Triphasic mitral inflow velocity with mid-diastolic flow: The presence of mid-diastolic mitral annular velocity indicates advanced diastolic dysfunction*

摘要

Mitral inflow filling pattern usually consists of 2 forward flow velocities in sinus rhythm: early rapid filling (E) and late filling with atrial contraction (A). However, additional mid-diastolic flow velocity may be present resulting in triphasic mitral inflow filling pattern. When mitral inflow is triphasic, mitral annulus velocity recorded by tissue Doppler imaging (TDI) frequently demonstrates a mid-diastolic component (L′). The significance of L′ has not been explored previously. The purpose of this study was to explore possible mechanisms and clinical implications of triphasic mitral inflow with or without L′ using TDI and proBNP. Of 9004 patients who underwent transthoracic echocardiography from March to November 2003, 83 (0.9%) patients (33 male, 50 female; mean age, 63±10 years) with a triphasic mitral inflow velocity pattern, including mid-diastolic flow velocity of at least 0.2m/s, and sinus rhythm were prospectively identified in our clinical echocardiography laboratory. Peak velocity of E, mid-diastolic (L), and A, and deceleration time (DT) of the E wave velocity were measured. Diastolic mitral annular velocities were measured at the septal corner of the mitral annulus by TDI from the apical 4-chamber view. ProBNP was measured at the time of echocardiogram using a quantitative electrochemiluminescence immunoassay. Mean heart rate was 54±6beats/min (range, 40–67). Mean left ventricular (LV) ejection fraction (EF) was 64±13% and LV systolic dysfunction (EF<40%) was present in only 6 (7%). Patients were classified into 2 groups: group 1 (n=47) included those who had L′ and group 2 (n=36) included those without L′. Group 1 patients had significantly higher peak velocity (35±14 vs 26±6cm/s, p=0.0002) and TVI (35±14 vs 26±6cm/s, p=0.0002) of L, E/E′ (18±8 vs 14±6, p=0.02), and left atrial volume index (42±14 vs 34±10ml/m2, p=0.0037). E′ (4.7±1.3 vs 6.2±2.3cm/s, p=0.001) and A′ (6.2±2.0 vs 8.6±3.4cm/s, p=0.0006) were significantly lower in group 1 compared with those of group 2. ProBNP was significantly higher in group 1 (847±1461 vs 438±1039pmol/l, p=0.0012) and it was above normal in all except in 1 patient of group 1. In conclusion, the presence of L′ in subjects with triphasic mitral inflow velocity pattern with mid-diastolic flow is associated with higher E/E′, elevated proBNP and enlarged left atrium indicating advanced diastolic dysfunction with elevated filling pressures. This unique mitral annular velocity pattern should be helpful in identifying the patients with advanced diastolic dysfunction and increased LV filling pressures.