The incidence of permanent pacemaker implantation (PPM) after mitral valve surgery (MVS) is highly heterogeneous, ranging approximately from 1% to 10% of procedures. This variability is largely related to differences in baseline conduction system involvement, including sinus node disease, sinus bradycardia, atrioventricular block (AVB), and the presence of bundle branch blocks, among others.

Preoperative risk factors include those described in the Risk Score to Predict Permanent Pacing After Valve Surgery (bundle branch blocks, PR interval >200 ms, age ≥70 years, prior valve surgery, and inclusion of tricuspid valve procedures), as well as pre-existing conduction disturbances on ECG, atrial fibrillation (AF), left ventricular dysfunction, vascular and renal comorbidity, and, in some series, male sex. These features identify a more vulnerable conduction system. The close anatomical relationship between the conduction system and the mitral annulus, together with potential injury from deep sutures, extensive debridement, rigid annuloplasty rings, mitral annulus calcification (MAC), reoperations, combined procedures, and prolonged cardiopulmonary bypass times, further increases the risk of PPM implantation.

For the literature review, randomized controlled trials, observational cohort studies, case–control studies, and narrative or systematic reviews published between 2004 and 2024 were considered. Case reports, conference abstracts, editorials, congenital or pediatric populations, studies without sufficient PPM data, and articles not published in English were excluded. Two reviewers performed study selection according to the PRISMA framework, yielding a final total of 64 studies. As this was a scoping review, no meta-analysis was performed, and results were presented in tabular and narrative form.

Overall, mitral valve replacement (MVR) is associated with a PPM incidence approximately 2–3 times higher than mitral valve repair (MVr). In MVr, resective techniques and annuloplasty with a rigid ring were associated with higher PPM rates compared with non-resective techniques and band annuloplasty (5.8% vs 1.9%), likely due to greater annular deformation and undersizing. Part of this difference may be explained by a higher prevalence of concomitant tricuspid surgery in the resective group, acting as a confounding factor.

Regarding underlying pathology, early studies suggested that mitral infective endocarditis was associated with a higher risk of PPM implantation. However, more recent studies do not identify endocarditis as an independent risk factor, and in valvular endocarditis series, mitral involvement has even behaved as a negative predictor compared with aortic involvement, which is more prone to annular abscess formation.

The association between valve pathology (mitral stenosis vs mitral regurgitation) and PPM risk remains inconclusive. Concerning surgical access, one meta-analysis suggests a slightly higher prevalence of PPM implantation with a transseptal approach compared with left atriotomy, although this finding may be influenced by longer operative times and potential compromise of conduction system perfusion. Minimally invasive mitral surgery, including robotic approaches, is associated with lower PPM rates and clear clinical advantages, although centre experience and case volume are key determinants.

Concomitant tricuspid surgery is a particularly relevant factor. In the CTSN trial, the incidence of PPM implantation was 14.1% with tricuspid annuloplasty compared with 2.5% with conservative management of moderate tricuspid regurgitation. In contrast, other registries do not confirm this effect after adjustment for covariates. Volume-based studies indicate that PPM prevalence increases significantly in centres performing fewer than 10 tricuspid annuloplasties per year, underscoring the importance of surgical experience.

Surgical ablation of AF performed in conjunction with MVS, a class I A recommendation in ESC guidelines, does not appear to independently increase the need for PPM implantation when an appropriate lesion set is used.

From a pharmacological prevention standpoint, there is currently no robust pharmacological strategy proven to reduce PPM incidence after mitral surgery.

With respect to implantation timing, European guidelines recommend at least 5 days of observation for advanced or complete AVB and up to 6 weeks for sinus node disease. The review highlights wide inter-centre variability (2–12 days) and data suggesting that systematically prolonging observation beyond 5–7 days does not reduce long-term pacemaker dependency and may even increase it.

Long-term PPM dependency ranges between 20% and 60% across studies, with higher rates observed in patients implanted for AVB and in those operated on for endocarditis.

