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Left atrial appendage blood flow determined by transesophageal echocardiography in healthy subjects

Transesophageal echocardiography was performed in 46 healthy subjects to define characteristics of normal left atrial appendage blood flow. Three different flow wave patterns were observed that were heart rate dependent (p < 0.01). A quadriphasic pattern, consisting of 2 diastolic forward (emptying) flow waves each followed by a backward (filling) flow wave, was present in 36 subjects (78%). Triphasic appendage flow was observed in 6 subjects (13%) and biphasic flow in 4 (9%). Mean heart rates among subjects with quadri-, tri- and biphasic flows were 75 +/- 11, 95 +/- 6 and 112 +/- 7 beats/min, respectively. Analysis of pulsed Doppler recordings of subjects with quadriphasic or triphasic appendage flow patterns showed that the onset of transmitral early diastolic peak flow wave was followed at 17 +/- 15 ms by the onset of pulmonary venous diastolic flow and at 43 +/- 17 ms by the onset of the first diastolic forward flow in the appendage. This sequence was constant and independent of heart rate (p < 0.01), suggesting a causal relation between left ventricular relaxation and the first diastolic forward flow wave in the appendage. The second diastolic forward flow followed the P wave on the electrocardiogram at 79 +/- 23 ms. Thus, left atrial appendage blood flow pattern in normal subjects is heart rate dependent, and ventricular relaxation appears to initiate early diastolic emptying of the appendage.

Pathogenesis of mitral regurgitation in acute myocardial infarction: Importance of changes in left ventricular shape and regional function☆

The pathogenesis of mitral regurgitation (MR) was determined by quantitative echocardiography in 188 patients with acute myocardial infarction (AMI) within 48 hours after admission. MR was classified, by using color Doppler, as significant (grades 3 to 4) or trivial (grades 0 to 2). Left ventricular (LV) function (global and regional), volume, and shape, as well as mitral valvular features, were measured and analyzed by stepwise logistic regression. Significant MR occurred in 25 (13%) patients. Univariately, recurrent infarction (p < 0.01), LV dilation (p < 0.001) and sphericity (p < 0.001), inferoposterolateral asynergy (p < 0.001), mitral annular dilatation (p < 0.005), and mitral leaflet restriction (p < 0.05) were associated with significant MR. In regression analysis, only recurrent infarction (odds ratio 5.08), LV sphericity index (odds ratio 1.12), and inferoposterolateral asynergy (odds ratio 6.07) were independently associated with significant MR, whereas none of the mitral valvular features examined had an independent association. In conclusion, changes in LV shape and regional function and not mitral valvular changes are prime determinants of significant MR after AMI.

Prediction of apical thrombus formation in acute myocardial infarction based on left ventricular spatial flow pattern

The predictive value of the left ventricular spatial flow pattern for thrombus formation was determined in 62 patients with acute myocardial infarction. A normal flow pattern by pulsed Doppler echocardiography was characterized by 1) simultaneous onset of blood motion at the mitral valve and apical level, and 2) a discontinuous Doppler signal along the lateral wall and interventricular septum. The flow pattern was assessed by these criteria, within 24 h after the onset of complaints and after 6 and 12 weeks. In 46 of the 62 patients, a normal flow pattern was found at the first examination; none of these 46 patients developed a thrombus during the study period. An abnormal flow pattern was seen at the first examination in 16 patients; this pattern normalized during follow-up in 6 patients, none of whom developed a thrombus. In the other 10 patients the abnormal flow pattern persisted, and 7 of these developed a thrombus. These findings suggest that a normal left ventricular flow pattern in the setting of acute myocardial infarction is not associated with subsequent thrombus formation. This observation may be of importance if anticoagulation is considered.

Limits of reproducibility of blood flow measurements by doppler echocardiography

This study evaluates the variability of a quantitative Doppler echocardiographic method for blood flow calculation at the mitral and tricuspid orifice. Four subjects underwent 2-dimensional Doppler echocardiography during normal respiration and nonrespiration. Doppler recordings were integrated to determine mean temporal velocity (MTV) for each cardiac cycle separately. MTV during inspiration and expiration were compared, as were MTVs of 20 consecutive cycles during nonrespiration. Diameters of mitral and tricuspid orifice and interception angles were measured in 10 consecutive cycles at 4 predetermined moments. All results were averaged to a mean subject situation. MTVs were significantly (p less than 0.001) higher during expiration than during inspiration (12.4 and 11.0 cm-2) for the mitral orifice and lower (9.2 and 11.0 cm-2) for the tricuspid orifice. MTV at both orifices showed a significantly smaller variability (7.7% and 9.0%) during nonrespiration than during respiration (14.5% and 13.2%). Diameters of mitral orifice and tricuspid orifice were significantly (p less than 0.001) larger during diastole than during systole whereas standard error of the mean for both was 5.0%. Interception angles measured at mitral orifice are all close to 0 degrees and show minimal variability, while at the tricuspid orifice the angle varied from 15 degrees in diastole to 25.5 degrees in systole, constituting a significant difference in cosine (0.96 to 0.90).

