His bundle pacing versus right ventricular pacing in heart failure

Pacing strategy can influence ventricular synchrony, symptoms and long-term cardiac function in people with heart failure who require permanent bradycardia support. Right ventricular pacing remains familiar and widely available, while His bundle pacing aims to preserve the heart’s native electrical activation by stimulating the His–Purkinje conduction system.

The choice is rarely determined by ejection fraction alone. The expected pacing burden, underlying conduction disease, QRS morphology, venous access, lead stability, operator experience and the feasibility of future device follow-up all matter. For Australian clinicians, these considerations also sit within a health system that spans high-volume electrophysiology services in Sydney, Melbourne and Brisbane and long travel distances for patients in regional and remote communities.

Why right ventricular pacing can worsen ventricular function

Traditional right ventricular apical pacing activates the ventricles in a pattern that differs from normal conduction. The electrical wavefront travels from the pacing site through the myocardium rather than rapidly through the His–Purkinje network. This can produce a wider paced QRS complex and mechanical dyssynchrony, particularly when the cumulative ventricular pacing percentage is high.

Some patients tolerate this pattern for years, especially when ventricular function is preserved and pacing is intermittent. Others develop a fall in left ventricular ejection fraction, worsening mitral regurgitation, atrial fibrillation or clinical heart failure. This syndrome is commonly described as pacing-induced cardiomyopathy. A review of practical recognition and treatment pathways is available in pacing-induced dysfunction.

The risk is influenced by more than the pacing site. Baseline ventricular function, pre-existing cardiomyopathy, native QRS duration, the proportion of paced beats and the duration of exposure all affect susceptibility. Device interrogation should therefore be combined with echocardiographic surveillance and assessment of symptoms, rather than relying on a single threshold for every patient.

How His bundle pacing preserves conduction

His bundle pacing places the lead at, or close to, the His bundle so that activation can use the patient’s own conduction pathways. When capture is successful, the paced QRS may be narrower and ventricular contraction can be more coordinated than with conventional right ventricular stimulation. This physiological approach is attractive for patients expected to require frequent or lifelong pacing.

The technique can correct some forms of infra-Hisian conduction disease, but it is not universally successful. Selective capture activates the His bundle alone, whereas non-selective capture also recruits nearby myocardium. In either case, the surface ECG, pacing threshold and response to programming help establish whether the desired conduction pattern has been achieved.

His bundle pacing may be considered in patients with atrioventricular block and a substantial anticipated pacing burden, particularly when left ventricular function is reduced or vulnerable. It can also be used as an upgrade strategy when a patient has developed pacing-related ventricular dysfunction. However, the decision should be individualised, with cardiac resynchronisation therapy or left bundle branch area pacing considered when His capture is unlikely to deliver adequate resynchronisation.

Comparing clinical benefits and limitations

Observational studies and smaller comparative trials suggest that His bundle pacing can reduce paced QRS duration and may better preserve left ventricular systolic function than conventional right ventricular pacing. Potential benefits include fewer signs of dyssynchrony, a lower risk of pacing-induced cardiomyopathy and improved ventricular performance in selected patients.

The evidence base still has important limitations. Many studies are non-randomised, follow-up periods vary and the populations receiving His bundle pacing often differ from those treated with right ventricular leads. Hard outcomes such as mortality, heart failure admission and sustained quality-of-life improvement require stronger prospective evidence. A physiologically appealing ECG does not automatically translate into a superior outcome for every person with heart failure.

Lead performance is another practical issue. His bundle leads may have higher implantation or follow-up thresholds, sensing challenges and a greater need for programming expertise. Threshold rise can shorten generator longevity and occasionally requires lead revision or an additional backup lead. Right ventricular pacing is generally simpler, more predictable and supported by extensive experience across public and private hospitals.

Selecting patients with heart failure

A useful assessment begins with the indication for pacing and the likely percentage of ventricular pacing. A person with intermittent atrioventricular block, preserved ejection fraction and a low expected pacing burden may gain little from a technically complex strategy. Conversely, a patient with reduced ejection fraction, complete heart block and near-continuous pacing has a stronger reason to avoid unnecessary electrical dyssynchrony.