Early complications after PPM implantation, including pocket infection, lead dislodgement, pacing-induced tricuspid regurgitation, and pacing-related arrhythmias, occur in approximately 5% of cases. Long-term outcomes are more controversial: some studies report no increase in mortality, whereas others describe higher rates of heart failure hospitalization, prosthetic material endocarditis, and possible excess mortality in more complex subgroups. The extent to which this risk is attributable to the device itself versus underlying disease severity and comorbidity burden remains unclear.

COMMENTARY:

Traditionally, PPM implantation after valve surgery has been more extensively studied in aortic than in mitral pathology, likely leading to underestimation of this issue in MVS.

This review provides a broad, structured overview of the field, addressing prevalence, indications, risk factors, implantation timing, dependency, and outcomes. As a scoping review, it maps the existing evidence rather than establishing firm causality, but it offers a solid foundation for future targeted studies. Its aim is not to close ongoing debates, but to organize and contextualize the available data.

From a methodological standpoint, the review is appropriate for its purpose, with a comprehensive search strategy, reasonable inclusion criteria, and clear organization. However, it does not include a meta-analysis, detailed effect estimates, or a formal assessment of risk of bias. Consequently, the overall message is more qualitative than quantitative.

Clinically, the review captures the entire PPM trajectory: how often pacemakers are implanted, which patients are at higher risk (older age, pre-existing conduction abnormalities, impaired left ventricular function, comorbidity burden), how the underlying mitral pathology (functional vs degenerative mitral regurgitation, mitral stenosis, endocarditis, MAC) influences risk, and how surgical technique (MVR vs MVr, annuloplasty type, surgical access) and adjunctive procedures (tricuspid annuloplasty, AF ablation) may modify outcomes. It also addresses implantation timing, subsequent dependency, and long-term consequences. The manuscript is easy to read, and the figures and tables are particularly useful for everyday clinical practice.

One of the most valuable aspects of the review is its explicit identification of persistent knowledge gaps:

• A substantial proportion of evidence is still extrapolated from “valve surgery” in general rather than being mitral-specific.
• There is no true consensus on optimal implantation timing or on how to rigorously define pacemaker dependency, highlighting the need for clear criteria to distinguish transient from persistent conduction disturbances and for structured follow-up programs assessing dependency, atrial and ventricular remodeling, and heart failure events, areas that are often underappreciated.
• The true impact of specific technical details, tricuspid annuloplasty, and AF ablation in the specific context of MVS remains insufficiently defined.
• Optimal device selection (conventional pacemaker, CRT, leadless systems) is poorly studied in this setting, and pragmatic, individualized protocols based on conduction disorder evolution are needed.
• Preventive strategies are scarce, with few studies specifically designed to reduce PPM implantation, and current practice largely relies on empiricism rather than solid evidence.

The main limitations of the review stem from the heterogeneity of study designs and patient populations, which limits generalizability and precludes strong recommendations. Nonetheless, the work makes a meaningful contribution by systematizing the available evidence on PPM implantation after mitral surgery and by emphasizing the lack of effective preventive strategies and the need to explore more physiological pacing modalities in this population. We agree with the authors that a multidisciplinary approach integrating cardiac surgeons, cardiologists, and electrophysiologists is essential to optimize patient selection, implantation timing, and pacing strategy, with the ultimate goal of improving long-term outcomes after mitral valve surgery.

REFERENCE:

Finke J, Pasierski M, Dąbrowski EJ, Kurasz A, Brączkowski J, Drzażdżynska A, et al.; Thoracic Research Centre; Endorsed by ESC Working Group on Cardiovascular Surgery. Permanent pacemaker implantation following mitral valve surgery. State-of-the-art scoping review. Eur J Cardiothorac Surg. 2025 Jul 1;67(7):ezaf210. doi: 10.1093/ejcts/ezaf210.