Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada.
Stephenson Cardiac Imaging Centre, Libin Cardiovascular Institute, University of Calgary, Calgary, Alberta, Canada; Department of Diagnostic Imaging, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada.
Can J Cardiol. 2022 Nov;38(11):1676-1683. doi: 10.1016/j.cjca.2022.07.017. Epub 2022 Aug 6.
Acute myocarditis is a rare complication of mRNA-based COVID-19 vaccination. Little is known about the natural history of this complication.
Baseline and convalescent (≥ 90 days) cardiac magnetic resonance (CMR) imaging assessments were performed in 20 consecutive patients meeting Updated Lake Louise Criteria for acute myocarditis within 10 days of mRNA-based vaccination. CMR-based changes in left ventricular volumes, mass, ejection fraction (LVEF), markers of tissue inflammation (native T1 and T2 mapping), and fibrosis (late gadolinium enhancement [LGE] and extracellular volume [ECV]) were assessed between baseline and convalescence. Cardiac symptoms and clinical outcomes were captured.
Median age was 23.1 years (range 18-39 years), and 17 (85%) were male. Convalescent evaluations were performed at a median (IQR) 3.7 (3.3-6.2) months. The LVEF showed a mean 3% absolute improvement, accompanied by a 7% reduction in LV end-diastolic volume and 5% reduction in LV mass (all P < 0.015). Global LGE burden was reduced by 66% (P < 0.001). Absolute reductions in global T2, native T1, and ECV of 2.1 ms, 58 ms, and 2.9%, repectively, were documented (all P ≤ 0.001). Of 5 patients demonstrating LVEF ≤ 50% at baseline, all recovered to above this threshold in convalescence. A total of 18 (90%) patients showed persistence of abnormal LGE although mean fibrosis burden was < 5% of LV mass in 85% of cases. No patient experienced major clinical outcomes.
COVID-19 mRNA vaccine-associated myocarditis showed rapid improvements in CMR-based markers of edema, contractile function, and global LGE burden beyond 3 months of recovery in this young patient cohort. However, regional fibrosis following edema resolution was commonly observed, justifying need for ongoing surveillance.
急性心肌炎是 mRNA 新冠疫苗接种的罕见并发症。对于这种并发症的自然病程，人们知之甚少。
对 20 名连续的符合急性心肌炎更新的莱克路易斯标准的患者在 mRNA 疫苗接种后 10 天内进行基线和恢复期（≥90 天）心脏磁共振（CMR）成像评估。在基线和恢复期之间评估左心室容积、质量、射血分数（LVEF）、组织炎症标志物（原生 T1 和 T2 映射）和纤维化（晚期钆增强[LGE]和细胞外容积[ECV]）的 CMR 变化。记录心脏症状和临床结局。
中位年龄为 23.1 岁（范围 18-39 岁），17 名（85%）为男性。中位（IQR）恢复期评估时间为 3.7（3.3-6.2）个月。LVEF 平均绝对提高 3%，同时 LV 末期容积减少 7%，LV 质量减少 5%（均 P<0.015）。整体 LGE 负担减少 66%（P<0.001）。整体 T2、原生 T1 和 ECV 的绝对值分别减少 2.1 ms、58 ms 和 2.9%（均 P≤0.001）。5 名患者基线 LVEF≤50%，所有患者在恢复期均恢复至该阈值以上。尽管 85%的病例中纤维化负荷＜LV 质量的 5%，但 18 名（90%）患者仍存在异常 LGE。无患者发生主要临床结局。
在年轻患者队列中，COVID-19 mRNA 疫苗相关心肌炎在恢复期 3 个月后，CMR 标志物的水肿、收缩功能和整体 LGE 负担迅速改善。然而，水肿消退后常观察到区域性纤维化，因此需要持续监测。
