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We previously developed an operator-interactive method for the measurement of left ventricular (LV) and right ventricular (RV) ejection fraction (EF) and end-systolic volume (ESV) and end-diastolic volume (EDV) using single-photon emission tomographic equilibrium radionuclide angiocardiography (SPECT ERNA). We aimed to compare our SPECT ERNA method with cardiac MRI (CMRI) for the determination of ventricular measures.Paired measurements of LV and RV EFs and ESV and EDV were carried out by SPECT ERNA and CMRI in a group of patients who had myocardial infarction due to left anterior descending coronary artery thrombosis.SPECT ERNA and CMRI provided similar estimations of the mean (SD) LV ESV [61 (23) vs. 61 (32) ml; P=0.99] and LV EDV [134 (29) vs. 141 (44) ml; P=0.28]. The mean (SD) LV EF by SPECT ERNA was slightly but significantly smaller than that by CMRI [0.55 (0.10) vs. 0.58 (0.11) ml; P=0.03]. SPECT ERNA, compared with CMRI, produced similar mean (SD) values of RV ESV [62 (17) vs. 67 (17) ml; P=0.10] and RV EDV [153 (28) vs. 149 (29) ml; P=0.51] and somewhat larger mean (SD) RV EF [0.60 (0.06) vs. 0.55 (0.06) ml; P0.001]. Excellent correlations were found between SPECT ERNA and CMRI for combined LV ESV and EDV (R=0.85, P0.001) and combined RV ESV and EDV (R=0.85, P0.001).This study further validates SPECT ERNA as a method to measure LV and RV EF, ESV, and EDV.

Left ventricular function is modified by respiration and pericardial constraint. The aim of this study was to compare left ventricular systolic and diastolic function during inspiration and expiration in four patient groups: patients (1) without cardiac disease, (2) with severe pulmonary disease, (3) with cardiac amyloid and (4) with pericardial constriction (before and after pericardiectomy). Using blood-pool left ventriculography with modified gating, we obtained time-activity curves at the onset of inspiration and expiration. On inspiration and expiration, patients with pericardial constriction and patients with cardiac amyloid were significantly different from those without cardiac disease and those with severe pulmonary disease, in that left ventricular ejection fraction (LVEF) was less, peak filling rate was greater, time to peak filling rate was shorter, and rapid filling fraction was increased. When inspiration and expiration were compared, time to left ventricular peak filling rate was shorter (P = 0.05) on inspiration (118 +/- 48 ms) than on expiration (168 +/- 35 ms) in patients with pericardial constriction. No other measures differed between inspiration and expiration in pericardial constriction, and left ventricular function was unaffected by respiration in the other groups. Time to left ventricular peak filling rate was 49 +/- 69 ms less on inspiration than on expiration in pericardial constriction and this difference was significantly different (P = 0.04) from that in patients with cardiac amyloid (34 +/- 58 ms greater), patients without cardiac disease (2 +/- 69 ms greater) and patients with severe pulmonary disease (19 +/- 63 ms less). In pericardial constriction, pericardial resection caused an increase in LVEF without a change in left ventricular diastolic filling but abolished the differences present between inspiration and expiration in time to left ventricular peak filling rate. This respiratory response in time to left ventricular peak filling rate may be valuable in the diagnosis of pericardial constriction.

Left ventricular volume measurements are useful in the evaluation of cardiac function and are important in the long-term management of patients with various cardiac diseases. Although there are many methods of measuring left ventricular volumes, a non invasive and reproducible method relies on radionuclide techniques. The errors in estimation of left ventricular volumes have previously been well studied. To date there is little information on the reproducibility of left ventricular volume measurements made by this technique at different points in time. This study evaluated 61 patients with stable coronary artery disease over a period of approximately 1 year. All patients had two resting radionuclide gated blood pool studies. Patients had no changes in symptoms, electrocardiographic findings or medication between studies. Using +/- 2 SD as 95% confidence limits for a true change, an end diastolic volume index change greater than -34 ml m-2 and +38 ml m-2 or an end systolic volume index change greater than -24 ml m-2 and +26 ml m-2 are required to state with confidence that a change has occurred between two examinations. These data provide guidelines to assess whether interval changes in left ventricular volumes are real or are due to variations within the technique.