Atlas Contents
The approaches
Access to the heart begins outside the cardiac silhouette. Safe catheterisation depends on understanding the continuity between surface landmarks, vessels, mediastinal structures, pericardium, and cardiac chambers. The femoral, jugular, and subclavian approaches enter the circulation through different vascular axes, whereas the subxiphoidal route enters the pericardial space directly. Each approach therefore presents a distinct geometry, set of anatomical variants, and pattern of potential complications. [1-4]
This chapter describes the anatomical framework rather than prescribing a puncture technique. Ultrasound, fluoroscopy, and cross-sectional imaging reveal different parts of that framework and should be integrated when the course of a vessel or the position of an adjacent organ is uncertain.
1 The femoral approach
The femoral vessels pass beneath the inguinal ligament within the femoral triangle. From lateral to medial, the principal structures are the femoral nerve, common femoral artery, common femoral vein, and lymphatic channels. This familiar order is not invariant: the artery and vein can overlap, particularly when viewed in a transverse plane or when the hip is rotated. The vein is compressible and changes calibre with respiration, hydration, abdominal pressure, and venous obstruction. [3,5]
Venous access is usually obtained in the common femoral vein below the inguinal ligament and above the confluence of the femoral and deep femoral veins. A puncture that is too superior may enter the external iliac vessel above the inguinal ligament, where haemorrhage can extend into the retroperitoneum and cannot be controlled by effective external compression. A puncture that is too inferior may involve a smaller branch, cross a bifurcation, or increase the likelihood of venous thrombosis and local haematoma. Ultrasound identifies the ligament indirectly, vessel bifurcation, arterial overlap, thrombus, and the course of the needle in real time. [5]
From the common femoral vein, catheters pass through the external and common iliac veins to the inferior caval vein. The right iliac venous axis usually provides a relatively direct route. The left common iliac vein passes beneath the right common iliac artery before joining its counterpart, and compression, tortuosity, previous thrombosis, filters, or congenital interruption can alter the expected course. The inferior caval vein enters the inferior right atrium in a direction that favours access to the interatrial septum, tricuspid valve, His region, and right ventricle.
Multiple femoral sheaths can crowd the vein and groin. Their intravascular relationship cannot be inferred solely from the skin puncture sites. The femoral artery lies close enough for inadvertent arterial entry, arteriovenous fistula, or pseudoaneurysm. The femoral nerve remains lateral to the artery and can be affected by a large haematoma. Anatomical assessment is especially important in obesity, prior vascular intervention, abnormal pulses, and known venous disease.
2 The jugular approach
The internal jugular vein descends within the carotid sheath from the jugular foramen to join the subclavian vein behind the sternoclavicular joint. In the neck it usually lies lateral or anterolateral to the common carotid artery, but overlap is common and changes with head rotation and level of examination. The vagus nerve lies posteriorly between the artery and vein. The vein is superficial beneath the sternocleidomastoid muscle and is readily assessed with ultrasound. [3,6]
The right internal jugular vein forms a comparatively straight route through the right brachiocephalic vein and superior caval vein to the right atrium. This superior approach is useful when the inferior caval route is unavailable and for selected lead, biopsy, mapping, or ablation procedures. Entering from above changes catheter orientation: the superior caval vein directs the catheter towards the inferior right atrium, tricuspid valve, and right ventricular cavity, whereas engagement of the coronary sinus or inferior septal structures may require different curves from those used through the femoral route.
At the lower neck, the pleural dome and lung apex extend behind the clavicle, and the thoracic duct terminates near the left venous angle. These relations explain the risks of pneumothorax and, on the left, chylous injury. Arterial puncture, cervical haematoma, nerve injury, and air embolism are additional access-related hazards. Excessive head rotation may increase overlap between the vein and carotid artery rather than improving separation.
The left jugular route joins the longer and more transverse left brachiocephalic vein, which crosses anterior to the branches of the aortic arch before reaching the superior caval vein. Its angulation and greater length make the geometry different from the right-sided route. Persistent left superior caval vein or brachiocephalic venous obstruction can redirect a catheter into the coronary sinus or collateral veins. Unexpected left-sided descent should therefore be defined before force is applied.
3 The subclavian approach
The subclavian vein is the continuation of the axillary vein at the lateral border of the first rib. It passes medially over the first rib, anterior to the anterior scalene muscle, while the subclavian artery and brachial plexus lie posterior to that muscle. Behind the medial clavicle, the vein joins the internal jugular vein to form the brachiocephalic vein. The narrow space between the clavicle and first rib is clinically important because leads traversing it can be compressed. [3,6]
The term subclavian approach is often used broadly for access obtained beneath the clavicle. Anatomically, a puncture or cutdown may involve the axillary vein lateral to the first rib, the true subclavian vein medial to that border, or the cephalic vein in the deltopectoral groove. These routes should be distinguished because their relationships to the pleura, artery, and clavicle differ. Ultrasound-guided axillary venous access can visualise the vein in a more lateral, compressible segment and avoids the most confined costoclavicular region.
