Abstract
Dobutamine improves systolic as well as diastolic function, but its effect on left ventricular (LV) asynchrony is unknown. An on-line automated segmental motion analysis (A-SMA) system was developed, based on an automatic border detection technique, to evaluate the effect of dobutamine on LV asynchrony in patients with LV hypertrophy (LVH). Low dose (5 μg · kg -1 · min-1) dobutamine stress echocardiography was performed in 15 patients with LVH and in 15 healthy subjects. Short-axis LV views were obtained and divided into 4 wedge-shaped segments using A-SMA. The time - area curve and its first derivative curve in each segment were displayed. Total normalized peak filling rates (nPFR) were obtained. Systolic and diastolic asynchronies were assessed from the coefficient of variation (CV) of the regional time intervals from end diastole to the peak ejection rate (T-PER), and from end systole to the peak filling rate (T-PFR), respectively. At baseline, the CV of T-PER and T-PFR in patients with LVH were greater than those in healthy subjects (CV-T-PER: 18.8±9.2 vs 9.6±4.3%, CV-T-PFR: 19.5±7 vs 8.1±4.1%, both p<0.01). During dobutamine infusion, differences among groups at baseline disappeared and systolic and diastolic asynchronies improved (CV-T-PER: 7.3±4.8 vs 5.7±2.1%, CV-T-PFR: 6.8±3.5 vs 5.1±1.3%, both p>0.05). Total nPFR increased (from 3.2±1.0 /s to 5.6±1.3 /s, p<0.01) with dobutamine infusion in patients with LVH. Dobutamine improved LV diastolic asynchrony, as evaluated by A-SMA, in patients with LVH demonstrating that the lusitropic effect of dobutamine improved LV regional diastolic asynchrony, playing an important role in the improvement of global LV diastolic filling. (Circ J 2003; 67: 119 - 124)
