Ventricular function following coronary artery bypass grafting: comparison between gated SPECT and cardiac magnetic resonance imaging.

BACKGROUND The assessment of left ventricular function may be impaired by the abnormal interventricular septal motion frequently found after coronary artery bypass grafting (CABG). Studies on the validation of gated SPECT as a tool for the assessment of left ventricular function in this patient group are scarce. OBJECTIVE We investigated the agreement and correlation between left ventricular ejection fraction (LVEF), end-diastolic volume (EDV), and end-systolic volume (ESV) as obtained using electrocardiogram-gated myocardial perfusion scintigraphy (gated SPECT) and cardiac magnetic resonance imaging in 20 patients undergoing coronary artery bypass grafting. METHODS Correlation was measured using Spearman's correlation coefficient (rho). Agreement was assessed using Bland-Altman analysis. RESULTS A good correlation was found between gated SPECT and cardiac magnetic resonance imaging in patients after CABG with regard to left ventricular ejection fraction (rho = 0.85; p =0.0001), moderate correlation for end-diastolic volume (rho = 0.51; p = 0.02), and non-significant correlation for end-diastolic volume (rho = 0.13; p = 0.5). Agreement ranges for LVEF, ESV and EDV were: -20% to 12%; -38 to 54 ml and; -96 to 100 ml, respectively. CONCLUSION A reliable correlation was found for left ventricular ejection fraction as obtained by gated SPECT and magnetic resonance imaging in patients undergoing CABG. For ventricular volumes, however, the correlation is not adequate.