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............................................................................................................................................................................. increased risk of pneumothorax.658 Prospective data on axillary vein puncture suggest a lower risk of access-related complications compared with subclavian puncture.659 Ultrasound guidance for axillary vein puncture has been described as a helpful technique for achieving a safe and uncomplicated puncture.660

With regards to lead failure after implantation, there is evidence that the axillary vein route is associated with a lower rate of lead failures in long-term follow-up. In a retrospective study comprising 409 patients and mean follow-up of 73.6 ± 33.1 months, lead failure occurred in 1.2% of patients with contrast-guided axillary vein puncture, 2.3% of patients with cephalic vein cutdown, and 5.6% of patients with subclavian vein puncture. In multivariable regression analysis, the only predictor of lead failure was subclavian vein puncture instead of axillary vein access (HR 0.26, 95% CI 0.0710.954; P = 0.042). When analysing the success rates of the different venous access approaches, the cephalic vein approach showed the lowest success rate (78.2% vs. axillary vein 97.6% and subclavian vein 96.8%; P < 0.001).661

9.6 Lead considerations

In choosing between active or passive fixation pacemaker leads in the RA or RV, one should consider the potential for perforation and pericarditis, as well as extractability. Active fixation leads have a higher tendency to create pericardial effusions as well as overt perforations. Passive fixation leads, due to the non-isodiametric design of the lead tip, may be a factor in lower procedural success rates and higher risk for complications with lead extraction, although this point is far from being clear and is still under evaluation.662 An RCT is required to clarify this issue. Regarding perforations, an uncontrolled, non-randomized study comprising 3815 patients with implant of an RV lead showed no significant difference with regards to myocardial perforations between active and passive fixation leads (0.5% vs. 0.3%; P = 0.3).663 Active fixation leads also allow selective site pacing in regions of the RV that are smooth walled (e.g. the mid-septum). The RA is, however, thin walled, and perforation of the RA free wall by active fixation leads has been demonstrated. Some implanting physicians prefer to implant passive leads in patients at elevated risk of perforation (e.g. elderly patients). However, based on expert opinion and on the results of a single-centre, retrospective study on ICD leads (637 patients), in young patients, the use of active fixation leads in the RA and RV is recommended in terms of future extractability.664 Lead stability and phrenic nerve stimulation are important aspects of coronary sinus lead implantation. With regards to both, quadripolar leads seem to have relevant advantages. The rate of phrenic nerve stimulation requiring lead revision is significantly lower compared with that in bipolar coronary sinus leads.665,666 Furthermore, lead stability is increased because quadripolar leads can usually be implanted in the wedged position. If implanted in an apical position due to wedging, the use of the proximal poles avoids apical stimulation. Therefore, quadripolar leads are recommended for coronary sinus lead implantation. Active fixation LV leads via a side helix have been developed, and results have proved reliable stability, easy access to the target pacing site, and stable LV pacing threshold in the long term. In comparison with passive fixation quadripolar leads, active fixation bipolar and quadripolar leads achieved similar results. The lead design with an active fixation mechanism via a side helix was developed to allow for full extractability in the long term. However, the ease of extractability at long term has not yet been proven.667669

9.7 Lead position

Ventricular pacing has traditionally been performed from the RV apex. Since the introduction of active fixation leads, alternative pacing sites such as the RVOT septum or the mid-septum have been evaluated in order to provide more physiological pacing. However, despite two decades of research, the clinical benefit of RV non-apical pacing remains uncertain.670 This may be partly explained by variability in the position of the lead, which is often unintentionally placed on the anterior free wall, where it may be associated with adverse outcome.671673 The main advantage of septal pacing probably lies in the avoidance of perforation of the free wall. In a study of 2200 patients implanted with a pacemaker or ICD lead, an apical position was independently associated with cardiac perforation (OR 3.37; P = 0.024).420 A septal position may therefore be preferable in patients at increased risk of perforation, such as elderly patients especially with a body mass index <20 kg/m2, as well as women.670,674 Placing the lead on the mid-septum may be challenging (even more so in the RVOT septum, which is a smaller target area). The use of multiple fluoroscopic views and specially shaped stylets is useful for this purpose and is outlined in a recent EHRA consensus paper.34 In this context, it is important to mention that the accuracy and reproducibility of fluoroscopic assessment of RV lead positions is often inaccurate.421 Multiple fluoroscopic views are also recommended for placing RVA leads, to ensure there is no inadvertent placement of the lead in a coronary sinus tributary or in the LV via an intracardiac shunt or arterial access. The coronary sinus may be used for LV pacing without the need to cross the tricuspid valve. It may also be used in the case of other difficulties in deploying an RV lead (e.g. in the case of a tricuspid valve prosthesis). In selected patients, the outcome is similar to RV pacing.675,676 The RA appendage is usually the preferred site for atrial pacing. The lateral atrium may carry a risk of phrenic nerve capture.677,678 Alternative pacing sites to avoid AF such as Bachman’s bundle and the region of the coronary sinus ostium have not shown benefit and are not to be recommended in routine practice.679,680

9.8 Device pocket

In recent years, there has been increasing awareness of the device pocket as a source of complications. Avoidance of pocket infections has become a special focus in device therapy. The role of pocket haematomas in the development of infections has been discussed earlier. It is evident that besides adequate management of anticoagulation, a proper surgical technique with meticulous haemostasis is of utmost importance. Most pacemakers are implanted with the creation of a subcutaneous pocket.681 In patients with a low body mass index and therefore little subcutaneous tissue, in the case of Twiddler’s syndrome, or for aesthetic reasons, creation of a submuscular pocket may be preferable. However, this may require deeper sedation for implantation and generator replacements due to pain. To date, there are no data from RCTs comparing the two approaches for creating device pockets. Downloaded from academic.oup.com/eurheartj/article/42/35/3427/6358547 by guest on 07 October 2026