Cardiac performance with chronic hypoxia: mechanisms regulating stroke volume

When humans are exposed to high altitude hypoxia for a sustained period, the cardiac stroke volume is reduced. The changes in cardiac performance seen at high altitude are a result of complex and concomitant changes in preload, afterload and contractility, although the precise mechanisms underpinning the decrease in stroke volume are not known despite being of scientific interest for over fifty years. In this review, we briefly revisit the seminal work performed in the area before focusing on recent developments that have applied mechanistic experimental models and novel imaging technologies to further understand why stroke volume is decreased in chronic hypoxia. First, the review focuses on systolic contractile function before considering the role of diastolic function and ventricular filling.