Baseline ECG and imaging are central. Clinicians should document QRS width and morphology, left ventricular ejection fraction, right ventricular function, valve disease and the presence of atrial fibrillation. If the patient has heart failure with reduced ejection fraction and a broad left bundle branch block pattern, biventricular CRT may remain the established option, especially when guideline criteria are met. His bundle pacing may be considered as an alternative or rescue approach in selected cases.

Shared decision-making should address procedural complexity, expected device longevity, future upgrades and access to specialist follow-up. For an older patient living several hours from an Australian tertiary centre, repeated threshold checks or lead revision can carry substantial travel and caregiving costs. Telehealth can support some reviews, but it cannot replace in-person device interrogation and imaging when lead performance or ventricular function is uncertain.

Australian practice considerations

Australia has major electrophysiology capability in metropolitan centres, including Sydney, Melbourne, Brisbane, Adelaide and Perth, but access is less uniform outside capital cities. Public hospital waiting lists, private insurance arrangements and the availability of operators experienced in conduction system pacing can affect the timing and choice of implantation. A clinically suitable plan must therefore be achievable within the patient’s local referral pathway.

Device components and pacing systems must be included on the Australian Register of Therapeutic Goods, overseen by the Therapeutic Goods Administration. Regulatory listing does not remove the need for local assessment of operator training, lead availability, stock arrangements and technical support. Funding and hospital procurement processes also differ between jurisdictions and between public and private services, so the most advanced pacing approach may not be equally accessible in every setting.

Routine follow-up should account for Australian travel patterns and geography. A patient from regional New South Wales may attend a metropolitan centre for implantation but need local cardiology support for wound review, ECGs and symptom assessment. People living in tropical Queensland may also face seasonal travel disruption, while remote patients can have limited access to echocardiography. Clear escalation plans, shared records and coordination between tertiary electrophysiology teams and local services are especially important.

Heart failure care is also shaped by medication access, comorbidity and the need to coordinate cardiology, general practice and allied health. Medicare-supported consultations and hospital pathways can reduce some barriers, while private care may offer faster access but involve out-of-pocket costs. These realities should be discussed alongside technical pacing advantages rather than treated as administrative details.

Monitoring outcomes and evolving alternatives

After implantation, surveillance should combine symptoms, device data, ECG findings and periodic echocardiography. A rising His bundle capture threshold, loss of conduction capture, increasing paced QRS width or a decline in ejection fraction may signal the need for reprogramming, lead assessment or an upgrade. For right ventricular pacing, a high pacing burden and progressive ventricular dysfunction should prompt review of whether conduction system pacing or CRT could improve synchrony.

Left bundle branch area pacing is increasingly relevant because it may provide more stable thresholds and a wider target than His bundle pacing while retaining a relatively physiological activation pattern. It is not a universal substitute: septal anatomy, lead depth, perforation risk, coronary anatomy and the distinction between conduction capture and myocardial capture require careful assessment. Long-term comparative data are still developing.

The broader electrophysiology literature demonstrates why procedural technique should be evaluated through durability and patient outcomes, not implantation success alone. Work on cryoballoon durability findings illustrates the value of studying what happens after the initial procedure. Similar principles apply to pacing: stable thresholds, preserved ventricular function, fewer admissions and meaningful quality of life are more important than a technically impressive acute result.

For clinicians and trainees seeking current research, guidelines and educational material, the Journal of Arrhythmia articles provide access to peer-reviewed work across cardiac pacing, ablation, implantable devices and electrophysiology. Ongoing randomised studies and registry data should help clarify which heart failure phenotypes benefit most from His bundle pacing, left bundle branch area pacing or CRT.

Choosing between His bundle pacing and right ventricular pacing requires a patient-specific balance of electrical physiology, evidence quality, procedural reliability and follow-up feasibility. In people with a high pacing burden and vulnerable left ventricular function, avoiding chronic dyssynchrony deserves serious consideration. In lower-risk patients, the reliability and simplicity of right ventricular pacing may remain appropriate.

Australian heart failure and electrophysiology teams can strengthen care by documenting pacing burden, reviewing ventricular function over time and building referral pathways between metropolitan implanting centres and regional services. Researchers should continue reporting long-term lead performance, hospitalisation, ventricular recovery and patient-reported outcomes so that future decisions are guided by clinically meaningful evidence.