**4.2 Needle-in-needle method**

A 'needle-in-needle' technique for epicardial access has been described by Kumar et al [58]. In this approach, a 7-cm 18-gauge needle is inserted beneath the sternum. The purpose of this short needle is to provide stability and tactile feedback for a long (15- or 20-cm) micropuncture 21-gauge needle, which is inserted through the 18-gauge needle. Once the 21-gauge needle is inserted into the pericardial space, along 0.018-inch guidewire with a floppy tip is advanced into the pericardial space. Upon fluoroscopic confirmation that the guide wire has been inserted into the pericardium both needles are then removed. Micropuncture dilators are then used to upsize the guide wire to a 0.35-inch wire and ultimately, an 8-Fr sheath is introduced into the pericardial space. The 'needle-in-needle' approach was compared to the traditional methods. Successful epicardial access was achieved in 100% of the 'needle-in-needle' cases, as compared to 94% with the Sosa technique. Failure of epicardial access in the traditional method were due to prior cardiac surgery [13] or

#### **Figure 7.**

*Angiography before epicardial ablation. After a successful epicardial puncture through posterior approach, the angiography was performed before the ablation to avoid coronary injury.*

adhesions from prior epicardial mapping/ablation or episodes of pericarditis [7]. Major pericardial bleeding was similar between both techniques [58].

#### **4.3 Anterior approach vs. posterior approach**

In anatomic, there is a potential space below the sternum and xyphoid process. While puncturing below the xyphoid process, the needle might directly pass through the fibrous pericardium avoiding the puncture through the diaphragm [59]. The term of "anterior approach" was used for the epicardial approach via this potential space (**Figure 8**). This approach was based on the previous finding that an increased fluid in the anterior part of the heart during supine position [60, 61]. Theoretically, the density of myocardium is heavier than and pericardial fluid. During supine position, the heart might force the pericardial fluid to the anterior part within the pericardium. Keramati et al. reported the anterior approach was successfully performed in 100% of patients in their study cohort [62]. The success rate was similar between the anterior approach and the needle in needle approach. On the other hand, the success rate of the anterior approach was higher than the traditional approach. In the report, there were no major pericardial hemorrhage and even the PV puncture. **Figure 9** demonstrated the illustration of the anterior approach and posterior approach.

#### **4.4 Fluoroscopic approach with carbon dioxide insufflation**

The technique of carbon dioxide insufflation was first reported with right atrial exit in human study by Greenbaum et al [63]. A modified approach with exit from the coronary sinus was reported by Silberbauer et al [64]. The pericardial space was insufflated with carbon dioxide after creating the exit, which allowing visualization of the pericardial membrane and separated membrane to the myocardium. The epicardial space with carbon dioxide allowed safe epicardial puncture and minimized the risk of RV perforation. A multi-center registry was conducted with

#### **Figure 8.**

*An illustration of anterior and posterior approach. The figure showed the X-ray from the lateral view. The green arrow indicated the anterior approach and the red arrow indicated the posterior approach. The horizontal cut of the hears from lower caudal part of the cranial part. The white arrow indicates the sequence from the lower part of the higher part. Each cut was corresponding to the horizontal while line in the X-ray.*

#### **Figure 9.**

*Example of anterior approach. Anterior approach was performed successfully. The guide wire was exchanged with an 8 Fr sheath after confirming the location.*

this modified approach. There was no patient complicated with the RV puncture of coronary artery injury [65]. However, the operator needs to take care of the potential risk of bleeding from the exit site.

#### **4.5 Wire-guided puncture**

This approach was first described by Long et al [64] in 2019. This approach was different from traditional approach using the contrast-filled syringe to the needle.

*Epicardial Radiofrequency Ablation: Who, When, and How? DOI: http://dx.doi.org/10.5772/intechopen.99824*

In the wire-guided approach, a J-tipped guide wire is within the needle during puncture. After advancing the needle the adjacent area of the pericardium, the wire was advanced. The wire would curve back if it reached the parietal pericardium, and the operator could feel the heart pulsations. The wire was dragged back to the needle's tip at this point. The wire and needle were both pressed again at the same time. While the needle was traveling through the epicardium, the wire would fall into the pericardial region. The study found that this method was safe and that the success rate was comparable to that of the traditional method.

#### **4.6 Surgical access**

Pericardial window provides clear visualization of the epicardial myocardium and manipulation of the mapping catheter and Realtime feedback for the location of the mapping catheter cooperating with the 3-D anatomic mapping system. The operator might not able to perform percutaneous subxiphoid access in patients with pericardial adhesions. In these patients, a surgical window may be required to gain access to the pericardium. This technique involves a subxiphoid incision, followed by manual lysis of adhesions to visualize the epicardial surface. A sheath was then placed into the pericardial space after opening a small window in the pericardium [66]. This technique should be considered in patients with a prior history of cardiac surgery with dense pericardial adhesions [67].
