Abnormal intraventricular flow patterns in left ventricular dysfunction determined by color Doppler study

Left ventricular mass increases with deteriorating glucose tolerance, especially in women: independence of increased arterial stiffness or decreased flow-mediated dilation: the Hoorn study

OBJECTIVE

Type 2 diabetes and impaired glucose metabolism (IGM) are associated with an increased cardiovascular disease (CVD) risk. Increased left ventricular mass (LVM) is thought to increase CVD risk through several unfavorable cardiac changes. Type 2 diabetes and IGM are associated with increased LVM, but the underlying mechanism is unclear. We investigated the association between glucose tolerance status (GTS) and LVM and explored whether any such association could be mediated through increased arterial stiffness, impaired endothelial function, or the presence of atherosclerosis.

RESEARCH DESIGN AND METHODS

We used ultrasound to measure LVM, carotid and femoral stiffness, carotid-femoral transit time, and flow-mediated vasodilation (FMD) and tonometry to estimate compliance and augmentation index. The study population (n = 780) consisted of 287 individuals with normal glucose metabolism (NGM), 179 with IGM, and 314 with type 2 diabetes, and the mean age was 68.4 years.

RESULTS

In women, after adjusting for age, height, BMI, and mean arterial pressure, LVM increased significantly with deteriorating GTS (LVM 157 g in NGM, 155 g in IGM, and 169 g in type 2 diabetes; P for trend <0.018). Additional adjustment for arterial stiffness, FMD, or the presence of atherosclerosis did not materially alter the results, even though these variables were significantly associated with both GTS and LVM. Indexes of hyperglycemia/-insulinemia or insulin resistance explained at most 7% of the association between GTS and LVM. In men, no statistically significant associations were observed.

CONCLUSIONS

Our data expand the conceptual view of the pathogenesis of GTS-related changes in LVM because we show that the increase in LVM in women is independent of increased arterial stiffness, impaired FMD, or the presence of atherosclerosis. In addition, we show that this increase in LVM is only minimally explained by indexes of hyperglycemia/-insulinemia or insulin resistance. Our data may, in part, explain the increased CVD risk seen in women with deteriorating GTS.

An assessment of two different methods of left ventricular ejection time measurement by transesophageal echocardiography

Left ventricular ejection time (LVET) is an important component in evaluating left ventricular performance. This measurement is usually made by measuring the timing of the transaortic valve flow velocity by continuous-wave Doppler. Although M-mode has also been used for measuring LVET, it has not been compared with the Doppler method. We tested the hypothesis that the M-mode-measured duration of aortic valve opening is comparable to Doppler-derived measurement of LVET by transesophageal echocardiography (TEE). Measurements were made in 31 patients undergoing nonaortic valve cardiac surgery. The timing of transaortic flow by continuous-wave Doppler was compared with the M-mode-derived timing of aortic valve opening. There was close correlation (Pearson correlation coefficient, r = 0.86; P < 0.0001) between M-mode and Doppler measurements. There was no significant difference between the two techniques by linearity tests (P > 0.1). Bland-Altman analysis showed no significant bias. We confirmed the hypothesis that M-mode-derived measurement of LVET is comparable to Doppler-derived measurement of LVET. M-mode may be an acceptable alternative to the Doppler method, especially when transvalvular velocity gradients cannot be readily obtained. M-mode is a simple, yet often underused, method of evaluating LVET during TEE.

Defining left ventricular segmental and global function by echocardiographic intraventricular contrast flow patterns

