Baroreflex sensitivity impairment is associated with cardiac diastolic dysfunction in rats

Area of Science:

• Cardiovascular Physiology
• Autonomic Nervous System Research
• Cardiac Electrophysiology

Background:

• Impaired baroreflex sensitivity is linked to higher mortality.
• The specific impact of baroreflex dysfunction on cardiac diastolic function remains unclear.

Purpose of the Study:

• To investigate the morphofunctional cardiac changes associated with baroreflex impairment.
• To evaluate the influence of chronic sinoaortic denervation (SAD) on cardiac function, particularly diastolic properties.

Main Methods:

• Sinoaortic denervation (SAD) model in animals, with a control group.
• Assessment of baroreflex sensitivity using vasoactive drug responses.
• Echocardiography and left ventricle (LV) catheterization for cardiac function analysis.
• Quantification of LV collagen and proteins regulating intracellular calcium (Ca2+).

Main Results:

• SAD animals exhibited increased LV mass compared to controls.
• Diastolic dysfunction was evidenced by increased E-wave deceleration time and elevated LV end-diastolic pressure.
• Reduced minimum dP/dt and altered SERCA/NCX and SERCA/PLB ratios indicated impaired calcium handling and relaxation in SAD rats.

Conclusions:

• Baroreflex dysfunction is independently associated with cardiac diastolic dysfunction.
• These findings highlight a direct link between autonomic dysfunction and impaired heart relaxation.