Ultrasonographic study of left ventricular function at rest in a group of highly trained black African handball players.

Aims: Most of the studies of athlete's heart have been performed on Caucasian and yet, evidence suggests that there are racial differences in the response of the heart to certain pathological conditions such as hypertension. This study aimed to evaluate the morphologic cardiac changes in a group of highly trained Cameroonian handball players.

Methods And Results: We studied cardiac morphology and function as assessed by echocardiography at rest in 21 asymptomatic international level handball players and 21 age-, sex-, height- and weight-matched sedentary controls.

Nocturnal autonomic nervous system activity impairment in sickle cell trait carriers.

Sickle cell trait (SCT) is a genetic disease affecting the synthesis of normal haemoglobin (Hb) and marked by the heterozygous presence of HbA and HbS. Some studies have suggested that SCT carriers might be prone to vascular alterations, cardiac ischaemia and arrhythmias leading, in some subjects, to sudden death. It is well known that a loss or a disequilibrium of autonomic activity are powerful predictors of sudden cardiac death.

Effects of extreme endurance running on cardiac autonomic nervous modulation in healthy trained subjects.

This study examined spectral components of heart rate variability (HRV) during endurance mountain running in 8 healthy trained subjects. The data showed that during this type of mountain running, all spectral components of HRV may severely decrease, particularly very-low-frequency and low-frequency (LF) power, suggesting extreme activation of the sympathetic nervous system. The physiologic response of the heart in this situation was the downregulation of the beta-adrenergic receptors to protect myocardial function, with a subsequent increase in parasympathetic tone, reflected by an increase in high-frequency (HF) power and a decrease in the LF/HF ratio.