Percutaneous access to the pericardial cavity (pericardiocentesis) is typically performed for drainage of pericardial effusions. In the absence of effusion, epicardial access can also be obtained during epicardial ablation of arrhythmias, certain structural heart disease procedures such as percutaneous closure of the left atrial appendage, and, more rarely, balloon pericardiotomy.¹,²,³,⁴,⁵,⁶,⁷ A systematic approach to the patient evaluated for such procedures is paramount (FIGURE 25.1). The presence of adhesions (more frequent in patients with prior cardiac surgery or history of pericarditis) can complicate percutaneous access to the pericardial space.⁷ In this situation, surgical consultation for possible pericardial window and lysis of adhesions should be considered.

The pericardial cavity is a virtual space between the parietal and visceral layers of the serous pericardium. It is continuous with the epicardium and reflects around the roots of the great vessels and onto the visceral surface of the fibrous pericardium. The visceral surface of the pericardium is continuous with the adventitia of the great vessels superiorly, and it is related posteriorly to the bronchi, esophagus, descending thoracic aorta, and mediastinal surface of each lung. The phrenic nerves descend between the visceral pericardium and the mediastinal pleural layers that adhere to its lateral sides (FIGURE 25.2).⁶

The oblique sinus, a recess located behind the left atrium, is formed as the pericardium envelopes the pulmonary veins and vena cava. Within it lies the vein of Marshall, connected by the fetal remnant of the duct of Cuvier to the highest left intercostal vein and draining into the coronary sinus. The transverse sinus is located superior to the heart between the arterial mesocardium, which envelopes the ascending aorta and pulmonary trunk anteriorly, and the venous mesocardium, which covers the superior vena cava (SVC), left atrium, and pulmonary veins posteriorly and inferiorly (FIGURE 25.2).⁶

Although most of the pericardial cavity can be easily accessed using standard catheters, reaching the posterior wall of the left atrium (LA) can be challenging given the complex pericardial reflections that form the pulmonary vein (PV) recesses and the 2 major sinuses. On the other hand, the epicardial surfaces of both ventricles are free of reflections. In the absence of prior severe pericarditis or cardiac surgery, this allows for simple manipulation of the catheters during epicardial procedures. The inferior and anterior approach taken during percutaneous epicardial access allows for easier access to the respective surfaces of the heart (FIGURE 25.2).¹,²,³,⁴,⁵

The technique for safely accessing the normal pericardial space for the purposes of epicardial interventions was first described by Sosa and colleagues using a modification of the traditional method.¹,² This approach allows free access to the entire ventricular surfaces, the right atrium, and the majority of the right and left atrium (FIGURES 25.3, 25.4, 25.5, 25.6, 25.7, 25.8, 25.9 and 25.10).

Conceptually, entering the pericardial space is simple when draining pericardial effusions. However, in the absence of an effusion, epicardial access can be challenging, as there is little room for error. The normal pericardial cavity contains only 20 to 25 cc of physiologic fluid with only virtual space. Thus, there is an increased risk of perforating the right ventricle (RV) wall and/or of damaging epicardial vessels when attempts are made to access the space percutaneously with a regular pericardiocentesis needle. In a series of 200 patients, Sosa et al reported a bleeding rate of 10% and “dry” RV puncture rate of 4.5% that decreases with experience.¹,²,³,⁴