Abstract 2577: Tissue Doppler Imaging to Identify Patients with a Substrate Vulnerable for Atrial Fibrillation
Introduction: Previous studies have demonstrated that several cardiovascular conditions are associated with Atrial Fibrillation (AF) by providing a substrate necessary to sustain AF. This substrate is characterised by atrial dilatation and conduction slowing, leading to an increase in total atrial conduction time (TACT), which has shown to be the most powerful predictor of AF. Recently, we validated a novel transthoracic echocardiographic technique to determine TACT, by means of tissue Doppler imaging (PA-tdi). This study was designed to see whether PA-tdi could discriminate patients with or without a history of AF.
Methods: PA-tdi (defined as the interval between the onset of electrocardiographic P-wave to the A-wave of the lateral left atrial tissue Doppler signal) and standard echocardiographic parameters were measured in 427 randomly selected patients in sinus rhythm without anti-arrhythmic drugs. Patient characteristics were derived from (electronic) charts and ECG database.
Results: A total of 188 (44%) patients had a history of AF. The mean PA-tdi in these patients was significantly prolonged (164 ± 22ms vs. 152 ± 21ms, p<0.001) and in comparison to patients without AF in the past they were significantly older, more often male, more often had hyperthyroidism, atrial dilatation or a diminished A-wave velocity. Multivariate analysis revealed that PA-tdi (OR:1.024; 95%CI:1.005–1.043), age (OR:1.059; 95%CI:1.027–1.093), right atrial volume (OR:1.033; 95%CI:1.007–1.060) and mitral valve A-wave velocity (OR:0.977; 95%CI:0.959 – 0.996) were independent discriminators of AF history. Furthermore, PA-tdi was significantly prolonged in all of the known conditions associated with AF (hypertension, coronary artery disease, valvular heart disease and heart failure), except for hyperthyroidism.
Conclusion: PA-tdi is significantly prolonged in patients with a history of AF and strongly associated with heart diseases forming an atrial substrate for AF. Hyperthyroidism was not associated with a prolonged TACT, possibly because AF in this condition is not caused by structural atrial remodelling. Therefore PA-tdi plays an important role in identifying patients with a substrate vulnerable for AF.