Admission clinical and electrocardiographic characteristics predicting in-hospital development of high-degree atrioventricular block in inferior wall acute myocardial infarction.

This study assessed the ability of simple clinical and electrocardiographic variables routinely obtained on admission to identify patients who are at high risk of developing high-degree atrioventricular (AV) block during hospitalization in 1,336 patients with inferior wall acute myocardial infarction (AMI). Patients were classified into 2 initial electrocardiographic patterns based on the J-point to R-wave amplitude ratio: pattern 1: those with J point/R wave <0.5 and pattern 2: patients with J point/R wave > or =0.5 in > or =2 leads of the inferior leads II, III, and aVF. High-degree AV block was found in 6.7% of patients (41 of 615) with pattern 1 versus 11.8% of the patients (85 of 721) with pattern 2 on admission electrocardiogram (p = 0.0008). Multivariate logistic regression analysis revealed that the only variables found to be independently associated with high-degree AV block were female gender (odds ratio [OR] 1.48; 95% confidence interval [CI] 0.98 to 2.23; p = 0.06); Killip class on admission > or =2 (OR 2.24; CI 1.43 to 3.51; p = 0.0004); initial electrocardiographic pattern 2 versus pattern 1 (OR 1.82; CI 1.22 to 2.21; p = 0.003); and absence of abnormal Q waves on admission (OR yes vs no 0.68; CI 0.44 to 1.05; p = 0.08). A simple electrocardiographic sign (J point/R wave > or =0.5 in > or =2 leads) is a reliable predictor of the development of advanced AV block among patients receiving thrombolytic therapy for inferior wall AMI.