(P115) SEVERITY OF LEFT VENTRICULAR DYSFUNCTION IN PATIENTS WITH TACHYCARDIA-INDUCED CARDIOMYOPATHY: IMPACTS ON REMODELING AFTER ATRIAL FLUTTER ABLATION

Background: Tachycardia-induced cardiomyopathy (TIC) is defined as a reversible systolic left ventricular (LV) dysfunction resulting from an elevated heart rate. It has been reported in patients with incessant or very frequent tachyarrhythmias, including atrial flutter. However, little is known about the evolution of LV remodeling in these patients, especially when severe LV dysfunction is present at diagnosis. Hence, the objectives of this study were to evaluate the proportion of severe LV dysfunction, and to describe the timing of LV recovery after atrial flutter ablation in patients with a presumed TIC.

METHODS AND RESULTS: In this retrospective observational study, we identified patients with a documented left ventricular ejection fraction (LVEF) ≤ 50% likely attributed to TIC among all patients who underwent atrial flutter ablation at our center between January 2012 and January 2021. These patients were further classified into 3 groups: severe dysfunction (SD) (LVEF ≤ 20%), moderate dysfunction (MoD) (21-40%) and mild dysfunction (MiD) (41-50%). Transthoracic echocardiography was performed at baseline, and at least once during follow-up. Fifty-nine patients were identified (mean baseline LVEF of 29±12%). Twenty patients had SD (34%), 28 patients had MoD (47%), and 11 patients had MiD (19%). Patients with SD had higher LV telediastolic diameter (LVTDD) and LV telediastolic volume (LVTDV). On last follow-up visit (180±130 days), LVEF was 48±10%, 55±7%, and 59±19% respectively among the 3 groups (P < 0,05 for SD vs MoD and SD vs MiD). There was no significant difference in LVTDD and LVTDV between groups. Overall, 41 patients (71%) fully recovered (LVEF≥50%) on last follow-up visit. In a subgroup of patients with SD, LVEF recovery > 35% was observed only after 3 months. Two patients with SD (10%) and 1 patient with MoD (4%) did not recover a LVEF > 35% on last follow-up visit. In patients with MoD to SD, 77% were on beta-blockers, 71% were on ACEi, ARB or ARNI, and 23% were on MRA.

Conclusion: Among our patients with TIC who underwent atrial flutter ablation, 1/3 of patients had severe LV dysfunction. These patients had longer time to LVEF recovery and LVEF recovered over 35% after 3 months in a subgroup of patients. Our study reinforces the importance of guideline-directed medical therapy in these patients in addition to arrhythmia control. Time to LVEF recovery could be more than 3 months and this could be important when an implantable cardioverter defibrillator or advanced heart failure therapy is considered.