Blunted rate-dependent left atrial pressure response during isoproterenol infusion in atrial fibrillation patients with impaired left ventricular diastolic function: a comparison to pacing

AIMS: A heart rate (HR)-dependent haemodynamic linkage between peak left atrial (LA) pressure during sinus rhythm (LAPpeak) and estimated left ventricular (LV) filling pressure (E/Em) has not yet been explored. We hypothesized that rate-dependent LAPpeak response differs depending on E/Em in patients with atrial fibrillation (AF). METHODS AND RESULTS: A total of 331 patients (68.0% male, 59.8 ± 10.8 years old) undergoing radiofrequency catheter ablation (RFCA) for AF were included, and their LAPpeak in sinus rhythm was recorded at the beginning of the procedure and at the HRs of 90, 100, 110, and 120 b.p.m. during right atrial pacing and isoproterenol (ISO-stress) infusion. We compared LAPpeak changes between patients with E/Em ≥ 15 (n = 58) and those with <15 (n = 273). (i) The patterns of pacing rate-dependent LAPpeak increase were similar in both the E/Em < 15 (P < 0.001) and E/Em ≥ 15 groups (P = 0.002). (ii) The ISO-stress reduced LAPpeak in patients with E/Em < 15 (P = 0.015), but not in those with E/Em ≥ 15 (P = 0.582). (iii) Paradoxical ISO-stress LAP elevation in patients with E/Em ≥ 15 was independently associated with 1-year follow-up E/Em reduction (B = -4.07, 95% CI -5.41 to -2.72, P < 0.001). Coexistence of E/Em ≥ 15 and ISO-stress LAP elevation increased specificity in predicting 1-year follow-up E/Em reduction after AF ablation than E/Em alone. CONCLUSION: Isoproterenol LAPpeak reduction was blunted in patients with impaired LV diastolic function estimated by E/Em ≥ 15. The improvement of LV diastolic dysfunction 1 year after AF ablation was independently associated with both paradoxical ISO-stress LAP elevation and E/Em ≥ 15 at the time of procedure. CLINICALTRIALSGOV: NCT02138695.ope