Abstract 18495: Right and Left Ventricular Starling Function in Heart Failure With Preserved Ejection Fraction

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Background: Efficient conversion of cardiac filling pressure to stroke volume (SV) is described by the Frank-Starling mechanism. Our group has previously characterized dynamic Starling mechanisms (DSM) in the frequency domain using respiratory mediated changes in beat-by-beat SV as a function of changes in pulmonary artery diastolic pressures (PAD) and shown this to be impaired in heart failure with preserved ejection fraction (HFpEF). Right ventricular (RV) dysfunction is common in HFpEF but efficiency of the RV Starling mechanism is unknown. The goal of this study was to characterize RV and LV DSM in patients with HFpEF. Methods: We studied 16 HFpEF patients (10 females; age: 68 ± 6 years) at seated rest following the placement of a radial arterial and right heart catheter. DSM was quantified by transfer function (input/output frequency) analyses of beat-by-beat changes in PAD (for LV) and A wave right atrial pressures (for RV) as input variables. Output variable was SV (Modelflow from radial arterial line waveform) and normalized for LV DSM using direct-Fick derived SV and for RV DSM using acetylene rebreathing derived SV as a measure of pulmonary blood flow. Results: The power spectral density (PSD) was higher for LV compared to RV filling pressure (521 ± 446 vs 125 ± 111 mmHg 2 , P = 0.001); there was no difference for adjusted SV PSD (819 ± 764 vs 808 ± 765 ml 2 , P = 0.232). DSM gain was higher for LV compared to RV for all but 1 subject (0.58 ± 0.29 vs 0.30 ± 0.16 ml/mmHg, P = 0.002; Figure). Conclusions: RV DSM gain was significantly worse than LV DSM gain suggesting decreased RV contractile and/or compliance reserve in patients with HFpEF. These results highlight the utility of RV DSM gain to characterize RV dysfunction in patients with HFpEF.

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