Regional left ventricular ejection fraction from real-time two-dimensional echocardiography

Myocardial Velocity Gradient Assessed by a Tissue Doppler Imaging Technique

Although tissue Doppler imaging (TDI) is a promising technique for quantitative regional left ventricular wall motion analysis, Doppler angle of incidence and translational motion of the heart influence the velocity measurement by TDI because, in principle, TDI detects the velocity against the transducer. Myocardial velocity gradient (MVG) is derived from TDI as the slope of the regression line for a transmural velocity profile across the myocardial wall, which reflects regional wall thickening and thinning dynamics. Thus, regional diastolic and systolic function may be quantified by using MVG. MVG is also validated to be independent of the translational motion both theoretically and clinically. MVG may therefore be used as an indicator of regional wall motion even under such a condition that the translational motion of the heart cannot be neglected. Our preliminary experience suggests that the quantitative and objective nature of MVG enhances the diagnostic power of stress echocardiography. Further development of the automated, real time processing system and the algorithm for the apical approaches should be awaited for the practical approaches of MVG to be applied to daily clinical practice.

Myocardial velocity gradient as a new indicator of regional left ventricular contraction: detection by a two-dimensional tissue Doppler imaging technique

OBJECTIVES

This study was performed to assess a new indicator of regional left ventricular contraction determined by a two-dimensional tissue Doppler imaging technique.

BACKGROUND

Recent studies have demonstrated that instantaneous tissue motion velocity can be noninvasively assessed by tissue Doppler imaging. However, quantitative assessment of regional left ventricular contraction is still difficult because of the effects of the Doppler angle of incidence and parallel motion of the whole heart.

METHODS

We assessed left ventricular wall motion in 11 normal subjects, 14 patients with an old myocardial infarction (anteroseptal in 7, posterior in 7) and 8 patients with dilated cardiomyopathy. Tissue Doppler velocity was corrected by the Doppler angle of incidence after the hypothetical center of contraction was set. Subsequently, the myocardial velocity gradient between the endocardium and epicardium was determined from the velocity profile along each radial line from the center of contraction by using least squares linear regression.

RESULTS

In normal subjects, peak myocardial velocity gradient was lower in the anteroseptal wall (mean [+/- SD] 1.69 +/- 0.53 s-1) than in the posterior wall (3.28 +/- 0.67 s-1, p < 0.01). Myocardial velocity gradient in the infarct regions was significantly lower (anteroseptal 0.58 +/- 0.41 s-1, p < 0.05; posterior 0.17 +/- 0.27 s-1, p < 0.01) than that in normal subjects as well as that in the corresponding noninfarct regions (2.84 +/- 0.37 s-1 and 1.48 +/- 0.25 s-1, p < 0.01, respectively). In patients with dilated cardiomyopathy, myocardial velocity gradient was generally lower (anteroseptal 0.72 +/- 0.59 s-1; posterior 0.93 +/- 0.67 s-1) than that in normal subjects (p < 0.01).

CONCLUSIONS

These results demonstrate that regional left ventricular contraction can be quantitatively assessed by the myocardial velocity gradient derived from two-dimensional tissue Doppler imaging. We suggest that myocardial velocity gradient has potential for the quantitative assessment of regional left ventricular contraction abnormalities in patients.

Left ventricular mechanics in the normal newborn

The transition from fetal to neonatal circulatory status is accompanied by marked alteration in relative right and left ventricular systolic and diastolic pressure. These alterations would be expected to influence both global and regional performance of the left ventricle. To address this issue, sequential two-dimensional echocardiographic studies were performed in normal newborns during the first days of life. Global and regional left ventricular wall motion were quantified by computer digitization with the use of an automated edge detection algorithm and a floating-center-of-mass model. Comparison was made with a control group of normal infants and young children and the sequential change over the first 5 days of life was assessed. Newborns were found to have a circular left ventricular configuration at end-diastole beginning on day 1. At end-systole, however, there was significant left ventricular distortion due to septal flattening, which persisted until day 3 and resolved entirely by day 5 of life. Regional wall motion analysis demonstrated a corresponding augmentation of septal and contralateral left ventricular free wall systolic movement during the first days of life, with a normal pattern attained by day 4. Due to the nonhomogeneity of the left ventricular wall motion in the first few days of life, standard single-dimension shortening fraction provided an unreliable measure of global left ventricular performance before day 4. Thus, systolic right ventricular hypertension at a level sufficient to distort the left ventricular configuration is present until day 4 or 5 of life, resulting in altered left ventricular regional wall motion. As a result, usual M mode echocardiographic assessment of left ventricular function is unreliable in this age group.(ABSTRACT TRUNCATED AT 250 WORDS)

Regional and global left ventricular function in infants with anomalous origin of the left coronary artery from the pulmonary trunk: preoperative and postoperative assessment

Anomalous origin of the left coronary artery from the pulmonary trunk (ALCA) remains a diagnostic as well as a therapeutic problem. The purposes of this study were: (1) to analyze left ventricular mechanics, including regional wall motion, in infants with ALCA, (2) to determine if the pattern of wall motion in infants with ALCA distinguishes these patients from those with congestive cardiomyopathy of other causes, and (3) to evaluate the potential for recovery of left ventricular function after successful restoration of a dual coronary artery system. Left ventricular mechanics were studied before and serially after surgery in six infants (2 to 13 months old) with ALCA. Fifteen age-matched normal subjects and seven age-matched patients with idiopathic congestive cardiomyopathy were also studied for comparison. Preoperatively, the end-diastolic volume in infants with ALCA was about four times larger than normal and did not differ from that in infants with CM; the myocardial volume was also about three times larger than normal, similar to that in the patients with CM. The myocardial volume/end-diastolic volume ratio was extremely low in patients with ALCA and in those with CM. The infants with ALCA did not exhibit specific segmental wall motion abnormalities but rather had global hypokinesis indistinguishable from that in the patients with CM. After successful repair, end-diastolic volume index rapidly decreased, reaching near normal values by 7 to 22 months after surgery, while myocardial volume index decreased at a slower rate, leading to an early phase of "overshoot hypertrophy," but reaching normal values by 7 to 22 months after surgery.+