Measurement of left ventricular volume after anterior myocardial infarction: comparison of magnetic resonance imaging, echocardiography, and radionuclide ventriculography.

We have compared echocardiography (echo) and radionuclide ventriculography (RNV) with magnetic resonance imaging (MRI) for the measurement of left ventricular (LV) volume and ejection fraction. Seventy asymptomatic patients were studied up to 12 days after first Q wave anterior myocardial infarction and again after 6 months. Each patient had LV volume measured by all three techniques within 24 hours of each other on each occasion. LV end-systolic and end-diastolic volume index (LVESVI and LVEDVI) and LV ejection fraction (LVEF) were measured using the modified Simpson formula (echo), a counts-based method (RNV), and a multislice area summation method (MRI). Radionuclide volumes were measured both with and without correction for attenuation of isotope. Echocardiography overestimated LV volume compared with MRI. Mean (SD) differences (echo-MRI) were: LVEDVI + 10.6 ml/m2 (16.8), LVESVI + 13.7 ml/m2 (12.9), LVEF -8.5% (11.2). RNV underestimated both volume and ejection fraction compared with MRI. Mean differences (RNV-MRI) were: LVEDVI -25.4 ml/m2 (23.8), LVESVI -5.0 ml/m2 (18.6), LVEF -13.8% (10.4). Variability in the difference between echo and MRI and between RNV and MRI was very similar for LVEF (coefficient of variation 23.9% echo, 22.2% RNV) but there was greater variability in the radionuclide than the echo measurements of absolute volume. Variability of the radionuclide measurements was reduced by not correcting for attenuation, and this finding may improve the radionuclide technique for serial measurements of percentage change in volume. Long-term inter-study reproducibility of MRI for LVEF (coefficient of reproducibility) was 10.9%, for echo it was 10.6%, and for RNV it was 14.6%. We conclude that measurements of LV volume depend on the method used and are not interchangeable. Echocardiography agrees more closely with MRI than RNV for the measurement of absolute volume, but the two techniques are similar for the measurement of LVEF.

Rapid assessment of left ventricular volume by short axis cine MRI.

MRI is an established and accurate method of measuring left and right ventricular volumes by summing chamber areas in multiple contiguous slices. Acquisition time may be up to 45 min. We have estimated volumes with gradient echo imaging to test the accuracy of a more rapid method (total acquisition time 15 min) using a recognized echocardiographic algorithm. The results were compared with the spin echo method. We studied 20 patients (mean age 52 years, 15 male) within 6 months of anterior myocardial infarction and 20 normal subjects (mean age 40 years, 19 males). For the rapid method, cine acquisitions were made in the horizontal long axis plane and in two short axis planes which divided the long axis into three equal parts. Volume was calculated assuming the ventricle to be composed of a cylinder, a truncated cone and a cone. There was good agreement between the two methods at end diastole with a mean difference (+/- standard error, +/- 95% confidence interval for limits of agreement) of -3 ml (+/- 8.3, +/- 37%) for normal subjects and 1.5 ml (+/- 4.2, +/- 25%) for patients. Agreement was less good at end systole with mean difference of 12.1 (+/- 3.5, +/- 41%) for normal subjects and 25.7 (+/- 3.7, +/- 47%) for patients. The rapid method, therefore, significantly underestimated end systolic volume compared with the previous method. Rapid measurements of end diastolic volume are more accurate than those of end systolic volume and hence ejection fraction. Provided the potential error is recognized, the rapid technique can be used in routine clinical practice in both normal and abnormal ventricles.

Left ventricular volume in thrombolysed patients with acute anterior myocardial infarction: the effect of captopril and xamoterol.

We measured left ventricular volume in 70 asymptomatic patients after first Q-wave anterior myocardial infarction in order to determine whether ventricular dilatation occurs and whether there is evidence for its attenuation or prevention by treatment with captopril or xamoterol--PRevention Of VEntricular Dilatation?: the PROVED? study. 77% of patients received thrombolytic treatment. Patients were randomised a mean of 11 days after infarction to receive either captopril 25 mg three times daily, xamoterol 200 mg twice daily or matching placebo. After 6 months of treatment, 6 patients from the placebo group (n = 24), 1 from the captopril group (n = 23) and 3 from the xamoterol group (n = 23) had been withdrawn from the study because of clinical complications. Left ventricular volume was measured using magnetic resonance imaging, before randomisation and after 6 months of treatment. Changes in left ventricular end-diastolic and end-systolic volume after 6 months of treatment were defined prospectively as the primary endpoints. Mean initial end-diastolic volume index was 85 (S.D. 19) ml/m2, mean end-systolic volume index was 45 (S.D. 18) ml/m2, and mean ejection fraction was 48 (S.D. 11)% for the whole group. There was no significant change in left ventricular volume index in the placebo or either treatment group after 6 months of treatment. Only minimal left ventricular dilatation was evident at 11 days. No further increase in left ventricular volume occurred after six months and there was no additional benefit from treatment with either captopril or xamoterol.(ABSTRACT TRUNCATED AT 250 WORDS)