Abstract: Objective：To evaluate the relationship between left atrial size and the risk of cardiac events in patients with non-obstruction hypertrophic cardiomyopathy.  Methods:In the study, 39 patients who met inclusion criteria were followed up for (28.0±7.7) months. The patients were divided into two groups with or without major adverse cardiac events (a composite of arrhythmia, angina, syncope and congestive heart failure). Clinical and echocardiographic data of the two groups were compared. The predictive value of left atrial diameter (LAD) and left atrial volume index (LAVI) were reviewed by using receive operating characteristic curve (ROC). The events analysis was performed by using the Kaplan-Meier analysis. Results:Cardiac events occurred in 11 patients (28.2%). LAD, LAD index (LADI), LAV and LAVI were significantly greater in the patients with cardiac events than those without cardiac events ［LAD: (4.28±0.63) cm vs. (3.85±0.48) cm, P=0.025; LADI: (0.048 9±0.011 1) cm/m²  vs. (0.040 8±0.005 8) cm/m², P=0.005; LAV: (60.8±16.2) mL vs. (46.2±14.0) mL, P=0.008; LAVI: (66.5±23.8) mL/m² vs. (49.6±15.9) mL/m², P=0.014］. An LAD of >4.29 cm identified patients with cardiac events with a sensitivity of 63.6% and a specificity of 89.3%. An LAVI of >53.1 mL/m² identified patients with cardiac events with a sensitivity of 72.7% and a specificity of 71.4%. The Kaplan-Meier analysis indicated that the patients with LAD>4.29 cm or LAVI>53.1 mL/m² had higher incidence of cardiac events. Conclusion:LAD and LAVI may be effective markers for predicting adverse cardiac events in patients with non-obstruction hypertrophic cardiomyopathy.

Key words: Cardiac volume, Cardiomyopathy, hypertrophic, Cardiovascular diseases, Sensitivity and specificity, Survival analysis