Right ventricular ejection function assessed by cineangiography--Importance of bellows action

Area of Science:

• Cardiology
• Cardiac Physiology
• Medical Imaging

Background:

• Right ventricular ejection fraction (RVEF) is a key indicator of cardiac function.
• Understanding the primary drivers of RVEF is crucial, especially in conditions without overt left ventricular abnormalities or right ventricular overload.
• The relative contribution of different right ventricular dimensions to RVEF requires clarification.

Purpose of the Study:

• To determine the most significant dimensional change contributing to right ventricular ejection fraction (RVEF).
• To investigate the relationship between percent shortening in three axial dimensions (septum-free wall, anterior-posterior, tricuspid valve-apex/long axis) and RVEF.
• To differentiate the role of these dimensions in various cardiac conditions.

Main Methods:

• Biplane right ventricular cineangiography was performed on 44 subjects.
• Measurements included percent shortening of the septum-free wall (SF), anterior-posterior (AP), and tricuspid valve-apex (TA) or long axis (LA) dimensions.
• Subjects included healthy individuals, and patients with hypertrophic cardiomyopathy and dilated cardiomyopathy.

Main Results:

• Septum-free wall (SF) dimension shortening (34.8%) was significantly greater than AP (23.2%), TA (21.0%), and LA (18.3%) dimensions (p<0.001).
• A linear correlation was observed between the percent shortening of each dimension and RVEF.
• The regression analysis indicated SF shortening is a primary determinant of RVEF, particularly in normal to moderately reduced ejection fractions.

Conclusions:

• Systolic shortening of the septum-free wall dimension, akin to a bellows action, is a major contributor to right ventricular ejection fraction.
• This finding holds true except in cases of significantly reduced ejection fraction.
• The study highlights the importance of the 'bellows action' in right ventricular function.