Abstract：Objective To compare the detection rate, sensitivity and specificity of two diagnostic criteria in the diagnosis of left anterior fascicular block(LAFB). The two diagnostic criteria were separately proposed in a book named “Clinical arrhythmology” and “2019 AHA/ACCF/HRS recommendations for the standardization and interpretation of the electrocardiogram”, namely diagnostic criterion 1 and 2, respectively. Methods A retrospective study was carried out on routine ECGs with QRS axis between －45° and －90° in our hospital. Those individuals with inferior and lateral wall myocardial infarction, ventricular preexcitation, complete right bundle branch block, and ventricular hypertrophy were excluded. Taking vectorcardiogram(VCG) diagnostic criterion as a standard, the detection rate, sensitivity and specificity of the two ECG diagnostic methods for LAFB were analyzed. Results A total of 3503 cases are involved from which VCG detects 1137 cases(32.46%), diagnostic criterion 1 detects 1376 cases(39.28%), and diagnostic criterion 2 detects 2431 cases(69.40%). The sensitivity and specificity of diagnostic criterion 1 are separately 59.37% and 70.37% while those of diagnostic criterion 2 are 87.25% and 39.18%, respectively. The specificity of diagnostic criterion 1 is significantly higher than that of diagnostic criterion 2(P＜0.05), however, the detection rate and sensitivity of the latter is significantly higher(P＜0.05). Conclusion The diagnostic criterion 2 is more suitable for pure LAFB screening because of its higher detection rate and sensitivity.
