Differences in the prognostic value of the electrocardiographic pattern after cardiac resynchronization therapy according to age

In this cohort study, we analyzed if a specific pattern in three leads of the electrocardiogram (Rs in V1, Qr in aVL, or rS in I) was associated with outcomes after cardiac resynchronization therapy (CRT) depending on age.Patients with CRT devices were included from January 2012 to April 2019. We divided the sample into 2 groups, those with age ≥ 75 years old and those younger. The primary endpoint was a composite of all-cause death and heart failure (HF) hospitalization at 1 year.We included 111 patients. Patients older than 75 years (26.1%, n = 29) had a significantly higher rate of hypertension and atrial fibrillation and received less frequently optimal medical therapy. The patterns were observed in 32 (39.0%) younger patients and 11 (37.9%) older patients. Patients who presented any of them had a lower incidence of the primary endpoint in the younger group (0 vs. 14%, p = 0.029), but not in the older group (9.1 vs. 27.8%, p = 0.24). The presence of a basal QRS duration greater than 160 ms was associated with a higher rate of the primary endpoint in the elderly (50 vs. 13%, p = 0.015), but not in the younger group (16.7 vs. 7.1%, p = 0.254).The presence of the selected patterns after CRT is associated with a lower incidence of all-cause death and hospitalization for HF in patients younger than 75 years, but not in those older than 75 years. Conversely, baseline QRS duration was associated with worse outcomes in older patients, but not in the younger group.