudden cardiac death in young athletes. Causes, athlete's heart, and screening guidelines

Sudden cardiac death of a young competitive athlete is a rare but tragic event. Hypertrophic cardiomyopathy and coronary artery anomalies are the most frequent causes. Most cardiovascular abnormalities go unrecognized until the time of death owing to the lack of preceding signs or symptoms suggestive of disease. Physicians responsible for the care of athletes should be familiar with the various causes of sudden cardiac death, the physiologic adaptations seen in so-called athlete's heart, and existing cardiovascular screening guidelines. The preparticipation evaluation, although it has limitations, is the major instrument readily available for prevention of sudden cardiac death. Effort should be made to follow established consensus guidelines.     

The problem of scars in heart surgery with special reference to the use of static magnetic fields

An attempt is made to survey the pathophysiology of wound healing, as well as the aetiological factors involved and the possibilities of therapeutic intervention to prevent the formation of hypertrophic scars and keloid after cardiac operations. Several prophylactic measures are discussed, with special reference to the use of static magnetic fields. Their application to scars after cardiac operations was carried out by energy pak foils. Patients treated with these foils showed slightly improved results as compared with a control group. The results, however, were not statistically significant.     

The hazards of caring

Nurses may be at increased risk of non-communicable diseases such as cancer and asthma because of their exposure to hazardous substances in the workplace. Environmental and health groups are working together to persuade hospitals to adopt green practices that are better for the planet and safer for healthcare staff.