Temporary transvenous pacing (TVP) is a lifesaving procedure which is mainly indicated in patients with symptomatic bradyarrhythmias as well as in patients with specific tachyarrhythmias (i.e., overdrive pacing) [1,2,3,4].
Temporary transvenous pacing consists in inserting a temporary pacing electrode catheter (EC) into the right ventricle and then applying an electric stimulus with the goal of restoring effective cardiac depolarization and heart contraction, resulting in the delivery of an adequate heart rate and cardiac output .
Several complications can result from this critical procedure such as failure to secure venous access, failure to place the lead correctly, sepsis, puncture of arteries, lungs or myocardium and life-threatening arrhythmias . Giving these facts, a safe method to monitor the EC insertion is desirable .
The placement of the EC can be achieved in several ways, including a blind technique as well as a couple of guided techniques, such as intracavitary electrocardiography (ECG) [6, 7], ultrasonographic-guided insertion (US) [8,9,10] and fluoroscopy [9, 10]. Since the blind technique is neither safe nor effective most of the times, and considering that fluoroscopy is not usually available at the bedside or patients are commonly unstable to be transferred to the radiology department, ECG and/or real-time ultrasonographic (US) guidance are generally chosen to assist in the procedure at the patient’s bedside. The combination of guided techniques for the placement of the EC is a valid and useful strategy, with the intention of making the procedure easy, safe, and effective. This is the case of the combination of US guidance with intracavitary ECG, which is easy to perform, may lead to a reduction in the time to active pacing and may avoid complications.
Regarding the selection of the route of insertion, this may be guided by several factors, such as the presence of hypovolemia, anticoagulation status, or adequate anatomy. As a general rule, the right-sided veins are preferred over the left because permanent systems are usually inserted on the left side and because it is often technically easier from the right side . In general, the right internal jugular vein provides the most direct route to the right ventricle and it is associated with lowest rate of loss of ventricular capture and thus is the recommended route for using in practice . Right subclavian/axillary route follows the right IJV and is preferred in patients with hypovolemia, given the ability of these vessels to remain patent even in patients with volume depletion. Femoral access can be performed with ease; however, it can be more difficult to advance the electrodes to the right ventricle, limits patient mobility, has a higher risk of venous thromboembolism, and offers the least stable wire position . Of note, securing a venous access is not a minor issue, with a high failure rate reported among studies (average 15%, range 6–40%) . Ultrasound-guided insertion of the introducer sheath, which is in fact a central venous canulation, has proven to improve canulation success and reduce complications related to the procedure . Thus, all introducer sheaths should be placed under ultrasound guidance, unless there is no time to prepare the ultrasound equipment, such as in extreme situations (e.g., cardiopulmonary resuscitation), or eventually when ultrasound cannot be used for technical reasons (e.g., subcutaneous emphysema).
The combined technique (ultrasound and intracavitary ECG) will be described after discussing some aspects of both techniques when used in isolation.