Left ventricular adaptation to high altitude: speckle tracking echocardiography in lowlanders, healthy highlanders and highlanders with chronic mountain sickness.

Hypoxic exposure depresses myocardial contractility in vitro, but has been associated with indices of increased cardiac performance in intact animals and in humans, possibly related to sympathetic nervous system activation. We explored left ventricular (LV) function using speckle tracking echocardiography and sympathetic tone by spectral analysis of heart rate variability (HRV) in recently acclimatized lowlanders versus adapted or maladapted highlanders at high altitude. Twenty-six recently acclimatized lowlanders, 14 healthy highlanders and 12 highlanders with chronic mountain sickness (CMS) were studied.

Quantification of low-gradient severe aortic stenosis using a hybrid approach combining Doppler echocardiography and thermodilution.

Background And Aim Of The Study: Estimation of stroke volume in the left ventricular outflow tract (LVOT) is a main limitation to aortic valve area (AVA) calculation by echocardiography when using the continuity equation. In this study, the hypothesis was tested that a hybrid method using thermodilution-derived cardiac output measurement and simultaneous Doppler estimation of the systolic ejection period and transvalvular aortic velocities could be used to accurately assess AVA in patients with low-gradient severe aortic stenosis (AS).

Methods: Eighteen patients with low mean gradient (< 40 mmHg) and nine patients with conventionally defined (> or = 40 mmHg) severe AS (< 1 cm2), as assessed by the echocardiographic continuity equation (baseline echocardiography), underwent catheterization and simultaneous Doppler recording of trans-aortic velocities.

Looking at the frame after the picture: "retrocardiac echocardiography".

We report three cases of mediastinal structures encroaching on the left atrium without haemodynamic compromise. These cases emphasize the potential role of echocardiography for the diagnosis and the management of several extracardiac mediastinal abnormalities.

Left ventricular adaptation to acute hypoxia: a speckle-tracking echocardiography study.

Background: Hypoxia depresses myocardial contractility in vitro but does not affect or may even improve indices of myocardial performance in vivo, possibly through associated changes in autonomic nervous system tone. The aim of this study was to explore the effects of hypoxic breathing on speckle-tracking echocardiographic indices of left ventricular function, with and without β1-adrenergic inhibition.

Methods: Speckle-tracking echocardiography was performed in 21 healthy volunteers in normoxia and after 30 min of hypoxic breathing (fraction of inspired oxygen, 0.

Pulmonary hypertension and the right ventricle in hypoxia.

Hypoxia causes pulmonary vasoconstriction. Regional hypoxic vasoconstriction improves the matching of perfusion to alveolar ventilation. Global hypoxic vasoconstriction increases right ventricular afterload.