Doppler left ventricular flow pattern versus conventional predictors of left ventricular thrombus after acute myocardial infarction

OBJECTIVES The value of Doppler-derived left ventricular spatial flow patterns in predicting left ventricular thrombus formation after myocardial infarction was compared with that of conventional clinical and echocardiographic variables. BACKGROUND Assessment of left ventricular thrombosis risk after myocardial infarction is important because of potential embolic sequelae that are reduced by oral anticoagulant agents. METHODS Clinical, two-dimensional and Doppler echocardiographic data were prospectively obtained in 104 patients with acute myocardial infarction within 48 h of admission. Ventricular flow was assessed by Doppler echocardiography and considered normal when brisk ventricular inflow with simultaneous onset at the mitral valve and apical levels was present, together with alternating directions of apical flow throughout the cardiac cycle. In addition to normal flow, two abnormal flow patterns were recognized: apical rotating flow and vortex ring formation. Oral anticoagulant agents were prescribed only to patients with abnormal flow at admission. The incidence of left ventricular thrombosis was assessed by echocardiography during 9 months of follow-up. RESULTS Abnormal flow pattern had a positive predictive value of 63% and a negative predictive value of 99%. On stepwise logistic regression analysis, only abnormal flow pattern had an independent relation to left ventricular thrombus (odds ratio 92). CONCLUSIONS Left ventricular flow pattern derived by Doppler echocardiography soon after admission is superior to conventional clinical and two-dimensional echocardiographic assessment in estimating the risk of left ventricular thrombosis after myocardial infarction.

Predictive value of indium-111 antimyosin uptake for improvement of left ventricular wall motion after thrombolysis in acute myocardial infarction☆

In 21 patients treated with thrombolysis for acute myocardial infarction (AMI), the degree of myocardial uptake of indium-111 monoclonal antimyosin antibodies injected within 24 hours after onset of AMI was compared with the degree and extent of regional asynergy on admission and discharge, as assessed by 2-dimensional echocardiography. On the first day of AMI, 80 MBq of indium-111 antimyosin was injected and planar images were made 24 hours later. Indium-111 antimyosin uptake was evaluated for count density index (count density of infarct zone/left lung count density) in the left anterior oblique projection, in which the infarction zone was well displayed in all patients. Using 2-dimensional echocardiography, the left ventricle was divided into 13 segments and evaluated for regional asynergy, which was considered severe (akinesia or dyskinesia) or mild (hypokinesia). The extent of regional asynergy was measured by the number of asynergic segments. All 21 patients had severe regional asynergy on admission. Nine of 21 showed only mild regional asynergy on discharge and 12 of 21 had persistent severe regional asynergy in at least 1 segment. The count density index was significantly lower in patients with mild regional asynergy on discharge compared with patients with severe regional asynergy (1.63 +/- 0.27 vs 2.50 +/- 0.42, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Usefulness of mitral regurgitation in protecting against left ventricular thrombus after acute myocardial infarction

In conclusion, we documented an increased incidence of LV thrombus in patients with MR after AMI.

Early Indium-111 antimyosin scintigraphy for assessment of regional wall motion asynergy on discharge after myocardial infarction.

SummaryTo assess the relation between early Indium-111 monoclonal antimyosin antibody scintigraphy and degree of regional asynergy on discharge, 38 patients with a first acute myocardial infarct were studied (18 anterior, 20 inferoposterior infarctions). In 21 patients thrombolytic therapy was administered. On the first day of myocardial infarction, 80 MBq Indium-111 Antimyosin was injected. Planar images, anterior, lateral and left anterior oblique, were made 24 hours later. Localized myocardial uptake was present in 37/38 patients, and was evaluated for Count Density Index (count density of infarct zone/left lung count density) in the left anterior oblique images, which displayed the infarct zone well. Regional asynergy on discharge was evaluated by cross-sectional echocardiography and defined mild (hypokinesia) or severe (akinesia or dyskinesia). Count density index was significantly lower in 15 patients with mild asynergy, compared with 22 patients with severe asynergy (1.61±0.25 vs. 2.42±0.40, p<0.001). This difference was present in both patient groups treated with or without thrombolysis. We conclude that early count density index, reflecting the amount of local necrosis, is highly correlated to the ultimate degree of wall motion impairment.

Free vortex ring formation in the left atrium originating in the left auricle.

An 80-year-old woman was evaluated by transesophageal echocardiography after coronary artery bypass surgery and subsequent cardioembolic stroke. In addition to spontaneous echo contrast demonstrating a counterclockwise rotating blood flow pattern, we observed free vortex ring formation in the left atrium, originating in the left auricle. To our knowledge, this is the first reported case of abnormal free vortex ring type flow pattern in the left atrium.