Preventing right ventricular pacing-induced cardiomyopathy

Long-term right ventricular pacing can convert a conduction problem into a myocardial problem. When a ventricular lead repeatedly captures the right ventricle, activation may spread in a left bundle branch block pattern, impairing synchrony between the right and left ventricles. The resulting rise in wall stress can reduce left ventricular ejection fraction, alter regional strain, and eventually produce pacing-induced cardiomyopathy.

Risk is not determined by ventricular pacing alone. A high cumulative pacing burden, pre-existing ventricular dysfunction, atrial fibrillation, and impaired intrinsic atrioventricular conduction increase concern, while modern conduction system pacing can substantially change the expected mechanical and electrical consequences. Reports vary because patient groups and pacing sites differ, and the condition is not always clinically obvious.

Australian patients may enter this pathway through a public hospital cardiology service, a private electrophysiology practice, or a general practitioner referral using the familiar phrase “pacemaker check.” Medicare and the Medical Benefits Schedule support consultations and procedures, while private treatment may involve insurer and out-of-pocket costs. Complex lead placement is concentrated in major centres in Sydney, Melbourne, Brisbane, Perth, and Adelaide.

Geography shapes prevention as much as device technology. Patients around Alice Springs, regional New South Wales, or far north Queensland may rely on local echocardiography and device follow-up linked by telehealth to a tertiary electrophysiology service. The practical goal is to anticipate ventricular pacing, preserve native conduction where safe, and detect deterioration before heart failure becomes entrenched.

How ventricular pacing can impair ventricular function

The classic concern is right ventricular apical pacing. The impulse travels from the lower right ventricular septum through myocardium rather than rapidly through the specialised conduction system. Left ventricular contraction may begin late, septal motion may become paradoxical, and energy is spent stretching and contracting poorly coordinated muscle rather than propelling blood efficiently.

Chronic stimulation can then drive adverse remodelling: reduced ejection fraction, increased chamber size, elevated filling pressures, and fibrosis. The right ventricular myocardium may also become impaired, but pacing-induced cardiomyopathy usually refers to clinically important left ventricular dysfunction caused by the pacing strategy. Recovery can occur after pacing burden falls, especially before irreversible fibrosis develops.

No single percentage defines safety. Contemporary guidance therefore considers the anticipated burden, native conduction, baseline function, and clinical context together. High-burden pacing remains more concerning than occasional backup capture, and a short QRS from a septal or conduction system lead does not remove the need for follow-up.

Recognising deterioration before advanced heart failure

Breathlessness on stairs, reduced exercise tolerance, fatigue, orthopnoea, or ankle swelling can signal pacing-induced cardiomyopathy, but these symptoms overlap with ordinary ageing, obesity, pulmonary disease, and medication effects. A routine review may reveal a falling left ventricular ejection fraction before the patient volunteers a significant change. Comparing serial echocardiograms is often more informative than relying on symptoms alone.

Examination should combine device interrogation with clinical assessment and echocardiography. Useful measures include left ventricular ejection fraction, global longitudinal strain, right ventricular fractional area change, tricuspid annular plane systolic excursion, and septal motion. In patients with atrial fibrillation, percentage of ventricular pacing and the pattern of rapid pacing deserve particular attention because intrinsic atrioventricular conduction cannot rescue the ventricles.

Comorbid kidney disease adds both volume and rhythm complexity, especially for people on dialysis. Baseline ventricular arrhythmia risk should not be obscured by the pacing indication; the Journal of Arrhythmia review of renal-disease ECG risk markers provides a useful framework for interpreting that risk. Referral for pacing should include renal function, volume status, and goals of care rather than treating the device request in isolation.

Selecting a pacing site that preserves synchrony

His bundle pacing seeks to activate the native conduction system and is attractive when intrinsic conduction is expected to be limited but the His bundle itself remains functional. A narrow or relatively narrow paced QRS and more physiological activation may reduce dyssynchrony. Capture thresholds can be unstable in advanced His bundle disease, however, so technically successful implantation does not guarantee durable conduction system capture.

Left bundle branch area pacing provides another route, activating the left septal side of the heart before the remainder of the myocardium. It can offer lower pacing thresholds and broader applicability than His bundle pacing, but coronary venous anatomy, septal injury, phrenic nerve stimulation, and lead stability must be considered. Evidence is strongest for preserving ventricular function in patients likely to need substantial pacing.

Right ventricular septal pacing, multisite pacing, and biventricular pacing remain relevant alternatives. Biventricular systems may suit selected patients with impaired left ventricular function and a high anticipated pacing burden, while multisite approaches add procedural complexity. No site is best for every patient; the choice should integrate expected burden, conduction disease, cardiac function, anatomy, and the operator’s experience.

