IVRT
Also written as: IVRT — Isovolumetric Relaxation Time
Isovolumetric relaxation time, the period between aortic valve closure and mitral valve opening.
Full Definition
Isovolumetric relaxation time represents the interval between aortic valve closure and mitral valve opening, during which the left ventricle relaxes without volume change. IVRT is measured using continuous-wave or pulsed-wave Doppler by assessing the time between the end of aortic outflow and the beginning of mitral inflow. Normal IVRT ranges from 60-100 milliseconds and varies with age, heart rate, and loading conditions. Prolonged IVRT suggests impaired left ventricular relaxation (grade I diastolic dysfunction), while shortened IVRT may indicate elevated filling pressures. IVRT is a key component in the comprehensive assessment of diastolic function.
Usage
Usage note: Report in milliseconds; consider age-related normal variations and loading conditions in interpretation.
In Context
- "Prolonged IVRT of 120ms suggested impaired left ventricular relaxation." — Diastolic dysfunction evaluation
- "IVRT shortened from 110ms to 85ms, indicating improved diastolic function." — Treatment response assessment