Frontal QRS-T angle and left ventricular diastolic function assessed by ECG-gated SPECT in the absence of significant perfusion abnormality.

Abstract

The frontal QRS-T angle, defined as the angle between QRS and T-wave axes, has recently become an area of research interest. We tested the hypothesis that the frontal QRS-T angle is associated with left ventricular (LV) diastolic function in the absence of significant perfusion abnormality using ECG-gated SPECT. One hundred twenty eight patients with no significant perfusion abnormality and preserved LV ejection fraction were enrolled. The peak filling rate (PFR) and the one-third mean filling rate (1/3 MFR) were obtained as LV diastolic parameters on ECG-gated SPECT. There were 115 male and 13 female patients with a mean age of 70 ± 9years. The PFR and 1/3 MFR were 2.1 ± 0.4/s and 1.2 ± 0.3/s, respectively. The frontal QRS-T angle was 33° ± 31°, ranging from 0° to 151°. There were significant associations of frontal QRS-T angle with PFR (r = -0.29, p = 0.001) and 1/3 MFR (r = -0.30, p < 0.001). Multivariate linear regression analysis showed that age (β = -0.25, p = 0.003), heart rate (β = 0.26, p = 0.002), LV ejection fraction (β = 0.43, p < 0.001) and frontal QRS-T angle (β = -0.16, p = 0.03) were significant factors associated with PFR. Also, heart rate (β = -0.32, p < 0.001), LV mass index (β = -0.19, p = 0.03), LV ejection fraction (β = 0.30, p < 0.001) and frontal QRS-T angle (β = -0.26, p = 0.002) were significant factors associated with 1/3 MFR. Our data suggested that the frontal QRS-T angle was associated with LV diastolic function in the absence of significant perfusion abnormality.