Background .– The heart is one of the major organs involved in scleroderma, and the presence of cardiac injury usually portends poor prognosis. Ischaemia and fibrosis are the major mechanisms involved in scleroderma heart disease, and early detection is important. Echocardiography with modern ultrasound modalities such as tissue Doppler imaging (TDI) and 2D strain is considered as the best method for routine cardiac assessment, showing left and right ventricular systolic and diastolic function, pulmonary hypertension, and pericardial involvement. Besides, conduction defects are common in scleroderma, and among them, interatrial block (IAB) has been reported as a mark of atrial involvement.

Aims of the study .– To assess the prevalence of IAB by measuring the inter atrial electro-mechanical delay (IAMD) in scleroderma patients using TDI; to evaluate the correlation between IAMD and clinical, biological, and other echo-Doppler parameters.

Methods .– Patients with systemic sclerosis were selected if there were in sinus rhythm and were able to walk. The following data were collected: type and duration of the disease, NYHA functional class and distance walked in six minutes (6′WD), P wave duration on ECG, serum creatinine and Nt proBNP levels. Echo-Doppler study comprised: left ventricular (LV) mass, LV systolic function (LVEF: biplane Simpson’s method), LV diastolic function (mitral E and A waves velocities, E/A and E/e’ ratios), right ventricular (RV) function (TAPSE), pulmonary artery pressure (tricuspid regurgitation velocity–TRv), left atrial (LA) volumes and function (Simpson’s method). IAMD was assessed using colour TDI study, by measuring the delay between annular tricuspid and mitral a’ waves. A cut off value of 35 ms was chosen to define the presence of an IAB.

Results .– Forty patients were studied. Scleroderma was of the limited type in 32 patients, and of the diffuse type in 8. Forty percent of patients were found to have IAB at Doppler study. These patients were significantly older. After adjustment for age, they had more severe symptoms, lower 6′WD, higher Nt proBNP and creatinine levels, and longer P wave duration than patients without IAB. No difference was found regarding LV dimension and LVEF. LV mass was higher, E/A and E/e’ ratios were significantly different, LA volume was significantly higher, TAPSE was lower, and TRv was higher. Most importantly, IAMD correlated well with 6′WD ( r = 0.72, P = 0.0001).

Discussion .– IAB prevalence among sleroderma patients is high (40%). IAMD was found to be associated with lower exercise capacities, altered LV diastolic function, decreased LA and RV function, increased pulmonary pressure, and increased natriuretic peptides. This finding suggests that IAB may represent a marker of myocardial involvement and may indicate a poorly compliant left atrium.

Conclusion .– IAMD is a simple parameter showing good correlations with all other usual indices of heart involvement. We believe that it should be added to the routine echocardiographic evaluation of scleroderma patients, and that its prognostic value should be evaluated.