[Study of sinus node function. Preliminary results].
Direct exploration of the sinus node remains experimental. Indirect techniques have been put forward to assess the sinus function in man: high frequency atrial pacing; premature atrial pacing; pharmacodynamic tests using atropin and isoproterenol injection. 68 patients were so explored: in 10 of them were ECG signs suggestive of "sinus disease" or "atrium disease" (group I); 14 subjects had only a sinus bradycardia with a rate of 55/mn or below (group II); in 16 cases, the ECG tracing was normal, but there was the notion of paroxysmal tachycardia or various disturbances (group IIIa); finally, in 28 cases the ECG demonstrated atrio-ventricular or inter-ventricular conduction disturbances (group IIIb). The preliminary results reported here should be interpreted carefully; nevertheless, correlation of the data obtained by the various techniques used, seems to be able to allow a correct assessment of sinus automatism, and of sino-atrial conduction.