Cardiac resynchronization therapy in very old patients with pacemakers: a cardiogeriatric, physiology-based approach.

Cardiac resynchronization therapy (CRT) is an established treatment for selected patients with heart failure (HF), yet its role in advanced age remains insufficiently defined. Adults aged ≥ 80 years are markedly underrepresented in randomised trials, frequently present with multimorbidity and frailty, and often develop HF related to pacing-related mechanisms, including pacing-induced cardiomyopathy (with LVEF decline) and pacing-related dyssynchrony that is not fully addressed by guideline-based algorithms. In this context, CRT implantation or upgrade represents a complex cardiogeriatric decision rather than a purely electrophysiological intervention. This narrative review examines the physiological rationale, available evidence, and clinical challenges of CRT in advanced-age populations, illustrated by a representative clinical vignette of pacemaker-induced HF. We discuss age-related myocardial vulnerability, secondary mitral regurgitation, competing mortality risks, and the predominance of functional and quality-of-life outcomes over survival endpoints. Particular emphasis is placed on integrating geriatric domains—frailty, functional status, cognition, and proportionality of care—into CRT decision-making. We explicitly distinguish pacing-induced cardiomyopathy (with reduced LVEF) from isolated pacing-related dyssynchrony; in patients with preserved LVEF, congestion is more often driven by a severe haemodynamic substrate—particularly valve dysfunction—than by dyssynchrony alone. In selected older adults, CRT may provide meaningful symptomatic and functional benefit when HF is driven by potentially reversible dyssynchrony, even if survival gains are limited. A cardiogeriatric, physiology-based approach may help identify patients most likely to benefit from CRT while avoiding disproportionate interventions in individuals with advanced frailty or limited physiological reserve.