Selective denervation of the heart.

Area of Science:

• Cardiovascular Physiology
• Autonomic Nervous System Research
• Surgical Innovation

Background:

• The autonomic nervous system significantly influences cardiac function, controlling heart rate, contractility, and rhythm.
• Understanding the specific roles of sympathetic and parasympathetic innervations is crucial for managing cardiac diseases.
• Developing animal models that allow for precise manipulation of cardiac autonomic input is essential for research.

Purpose of the Study:

• To describe a stepwise surgical protocol for total denervation of the canine heart.
• To evaluate the effectiveness of each denervation stage in removing autonomic input.
• To assess the feasibility of selective denervation for creating chronic canine models.

Main Methods:

• A three-stage surgical protocol involving intrapericardial neural dissection and nerve transection was performed on canines.
• Specific structures dissected included the left atrium, pulmonary veins, pulmonary artery, vena cava, and azygos vein.
• Cardiac autonomic denervation was assessed by recording inotropic, chronotropic, and dromotropic responses to electrical stimulation of vagi and stellate ganglia before and after each stage.

Main Results:

• Stage I denervation removed most left autonomic input while preserving right sympathetic input.
• Stage II further reduced left autonomic input and partially preserved right sympathetic input.
• Stage III completed denervation of the sinoatrial and atrioventricular nodes and removed ventricular inotropic influences, indicating successful autonomic blockade.

Conclusions:

• The described three-stage surgical approach allows for progressive and effective denervation of the canine heart.
• Selective denervation of the sinoatrial and atrioventricular nodal regions is achievable.
• This methodology provides a viable method for preparing chronic canine models with specific autonomic denervation patterns for research.