Radar evidence of subglacial liquid water on Mars.

The presence of liquid water at the base of the martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.

The "Athlete's Heart": relation to gender and race.

Long-term athletic training is associated with changes in cardiac morphology, commonly described as "athlete's heart." Although numerous studies have investigated the effects of training on cardiac dimensions, most are limited to male Caucasian athletes, and few data are available regarding the effect of long-term exercise training on the woman's heart. This article reviews the athlete's heart in relation to gender and race.

Clinical significance of abnormal electrocardiographic patterns in trained athletes.

BACKGROUND-The prevalence, clinical significance, and determinants of abnormal ECG patterns in trained athletes remain largely unresolved. METHODS AND RESULTS-We compared ECG patterns with cardiac morphology (as assessed by echocardiography) in 1005 consecutive athletes (aged 24+/-6 years; 75% male) who were participating in 38 sporting disciplines. ECG patterns were distinctly abnormal in 145 athletes (14%), mildly abnormal in 257 (26%), and normal or with minor alterations in 603 (60%). Structural cardiovascular abnormalities were identified in only 53 athletes (5%). Larger cardiac dimensions were associated with abnormal ECG patterns: left ventricular end-diastolic cavity dimensions were 56. 0+/-5.6, 55.4+/-5.7, and 53.7+/-5.7 mm (P<0.001) and maximum wall thicknesses were 10.1+/-1.4, 9.8+/-1.3, and 9.3+/-1.4 mm (P<0.001) in distinctly abnormal, mildly abnormal, and normal ECGs, respectively. Abnormal ECGs were also most associated with male sex, younger age (<20 years), and endurance sports (cycling, rowing/canoeing, and cross-country skiing). A subset of athletes (5% of the 1005) showed particularly abnormal or bizarre ECG patterns, but no evidence of structural cardiovascular abnormalities or an increase in cardiac dimensions. CONCLUSIONS-Most athletes (60%) in this large cohort had ECGs that were completely normal or showed only minor alterations. A variety of abnormal ECG patterns occurred in 40%; this was usually indicative of physiological cardiac remodeling. A small but important subgroup of athletes without cardiac morphological changes showed striking ECG abnormalities that suggested cardiovascular disease; however, these changes were likely an innocent consequence of long-term, intense athletic training and, therefore, another component of athlete heart syndrome. Such false-positive ECGs represent a potential limitation to routine ECG testing as part of preparticipation screening.

Physiologic left ventricular cavity dilatation in elite athletes.

BACKGROUND: Absolute left ventricular cavity dimension may be substantially increased in some highly trained athletes. This raises questions about the differential diagnosis between athlete's heart and dilated cardiomyopathy as well as possible disqualification from competitive sports. OBJECTIVE: To evaluate the morphologic characteristics and physiologic limits of left ventricular cavity enlargement associated with intensive, long-term athletic conditioning. DESIGN: Evaluation of left ventricular cavity dimension in a large sample of highly trained athletes. SETTING: Institute of Sports Science, Rome, Italy. PARTICIPANTS: 1309 elite Italian athletes (957 men and 352 women), 13 to 59 years of age (mean, 24 years), participating in 38 different sports. MEASUREMENTS: Echocardiographic assessment of left ventricular cavity dimension and multivariate statistical analysis of the determinants. RESULTS: Left ventricular end-diastolic cavity dimensions varied widely (38 to 66 mm [mean, 48 mm] in women and 43 to 70 mm [mean, 55 mm] in men) and was within generally accepted normal limits for most participants (< or = 54 mm in 725 athletes [55%]). According to an arbitrary clinical cut-point of 60 mm, the left ventricular cavity was substantially enlarged in 185 participants (14%). These athletes had global left ventricular systolic function within normal limits and no regional wall-motion abnormalities; participants remained free of cardiac symptoms and impaired performance over 1 to 12 years (mean, 4.7 years). The major determinants of cavity dimension were greater body surface area and participation in certain endurance sports (cycling, cross-country skiing, and canoeing). CONCLUSIONS: In a sample of highly trained athletes, left ventricular cavity dimension varied widely but was strikingly increased to a degree compatible with primary dilated cardiomyopathy in almost 15% of participants. In the absence of systolic dysfunction, this cavity dilatation is most likely an extreme physiologic adaptation to intensive athletic conditioning. The long-term consequences and significance of this marked left ventricular remodeling of the athlete's heart is not known.