Planning rhythm control before device implantation

The best time to prevent pacing-induced cardiomyopathy may be before a lead is implanted. For sinus rhythm with intermittent atrioventricular block, clinicians can estimate the likelihood of sustained ventricular pacing, review reversible causes, and consider a device strategy that searches for intrinsic conduction. This planning should include the consequences of failure to capture and a safe backup plan.

Atrial fibrillation complicates that calculation because there is no organised atrial activity for a device to track. Control of a rapid ventricular response may reduce pacing burden, while a rhythm-control assessment may prevent long-term dependence on ventricular support. In selected persistent atrial fibrillation, specialist evaluation of hybrid convergent ablation may be relevant when symptom burden and anatomy justify a combined approach; it is not a substitute for pacing when bradycardia is irreversible.

Patient preference and procedural fitness matter alongside electrophysiology. Shared decision-making should address likely years of pacing, generator changes, lead complications, the possibility of future upgrade, and the value of preserving conduction. A pacing plan that looks efficient in the procedure room but ignores expected ventricular burden is incomplete.

Using algorithms to reduce unnecessary pacing

Several device algorithms search for intrinsic atrioventricular conduction before delivering ventricular pacing. Search modes can support patients with intermittent block, while managed ventricular pacing uses atrial tracking to preserve synchrony and promote conducted beats in sinus rhythm. These programs are useful when they match the rhythm, but they cannot create conduction that the His bundle or atrioventricular node no longer provides.

Algorithm choice is only part of the solution. In atrial fibrillation, atrial-based benefits are limited, and a high-rate response can still produce substantial ventricular pacing. Rate smoothing, programmed rate limits, and appropriate sensor settings may reduce extreme rates but should not be mistaken for proven protection from cardiomyopathy. Programming should be reviewed after every major rhythm change.

For patients likely to require a high pacing burden, conduction system pacing may reduce the need for algorithms designed to avoid ventricular capture. For patients with only occasional backup pacing, a simpler system with reliable backup may be appropriate. The device must fit the clinical trajectory rather than receive a generic “pacing-sparing” label.

Monitoring function, pacing burden, and early warning signs

Document the pacing burden at every check, not merely the current rate. Clinicians should record the percentage of atrial and ventricular pacing, mode changes, managed ventricular pacing episodes, atrial arrhythmia burden, and episodes of rapid pacing. A sharp rise in ventricular pacing after a period of intrinsic conduction may trigger an early review of programming, rhythm control, or lead function.

Echocardiography at baseline and approximately three to six months after implantation can identify early functional change, followed by intervals tailored to risk. New breathlessness or swelling warrants prompt clinical review rather than waiting for the next routine appointment. General practitioners, cardiac nurses, and remote device clinics all play a role in making this surveillance reliable across Australia.

Interpret the ECG in context. After prolonged pacing or tachycardia, repolarisation changes can persist briefly and mimic ischaemia; the phenomenon of pacing-related cardiac memory is a reminder to compare previous tracings rather than launch an unnecessary acute coronary pathway. Persistent QRS widening, new conduction block, or a rising pacing burden still demands investigation.

Device alerts and remote transmissions can flag battery or lead problems, but they do not measure ejection fraction. Conversely, stable device parameters do not exclude cardiomyopathy. Symptom review, ECG interpretation, and serial echocardiography remain complementary.

Implementing prevention in Australian cardiology practice

Australian care divides between public hospital networks and private electrophysiology services. Public patients receive device implantation through hospital pathways, although waiting lists can affect timing; private care may shorten scheduling time but can carry substantial gaps. Medicare, the Medical Benefits Schedule, private insurance, and hospital agreements interact differently across states, so cost discussions should happen before implantation rather than after a lead is committed.

Access is uneven outside metropolitan centres. Patients in Townsville, Cairns, Darwin, Alice Springs, or regional South Australia may need local imaging and follow-up coordinated with a tertiary pacing team. Device interrogation can often be performed close to home, with telehealth used for complex programming. Regional cardiac services should establish clear pathways for urgent in-person review when telemetry alone cannot resolve a problem.

Care for Aboriginal and Torres Strait Islander patients requires additional attention to access, communication, trust, and continuity. Aboriginal Medical Services and local clinicians can be valuable partners, with consent, interpreter support, and culturally safe review built into the pathway. Equity gaps are not solved by sending a device box and leaving follow-up to the patient.

Clinicians should make ventricular burden, preservation of intrinsic conduction, lead position, and serial echocardiography explicit in every pacing plan. Patients in Australia who develop new breathlessness, fatigue, or swelling while receiving ventricular pacing should promptly request a pacemaker check and clinical review instead of treating these changes as inevitable. Prevention begins before implantation and continues through structured follow-up.