There is limited evidence on characterization and natural history of supraventricular tachycardia (SVT)-induced left ventricular (LV) dysfunction. The aim of this work was to characterize clinical features and long-term evolution of SVT-induced LV dysfunction. Patients consecutively admitted with sustained SVT and heart rate >100 bpm as the only known cause of a new onset LV systolic dysfunction (i.e., LV ejection fraction [EF] <50%) were analyzed. Patients were then revaluated periodically. Recovered LVEF (i.e., ≥50%) and a composite of death, heart transplant or first episode of major ventricular arrhythmias were evaluated as study end-points. We enrolled 83 patients. After SVT therapy, 56 (67%) showed a recovered LVEF at the last follow-up of median 54 (interquartile range 36 to 87) months. Seventeen (30%) of those patients had a temporary new drop in LVEF during follow-up associated to high-rate SVT relapse. At presentation, patients with recovered LVEF were younger (52 vs 67 years respectively, p <0.001) and had higher LVEF (34% vs 27% respectively, p = 0.005) compared to non-recovered LVEF patients. Finally, 4% of recovered LVEF patients vs 26% of nonrecovered LVEF patients experienced death/heart transplant/major ventricular arrhythmias during follow-up (p = 0.004). In conclusion, after almost 5 years of follow-up, two-thirds of patients with high-rate SVT causing a newly diagnosed LV systolic dysfunction recovered and maintained normal LV function after SVT control, with a subsequent benign outcome. Long term individual surveillance is required in those patients, as arrhythmic recurrences and new drops in LVEF are common in the long term.
