Introduction

Heart enlargement, or cardiomegaly, is not a disease in itself but a clinical sign reflecting underlying structural heart disease. It is strongly associated with increased morbidity and mortality due to its progression toward overt heart failure and arrhythmogenic complications. Global prevalence of heart failure is estimated at more than 64 million individuals, with dilated cardiomyopathy and ischemic cardiomyopathy being among the most common causes of pathological cardiac enlargement.¹ Device-based interventions have historically transformed the management of heart failure and arrhythmias; CRT, ICDs, and LVADs have prolonged survival in patients who otherwise would face end-stage disease.²

Nevertheless, despite these advances, many patients remain symptomatic, with high rates of hospitalisation and limited functional recovery. Therefore, recent years have seen accelerated development of advanced device technologies specifically targeting mechanical and electrical dysfunction associated with cardiac enlargement. These devices range from next-generation CRT systems to miniaturised and durable LVADs, fully implantable monitoring technologies, and AI-driven platforms integrating wearable and implantable sensors.

Pathophysiology of heart enlargement

Cardiac enlargement arises from adaptive and maladaptive processes that alter ventricular geometry and myocardial function. Pressure overload, such as in systemic hypertension or aortic stenosis, leads to concentric hypertrophy, while volume overload, as in valvular regurgitation, promotes eccentric hypertrophy and dilation.³ In dilated cardiomyopathy, the left ventricle enlarges progressively, reducing systolic performance, impairing contractility, and inducing secondary mitral regurgitation due to annular dilation. Chronic ischemia or infarction leads to ventricular remodelling characterised by scar tissue, chamber enlargement, and functional mitral regurgitation.⁴

These structural alterations disturb the normal conduction pathways, producing dyssynchrony, arrhythmias, and reduced cardiac output. Maladaptive remodelling also predisposes patients to progressive heart failure with neurohormonal activation, fluid retention, and further dilation.⁵

Thus, device therapies are directed toward three central goals: restoring electrical synchrony to improve contractility (CRT),  preventing lethal arrhythmias (ICDs), and supporting or replacing failing ventricles (LVADs and artificial hearts). Emerging devices also focus on early detection and modulation of hemodynamic stress to prevent irreversible remodelling.

Traditional device-based therapies

Implantable cardioverter-defibrillators (ICDs)

ICDs are established in preventing sudden cardiac death (SCD) in patients with left ventricular systolic dysfunction (ejection fraction ≤35%) and cardiomegaly secondary to ischemic or non-ischemic cardiomyopathy. Randomised controlled trials, such as MADIT-II and SCD-HeFT, have confirmed their mortality benefit.^6,7 However, ICDs do not improve symptoms of heart failure or reverse remodelling, highlighting their limitations.

Cardiac resynchronisation therapy (CRT)

CRT improves systolic performance by synchronising ventricular contraction through biventricular pacing. The COMPANION and CARE-HF trials demonstrated reductions in hospitalisation and mortality in heart failure patients with QRS prolongation and left ventricular enlargement.^8,9 CRT also promotes reverse remodelling, reducing chamber dimensions and improving ejection fraction. However, up to one-third of patients are “non-responders,” necessitating refinements in device design and patient selection.¹⁰

Left ventricular assist devices (LVADs)

LVADs provide mechanical circulatory support in patients with advanced heart failure unresponsive to medical therapy. Devices such as the HeartMate II and HeartWare HVAD have extended survival and served as bridge-to-transplant or destination therapy.¹¹ Yet, complications including thrombosis, bleeding, and infection remain significant challenges.

While these conventional devices represent milestones, newer generations are being developed to address their limitations.

Latest advancements in cardiac devices

Leadless and multipoint cardiac resynchronisation therapy

Conventional CRT requires transvenous leads placed in coronary sinus tributaries, which can be technically challenging and associated with lead dislodgement, venous obstruction, or infection. Leadless CRT systems, such as the WiSE-CRT system, deliver wireless endocardial pacing via ultrasound energy, eliminating leads and improving procedural safety.¹² Trials such as WiSE-CRT have demonstrated feasibility in non-responders to conventional CRT.¹³

Additionally, multipoint pacing (MPP) allows simultaneous stimulation of multiple sites in the left ventricle, further improving synchronisation and contractility. The MORE-CRT MPP trial showed greater reverse remodelling and improved exercise capacity in selected patients.¹⁴

Next-generation LVADs

Recent innovations in LVAD design emphasise miniaturisation, improved hemocompatibility, and fully implantable systems. The HeartMate 3, incorporating a centrifugal-flow pump with magnetic levitation, significantly reduces pump thrombosis and stroke risk compared with older LVADs.¹⁵ Long-term data from the MOMENTUM 3 trial demonstrated improved survival and reduced device replacement.¹⁶

Additionally, Research is exploring fully implantable LVADs with wireless energy transfer, eliminating driveline infections, a major cause of morbidity.¹⁷ These advancements position LVADs as safer, more durable, and potentially earlier interventions in patients with refractory cardiomegaly.

