Intracardiac energy inefficiency during atrial fibrillation rhythm with heart failure: Assessment by echo-vector flow mapping

Abstract

AimsIntracardiac dynamics during atrial fibrillation(AF) complicated by heart failure(HF) are not fully understood. The aim of this study was to evaluate the impact of intracardiac dynamics assessed by echo-vector flow mapping on AF complicated by HF. Methods and resultsWe enrolled 76 AF patients receiving sinus restoration therapy and assessed energy loss(EL) by echo-vector flow mapping during both AF rhythm and sinus rhythm. Patients were divided into 2 groups according to serum NT-proBNP level: high NT-proBNP group(≥1800 pg/ml during AF rhythm: N = 19), and low NT-proBNP group(N = 57). Outcome measures were average ELs/stroke volume(SV) in left ventricle(LV) and left atrium(LA). Average EL/SVs during AF rhythm in the LV and LA were significantly larger in the high NT-proBNP group than the low NT-proBNP group(54.2 mE/m·L versus 41.2 mE/m·L, P = 0.02; 3.2 mE/m·L versus 1.9 mE/m·L, P = 0.01). The significantly larger EL/SV in the high NT-proBNP group was recorded for maximum EL/SVs. In patients with high NT-proBNP, large vortex formation with extreme EL was detected in the LV and LA during the diastolic phase. After sinus restoration, the average decrease of EL/SV in the LV and LA was larger in the high NT-proBNP group(−21.4 mE/m·L versus +2.6 mE/m·L, P = 0.04; −1.6 mE/m·L versus −0.3 mE/m·L, P = 0.02). Average EL/SV during sinus rhythm did not significantly differ between the high and low NT-proBNP groups in the LV and LA. ConclusionsHigh EL during AF rhythm as intracardiac energy inefficiency was associated with high serum NT-proBNP levels and improved after sinus restoration.