Impella in killip class IV acute myocardial infarction complicated by pulseless ventricular arrhythmia.

Mortality in acute myocardial infarction (AMI) complicated by cardiogenic shock remains high, particularly when accompanied by pulseless ventricular tachycardia (VT) or ventricular fibrillation (VF). The Impella device, a percutaneous mechanical circulatory support system that unloads the left ventricle, is increasingly used in AMI with shock. However, its impact on outcomes in patients with cardiogenic shock complicated by pulseless VT/VF remains unclear. We retrospectively analyzed Killip class IV AMI patients who developed pulseless VT/VF, using data from the Tokyo CCU Network registry (January 2019–December 2022). The primary endpoint was 30-day mortality. Outcomes in patients treated with Impella were compared with those without Impella using propensity score matching. Multivariate analysis was performed to identify independent predictors of mortality. Among 18,310 AMI patients, 1,986 were classified as Killip IV, of whom 715 developed pulseless VT/VF. Crude 30-day mortality did not differ significantly between the Impella and non-Impella groups (33.6% vs. 38.8%, p = 0.28). After propensity score matching, mortality was significantly lower in the Impella group (33.9% vs. 48.8%, p = 0.019). Multivariate analysis confirmed Impella use as an independent predictor of reduced mortality (odds ratio 0.32, 95% CI 0.19–0.56, p < 0.0001). Deaths due to VT/VF were less frequent in the Impella group (0.82% vs. 6.4%, p = 0.0030). In Killip IV AMI patients complicated by pulseless VT/VF, Impella use was associated with significantly lower 30-day mortality. These findings support early consideration of Impella in this high-risk population.