Aims: The total atrial conduction time (TACT) is an important electrophysiological parameter. We developed a new transthoracic echocardiographic tool (PA-TDI). The PA-TDI interval is a reflection of the TACT. In the present study, we evaluated the clinical and echocardiographic correlates of intra-atrial conduction delay.
Methods and results: We studied 427 patients without class I anti-arrhythmic agents or amiodarone. All patients underwent an echocardiogram and the PA-TDI interval was measured. Patient characteristics were recorded. The mean PA-TDI was 157 ± 22 ms. Multivariate linear regression analysis revealed that atrial fibrillation (AF) in history (B = 9.7; 95%CI 5.7-13.8; P < 0.001), hypertension (B = 5.5; 95%CI 1.4-9.8; P = 0.01), clinically relevant valve disease (B = 5.7; 95%CI 0.5-10.8; P = 0.03), age (B = 5; 95%CI 3.3-6.6; P < 0.001), and body mass index (BMI; B = 2.6; 95%CI 0.3-4.9; P = 0.026) were independently associated with the PA-TDI interval. On the echocardiogram: the aortic diameter (B = 0.7; 95%CI 0.2-1.2; P = 0.009), left atrial dimension (B = 0.9; 95%CI 0.5-1.3; P < 0.001), mitral valve E-wave deceleration time (B = 0.1; 95%CI 0.1-0.1; P < 0.001), aortic incompetence (B = 13; 95%CI 3.3-22.6; P = 0.008), and mitral incompetence (B = 11; 95%CI 3.6-17.5; P < 0.003) were independently associated with the PA-TDI interval.
Conclusion: This study is the largest to investigate the relation between the atrial conduction time, underlying heart diseases, and echocardiographic parameters. We found that the PA-TDI was independently prolonged in patients with a history of AF, hypertension, valve disease, higher age, and a higher BMI. Signs of diastolic dysfunction, valve incompetence, and enlarged atrium or aortic root on the echocardiogram were associated with a prolonged PA-TDI. This suggests that early and aggressive treatment of hypertension, diastolic dysfunction, and obesity could prevent intra-atrial conduction delay.