Abstract
Cardiac devices have transformed the management of heart failure, ventricular arrhythmias, ischemic cardiomyopathy, and valvular heart disease. Technologies such as cardiac resynchronization therapy (CRT), conduction system pacing, left ventricular assist devices (LVADs), and implantable cardioverter-defibrillators have contributed to abated global cardiovascular risk through action onto pathophysiological processes such as mechanical unloading, electrical resynchronization, or hemodynamic optimization, respectively. While their clinical benefits are well established, their long-term molecular and structural effects on the myocardium remain under investigation. Cardiac devices dynamically interact with myocardial and vascular biology, inducing molecular and extracellular matrix adaptations that vary by pathology. CRT enhances calcium cycling and reduces fibrosis, but chronic pacing may lead to pacing-induced cardiomyopathy. LVADs and Impella relieve ventricular workload yet alter sarcomeric integrity and mitochondrial function. Transcatheter valve therapies influence ventricular remodeling, conduction, and coronary flow. Understanding these remodeling processes is crucial for optimizing patient selection, device programming, and therapeutic strategies. This narrative review integrates the current knowledge on the molecular and structural effects of cardiac devices, highlighting their impact across different disease settings.