Cavoatrial junction

Last updated
The CAJ is the joint between the superior vena cava and the atrium. Diagram of the human heart (cropped).svg
The CAJ is the joint between the superior vena cava and the atrium.

The cavoatrial junction (CAJ) is the point at which the superior vena cava meets and melds into the superior wall of the cardiac right atrium. Both the superior and inferior vena cavae enter the right atrium, but only the superior entry is called the cavoatrial junction. This junction marks the inferior end of the superior vena cava, the continuation below that point being considered part of the heart.

For purposes of radiographic visualization, the most reliable indicator of junction location is to find the carina, then observe the vertebrae it overlies. The junction will lie two vertebral body units (VBUs) below the carina, counting the single intervertebral disc between them, but not the disc below them. It has been demonstrated that the more ordinary method of looking for the "bulge" in the cardiac outline is unreliable, since cardiac or other thoracic pathology can shift the apparent position of that landmark.

Hospitalized patients may need to receive solutions and medications that, if given through an ordinary intravenous therapy catheter, would severely damage both blood cells and the vascular system. In these cases, it is common to insert a central venous catheter. All such catheters placed for the purpose of venous access and being inserted in the upper body will ideally have the tip placed within the superior vena cava at or just above the cavoatrial junction. Passing the line through the junction and into the atrium is avoided by some practitioners, as they fear the result may be cardiac arrythmias and even cardiac tamponade, a potentially fatal outcome. However, other practitioners prefer the proximal RA and state that there is no evidence of harm. Modern catheter tip verification systems often rely on ECG readouts which correlate with tip position. A chest xray may still be obtained to confirm or when an ECG is contraindicated.

Related Research Articles

<span class="mw-page-title-main">Vein</span> Blood vessels that carry blood towards the heart

Veins are blood vessels in the circulatory system of humans and most other animals that carry blood towards the heart. Most veins carry deoxygenated blood from the tissues back to the heart; exceptions are those of the pulmonary and fetal circulations which carry oxygenated blood to the heart. In the systemic circulation, arteries carry oxygenated blood away from the heart, and veins return deoxygenated blood to the heart, in the deep veins.

<span class="mw-page-title-main">Central venous catheter</span> A tubular device placed in a large vein used to administer medicines

A central venous catheter (CVC), also known as a central line (c-line), central venous line, or central venous access catheter, is a catheter placed into a large vein. It is a form of venous access. Placement of larger catheters in more centrally located veins is often needed in critically ill patients, or in those requiring prolonged intravenous therapies, for more reliable vascular access. These catheters are commonly placed in veins in the neck, chest, groin, or through veins in the arms.

<span class="mw-page-title-main">Superior vena cava</span> One of two veinous trunks bringing deoxygenated blood back to the heart

The superior vena cava (SVC) is the superior of the two venae cavae, the great venous trunks that return deoxygenated blood from the systemic circulation to the right atrium of the heart. It is a large-diameter (24 mm) short length vein that receives venous return from the upper half of the body, above the diaphragm. Venous return from the lower half, below the diaphragm, flows through the inferior vena cava. The SVC is located in the anterior right superior mediastinum. It is the typical site of central venous access via a central venous catheter or a peripherally inserted central catheter. Mentions of "the cava" without further specification usually refer to the SVC.

<span class="mw-page-title-main">Inferior vena cava</span> One of two veinous trunks bringing deoxygenated blood back to the heart

The inferior vena cava is a large vein that carries the deoxygenated blood from the lower and middle body into the right atrium of the heart. It is formed by the joining of the right and the left common iliac veins, usually at the level of the fifth lumbar vertebra.

<span class="mw-page-title-main">Interventional radiology</span> Medical subspecialty

Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs both diagnostic and therapeutic procedures through very small incisions or body orifices. Diagnostic IR procedures are those intended to help make a diagnosis or guide further medical treatment, and include image-guided biopsy of a tumor or injection of an imaging contrast agent into a hollow structure, such as a blood vessel or a duct. By contrast, therapeutic IR procedures provide direct treatment—they include catheter-based medicine delivery, medical device placement, and angioplasty of narrowed structures.

<span class="mw-page-title-main">Atrial septal defect</span> Human heart defect present at birth

Atrial septal defect (ASD) is a congenital heart defect in which blood flows between the atria of the heart. Some flow is a normal condition both pre-birth and immediately post-birth via the foramen ovale; however, when this does not naturally close after birth it is referred to as a patent (open) foramen ovale (PFO). It is common in patients with a congenital atrial septal aneurysm (ASA).

<span class="mw-page-title-main">Fontan procedure</span> Surgical procedure used in children with univentricular hearts

The Fontan procedure or Fontan–Kreutzer procedure is a palliative surgical procedure used in children with univentricular hearts. It involves diverting the venous blood from the inferior vena cava (IVC) and superior vena cava (SVC) to the pulmonary arteries. The procedure varies for differing congenital heart pathologies. For example in tricuspid atresia, the procedure can be done where the blood does not pass through the morphologic right ventricle; i.e., the systemic and pulmonary circulations are placed in series with the functional single ventricle. Whereas in hypoplastic left heart syndrome, the heart is more reliant on the more functional right ventricle to provide blood flow to the systemic circulation. The procedure was initially performed in 1968 by Francis Fontan and Eugene Baudet from Bordeaux, France, published in 1971, simultaneously described in 1971 by Guillermo Kreutzer from Buenos Aires, Argentina, and finally published in 1973.

