Dynamic cardiac anatomy: the "cypress tree" papillary muscle root

Area of Science:

• Cardiovascular Imaging
• Cardiac Anatomy

Background:

• Traditional understanding of cardiac anatomy relies on autopsy findings.
• Dynamic imaging modalities like cardiac MRI offer in vivo insights.
• Previous descriptions of papillary muscles are based on fixed specimens.

Purpose of the Study:

• To investigate the detailed anatomy of left ventricular papillary muscles using cardiac magnetic resonance.
• To challenge existing anatomical models of papillary muscles.
• To explore the clinical implications of novel papillary muscle anatomy.

Main Methods:

• Retrospective analysis of 255 cardiac magnetic resonance (CMR) examinations.
• Detailed description of papillary muscle origin and insertion.
• Assessment of papillary muscle morphology in vivo.

Main Results:

• Papillary muscle insertions were visualized in all 255 patients.
• In 97.6% of patients, papillary muscles exhibited a complex 'cypress-tree' root-like structure, not uniform muscle.
• This complex structure involves slender trabeculae carneae before coalescing into the muscle head.

Conclusions:

• Cardiac magnetic resonance imaging reveals previously unappreciated complexity in left ventricular papillary muscle anatomy.
• The 'cypress-tree' morphology has potential implications for mitral regurgitation, myocardial remodeling, and cardiac electrical conduction.
• Non-invasive imaging is a valuable tool for studying cardiac anatomy in vivo.