Background
An association between uric acid (UA) and cardiovascular diseases, including heart failure (HF), has been reported. However, whether UA is a causal risk factor for HF is controversial. In particular, the prognostic value of lowering UA in patients with HF with preserved ejection fraction (HFpEF) is unclear.
Methods and Results
We enrolled patients with HFpEF from the PURSUIT‐HFpEF (Prospective Multicenter Observational Study of Patients With Heart Failure With Preserved Ejection Fraction) registry. We investigated whether UA was correlated with the composite events, including all‐cause mortality and HF rehospitalization, in patients with hyperuricemia and HFpEF (UA >7.0 mg/dL). Additionally, we evaluated whether lowering UA for 1 year (≥1.0 mg/dL) in them reduced mortality or HF rehospitalization. We finally analyzed 464 patients with hyperuricemia. In multivariable Cox regression analysis, UA was an independent determinant of composite death and rehospitalization (hazard ratio [HR], 1.15 [95% CI, 1.03–1.27],
P
=0.015). We divided them into groups with severe and mild hyperuricemia according to median estimated value of serum UA (8.3 mg/dL). Cox proportional hazards models revealed the incidence of all‐cause mortality was significantly higher in the group with severe hyperuricemia than in the group with mild hyperuricemia (HR, 1.73 [95% CI, 1.19–2.25],
P
=0.004). The incidence of all‐cause mortality was significantly decreased in the group with lowering UA compared with the group with nonlowering UA (HR, 1.71 [95% CI, 1.02–2.86],
P
=0.041). The incidence of urate‐lowering therapy tended to be higher in the group with lowering UA than in the group with nonlowering UA (34.9% versus 24.6%,
P
=0.06).
Conclusions
UA is a predictor for the composite of all‐cause death and HF rehospitalization in patients with hyperuricemia and HFpEF. In these patients, lowering UA, including the use of urate‐lowering therapy, may improve prognosis.
Introduction
Local impedance (LI) drop during radiofrequency (RF) application is monitored to assess the lesion formation. Recently, a novel ablation catheter has been introduced to clinical setting, which is capable of monitoring LI and catheter contact parameters including contact force (CF) and contact angle (CA). This study aimed to clarify the correlation between LI drop and catheter contact parameters.
Methods and results
This prospective study included 15 paroxysmal atrial fibrillation (AF) patients who underwent initial pulmonary vein isolation (PVI). First‐pass encircling point‐by‐point PV ablation was performed by using a 4.5‐mm irrigated ablation catheter, with monitoring LI, CF, and CA. RF energy was applied for 30 s at each site with 30 W. Stable ablation points were analyzed to examine the correlation between LI drop and catheter contact parameters. Among 903 ablation points, 499 stable ablation points (55.2%) were analyzed. CA showed good correlation with LI drop (ρ = 0.418, p < .001). Maximum CF, minimum CF, average CF, and initial CF all showed weak correlation with LI drop (ρ = 0.201, p < .001; ρ = 0.224, p < .001; ρ = 0.258, p < .001; and ρ = 0.212, p < .001, respectively). Multivariate analysis demonstrated that CA was an independent factor of LI drop among the catheter contact parameters (β = 0.139, 95% CI = 0.111–0.167, p < .001). The LI drop in the blocked segments was significantly higher than that in the electrical conduction gap segments (27.3 ± 9.8 vs. 19.6 ± 6.4 Ω, p < .001)
Conclusion
In clinical PVI use, both CF and CA were correlated with LI drop. More parallel CA could induce higher LI drop, which may lead to effective lesion formation.
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