E7
Letter to the Editor
Catheter Ablation of Atrial Fibrillation as Chronic Kidney Disease Treatment To the Editor We read with great interest the article by Navaravong et al.1 pointing to an association between restoration of sinus rhythm and improvement of renal function in patients with chronic kidney disease (CKD) undergoing atrial fibrillation (AF) catheter ablation. In their article, the authors demonstrated a general improvement of eGFR following catheter ablation. Interestingly, CKD was not associated with AF burden and was not a predictor for AF recurrences. Both AF and renal impairment are associated with increased morbidity and mortality.2,3 Individuals with CKD are more likely to develop AF,4 whereas patients with renal impairment are at higher risk for cardio- and cerebrovascular complications. Although catheter ablation is an effective treatment modality for the prevention and reduction of AF recurrence and improvement of symptoms, poor rhythm outcomes have been noted in patients with impaired renal function undergoing AF catheter ablation.5,6 Possible links between AF (and also AF recurrences) and renal dysfunction might include various inflammatory and fibrotic processes within the cardio-renal axis. Indeed, a higher AF recurrence rate in those patients with declining eGFR might represent a greater kidney-disease promoted AF substrate.7 The authors should be congratulated for their interesting finding on this topical and timely performed study that is in accordance with our research.8 Our observations concur with their main conclusion that restoration of sinus rhythm is associated with eGFR improvement. In our study of 783 patients who underwent de novo AF catheter ablation, we have seen that AF catheter ablation eGFR changes during mid-term follow-up were associated with AF recurrences.8 However, we still would like to highlight some issues. First, with 115 days (interquartile range [IQR] 92–130 days), the median time between pre- and postablation eGFR measurements was relatively short. Second, despite this short follow-up interval, the authors demonstrated substantial eGFR increases with relevant eGFR changes including even the changes within CKD stages (e.g., in stage 3B: 41 ± 5 vs. 77 ± 29 mL/min/1.73 m2 ; P = 0.003). This is in contrast to our observations during longer followup (median 20 months; IQR 12–27 months) revealing very small, but clinically irrelevant differences between baseline and follow-up eGFR (80 ± 18 vs. 78 ± 20 mL/min/1.73 m2 ; P < 0.001). Finally, in our study, patients with AF recurrences had worse eGFR at baseline and at follow-up than those without J Cardiovasc Electrophysiol, Vol. 25, p. E7, December 2014. doi: 10.1111/jce.12558
recurrences. On uni- and multivariable analyses, AF recurrences were associated with eGFR changes after AF catheter ablation. Of note, this is in accordance with our previous data from the Heart Center Leipzig AF Ablation Registry—where we demonstrated that eGFR
Letter to the Editor
Catheter Ablation of Atrial Fibrillation as Chronic Kidney Disease Treatment To the Editor We read with great interest the article by Navaravong et al.1 pointing to an association between restoration of sinus rhythm and improvement of renal function in patients with chronic kidney disease (CKD) undergoing atrial fibrillation (AF) catheter ablation. In their article, the authors demonstrated a general improvement of eGFR following catheter ablation. Interestingly, CKD was not associated with AF burden and was not a predictor for AF recurrences. Both AF and renal impairment are associated with increased morbidity and mortality.2,3 Individuals with CKD are more likely to develop AF,4 whereas patients with renal impairment are at higher risk for cardio- and cerebrovascular complications. Although catheter ablation is an effective treatment modality for the prevention and reduction of AF recurrence and improvement of symptoms, poor rhythm outcomes have been noted in patients with impaired renal function undergoing AF catheter ablation.5,6 Possible links between AF (and also AF recurrences) and renal dysfunction might include various inflammatory and fibrotic processes within the cardio-renal axis. Indeed, a higher AF recurrence rate in those patients with declining eGFR might represent a greater kidney-disease promoted AF substrate.7 The authors should be congratulated for their interesting finding on this topical and timely performed study that is in accordance with our research.8 Our observations concur with their main conclusion that restoration of sinus rhythm is associated with eGFR improvement. In our study of 783 patients who underwent de novo AF catheter ablation, we have seen that AF catheter ablation eGFR changes during mid-term follow-up were associated with AF recurrences.8 However, we still would like to highlight some issues. First, with 115 days (interquartile range [IQR] 92–130 days), the median time between pre- and postablation eGFR measurements was relatively short. Second, despite this short follow-up interval, the authors demonstrated substantial eGFR increases with relevant eGFR changes including even the changes within CKD stages (e.g., in stage 3B: 41 ± 5 vs. 77 ± 29 mL/min/1.73 m2 ; P = 0.003). This is in contrast to our observations during longer followup (median 20 months; IQR 12–27 months) revealing very small, but clinically irrelevant differences between baseline and follow-up eGFR (80 ± 18 vs. 78 ± 20 mL/min/1.73 m2 ; P < 0.001). Finally, in our study, patients with AF recurrences had worse eGFR at baseline and at follow-up than those without J Cardiovasc Electrophysiol, Vol. 25, p. E7, December 2014. doi: 10.1111/jce.12558
recurrences. On uni- and multivariable analyses, AF recurrences were associated with eGFR changes after AF catheter ablation. Of note, this is in accordance with our previous data from the Heart Center Leipzig AF Ablation Registry—where we demonstrated that eGFR
