The evaluation of left ventricular dyssynchrony in hypertensive patients with a preserved systolic function undergoing gated SPECT myocardial perfusion imaging.

Abstract

Hypertension as a known risk factor for cardiovascular diseases can result in left ventricular dyssynchrony (LVD) leading to uncoordinated contraction. The aim of our study was to evaluate whether systolic mechanical dyssynchrony measured by phase analysis of gated single-photon emission computed tomography (SPECT) imaging occurs in hypertensive patients with a low risk for coronary artery disease and a normal ejection fraction and its possible relationships with severity of hypertension and the influence of antihypertensive treatments. A total of 466 patients (328 females and 138 males, with a mean age of 59.62 ± 10.27years) who had a low risk factor for coronary artery disease, a normal perfusion study and, a normal ejection fraction were included of which 408 was hypertensive and 58 normotensive. Phase analysis parameters (derived using QGS software) were compared in patients with and without hypertension. Using different statistical methods, relationship between derived phase analysis indices (PSD, PHB) for LVD and amount of blood pressure and antihypertensive drugs consumption were evaluated. The prevalence of LVD in patients with hypertension was 63.2% (n = 258), while it was 6.9% in the normotensive group. The mean values of PSD and PHB were higher in hypertensive patients than normotensive ones (12.55 vs. 5.8 and 39.24 vs. 21.12), respectively, so that, statistically significant differences were found between the patients with and without hypertension (p < 0.001). Furthermore, there was a clear relationship between the severity of hypertension and the degree of LVD: by increasing 1mmHg in systolic and diastolic blood pressure, PSD and PHB increase by (0.034, 0.108 and 0.035,0.0311), respectively. The statistical results showed that the frequency of LVD in controlled hypertensive patients taking antihypertensive drugs was 55.2%, which significantly lower compared to the patient suffering from hypertension without taking any hypertensive drug (81.35%, p < 0.001). Our study findings are in favor of using phase analysis-gated SPECT imaging as a routine way for detection of LVD-known indicator of progression toward systolic dysfunction in the future-in hypertensive patients with a low risk for coronary artery diseases and a normal cardiac systolic function.