Atrial Involvement in Patients with Progressive Systemic Sclerosis: Relationship between Ultrasonic Tissue Characterization of the Atrium and Interatrial Conduction

OBJECTIVE: The aim of this study was to assess atrial lesions using ultrasonic tissue characterization and to determine the contribution of atrial lesions to the interatrial electromechanical coupling conduction time in patients with progressive systemic sclerosis (PSS). METHODS: Twenty patients with PSS and 20 age-matched healthy controls were evaluated. The cyclic variation in integrated backscatter value (CV-IB) was measured at the interatrial septum (IAS) from apical four chamber view. M-modes of ventricular long axis motion along with phono- and electrocardiograms were recorded simultaneously at the right lateral (RT) and left lateral (LT) sites of the atrioventricular (AV) rings and central fibrous body (CFB) in the apical four-chamber view. Intervals from the P wave on ECG to the echocardiographic onset of atrial contraction as a point of inflection in long axis M-mode echocardiogram were measured at the RT and LT sites of AV rings and CFB (P-RT, P-LT, P-SEP, respectively). Interatrial electromechanical coupling conduction time was determined as [(P-LT) - (P-RT)]. RESULTS: In patients with PSS compared to normal controls, P-RT, P-SEP, P-LT, and interatrial conduction time were greater, while CV-IB in IAS decreased. Furthermore, CV-IB in IAS correlated well with interatrial conduction time (r = 0.7, p < 0.01) in patients with PSS. CONCLUSIONS: Interatrial electromechanical coupling times may be prolonged due to atrial tissue damage in patients with PSS.