The Role of Apically Directed Intraventricular Isovolumic Relaxation Flow in Speeding Early Diastolic Left Ventricular Filling Atsumi Yanada, MD, Nobuyuki Ohte, MD, Hitomi Narita, MD, Sachie Akita, MD, Hiromichi Miyabe, MD, Norio Takada, MD, Toshihiko Goto, MD, Seiji Mukai, MD, Junichiro Hayano, MD, and Genjiro Kimura, MD, Nagoya, Japan Left ventricular (LV) systolic performance has been acknowledged to have a close relation to LV early diastolic filling and LV relaxation. However, the mechanism showing how good LV systolic function enhances the LV early diastolic filling has not been fully elucidated from the viewpoint of intraventric- ular flow dynamics. Thus, we investigated this issue in 82 patients with suggested coronary artery dis- ease who underwent cardiac catheterization. Api- cally directed intraventricular isovolumic relaxation flow (IRF) and the propagation velocity of early diastolic filling flow were measured using pulsed and color Doppler echocardiography. LV ejection fraction and LV relaxation time constant  were obtained in cardiac catheterization. As we were not able to measure the IRF velocity less than 14 cm/s that was limited by a Doppler low-cut filter, we analyzed the data collected from 78 patients with measurable IRF velocity. The IRF velocity signifi- cantly correlated with LV ejection fraction (r  0.74, P < .001) and with LV relaxation time constant  (r 0.31, P < .01). The propagation velocity of early diastolic filling flow significantly correlated with the IRF velocity (r  0.73, P < .001) and also signifi- cantly correlated with LV ejection fraction (r  0.70, P < .001). Good LV systolic performance augments LV early diastolic filling directly, mediated by IRF. A faster IRF velocity may play a role in delivering good LV systolic performance to LV early diastolic filling. (J Am Soc Echocardiogr 2003;16:1226-30.) Left ventricular (LV) systolic performance has been acknowledged to have a close relationship to LV early diastolic filling and LV relaxation. 1-9 The mech- anism showing how the good LV systolic function derivers to the LV early diastolic filling has been investigated from the viewpoint of intraventricular pressure gradient during early diastole. 2,3,8 How- ever, only a few reports have referred to the rela- tionship between apically directed intraventricular isovolumic relaxation flow (IRF) and early diastolic filling flow. 1,9 Accordingly, from the standpoint of intraventricular flow dynamics during early diastole, we hypothesized that good LV systolic performance produces faster IRF and that the IRF then accelerates LV early diastolic filling. METHODS Study Population Study patients consisted of 82 patients who underwent cardiac catheterization for the evaluation of chest pain. Of these, 54 were men and 28 were women, and their mean age was 61  11 years. They included 44 patients with coronary artery disease (CAD) with prior myocardial infarction (MI) and 23 patients with CAD without MI. CAD was defined as a narrowing of at least 50% in luminal diameter of 1 or more of the major coronary arteries as determined by selective coronary angiography. Prior MI was diagnosed on the basis of the finding of localized LV wall-motion abnormality by biplane contrast left ventricu- lography with related electrocardiographic changes. Among patients with prior MI, 30 were given the diagno- sis of anterior wall MI and 14 inferior wall MI on the basis of the extent of LV wall-motion abnormality. The remain- ing 15 patients were given the diagnosis of atypical chest pain; their electrocardiograms, echocardiograms, and left ventriculograms produced normal findings. Their coro- nary arteriograms did not meet the criteria for CAD. Of the patients with prior anterior MI, 4 had an apical aneurysm. Patients with aortic regurgitation observed by color Dopp- ler echocardiography and those with primary valvular heart disease or hypertrophic cardiomyopathy were ex- cluded from the study. With the exception of nitroglyc- erin, all heart medications were routinely discontinued at From the Department of Internal Medicine and Pathophysiology, Nagoya City University Graduate School of Medical Sciences. Reprint requests: Nobuyuki Ohte, MD, Department of Internal Medicine and Pathophysiology, Nagoya City University Graduate School of Medical Sciences, 1 Kawasumi, Mizuho-cho, Mizuho- ku, Nagoya 467-8601, Japan (E-mail: ohte@med.nagoya-cu.ac.jp). Copyright 2003 by the American Society of Echocardiography. 0894-7317/2003/$30.00 + 0 doi:10.1067/j.echo.2003.08.005 1226