Skip to Main Content

Electrophysiology of the Heart

The content provides an in-depth exploration of the electrophysiology of the heart, focusing on its pacemaking system and the role of the autonomic nervous system in regulating heart function, essential for MCAT preparation.
  • The SA node is identified as the primary pacemaker of the heart, with the AV node serving as a secondary pacemaker.
  • Electrical impulses travel from the SA node to the AV node, then through the Bundle of His and into the left and right bundle branches, culminating in the Purkinje fibers which stimulate ventricular contraction.
  • The sequence of electrical conduction is crucial for understanding heart function and has been a focus in recent MCAT exams.
  • Heart innervation includes both parasympathetic and sympathetic nervous systems, with the former slowing and the latter speeding up heart rate, in addition to influencing contractility.
  • The heart's ability to beat is myogenic, meaning it does not require external innervation to function.
The Heart's Pacemaking System
Electrical Conduction Pathway
Innervation and Heart Rate Control