In advanced obstructive sleep apnea, what happens to left ventricular end-diastolic pressure and why?

In advanced obstructive sleep apnea, what happens to left ventricular end-diastolic pressure and why?

• A. It increases due to volume overload
• B. It decreases due to reduced pulmonary blood flow
• C. It remains unchanged
• D. It fluctuates with sleep stage

Answer: (B)

Left ventricular end-diastolic pressure mainly reflects preload, which depends on pulmonary venous return to the left atrium. In advanced obstructive sleep apnea, recurrent apneas cause hypoxemia that triggers hypoxic pulmonary vasoconstriction, increasing pulmonary vascular resistance and reducing overall pulmonary blood flow. With less blood returning to the left atrium, filling of the left ventricle at the end of diastole is diminished, so LVEDP decreases.

Left ventricular end-diastolic pressure mainly reflects preload, which depends on pulmonary venous return to the left atrium. In advanced obstructive sleep apnea, recurrent apneas cause hypoxemia that triggers hypoxic pulmonary vasoconstriction, increasing pulmonary vascular resistance and reducing overall pulmonary blood flow. With less blood returning to the left atrium, filling of the left ventricle at the end of diastole is diminished, so LVEDP decreases.