The mechanism of emergence and clinical significance of apically directed intraventricular flow during isovolumic relaxation☆

Abstract 

The mechanism of emergence and the clinical significance of apically directed intraventricular flow during isovolumic relaxation were investigated. The relation between the spatial distribution of the flow and left ventricular (LV) apical wall motion abnormality, as well as LV performance, was studied in 97 patients who underwent cardiac catheterization for evaluation of chest pain. According to the distribution of the flow, the patients were classified into the following 3 groups: flow observed in the whole area between the tip of the papillary muscle and the apex (spread flow) (n = 38), flow observed in the same area that did not fill the whole area (localized flow) (n = 15), and no apparent flow observed in the area (without flow) (n = 44). An absence of flow disclosed apical asynergy with a sensitivity of 97% and specificity of 87%. The time constant of LV relaxation was significantly shorter in patients with spread flow than in those without flow. A significant difference was also observed in end-systolic volume index (18.8 ± 6.8 vs 30.9 ± 7.7 vs 42.3 ± 20.2 mL/m², spread flow < localized flow < without flow, P < .05) among the 3 groups. The propagation velocity of LV early diastolic filling flow was significantly greater in patients with spread flow (47.0 ± 8.3 cm/s) than in those with localized flow (30.7 ± 7.8 cm/s) or without flow (28.6 ± 7.8 cm/s) (P < .001). These findings indicate that the greater magnitude of LV elastic recoil and the faster LV relaxation in patients without LV apical asynergy produce apically directed intraventricular flow during isovolumic relaxation, enhancing the speed of LV early diastolic filling. Apically directed intraventricular flow during isovolumic relaxation may play an important role as a mediator of better LV systolic performance and LV relaxation to LV early diastolic filling. Absence of apically directed intraventricular flow during isovolumic relaxation is a manifestation of LV apical asynergy and global LV dysfunction from end systole to early diastole. (J Am Soc Echocardiogr 2002;15:715-22.)