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[Left intraventricular flow during isovolumic relaxation. Frequency, significance, mechanism]
1Service de cardiologie B, CHU, Amiens.
Insights
Intraventricular flow during isovolumic relaxation was detected in most hypertrophic obstructive cardiomyopathy and aortic valve stenosis patients. This flow may indicate hyperkinetic wall motion and is distinct from the mitral E wave.
Area of Science:
- Cardiology
- Echocardiography
- Physiology
Background:
- The isovolumic relaxation flow (IRF) is a supplementary intraventricular flow occurring during left ventricular isovolumic relaxation.
- First described in 1987, its diagnostic significance, particularly in specific cardiac conditions, warrants further investigation.
Purpose of the Study:
- To investigate the prevalence and characteristics of isovolumic relaxation flow in patients with hypertrophic obstructive cardiomyopathy (HOCM) and aortic valve stenosis (AVS).
- To identify associated Doppler echocardiographic findings and understand the physiological basis of IRF.
Main Methods:
- Doppler echocardiography was used to detect and analyze isovolumic relaxation flow.
- The study included 13 HOCM patients, 58 AVS patients, and 41 normal controls.
Main Results:
- IRF was detected in 77% of HOCM patients, 50% of AVS patients, and 5% of normal controls.
- The flow averaged 104 ms in duration and 0.74 m/s in velocity, directed apically along the interventricular septum.
- Associated findings included small left ventricular chambers, hyperkinetic wall motion, and systolic apical cavity obliteration.
Conclusions:
- Isovolumic relaxation flow appears to be a marker of hyperkinetic wall motion in conditions like HOCM.
- It arises from intraventricular pressure gradients due to asynchronous relaxation.
- IRF should be differentiated from the mitral E wave, especially in patients with atrial fibrillation.
Abstract:
Supplementary intraventricular flow during the left ventricular isovolumic relaxation period "isovolumic relaxation flow", was described for the first time in 1987 by Sasson. This flow was searched for in 13 patients with hypertrophic obstructive cardiomyopathy (HOCM), 58 patients with aortic valve stenosis (AVS) and 41 normal control patients. It was detected in 77% of patients with HOCM, 50% of patients with AVS and 5% of normal controls. The flow was usually recorded throughout the isovolumic relaxation period and lasted an average 104 ms (range 70 to 140 ms) with a velocity of 0.74 m/s (range 0.25 to 1.70 m/s). It was detected along the middle third of the interventricular septum, directed towards the cardiac apex, coded in red in colour Doppler studies. The other Doppler echocardiographic signs associated with isovolumic relaxation flow were: small left ventricular chambers, normo- or hyperkinetic wall motion, systolic apical cavity obliteration, intraventricular systolic acceleration with a left systolic peak (74% of cases) but with no correlation between the velocity of this flow and that of isovolumic relaxation flow. Isovolumic relaxation flow results from an intraventricular pressure gradient related to asynchronous relaxation and the resulting redistribution of blood in the left ventricle. It would seem to be a marker of hyperkinetic wall motion together with systolic apical cavity obliteration and the resulting intraventricular systolic accelerated flow. It should not be confused with the mitral E wave, especially in patients with atrial fibrillation.