Diagnostic accuracy of apex-pulse deficit for detecting atrial fibrillation

Background: Screening for asymptomatic atrial fibrillation (AF) can identify patients at risk of stroke and help initiate treatment. Apex-pulse deficit, the difference between apex beat rate and peripheral pulse rate, has been described as a clinical sign to identify AF. However, the accuracy of this measure to identify AF has not been studied before. Aims: The primary aim of this study was to determine the sensitivity and specificity of apex-pulse deficit more than 10, measured over 1 min, to identify AF using 12-lead electrocardiogram (ECG) as the gold standard. Methods: This was a prospective cross-sectional study. Subjects were those above 30 years of age with known AF (cases) or not in AF (controls). Apex-pulse deficit was measured in each of them and correlated with rhythm detected in 12-lead ECG. Results: A total of 70 patients were studied, 35 cases and 35 controls. Apex-pulse deficit was significantly larger for cases as compared to controls and was a good discriminant to identify AF. Receiver operating characteristic curve analysis showed an area under the curve of 0.86. With a cutoff of 10, sensitivity and specificity to identify AF were 62.8% and 85.7%, respectively. Using a cutoff of 5 increased the sensitivity to 80%. Counting over 30 s was significantly less accurate than counting over one full minute. Conclusion: Apex-pulse deficit is a low-cost method to identify AF and may be useful for screening. A cutoff of 5 may enhance the sensitivity of measurement as compared to the traditional cutoff of 10.