Contrast echocardiography improves left ventricular (LV) endocardial border delineation by enhancement of the blood-tissue interface. In particular, the contrast appearing within the LV chamber exhibits characteristic flow patterns over the cardiac cycle, which may be related to the surrounding myocardial wall motion. To determine the relation between the LV intracavitary contrast flow pattern and surrounding wall motion, we reviewed the contrast-enhanced images of 348 consecutive patients studied at rest. We defined 2 different patterns of intracavitary contrast flow as visualized from apical views: a swift, vertical, and homogeneous flow towards the apex (pattern A), and a distinctly protracted, swirling, and heterogeneous flow (pattern B). Images recorded on videotapes were reviewed and the type of pattern (A or B) was determined within the initial 30 to 45 seconds of contrast appearance in the left ventricle. Contrast flow patterns interpreted by independent reviewer were then compared with the interpretation of the LV segmental and global function in each patient. Results demonstrate that 224 of 245 (91%) patients exhibiting pattern A had normal LV segmental function. Furthermore, all but 1 patient (102 of 103) with pattern B had > or =1 wall motion abnormality (p <0.0001). Contrast flow pattern B was observed irrespective of the location of LV wall motion abnormality. Global LV function was normal in 93% of patients exhibiting pattern A, whereas varying degrees of LV dysfunction were noted in 83% of patients with pattern B (p <0.0001). The presence of mitral regurgitation (p = 0.46), aortic insufficiency (p = 0.066), or mitral inflow Doppler abnormality (p = 0.102) was not significantly associated with either pattern. Thus, during contrast echocardiography, the LV intracavitary contrast flow pattern complements the assessment of global and segmental LV function.

Reversal of intraventricular flow propagation during isovolumic relaxation: A marker of anterior wall dysfunction

BACKGROUND

Myocardial infarction induces left ventricular (LV) wall motion abnormalities during isovolumic relaxation (IVR) and may potentially alter intraventricular flow during this period. This study evaluated whether 2-dimensional color Doppler measurements of intraventricular flow during IVR were able to identify LV dysfunction caused by coronary artery disease.

METHODS

Patients with single-vessel coronary artery disease and posterior wall infarction (21 patients) or anterior wall infarction (27 patients) were included. Eighteen healthy persons served as a control group. LV function was examined by 2-dimensional echocardiography, 2-dimensional color Doppler, and pulsed Doppler techniques.

RESULTS

All normal persons (23.6 +/- 10.9 cm/s) and patients with posterior infarction (19.6 +/- 9.3 cm/s) had flow propagation towards LV apex during IVR. Patients with anterior wall infarction had reversed flow direction (-12.2 +/- 8.7 cm/s, P <.001). The echocardiographic wall motion score index of the 4 apical segments correlated well with flow velocities (r = -0.78, P <.001).

CONCLUSION

Reversed flow propagation during IVR may become a sensitive clinical marker of regional ischemia.

Use of intraventricular dispersion of the peak diastolic flow velocity as a marker of left ventricular diastolic dysfunction in patients with atrial fibrillation

The aim of this study was to evaluate the use of intraventricular dispersion of the peak diastolic flow velocity as a marker of left ventricular diastolic dysfunction in patients with atrial fibrillation. Regional diastolic flow velocity patterns at 1, 2, and 3 cm away from the mitral tip toward the apex were simultaneously recorded with the mitral flow velocity pattern by using pulsed Doppler echocardiography in 24 patients with atrial fibrillation before electrical or medical cardioversion. Echocardiographic examination was repeated after 10 to 30 days (ie, at the time of recovery of left atrial mechanical functions) after cardioversion of atrial fibrillation in all patients. Thirteen patients were found to have diastolic dysfunction; the remaining 11 patients with a normal E/A ratio constituted the control group. Afterward, the data recorded before the cardioversion were analyzed for each patient. In subjects with normal diastolic function, the peak diastolic flow velocity (PDFV) at the mitral tips also was maintained at the positions 1 to 3 cm away from the tip in the left ventricular cavity (PDFV at the mitral tips: 0.84 m/s, PDFV at 3 cm: 0.85 m/s; P =.34). In contrast, the regional PDFV progressively decreased toward the apex in patients with diastolic dysfunction (PDFV at the mitral tips: 0.82 m/s, PDFV at 3 cm: 0.63 m/s; P =.0004). Only 77% of the initial velocity was maintained at 3 cm away from the mitral tips in patients with diastolic dysfunction, whereas almost 100% of the initial velocity was preserved in patients with normal diastolic function (P <.001). These findings suggest that the assessment of the intraventricular decrease in mitral PDFV may be used as a reliable marker of diastolic dysfunction in patients with atrial fibrillation.

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.