Measurement of interatrial dyssynchrony using tissue Doppler imaging predicts functional capacity and cardiac involvement in systemic sclerosis

Objective. We aimed to assess the prevalence of interatrial electromechanical dyssynchrony in systemic sclerosis (SSc) patients, and to study the correlation between interatrial delay and standard follow-up parameters. Methods. Forty consecutive patients with SSc were studied. Classical echocardiographic measurements were obtained, including indices of left ventricular (LV) systolic and diastolic function, right ventricular function, and pulmonary artery pressure (PAP). Left atrial (LA) function was studied using volume measurements. The interatrial mechanical (IAMD) delay was obtained by measuring the time delay between the peak atrial velocities at the lateral tricuspid and mitral annuli using tissue Doppler imaging. A cut-off value of 35 ms was chosen to define the presence of a significant interatrial delay. The IAMD was compared to NYHA class, six-minute walking test (6MWT), NT proBNP levels, and the carbon monoxide diffusion capacity over alveolar volume ratio (DLCO/VA), as well as to classical echocardiographic parameters. Results. Forty percent of patients were found to have significant interatrial dyssynchrony with an IAMD of 35 ms or more. Patients with interatrial dyssynchrony were more symptomatic, had a shorter 6MWT, higher NT proBNP levels, and a lower DLCO/VA compared with those without dyssynchrony. Regarding conventional echocardiographic parameters, increased IAMD was associated with more pronounced LV diastolic dysfunction, LA enlargement and dysfunction, altered RV funclion, and higher PAP. Conclusion. IAMD correlated with all of the standard follow-up parameters in SSc, and is probably a sensitive marker of LA involvement. This easy to measure parameter should be added to the routine echocardiographic assessment of these patients.