Absence of defects in SPECT thallium-201 myocardial images in patients with systemic hypertension and left ventricular hypertrophy.

Hypertension is common in patients undergoing stress and delayed single-photon emission computed tomography (SPECT) thallium-201 myocardial perfusion imaging. Investigators have reported that patients with end-stage renal disease and left ventricular hypertrophy due to hypertension have diminished lateral/septal count ratios on stress and delayed imaging mimicking lateral myocardial infarction in approximately 35% of patients. Subsequently, hypertension has been cited as a frequent cause of thallium-201 artifacts. The purpose of this study was to compare myocardial SPECT thallium-201 distribution in a broader group of patients with left ventricular hypertrophy resulting from hypertension with normal file subjects in order to determine the prevalence of abnormal studies and to compare the lateral/septal count ratio. Average counts in all myocardial regions in the male study group (n = 16) were compared with those in the normal male file patients (n = 49), with particular attention to the lateral and septal walls. In the group of 16 men with hypertension and left ventricular hypertrophy, as a whole, the mean lateral/septal wall count ratio was 4.4% lower (1.09 +/- 0.07) than that in the normal file (1.14 +/- 0.07; p < 0.01). At 3-hour delay, the ratio was virtually the same in the study group (1.06 +/- 0.09) as in the normal file (1.08 +/- 0.06; p = NS). Most important, for clinical purposes no patient had a defect, defined as a lateral/septal count ratio > 2.0 SD below normal limits. All thallium-201 studies were interpreted as normal. In conclusion, myocardial thallium-201 distribution is normal in patients with left ventricular hypertrophy due to hypertension.