(1) Background: Apolipoprotein E (ApoE) is a critical plasma apolipoprotein for lipid transport and nonlipid-related functions. Humans possess three isoforms of ApoE (2, 3, and 4). ApoE2, which exhibits beneficial effects on cardiac health, has not been adequately studied. (2) Methods: We investigated the cardiac phenotypes of the humanized ApoE knock-in (hApoE KI) rats and compared to wild-type (WT) and ApoE knock-out (ApoE KO) rats using echocardiography, ultrasound, blood pressure measurements, histology strategies, cell culture, Seahorse XF, cardiomyocyte contractility and intracellular Ca²⁺ tests, and Western blotting; (3) Results: hApoE2 rats exhibited enhanced heart contractile function without signs of detrimental remodeling. Isolated adult hApoE2 cardiomyocytes had faster and stronger sarcomere contractility because of more mitochondrial energy generation and stimulation-induced fast and elevated intracellular Ca²⁺ transient. The abundant energy is a result of elevated mitochondrial function via fatty acid β-oxidation. The fast and elevated Ca²⁺ transient is associated with decreased sarcoplasmic reticulum (SR) Ca²⁺ ATPase (SERCA2) and increased expression of cardiac ryanodine receptor 2 (RyR2) conducting a potent Ca²⁺ release from SR.; (4) Conclusions: Our studies validated the association of polymorphic ApoEs with cardiac health in the rat model, and revealed the possible mechanisms of the protective effect of ApoE2 against heart diseases.

Background: Electrical storm (ES) is a life‐threatening manifestation of ventricular tachycardia (VT) associated with highmorbidity and mortality. Catheter ablation is an established therapy for VT, but the impact of ES on ablation outcomes remains uncertain. Methods: We conducted a systematic review and meta‐analysis in accordance with PRISMA 2020 to compare VT ablation outcomes in patients with and without ES. PubMed, Cochrane Library, and ScienceDirect were searched from inception through January 2026. Eligible studies were comparative cohorts reporting periprocedural or long‐term outcomes. Random‐effects models were used to pool odds ratios (ORs), hazard ratios (HRs), and mean differences (MDs), with heterogeneity assessed using the I ² statistic. Results: Six observational cohort studies including 3531 patients (1183 with ES and 2348 without ES) were included. Acute procedural endpoints, including post‐ablation VT non‐inducibility and residual inducible VT, were similar between groups. Periprocedural or in‐hospital mortality was significantly higher in the ES group (OR 4.71, 95% CI 2.76–8.06), whereas complication rates, procedural duration, radiofrequency ablation time, and need for hemodynamic support did not differ significantly. During follow‐up, ES was associated with higher all‐cause mortality (OR 1.67, 95% CI 1.19–2.35) and greater VT recurrence in both arm‐based (OR 1.45, 95% CI 1.11–1.91) and time‐to‐event analyses (HR 1.35, 95% CI 1.16–1.57). Conclusions: VT ablation showed comparable acute procedural success and procedural safety in patients with and without ES. However, ES was associated with higher early and long‐term mortality and greater VT recurrence, supporting its role as a marker of adverse prognosis.