Fifty-five (44%) of the 125 patients who received ICDs or CRT-Ds for primary prevention of sudden death and never received appropriate antitachycardia therapy had partially improved (36%–49%) or normalized (≥50%) LVEF at the time of generator replacement.
During an overall follow-up of 25 ± 18 months after replacement, none of the 30 patients with normalized LVEF experienced a major ventricular tachyarrhythmic event, whereas 20% of the patients with partially improved LVEF required appropriate antitachycardia therapy.
Although generator replacement is necessary in patients with partially improved LVEF, these data suggest that patients whose LVEF normalizes over time may be at a lower risk for appropriate antitachycardia therapy.