SPECT myocardial perfusion imaging for the evaluation of left ventricular mechanical dyssynchrony in obese patients

Left ventricular dyssynchrony (LVD), the loss of coordinated contraction in the left ventricle, is an early sign of heart failure. LVD can be assessed using phase analysis techniques with gated single-photon emission computed tomography (SPECT) myocardial perfusion imaging (MPI). This study aimed to investigate the impact of obesity on LVD through phase analysis.

We retrospectively enrolled 152 obese patients and 80 age- and sex-matched nonobese patients who showed normal myocardial perfusion and normal left ventricular ejection fraction (LVEF) on MPI. Phase standard deviation (PSD) and phase histogram bandwidth (PBW), as phase analysis parameters, were compared between patients with and without obesity.

Although PSD values were within the normal range (cut-off value >23) for both groups, the PSD values of obese patients were higher than those of the nonobese (20.49 ± 8.66 vs. 14.81 ± 4.93; p < 0.05). PBW values of obese patients were statistically significantly higher than those of the nonobese (57.03 ± 23.17 vs. 41.40 ± 9.96; p < 0.05). The PBW values of obese patients exceeded the normal limits (cut-off value >49). A weak positive correlation was observed between body mass index (BMI) and PBW values in obese patients (r = 0.181, p < 0.05). In patients of normal weight, no correlations were found between BMI and phase analysis parameters.

LVD may develop in obese patients, even when myocardial perfusion and ejection fraction are preserved. The use of phase analysis with gated SPECT could be an additional finding improving the early detection of left ventricular dyssynchrony in obese patients.