<span class="mw-page-title-main">Dialysis catheter</span>

A dialysis catheter is a catheter used for exchanging blood to and from a hemodialysis machine and a patient.

<span class="mw-page-title-main">Cardiac catheterization</span> Insertion of a catheter into a chamber or vessel of the heart

Cardiac catheterization is the insertion of a catheter into a chamber or vessel of the heart. This is done both for diagnostic and interventional purposes.

<span class="mw-page-title-main">Peripherally inserted central catheter</span> Catheter intended for long periods of use

A peripherally inserted central catheter, less commonly called a percutaneous indwelling central catheter, is a form of intravenous access that can be used for a prolonged period of time or for administration of substances that should not be done peripherally. It is a catheter that enters the body through the skin (percutaneously) at a peripheral site, extends to the superior vena cava, and stays in place for days, weeks or even months.

<span class="mw-page-title-main">Hickman line</span> Central venous catheter

A Hickman line is a central venous catheter most often used for the administration of chemotherapy or other medications, as well as for the withdrawal of blood for analysis. Some types are used mainly for the purpose of apheresis or dialysis. They have also been used in total parenteral nutrition (TPN). Hickman lines may remain in place for extended periods and are used when long-term intravenous access is required.

<span class="mw-page-title-main">Inferior vena cava filter</span>

An inferior vena cava filter is a medical device made of metal that is implanted by vascular surgeons or interventional radiologists into the inferior vena cava to prevent a life-threatening pulmonary embolism (PE) or venous thromboembolism (VTE).

<span class="mw-page-title-main">Coronary sinus</span> Set of veins which drain blood from the myocardium (heart muscle)

The coronary sinus is the largest vein of the heart. It drains over half of the deoxygenated blood from the heart muscle into the right atrium. It begins on the backside of the heart, in between the left atrium, and left ventricle; it begins at the junction of the great cardiac vein, and oblique vein of the left atrium. It receives multiple tributaries. It passes across the backside of the heart along a groove between left atrium and left ventricle, then drains into the right atrium at the orifice of the coronary sinus.

<span class="mw-page-title-main">Groshong line</span>

A Groshong line is a type of intravenous catheter used for central venous access. It can be tunneled or non-tunneled.

<span class="mw-page-title-main">Umbilical line</span>

An umbilical line is a catheter that is inserted into one of the two arteries or the vein of the umbilical cord. Generally the UAC/UVC is used in Neonatal Intensive Care Units (NICU) as it provides quick access to the central circulation of premature infants. UAC/UVC lines can be placed at the time of birth and allow medical staff to quickly infuse fluids, inotropic drugs, and blood if required. It is sometimes used in term or near-term newborns in whom the umbilical cord stump is still connected to the circulatory system. Medications, fluids, and blood can be given through this catheter and it allows monitoring of blood gasses and withdrawing of blood samples. Transumbilical catheter intervention is also a method of gaining access to the heart, for example to surgically correct a patent ductus arteriosus.

<span class="mw-page-title-main">Port (medical)</span> Small completely implantable medical appliance that is installed entirely beneath the skin

In medicine, a port is a small medical appliance that is installed beneath the skin. A catheter connects the port to a vein. Under the skin, the port has a septum through which drugs can be injected and blood samples can be drawn many times, usually with less discomfort for the patient than a more typical "needle stick".

<span class="mw-page-title-main">Congenital stenosis of vena cava</span> Medical condition

Congenital stenosis of vena cava is a congenital anomaly in which the superior vena cava or inferior vena cava has an aberrant interruption or coarctation.

A vascular snare is an endovascular device that is used to remove foreign bodies from inside arteries and veins. The snare consists of several radiopaque loops of wire inside a catheter, which when extended flower out, and which collapse when withdrawn into the catheter.

In medicine, vascular access is a means of accessing the bloodstream through the peripheral or central blood vessels in order to obtain blood or deliver medications including chemotherapy. A vascular access procedure involves insertion of a sterile plastic tube called a catheter into a blood vessel. Types of catheters can be either peripherally or centrally located. Peripheral catheters are approximately one inch (25 mm) long and are inserted into the small veins of the forearm. Central catheters are bigger and longer and are inserted into the large veins of the extremities, neck, or chest. Central venous catheters are the primary modality used for delivery of chemotherapeutic agents. The duration of central venous catheterization is dependent on the type of treatment given.

Raghib syndrome is rare a congenital heart defect where the left superior vena cava (LSVC) is draining into the left atrium in addition to an absent coronary sinus and an atrial septal defect. This can be considered a dangerous heart condition because it puts the individual at a high risk of stroke. Other defects that are often associated with Raghib syndrome can include ventricular septal defects, enlargement of the tricuspid annulus, and pulmonary stenosis. While this is considered an extremely rare developmental complex, cases regarding a persistent left superior vena cava (PLSVC) are relatively common among congenital heart defects. It is also important to note that the PLSVC often drains into the right atrium, and only drains into the left atrium in approximately 10 to 20% of individuals with the defect.

References