His bundle pacing and right ventricular pacing in clinical practice
His bundle pacing (HBP) and conventional right ventricular pacing (RVP) address the same clinical need—reliable ventricular activation when the native conduction system cannot maintain an adequate rate—but they do so through different electrical pathways. RVP stimulates the ventricular myocardium directly, usually from the right ventricular apex or septum. HBP captures the His bundle and can preserve the downstream His–Purkinje sequence.
The choice becomes especially important in patients who will require frequent or continuous ventricular pacing. Chronic right ventricular stimulation may create electrical and mechanical dyssynchrony, particularly when pacing from the apical region. HBP seeks to reduce this effect, although its technical demands, variable thresholds, and lead stability have limited universal adoption.
Comparative evidence has expanded through prospective studies, registries, meta-analyses, and society guidance. Still, the clinical question is not simply whether conduction-system pacing is more physiological. Patient selection, baseline QRS duration, atrioventricular block location, left ventricular function, operator expertise, and the probability of pacing dependence all influence the balance between benefits and practical limitations.
Electrical foundations and pacing strategy
RVP activates the myocardium from the pacing electrode outward. Even with septal lead placement, ventricular depolarization may differ substantially from intrinsic conduction. A wide paced QRS, interventricular delay, and altered ventricular contraction can emerge over time. The consequences are most concerning when the pacing burden is high and the patient has pre-existing left ventricular dysfunction.
HBP directly recruits the His bundle when the lead achieves selective or nonselective capture. Selective capture produces a relatively narrow QRS resembling intrinsic activation, while nonselective capture includes adjacent septal myocardium but may still preserve rapid conduction through the His–Purkinje network. This distinction matters because paced QRS duration alone does not fully describe ventricular synchrony.
An HBP lead may be positioned distal to a proximal conduction defect, allowing correction of some forms of bundle branch or atrioventricular conduction disease. However, correction is not guaranteed. Infra-Hisian disease, extensive distal conduction-system fibrosis, and diseased bundle branches can produce a persistently wide QRS even when the His bundle is captured.
Effects on ventricular function
The strongest rationale for replacing conventional pacing with HBP is the potential to prevent pacing-induced cardiomyopathy. Repeated RVP can reduce left ventricular ejection fraction, increase ventricular volumes, and promote heart failure symptoms in susceptible patients. The risk rises with a greater cumulative pacing percentage, although no single threshold identifies every vulnerable patient.
Observational comparisons generally associate HBP with narrower paced QRS complexes, preserved ejection fraction, and fewer heart failure admissions than RVP. Some studies also report lower mortality or a reduced need for cardiac resynchronization therapy. These findings are clinically persuasive, but they are influenced by selection bias: patients receiving HBP may be treated at experienced centers and monitored more intensively.
Randomized evidence remains smaller and less definitive than the observational literature. Trials such as His-SYNC have shown the feasibility of physiological pacing but have also highlighted crossover, implantation difficulty, and challenges in maintaining consistent capture. The most reliable interpretation is that HBP is promising for preventing adverse remodeling, while the magnitude of its benefit over modern septal RVP in lower-risk patients remains uncertain.
Rhythm outcomes and procedural performance
A narrower QRS and more physiological ventricular contraction could reduce atrial functional deterioration and ventricular filling abnormalities. Several cohorts have linked HBP with a lower incidence of heart failure hospitalization and, in some populations, less atrial fibrillation. These signals are biologically plausible, yet rhythm outcomes are affected by age, atrial disease, structural heart disease, anticoagulation, and the indication for pacing itself.
HBP implantation is technically more demanding than standard RVP. Mapping the His potential, confirming capture, testing thresholds, and securing a stable lead require specialized equipment and experience. Procedure duration and fluoroscopy exposure can be greater during the learning phase. Anatomical variation, prosthetic valves, prior surgery, and severe conduction disease may further complicate lead placement.
Lead performance is a central consideration. HBP can have higher acute and chronic capture thresholds than RVP, and thresholds may rise during follow-up. Battery longevity may therefore be shorter, particularly in pacemaker-dependent patients. Lead revision or the addition of a backup ventricular lead can offset some of the safety advantages of a single stable lead, although programming strategies and newer lead designs continue to improve performance.
The Journal of Arrhythmia’s published research provides a useful route into the evolving evidence on conduction-system pacing, device therapy, and electrophysiology. Reviewing study design alongside outcomes helps distinguish physiological rationale from clinically demonstrated benefit.
| Clinical consideration | His bundle pacing | Right ventricular pacing |
|---|---|---|
| Ventricular activation | Uses the native His–Purkinje system when capture is successful | Direct myocardial activation from the RV lead |
| Paced QRS | Often narrow, though distal disease may limit correction | Frequently wider than intrinsic QRS |
| Left ventricular remodeling | Generally associated with better preservation in high-burden pacing cohorts | Greater concern for pacing-induced dysfunction |
| Implantation | Technically complex and dependent on operator experience | Familiar, efficient, and broadly available |
| Capture threshold | May be higher or increase over time | Usually lower and more stable |
| Lead revision risk | Can be higher, especially with threshold rise or loss of capture | Generally low with standard lead positioning |
| Evidence base | Growing, with many observational studies and limited randomized data | Extensive long-term experience and established outcomes |
| Best-supported role | Patients likely to require substantial pacing, particularly with ventricular dysfunction risk | Patients with low pacing burden or when conduction-system capture is impractical |
Patient selection and clinical outcomes
Patients with a high anticipated ventricular pacing burden deserve the most careful comparison. This includes advanced atrioventricular block, complete heart block, slow atrial fibrillation with regular pacing needs, and selected patients undergoing atrioventricular node ablation. In these settings, HBP may reduce the risk of dyssynchrony-related deterioration when reliable His capture can be achieved.
