The prevalence of left ventricular mechanical dyssynchrony as assessed by quantitative gated SPECT in patients with left ventricular systolic dysfunction

Abstract

M echanical dyssynchrony refers to the abnormal prolongation of timing of contraction or relaxation between the atrium and ventricle [atrioventricular], between the right ventricle and left ventricle [interventricular] or, between different ventricular segments[intraventricular]. Several imaging techniques have been utilized to identify mechanical dyssynchrony including ECHO, MRI, and phase analysis of gated SPECT MPI. Echo and conventional parameters lack reproducibility and unable to discriminate between CRT responder and non responder. Gated SPECT MPI is widely available technique that enables the assessment of both perfusion and functional parameters with low inter and intra-observer variability in a single investigation. The aim of this study was to detect the prevalence of left ventricular mechanical dyssynchrony among patients with left ventricular systolic dysfunction, and to detect the clinical, electrocardiographic and myocardial perfusion variables related to LVMD. Patients and methods: This study is a case control cross sectional observational study that was carried out in the nuclear cardiology lab of Ain shams university hospital in the period from January 2015- April 2015. We included 44 control patients with normal myocardial perfusion and function (control group) and 100 patients with LVEF >40% (study group). All patients were subjected to history taking and clinical examination. All patients had 12 lead rest-ECG for the analysis of QRS width and morphology. Rest gated SPECT MPI with phase analysis was done to all patients to calculate global dyssynchrony parameters [SD, BW].