Tachycardia-induced cardiomyopathy in de novo heart failure: prevalence, short-term outcomes, and the role of guideline-directed therapy in ejection fraction improvement.

Introduction: Heart failure (HF) secondary to tachycardia-induced cardiomyopathy (TIC) is often underdiagnosed due to inconsistent definitions and perceived reversibility. The treatment focuses on early arrhythmia control, but the impact of guideline-directed medical therapy (GDMT) on left ventricular ejection fraction (LVEF) improvement has not been fully explored.

Materials and methods: This multicentric prospective registry study included patients with newly onset HF and reduced ejection fraction (HFrEF). Data were collected on clinical characteristics, echocardiographic and laboratory parameters, pharmacological treatment, and follow-up events. The statistical analyses focused on TIC patients, analyzing the event rates and the influence of GDMT on LVEF improvement according to sinus rhythm (SR) restoration.

Results: Among 808 patients, 174 (21.5%) were diagnosed with TIC, with an age of 67.2 (SD: 9.4) years. After a median follow-up of 3.5 months [IQR: 2.6-4.3], SR was restored in 56.8% of patients, and LVEF improved from 29.6 to 49%. The increase was more pronounced in patients who restored SR compared to those remaining in atrial fibrillation (AF) (22.4% vs. 15.1%; p < 0.05). The natriuretic peptides significantly decreased in the SR group (- 1883.7 pg/mL) but did not in the AF group. The overall readmission rate was 25.1% and the overall mortality rate was 3.6%, with no significant differences between patients who achieved SR and those with persistent AF at the end of up-titration. HF readmission was infrequent (4%) despite AF persistence. Early GDMT was initiated in TIC patients, regardless of SR recovery and significantly improved LVEF, especially in AF patients [RR = 4.24 (95% CI: 1.44-12.45)] compared to SR patients [(RR = 1.41 95% CI: 1.02-1.92)].

Conclusions: TIC represents a significant proportion of HFrEF patients, with early restoration of SR leading to greater LVEF improvement. Despite AF persistence, HF readmissions were rare, highlighting the efficacy of early quadruple therapy. Enhanced adherence to GDMT should be prioritized, particularly in patients with persistent AF.