Effect of implantable cardioverter defibrillator intracardiac electrogram morphology changes on hospitalization and life quality

Background: Implantable Cardioverter Defibrillators (ICD) are standard therapy for patients at risk of life-threatening ventricular tachyarrhythmias. ICDs use morphology discrimination to compare ventricular electrogram during tachycardia with reference template during baseline rhythm. Baseline morphology match score (MMS) changes may predict arrhythmic events, but usefulness as a parameter for heart failure (HF) is still unknown.
Methods: The prospective single-center study included consecutive 88 patients undergoing device control at cardiology department from July 2022 to May 2023. Inclusion criteria were patients implanted with ICD or CRT for at least 3 months; the exclusion criteria were defined as communication barriers (n=1), depleted device battery during checks (n=1), total AV block (n=3), and auto-template activation (n=4). The data were analysed for changes in the baseline (MMS) relationship with demographic, clinical characteristics, quality of life (QOL), and hospitalisation with HF.
Results: We analyzed 79 patients with a mean age 64,9 13,6 and an average MMS of 98 1,8 morphology. During follow-up there were 12 (15%) patients hospitalized due to HF. ROC curve analysis showed that a MMS ≤ 97% had 73% sensitivity and 59% specificity for hospitalization (p: 0,033 Area 0.695). No significant differences were observed in demographics between the two groups. Although there was no significant difference in EF and BNP levels, patients with MMS <97% had lower QOL scores and more hospitalizations for heart failure (HF). Conclusion: EGM baseline MMS changes in ICD were associated with hospitalization for HF and QOL, apart from arrhythmia detection indications. It may be a follow-up parameter for HF, in addition to the current device algorithms.