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Conflict of interest
Introduction Over the last decade, the unabated increase in the number of transseptal catheterizations has been related to an increase in atrial fibrillation (AF) ablation procedures. Transseptal puncture (TP) is usually safe in experienced hands [1,2]. However, it diindolylmethane can be associated with life-threatening complications [3,4]. Conventionally, the procedure is performed under fluoroscopic guidance and pressure monitoring. To reduce the incidence of complications, TP can be performed under transesophageal echocardiography (TEE) or intracardiac echocardiography (ICE) guidance [5,6]. The use of echocardiographic guidance for TP allows direct visualization of the transseptal needle tip within the fossa ovalis (FO), and thus, a safe TP in every patient. It is also important to emphasize that the use of echocardiographic guidance enables puncture site selection within the FO according to the expected procedure type (e.g., a more anterior puncture for ablation of an accessory pathway at the mitral annulus or for ablation of ventricular tachycardia vs. a lower and more posterior puncture for ablation of AF). Thus, the puncture site location can make a significant difference in mapping and/or ablation catheter maneuverability. A neglected advantage of echocardiographic guidance during TP is the possibility of initiating anticoagulation safely before TP. This appears to be a very important additional benefit, especially in patients with AF. It has to be emphasized that the use of echocardiographic monitoring during the entire AF ablation procedure allows for additional benefits beyond safe TP. Echocardiographic monitoring throughout the ablation procedure may help in understanding the real-time anatomy of relevant cardiac structures such as the pulmonary veins, left atrial appendage, mitral isthmus, cavotricuspid isthmus, etc. To date, no randomized trial has compared the clinical outcomes and success rates between TEE-guided and traditional fluoroscopic TP. Many studies conclude that cardiac imaging may be better than fluoroscopy for guiding TP [5,6] especially in less experienced hands, but the advantages in routine use of imaging modalities have not yet been demonstrated.
Materials and methods
Results Clinical and echocardiographic data of the study population are given in Table 1. The study population consisted of 91 symptomatic patients with AF. Mean ages of the patients in the TEE-guided group (group 1) and fluoroscopy-guided group (group 2) were 55.5±9.8 years (16 men, 47%) and 55.0±10.4 years (28 men, 49%), respectively. Twenty-five patients (73.5%) in the TEE-guided group and 37 patients (64.9%) in the fluoroscopy-guided group presented with paroxysmal AF. The median durations of AF in the TEE-guided group and fluoroscopy-guided group were 3.5 (2.0–4.25) years and 3.0 (2.0–5.0) years, respectively. The median LA diameter was 40 (interquartile range (IQR): 37–43)mm in the TEE-guided group and 41 (IQR: 38.0–45.5)mm in the fluoroscopy-guided group. The median left ventricular ejection fraction was 60% (IQR: 55–65) in the TEE-guided group and in the fluoroscopy-guided group, similarly. Other demographic characteristics were similar between groups. The cryoablation procedural details are illustrated in Table 2. The median total procedural time was 68 (IQR: 64–74)min in the TEE-guided group and 83 (IQR: 72–97)min in the fluoroscopy-guided group (p<0.001). The fluoroscopy times in the TEE-guided group and in group 2 were 14 (IQR: 13–15)min and 16 (IQR: 14–22)min, respectively (p<0.001). The median total cryoablation times in the TEE-guided group and in group 2 were 32 (IQR: 32–36)min and 36 (IQR: 33–39)min, respectively (p=0.002). Acute procedural success was 100% in both groups. The maximal temperatures reached at each pulmonary vein were similar between the two groups (Table 2). Comparison of cryoablation times for each pulmonary vein showed shorter cryoablation times at the inferior pulmonary veins (8 [IQR: 8–8] vs. 8 [IQR: 8–11], p=0.007, at left inferior pulmonary veins [LIPVs] and 8 [IQR: 8–8] vs. 8 [IQR: 8–13], p=0.004, at right inferior pulmonary veins [RIPVs], respectively). Upper pulmonary vein cryoablation times were similar. The TEE-guided group was associated with a lower number of cryoenergy applications at the inferior pulmonary veins (2 [IQR: 2–2] vs. 2 [IQR: 2–3], p=0.007, for LIPVs and 2 [IQR: 2–2] vs. 2 [IQR: 2–4], p=0.005, for RIPVs, respectively). Other procedural data as presented in Table 2 were similar among groups.