Influence of Left Atrial Function on Exercise Capacity and Left Ventricular Function in Patients With Heart Failure and Preserved Ejection Fraction

Background-lthough left tril (L) dysfunction is common in hert filure with preserved ejection frction (HFpEF), its functionl implictions beyond the reflection of left ventriculr (LV) pthology re not well understood. The im of this study ws to further chrcterize L function in HFpEF ptients. Methods nd Results-We performed crdic mgnetic resonnce myocrdil feture trcking in 22 ptients with HFpEF nd 12 ptients without HFpEF. L reservoir strin, L conduit strin, nd L booster pump strin were quntified. Pek oxygen uptke (VO2mx) ws determined. Invsive pressure-volume loops were obtined to evlute LV distolic properties. LV erly filling ws determined from LV volume-time curves s derived from crdic mgnetic resonnce. L reservoir nd conduit strin were significntly lower in HFpEF (L reservoir strin, 22 +/- 7% versus 29 +/- 6%, P= 0.04; L conduit strin, -9 +/- 5% versus -15 +/- 4%, P< 0.01). Ptients with HFpEF showed lower oxygen uptke (17 +/- 6 versus 29 +/- 8 mL/(kg min); P< 0.01). Strin mesurement for L conduit function ws strongly ssocited with VO2mx (r= 0.80; P< 0.01). On multivrible regression nlysis, L conduit strin emerged s strongest predictor for VO2mx even fter inclusion of LV stiffness nd relxtion time (beta= 0.80; P<0.01). L conduit strin correlted with the volume of erly ventriculr filling (r= 0.67; P< 0.01), but not LV stiffness constnt (-0.34; P= 0.051) or relxtion constnt tau (r=-0.33; P= 0.06). Conclusions-Crdic mgnetic resonnce myocrdil feture trcking-derived conduit strin is significntly impired in HFpEF nd ssocited with exercise intolernce. Impired conduit function is ssocited with impired erly ventriculr filling, s potentil mechnism leding to impired oxygen uptke. Our results propose tht impired L conduit function represents distinct feture of HFpEF, independent of LV stiffness nd relxtion.