“…Echocardiographic assessment of acute hemodynamic response during optimization of resynchronization pace-maker using different pacing modalities and atrioventricular delays☆ In patients with the manifested heart insufficiency and bundle branch block with prolonged duration of QRS complex, cardiac resynchronization therapy (CRT) with its dyssynchrony reduction leads to symptom reduction, life quality improvement and better prognosis [1][2][3]. However in some number of patients this therapy does not improve symptoms and signs of the disease [4,5].…”