Objective：To explore the clinical application effects of del Nido and histidine-tryptophan-ketoglutarate（HTK） cardioplegia in patients with left ventricular hypertrophy（LVH）undergoing open-heart surgery. Methods：A total of 75 LVH patients who underwent cardiopulmonary bypass（CPB）surgery in our hospital from January 2021 to December 2022 were retrospectively collected and were divided into del Nido group（group D，39 cases）and HTK group（group H，36 cases）according to the type of cardioplegia used during open-heart surgery. General information，interoperative anesthesia and cardiopulmonary bypass data， postoperative clinical information，and changes in perioperative myocardial markers were compared between the two groups. Results： After releasing aortic cross-clamp（ACC），the incidence of ventricular fibrillation（VF）was lower in the group D than in the group H （P< 0.01）. Among patients with VF，the duration of VF，defibrillation times，and defibrillation energy were lower in the group D than in the group H（P< 0.05）. The group D had a longer time for spontaneous heart rhythm recovery than the group H（P< 0.05），and the temporary pacemaker usage rate was higher in the group D than in the group H（P< 0.05）.The group D had a higher vasoactive-inotropic score（VIS）score 15 minutes after the end of CPB than the group H（P< 0.001），while there was no significant difference in VIS scores between the two groups 15 minutes before the end of the operation and 6 hours after the operation（P > 0.05）. In terms of myocardial markers，only at 24 hours after surgery，the levels of creatine kinase isoenzymes-MB（CK-MB）and cardiac troponin T（cTnT） were higher in the group H than in the group D（P< 0.05）；there was no significant difference in myocardial markers between the two groups at 48 hours after surgery（P > 0.05）. Conclusion：Both del Nido and HTK cardioplegia can be safely used for myocardial protection in patients with LVH during surgery. However，the use of HTK cardioplegia is associated with a higher incidence of VF after ACC removal and higher levels of CK-MB and cTnT at 24 hours after surgery compared to del Nido cardioplegia. On the other hand，the use of del Nido cardioplegia is associated with a longer time to recovery of spontaneous heart rhythm，a higher temporary pacemaker usage rates，and a higher doses of vasoactive drugs at 15 minutes after ACC removal compared with HTK cardioplegia.