The implantable cardioverter-defibrillator (ICD) has been a key strategy for preventing sudden cardiac death (SCD) from ventricular tachyarrhythmias (VTAs). Current guidelines recommend prophylactic ICDs (also known as primary prevention ICDs) for heart failure with reduced ejection fraction (HFrEF) patients, even without a history of VTA. However, these recommendations largely stem from clinical trials over two decades old. Significant advancements in heart failure medical therapies mean contemporary HFrEF patients now exhibit a demonstrably lower arrhythmic risk. This development challenges the broad applicability of existing guidelines underscoring a pressing need for more precise primary prevention ICD patient selection.
In a recent Heart Rhythm publication, researchers, including the CVC’s Drs. Justin Ezekowitz and Roopinder Sandhu, examined evidence contributing to the ongoing clinical uncertainty regarding routine primary prevention ICD implantation in HFrEF, emphasizing the rationale for new clinical trials aimed at reassessing the device’s contemporary role in this patient population.
Advances in both pharmacological and nonpharmacologic therapies have driven a notable decline in the annual incidence of life-threatening VTAs and, consequently, the need for appropriate ICD interventions, now averaging approximately 2%. Furthermore, the recent integration of angiotensin receptor-neprilysin inhibitors (ARNIs) and sodium-glucose cotransporter-2 inhibitors (SGLT2i) has demonstrated benefits in cardiovascular morbidity, mortality, and SCD for patients with HFrEF.
Against this backdrop of evolving and increasingly effective guideline-directed medical therapy, several ongoing trials are critically re-evaluating the utility of primary prevention ICDs. Notably, the CONTEMP-ICD trial will compare ICD therapy with non-ICD management in HFrEF patients identified as having a low arrhythmic risk. Should CONTEMP-ICD affirm its hypothesis—that non-ICD therapy is non-inferior for all-cause mortality while offering superior outcomes for major cardiovascular events, healthcare utilization, and quality of life— this would signify a substantial change in clinical practice. Such a finding could prompt a re-evaluation of current guidelines, potentially reducing the indication for prophylactic ICD placement by approximately half for HFrEF patients globally, thereby impacting the management of a vast and growing patient population. Learn more about the CONTEMP-ICD trial here.