Bioresorbable scaffolds and novel structural devices

Cardiac enlargement often coexists with valvular dysfunction, particularly functional mitral regurgitation. Transcatheter mitral valve repair devices, such as MitraClip, have demonstrated clinical benefit in patients with secondary mitral regurgitation due to dilated cardiomyopathy.¹⁸ More recently, bioresorbable annuloplasty rings and scaffolds are under development to remodel the mitral annulus while preserving long-term flexibility.¹⁹

Implantable hemodynamic monitoring systems

Recurrent hospitalisations in heart failure are strongly linked to elevated filling pressures. The CardioMEMS HF System, a wireless pulmonary artery pressure sensor, enables continuous monitoring and early intervention. The CHAMPION trial showed a significant reduction in heart failure hospitalisations using this device.²⁰

Emerging devices with right atrial or left atrial pressure sensors are in development, aiming to detect hemodynamic deterioration even earlier and reduce progression of enlargement through proactive management.²¹

Wearable and AI-integrated cardiac devices

Digital health integration is rapidly expanding in cardiology. AI-enhanced wearables and implantables provide real-time arrhythmia detection, heart failure decompensation prediction, and remote monitoring of device performance. Machine learning algorithms applied to ECG, echocardiography, and device telemetry can refine patient selection for CRT and optimise programming.²²

Closed-loop pacing systems that adapt therapy dynamically based on intracardiac signals represent another innovation. Furthermore, integration of wearable sensors with implantable devices allows longitudinal monitoring of physical activity, respiratory rate, and fluid balance, providing a holistic view of patient status.²³

Clinical outcomes and quality of life

Advancements in device therapy are not only extending survival but also significantly improving functional capacity and quality of life. Patients with advanced LVADs report increased exercise tolerance and reduced heart failure symptoms.²⁴ Leadless CRT systems expand access to non-responders and those with venous complications. Hemodynamic monitoring devices reduce hospitalisations and empower patient engagement in self-care.

While costs remain high, studies suggest that reduced hospitalisation rates and improved productivity may offset long-term expenses.²⁵ Furthermore, personalised medicine supported by AI-driven devices is expected to optimise therapy allocation, minimising non-responder rates and improving resource utilisation.

Challenges and future directions

Despite these advancements, several challenges remain. Device-related infections, thromboembolic events, and bleeding complications persist as major risks. Long-term durability of newer devices, particularly wireless energy transfer LVADs and bioresorbable scaffolds, requires validation in large-scale trials.

Equitable access is another pressing issue; many advanced devices are limited to high-income healthcare systems. The integration of AI and digital platforms raises questions about data security, patient privacy, and regulatory oversight.

Future directions should include fully implantable energy systems for LVADs, biologically integrated pacing systems using stem-cell engineered tissue, and hybrid bioelectronic devices that combine mechanical support with regenerative therapies. Moreover, Gene-guided device therapy, where genetic profiles help select and tailor device interventions, may also become feasible.

Summary

Cardiac enlargement, commonly described as cardiomegaly, is a clinical manifestation of several underlying pathologies, including dilated cardiomyopathy, valvular heart disease, hypertension, and chronic ischemic heart disease. This condition predisposes patients to heart failure, arrhythmias, and sudden cardiac death. Conventional therapies, including pharmacological agents and device-based interventions such as implantable cardioverter-defibrillators (ICDs) and cardiac resynchronisation therapy (CRT), have significantly improved outcomes. However, persistent morbidity and mortality rates highlight the need for novel technologies. 

Recent advancements in cardiac devices, including leadless CRT systems, advanced left ventricular assist devices (LVADs), bioresorbable scaffolds, implantable hemodynamic monitors, 

and artificial intelligence (AI)-enabled cardiac technologies, represent a new frontier in addressing the structural and functional deterioration associated with heart enlargement. 

Conclusion

The treatment of cardiac enlargement and its associated conditions has undergone remarkable evolution with the advent of novel device technologies. From leadless CRT and multipoint pacing to advanced LVADs, implantable hemodynamic monitors, and AI-enabled digital integration, these innovations address unmet needs in managing structural and electrical dysfunction in cardiomegaly. While challenges remain regarding complications, cost, and accessibility, the trajectory of innovation suggests a future where personalised, durable, and minimally invasive devices will redefine outcomes for patients with heart enlargement. Continued collaboration between biomedical engineers, cardiologists, and data scientists will be essential to fully realise this potential.