Impact of diabetes mellitus and poor glycemic control on the prevalence of left atrial low-voltage areas and rhythm outcome in patients with atrial fibrillation ablation

INTRODUCTION

Left atrial low-voltage areas (LVAs) are known to be correlated with atrial scarring and atrial fibrillation (AF) recurrence after ablation. However, the association between LVAs and glycemic status before ablation has not been fully clarified. The purpose of this study was to investigate associations among the prevalence of diabetes mellitus (DM), glycemic control, and the prevalence of LVAs in patients with AF ablation.

METHODS

In total, 912 (age, 68 ± 10 years; female, 299 [33%]; persistent AF, 513 [56%]) consecutive patients who underwent initial AF ablation were included. A preprocedure glycated hemoglobin A1c (HbA1c) ≥7% was set as the cutoff for poor glycemic control in patients with DM. LVAs were defined as areas with a bipolar voltage of <0.5 mV covering ≥5 cm2 of left atrium.

RESULTS

LVAs existed in 208 (23%) patients, and 168 (18%) patients had DM. LVAs were found more frequently in patients with DM and poor glycemic control. On multivariate analysis, DM with HbA1c ≥7% was an independent predictor of LVAs (odds ratio, 3.3; 95% confidence interval: 1.6-6.7; p = .001). In patients with LVAs, freedom from AF recurrence during the 24-month study period was significantly lower in patients who had DM with HbA1c ≥7% than in those without DM (37.9% vs. 54.7%, p = .02).

CONCLUSION

In patients with AF ablation, LVAs were found more frequently in patients with DM and poor glycemic control. DM with HbA1c ≥7% was an independent predictor of LVAs.

Association of extra-pulmonary vein triggers with low-voltage area and clinical recurrence in patients with atrial fibrillation undergoing catheter ablation

Background and Objectives

Although extra-pulmonary vein (PV) triggers (ExPVTs) play a role in atrial fibrillation (AF) recurrence after catheter ablation (AFCA), the mechanism is unknown. We explored whether the locations of ExPVTs were associated with low-voltage scar areas (LVAs).

Methods

Among 2255 consecutive patients who underwent a de novo AFCA, 1696 (male 72.1%, median 60 years old, paroxysmal 64.7%) were included who underwent isoproterenol provocation and voltage mapping of the left atrium (LA) during their procedures. We investigated the associations between ExPVTs and their mean LA voltage and colocalization of ExPVTs within LVAs (<0.2 mV).

Results

We observed ExPVTs in 181 (10.7%) patients (60 in the LA, 99 in the right atrium [RA], 16 biatrial, and 6 unmappable). A lower mean LA voltage was independently associated with the existence of ExPVTs (OR 0.77 per 1 SD mV increase, 95% CI 0.60-0.99, p = .039). Among 76 patients who had ExPVTs[LA], 43 (56.6%) had ExPVTs within LVAs. During a median of a 42-month follow-up, patients with ExPVTs had a higher AF recurrence than those without (HR 1.87, 95% CI 1.48-2.37, Log-rank p < .001), but colocalization of ExPVTs and LVAs (Log-rank p = .544) and the anatomical location of ExPVTs (Log-rank p = .084) did not affect the rhythm outcome.

Conclusions

The presence of ExPVTs was associated with low LA voltage and poor rhythm outcome post-AFCA, but the colocalization of ExPVTs and LVA in LA did not affect rhythm outcome.

Comparison of the electrophysiological properties of the pulmonary veins between paroxysmal and persistent atrial fibrillation

Background

The role of the pulmonary veins (PVs) as triggers in atrial fibrillation (AF) is well-known; however, their detailed electrophysiological properties have not been thoroughly examined.

Objective

This study aimed to investigate the electrophysiological properties of the PVs between paroxysmal AF (pAF) and persistent AF (perAF).

Methods

Prior to catheter ablation in patients with pAF (n = 51) and perAF (n = 41), a voltage map of the left atrium and PVs was created under sinus rhythm, and the area of the myocardial sleeves in the PVs and their electrophysiological characteristics, including the pacing threshold and effective refractory period (ERP), were compared between the two groups.

Results

Compared with perAF, the myocardial sleeves of PVs for pAF were significantly larger for all PVs. The ERP for perAF was significantly shorter than that for pAF for all PVs. The pacing threshold for perAF was significantly higher than that for pAF for the right and left superior PVs.

Conclusion

In patients with perAF, a decrease in the normal myocardial sleeves and a shortening of the ERP were observed for all PVs. Those changes in the electrophysiological properties of the PVs might be related to the persistence of AF.

Evaluation of the atrial substrate based on low-voltage areas and dominant frequencies after pulmonary vein isolation in nonparoxysmal atrial fibrillation

BACKGROUND

This study aimed to evaluate the atrial substrate in the left atrium (LA) by low-voltage areas (LVAs) and high-dominant frequencies (DFs) after circumferential pulmonary vein isolation (PVI) in nonparoxysmal atrial fibrillation (AF).

METHODS

In 70 patients with nonparoxysmal AF patients (41 persistent AF), LA voltage maps were created during sinus rhythm by external cardioversion after PVI and DF mapping. The patients were divided into AF-free and AF-recurrent groups.

RESULTS

The AF freedom rate without antiarrhythmic drugs was 69.0% after PVI after 1 procedure during a 12-month follow-up. There was a significant difference in the LVA (<0.5 mV)/LA surface area after PVI between the AF-free and AF-recurrent groups (15% vs 23%, P = .033). AF freedom was significantly greater in those with LVAs of ≤24% than in those with LVAs of >24% during 12 months of follow-up (78.6% vs 53.8%, Log-rank test P = .020). Fifty-six (72%) of the 78 high-DF sites (≥8 Hz) overlapped with LVAs. Thirty-one (55%) of 56 high-DF sites overlapped with LVAs that existed at LVA border zones. There were no significant differences in number of high-DF sites that overlapped with LVAs in the LA between the two groups. However, in persistent AF patients, the max-DF value in the LA exhibited a significant difference between the two groups (P = .008).

CONCLUSIONS

LVAs were associated with AF recurrences after PVI in nonparoxysmal AF patients and overlapped with many high-DF sites. PVI alone may be enough to treat patients with mild-to-moderate extent (≤24%) of LVAs.