The myocardial performance index in children with isolated left-to-right shunt lesions

Area of Science:

• Pediatric Cardiology
• Echocardiography
• Ventricular Function Assessment

Background:

• The myocardial performance index (MPI) quantifies ventricular function by assessing isovolumic time intervals relative to ventricular ejection time.
• The influence of altered ventricular preload or afterload on MPI remains incompletely understood.
• Investigating MPI's response to preload variations is crucial for accurate ventricular function assessment in pediatric cardiac conditions.

Purpose of the Study:

• To determine the impact of altered preload on left and right ventricular MPI in children with left-to-right shunt lesions.
• To evaluate MPI's utility as a preload-independent measure of ventricular function.
• To compare MPI values in children with atrial septal defects (ASD) and ventricular septal defects (VSD) to healthy controls.

Main Methods:

• Echocardiographic assessment of left and right ventricular MPI in 17 children with ASD, 23 with VSD, and 24 healthy controls.
• Measurements included 2-dimensional and Doppler echocardiography.
• Patient ages ranged from 2 to 160 months.

Main Results:

• Left ventricular MPI values were 0.38 (ASD), 0.37 (VSD), and 0.32 (controls).
• Right ventricular MPI values were 0.24 (ASD), 0.21 (VSD), and 0.20 (controls).
• No significant differences in MPI were observed between children with left-to-right shunt lesions and controls.

Conclusions:

• The myocardial performance index is a quantitative measure of ventricular function.
• MPI appears to be relatively independent of changes in preload in the studied pediatric population.
• MPI serves as a robust indicator of ventricular function, even in the presence of preload alterations associated with left-to-right shunts.