Wang Hanjay, Pong Terrence, Obafemi Oluwatomisin O, Lucian Haley J, Aparicio-Valenzuela Joy, Tran Nicholas A, Mullis Danielle M, Elde Stefan, Tada Yuko, Baker Sam W, Wang Caroline Y, Cyr Kevin J, Paulsen Michael J, Zhu Yuanjia, Lee Anson M, Woo Y Joseph
Department of Cardiothoracic Surgery, Stanford University, Stanford, CA, United States.
Stanford Cardiovascular Institute, Stanford University, Stanford, CA, United States.
Front Cardiovasc Med. 2022 Mar 9;9:829546. doi: 10.3389/fcvm.2022.829546. eCollection 2022.
Newborn mammals, including piglets, exhibit natural heart regeneration after myocardial infarction (MI) on postnatal day 1 (P1), but this ability is lost by postnatal day 7 (P7). The electrophysiologic properties of this naturally regenerated myocardium have not been examined. We hypothesized that epicardial conduction is preserved after P1 MI in piglets. Yorkshire-Landrace piglets underwent left anterior descending coronary artery ligation at age P1 ( = 6) or P7 ( = 7), After 7 weeks, cardiac magnetic resonance imaging was performed with late gadolinium enhancement for analysis of fibrosis. Epicardial conduction mapping was performed using custom 3D-printed high-resolution mapping arrays. Age- and weight-matched healthy pigs served as controls ( = 6). At the study endpoint, left ventricular (LV) ejection fraction was similar for controls and P1 pigs (46.4 ± 3.0% vs. 40.3 ± 4.9%, = 0.132), but significantly depressed for P7 pigs (30.2 ± 6.6%, < 0.001 vs. control). The percentage of LV myocardial volume consisting of fibrotic scar was 1.0 ± 0.4% in controls, 9.9 ± 4.4% in P1 pigs ( = 0.002 vs. control), and 17.3 ± 4.6% in P7 pigs ( < 0.001 vs. control, = 0.007 vs. P1). Isochrone activation maps and apex activation time were similar between controls and P1 pigs (9.4 ± 1.6 vs. 7.8 ± 0.9 ms, = 0.649), but significantly prolonged in P7 pigs (21.3 ± 5.1 ms, < 0.001 vs. control, < 0.001 vs. P1). Conduction velocity was similar between controls and P1 pigs (1.0 ± 0.2 vs. 1.1 ± 0.4 mm/ms, = 0.852), but slower in P7 pigs (0.7 ± 0.2 mm/ms, = 0.129 vs. control, = 0.052 vs. P1). Overall, our data suggest that epicardial conduction dynamics are conserved in the setting of natural heart regeneration in piglets after P1 MI.
新生哺乳动物，包括仔猪，在出生后第1天（P1）发生心肌梗死后（MI）可表现出自然的心脏再生能力，但这种能力在出生后第7天（P7）会丧失。尚未对这种自然再生心肌的电生理特性进行研究。我们假设仔猪在P1期心肌梗死后心外膜传导得以保留。约克夏-长白仔猪在P1期（n = 6）或P7期（n = 7）接受左前降支冠状动脉结扎，7周后，进行心脏磁共振成像及钆延迟增强扫描以分析纤维化情况。使用定制的3D打印高分辨率标测阵列进行心外膜传导标测。年龄和体重匹配的健康猪作为对照（n = 6）。在研究终点，对照组和P1期仔猪的左心室（LV）射血分数相似（46.4±3.0%对40.3±4.9%，P = 0.132），但P7期仔猪的射血分数显著降低（30.2±6.6%，与对照组相比P<0.001）。对照组左心室心肌纤维化瘢痕体积占比为1.0±0.4%，P1期仔猪为9.9±4.4%（与对照组相比P = 0.002），P7期仔猪为17.3±4.6%（与对照组相比P<0.001，与P1期相比P = 0.007）。等时激活图和心尖激活时间在对照组和P1期仔猪之间相似（9.4±1.6对7.8±0.9毫秒，P = 0.649），但在P7期仔猪中显著延长（21.3±5.1毫秒，与对照组相比P<0.001，与P1期相比P<0.001）。传导速度在对照组和P1期仔猪之间相似（1.0±0.2对1.1±0.4毫米/毫秒，P = 0.852），但在P7期仔猪中较慢（0.7±0.2毫米/毫秒，与对照组相比P = 0.129，与P1期相比P = 0.052）。总体而言，我们的数据表明，仔猪在P1期心肌梗死后自然心脏再生过程中心外膜传导动力学得以保留。