Preserved left ventricular function does not eliminate the issue. A patient with normal ejection fraction may tolerate RVP for years, but a high pacing burden can gradually expose latent vulnerability. Conversely, someone with established cardiomyopathy may require a broader resynchronization strategy. HBP can be appropriate in selected cases, yet cardiac resynchronization with biventricular pacing or left bundle branch area pacing may provide a more dependable option when His capture is inadequate.
Baseline conduction disease should guide expectations. HBP is more likely to produce a narrow QRS when the block is proximal and the distal conduction system remains intact. A long HV interval, extensive His–Purkinje disease, or bundle branch block may require higher outputs or fail to achieve complete correction. Testing for output-dependent changes in QRS morphology can help identify selective capture and reveal whether conduction disease is being bypassed.
Clinical outcomes should be assessed beyond ejection fraction. Hospitalization for heart failure, changes in functional status, arrhythmia burden, generator longevity, lead revisions, infection, and mortality all matter. A modest improvement in ventricular synchrony may be outweighed by repeated procedures if the lead is unreliable, while a technically successful HBP implant may offer meaningful protection in a pacing-dependent patient.
Evidence interpretation and guideline context
Comparative studies frequently favor HBP for heart failure hospitalization and preservation of systolic function, but many are retrospective and single-center. Differences in programming, follow-up duration, pacing burden, and definitions of HBP capture make direct comparison difficult. Confounding by indication is especially important because clinicians may choose HBP for patients perceived to be at greater risk of pacing-related harm.
Guideline and consensus documents generally frame conduction-system pacing as an important option rather than a universal replacement for RVP. Recommendations commonly emphasize substantial anticipated pacing, prevention of pacing-induced cardiomyopathy, and consideration of physiological pacing in patients with reduced ejection fraction. They also stress operator training, backup planning, follow-up of capture thresholds, and the availability of alternative resynchronization approaches.
The author guidelines are relevant for investigators reporting comparative pacing studies, since transparent definitions of lead position, capture type, pacing burden, QRS measurements, and adverse events are essential. Without consistent endpoints, meta-analysis can exaggerate apparent agreement between studies that use materially different methods.
Future trials should compare HBP with contemporary alternatives rather than with outdated apical pacing alone. Left bundle branch area pacing, optimized biventricular pacing, and modern septal RVP each occupy different clinical niches. Randomized studies with long follow-up are needed to clarify mortality, heart failure events, atrial fibrillation, lead durability, cost, and quality of life.
Practical recommendations for device teams
A structured pre-implant assessment can make the comparison more clinically useful than a default choice based on habit. The team should estimate pacing burden, document baseline QRS and ventricular function, identify the level of conduction disease, and discuss the possibility of a backup lead or later system revision.
- Favor HBP or another conduction-system strategy when substantial ventricular pacing is expected and preservation of ventricular synchrony is a priority.
- Consider conventional RVP when pacing burden is low, ventricular function is robust, and procedural simplicity or lead reliability is the dominant concern.
- Use detailed intraoperative testing to document capture threshold, QRS response, sensing, impedance, and the presence or absence of bundle branch correction.
- Monitor HBP thresholds and ventricular function over time, with a clear plan for rising thresholds, loss of capture, or battery depletion.
- Select biventricular pacing or left bundle branch area pacing when HBP cannot reliably correct conduction disease or when established resynchronization indications are present.
These recommendations should be adapted to local expertise and patient preferences. A technically excellent RVP implant may be safer than an uncertain HBP implant in a setting without adequate experience or follow-up infrastructure. Conversely, avoiding physiological pacing in a pacing-dependent patient with reduced ventricular reserve may expose the patient to preventable remodeling.
Integrating the evidence into practice
HBP has a compelling physiological basis and an increasingly supportive clinical evidence base. Its clearest potential advantage over RVP lies in patients exposed to a high ventricular pacing burden, particularly those with reduced or borderline left ventricular function. The trade-off is greater implantation complexity and a less predictable long-term lead profile.
RVP remains a dependable and well-understood therapy. It is not uniformly harmful, especially when pacing is infrequent or ventricular function is stable. The most appropriate choice therefore depends on the interaction between expected pacing exposure, substrate, procedural expertise, and the consequences of lead failure.
Clinicians and researchers can follow emerging evidence through the journal’s themed collections, where reviews, original investigations, and practice-focused material place individual studies in a broader electrophysiology context. Applying that evidence at the bedside means matching the pacing method to the patient’s projected risk rather than treating any single technology as universally superior.
For every new pacemaker consultation, document the anticipated pacing burden and ventricular function, discuss the relative durability and physiological effects of HBP and RVP, and establish a follow-up plan that can detect pacing-related dysfunction early. That disciplined process turns comparative evidence into safer, more individualized device care.