[Paroxysmal atrial fibrillation in patients with chronic ischemic cardiopathy: a study of high-resolution atrial activation]. / Fibrillazione atriale parossistica in pazienti con cardiopatia ischemica cronica: studio dell'attivazione atriale ad alta risoluzione.

BACKGROUND: Patients with ischemic heart disease and episodes of paroxysmal atrial fibrillation are at major risk of stroke. In order to prevent such episodes, through the identification of patients prone to atrial fibrillation, we investigated the high-resolution atriogram of 65 patients with chronic ischemic heart disease, 54 male and 11 female, mean age 60.22 +/- 9.04 years. Based on previous documented episodes of atrial fibrillation, the patients were divided into two groups: group A, 45 males and 3 females, mean age 58.92 +/- 7.68 years, without atrial fibrillation; group B, 9 males and 8 females, mean age 63.88 +/- 11.6 years, with atrial fibrillation. RESULTS: High resolution atrial duration (100-300 Hz) in group B (with atrial fibrillation) was higher than in group A (without atrial fibrillation) (140.59 +/- 16.85 ms vs 121.77 +/- 11.27 ms, p < 0.001); Non filtered atrial duration (0-300 Hz) was not different between the two groups, A and B (118.54 +/- 10.96 ms vs 123.53 +/- 18.77 ms, p = NS); The prevalence of late atrial potentials was higher in group B than in group A (60.8% vs 7.1%, p < 0.001); No relation was observed between high resolution atriogram data and echocardiographic measurements; Sensibility was 82%, specificity 81%, and predictivity 60%. CONCLUSIONS: Data from our study show that high resolution electrocardiography is a valid tool for identifying patients prone to atrial fibrillation. Such patients can be identified by the presence of "late atrial potentials" that, like late ventricular potentials for ventricular tachycardia, are correlated with atrial fibrillation. Nevertheless, a larger cohort of patients is necessary to confirm these results.

[Ventricular late potentials in hypertrophic cardiomyopathy: personal contribution and analysis of the literature]. / I potenziali tardivi ventricolari nelle cardiomiopatie ipertrofiche: contributo personale ed esame della letteratura.

BACKGROUND: Patients with hypertrophic cardiomyopathy are at increased risk of sudden death. Recently it has been investigated whether late potentials can be useful markers of that risk in such patients, with discordant results. The aim of our study was to detect a correlation, if any, between late potentials, ventricular tachycardia and the hypertrophy extension. METHODS: Twenty-five patients were enrolled, 19 males and 6 females, mean age 40.40 +/- 15.02 years. Each underwent 24h Holter monitoring, averaged ECG, M-Mode and 2-D Echo. The hypertrophy was considered extensive (septum and free wall) or non extensive (septum and/or apex). RESULTS: Late potentials of a mean duration of 37 +/- 14.83 ms were recorded in 5/7 patients with documented ventricular tachycardia vs in none of the non tachycardia group. Sensibility was 100%, specificity 71% and predictive value 100%. Late potentials were present in 8.3% of patients with non extensive and in 30.8% of patients with extensive hypertrophy (p = NS). CONCLUSIONS: From our data it seems that extensive hypertrophy is present in about half of patients with hypertrophic cardiomyopathy, and this roughly correlates with a more frequent ventricular tachycardia and with late potentials. Furthermore, late potentials are strictly related to the incidence of ventricular tachycardia in this disease, just as in ischemic heart disease or in idiopathic dilated cardiomyopathy. The small number of our cases may not be sufficient to reach a significant statistical correlation between late potentials and hypertrophy, but we believe that the trend is very promising.

[Aneurysms of the abdominal aorta]. / Gli aneurismi dell'aorta addominale.

The authors report 73 cases of abdominal aortic aneurysms with particular emphasis to early and long-term results as well as postoperative complications: 4 patients died at admission, 16 were treated with medical therapy, and 53 underwent surgery. Surgical patients were stratified in two groups: 18 emergency cases (group 1) and 35 elective cases (group 2). Early results showed the highest mortality in group 1 cases presenting with shock. Late results, at the end of the follow up, (6 months-8 years), showed a 56.6% 5-year survival rate, with overlapping survival rates after the immediate postoperative period. The most frequent postoperative complications were thrombosis of prosthesis and lymphorrhea. Survival rates of emergency cases were influenced by early diagnosis and prompt aorta clamping. Before surgery an haemodynamic evaluation of all vascular districts seems necessary in elective cases to prevent complications of atherosclerotic disease.