ATRIAL CONDUCTION ABNORMALITIES IN PATIENTS WITH SYSTEMIC PROGRESSIVESCLEROSIS

Background Atrial abnormalities in patients with progressive systemic sclerosis have not been evaluated in terms of intra-artrial conduction . We hypothesized that a delay in atrial conduction in these patients might produce diastolic abnormalities as well as atrial arrhythmias. O bjective To evaluate the atrial function of patients with progressive systemic sclerosis by using echocardiography to measure the intra-atri al electromechanical activation coupling interval. Methods Twenty pati ents with progressive systemic sclerosis were assessed by Doppler echo cardiography. Twenty age-matched healthy controls were also evaluated. Two-dimensional guided M-modes of ventricular long axes were recorded using simultaneous phono- and electrocardiograms of the apical four c hamber view at the right lateral, septal and left lateral sites of the atrioventricular rings. Transmitral and tricuspid pulsed Doppler flow velocities were also recorded. Filtered P wave duration was measured on the signal averaged ECG to determine the duration of atrial electri cal activation. Results There was a delay in P on the electrocardiogra m (P) at the onset of atrial contraction on long axis M-modes at all t hree atrioventricular ring sites in patients with progressive systemic sclerosis as compared with controls (P-right; 56+/-13 vs 47+/-10 ms, P-septal; 74+/-14 vs 55+/-10 ms, and P-lateral; 93+/-16 vs 72+/-11 ms, P<0.01). Inter-atrial conduction time [(P-lateral)-(P-right)] was del ayed in patients with progressive systemic sclerosis, compared with he althy controls (37+/-15 vs 25+/-6 ms, P<0.01). Mitral A waves accelera tion and deceleration times were also decreased in the patients. The i nterval was prolonged between P to the onset and the peak of the A wav e in transmitral flow. Duration of the filtered P wave was significant ly prolonged in progressive systemic sclerosis as compared with contro ls (124+/-12 ms vs 106+/-8 ms, P<0.01). PQ intervals, E waves and acce leration and deceleration times did not differ significantly in progre ssive systemic sclerosis vs, controls. The A wave acceleration rate on transmitral flow (peak A wave velocity/acceleration time) showed a si gnificant correlation with inter-atrial conduction delay (r=0.55, P<0. 01). Conclusions Intra-atrial electromechanical coupling intervals wer e delayed in patients with progressive systemic sclerosis. Thus, the m echanical late diastolic filling time due to atrial contraction in the total diastolic phase was severely limited, and this resulted in a re stricted mitral A wave. We should therefore evaluate patients with pro gressive systemic sclerosis for significant atrial abnormalities.