BACKGROUND: Relatively limited and conflicting data are available on the effects of cardiac resynchronization therapy (CRT) on coronary blood flow (CBF). AIMS: To investigate changes in the left anterior descending coronary artery (LAD) flow under different CRT pacing modes by means of transthoracic Doppler echocardiography (TTE). METHODS: Twenty-two responders to CRT (67+/-11 years) with idiopathic dilated cardiomyopathy underwent TTE assessment of LAD flow and Tissue Velocity Imaging during 4 programming modes: intrinsic conduction (IC), right ventricular pacing (RV), simultaneous biventricular pacing (BVP), BVP with left ventricular (LV) pre-activation. RESULTS: Mean coronary flow velocity (CFV) was increased by simultaneous BVP (p=0.0063 vs. IC) and BVP with LV pre-activation (p<0.0001 vs. IC; p=0.027 vs. simultaneous BVP). Peak CFV and LAD flow velocity/time integral were highest during BVP with LV pre-activation. A reduction in septal-to-lateral delay and an increase in peak systolic velocity in the basal septum were observed during simultaneous BVP and BVP with LV pre-activation. CONCLUSIONS: In CRT responders with idiopathic dilated cardiomyopathy, an increase in LAD flow, assessed by TTE, was observed during simultaneous BVP and BVP with LV pre-activation. This was associated with an improvement in regional myocardial contraction and a decrease in intraventricular dyssynchrony.
BACKGROUND: Relatively limited and conflicting data are available on the effects of cardiac resynchronization therapy (CRT) on coronary blood flow (CBF). AIMS: To investigate changes in the left anterior descending coronary artery (LAD) flow under different CRT pacing modes by means of transthoracic Doppler echocardiography (TTE). METHODS: Twenty-two responders to CRT (67+/-11 years) with idiopathic dilated cardiomyopathy underwent TTE assessment of LAD flow and Tissue Velocity Imaging during 4 programming modes: intrinsic conduction (IC), right ventricular pacing (RV), simultaneous biventricular pacing (BVP), BVP with left ventricular (LV) pre-activation. RESULTS: Mean coronary flow velocity (CFV) was increased by simultaneous BVP (p=0.0063 vs. IC) and BVP with LV pre-activation (p<0.0001 vs. IC; p=0.027 vs. simultaneous BVP). Peak CFV and LAD flow velocity/time integral were highest during BVP with LV pre-activation. A reduction in septal-to-lateral delay and an increase in peak systolic velocity in the basal septum were observed during simultaneous BVP and BVP with LV pre-activation. CONCLUSIONS: In CRT responders with idiopathic dilated cardiomyopathy, an increase in LAD flow, assessed by TTE, was observed during simultaneous BVP and BVP with LV pre-activation. This was associated with an improvement in regional myocardial contraction and a decrease in intraventricular dyssynchrony.
Authors: Andreas S Barth; Takeshi Aiba; Victoria Halperin; Deborah DiSilvestre; Khalid Chakir; Carlo Colantuoni; Richard S Tunin; Victoria Lea Dimaano; Wayne Yu; Theodore P Abraham; David A Kass; Gordon F Tomaselli Journal: Circ Cardiovasc Genet Date: 2009-05-15