On the right, the brachiocephalic vein descends steeply into the superior caval vein. On the left, the brachiocephalic vein crosses the superior mediastinum and can be compressed between the sternum and arch vessels. Venous valves, stenosis from prior leads, dialysis access, previous surgery, or collateral networks can obstruct passage. Pre-existing transvenous leads alter the available lumen and may adhere to the venous wall or tricuspid apparatus.
The pleural dome, lung apex, subclavian artery, internal thoracic vessels, and brachial plexus are the principal neighbouring structures at risk. A medial and deep trajectory increases the chance of pneumothorax or arterial injury. For permanent cardiac devices, the anatomy continues beyond venous entry: lead curvature through the brachiocephalic vein and superior caval vein, interaction with the tricuspid leaflets, and the final target within the right atrium, ventricle, coronary veins, or conduction system all determine long-term mechanical behaviour.
4 The subxiphoidal region
The subxiphoidal region provides the conventional percutaneous route to the pericardial space. The xiphoid process is variable in length, angulation, and ossification. Immediately deep are the linea alba, diaphragmatic attachments, and central tendon. The fibrous pericardium is fused inferiorly to the central tendon, while the parietal serous layer lines its inner surface. The potential pericardial cavity lies between parietal and visceral serosa. [2,7]
The diaphragmatic surface of the heart is formed predominantly by the left ventricle with a contribution from the right ventricle. The acute margin and anterior right ventricular wall approach the sternum, whereas the inferior cardiac surface rests on the diaphragm. A subxiphoid trajectory must therefore negotiate a narrow three-dimensional corridor between the costal margin, xiphoid, diaphragm, pleura, liver, stomach, and heart. The exact relationship changes with respiration, body habitus, cardiac enlargement, and previous thoracic or abdominal surgery. [2,7]
The liver lies directly inferior to the right hemidiaphragm and may extend across the midline. The stomach and left hepatic lobe can approach the left subxiphoidal region. The pleural reflections descend towards the costal margins but leave a variable central area where the pericardium is related to the diaphragm without intervening pleura. Cross-sectional imaging is valuable when organ position or an unusual xiphoid configuration narrows this window.
Within the pericardial space, the visceral serosa covers the epicardium, coronary arteries, veins, and epicardial fat. The phrenic nerves descend on the lateral pericardium, with the left nerve particularly relevant to procedures on the lateral left ventricular surface. Coronary arteries and the right ventricular free wall are immediate hazards during entry. Contact with the right ventricle does not guarantee that the needle has entered the pericardial cavity, and blood return does not by itself distinguish vascular from ventricular entry.
Prior cardiac surgery, pericarditis, or previous epicardial ablation can produce adhesions that obliterate the potential cavity and tether the heart to the parietal pericardium. These adhesions change both access feasibility and the direction in which a guidewire can move. Subxiphoid access should consequently be planned as entry into an individual anatomical space, not as a fixed angle defined only by the skin and xiphoid process.
Key Anatomical Messages
- The femoral vein and artery frequently overlap and should be assessed in real time.
- The right jugular route provides the most direct superior venous axis to the right atrium.
- Subclavian axillary and cephalic venous access routes are anatomically distinct.
- The pleural dome and arterial structures are critical neighbours of superior venous access.
- The subxiphoidal corridor is defined by the xiphoid diaphragm pericardium pleura liver stomach and cardiac surface.
- Previous surgery or inflammation can replace the pericardial cavity with adhesions.
- Imaging complements surface landmarks whenever anatomy is variable or obscured.
References
- Cabrera JA, Sánchez-Quintana D. Cardiac anatomy: what the electrophysiologist needs to know. Heart. 2013;99:417-431. doi:10.1136/heartjnl-2011-301154.
- Sánchez-Quintana D, Cabrera JA, Climent V, Farré J, Mendonça MC, Ho SY. How close are the phrenic nerves to cardiac structures? Implications for cardiac interventionalists. J Cardiovasc Electrophysiol. 2005;16:309-313. doi:10.1046/j.1540-8167.2005.40759.x.
- Standring S, ed. Gray’s Anatomy. 42nd ed. Elsevier; 2020.
- Anderson RH, Spicer DE, Hlavacek AM, Cook AC, Backer CL. Wilcox’s Surgical Anatomy of the Heart. 4th ed. Cambridge University Press; 2013.
- Seto AH, Abu-Fadel MS, Sparling M, et al. Real-time ultrasound guidance facilitates femoral arterial access: the FAUST trial. JACC Cardiovasc Interv. 2010;3:751-758. doi:10.1016/j.jcin.2010.04.015.
- McGee DC, Gould MK. Preventing complications of central venous catheterization. N Engl J Med. 2003;348:1123-1133. doi:10.1056/NEJMra011883.
- Sosa E, Scanavacca M, d’Avila A, Pilleggi F. A new technique to perform epicardial mapping in the electrophysiology laboratory. J Cardiovasc Electrophysiol. 1996;7:531-536. doi:10.1111/j.1540-8167.1996.tb00559.x.
